Electric Car Conversion
Electric Car Conversion
(OP)
How have I missed this forum until now? Wow, I've been missing the really good stuff!!!!
As my handle may suggest, one of the things I do for fun is to melt metal. I've built a simple propane-fired box kiln and pour brasses and bronzes mostly, using home-made greensand and more recently oil-bonded sand molds. I make mostly drawer pulls and knobs/handles and even a few chisel planes, all for one of my other passions- my woodworking projects.
But I got bored...so time for something new!
I've owned a 1975 Triumph Spitfire since the late '80s when I was in uni and wanted to learn about cars from my dad, a long-retired auto and diesel mechanic. Oh, and it taught me, the hard way- the Leyland 1500 engine was an utter piece of crap, disappointing me numerous times. I put a Toyota 20R engine and transmission in it in the early '90s, but it never really fit the car. The last sticker on the license plate was the year I moved in with the girl who DIDN'T like this car- we've been married now for 15 years. I kept the car though, with the intention to do something fun with it some day.
My son is 11- old enough to be useful (when he can be pried away from video games), but young enough to still think what his dad does is worth paying attention to. So the two of us have embarked on an electric conversion of the Spitfire. Goal is a daily driver for my commute in the spring, fall, and days in the summer where the lack of A/C won't roast me to death. 60 km one way, with a charge at work to get home.
Current status is that we've pulled the engine, exhaust system, gas tank etc., separated the body from the frame, restored the frame (lots of practice welding!), painted it with surface tolerant epoxy, replaced the brake lines and hoses, and ordered the parts for the conversion. Body is going to take quite a bit of work- floor pans, rocker panels etc.
Going with an AC system- a HPEV AC50 motor and Curtis controller, and LiFePO4 prismatic cell battery pack. I've seen lots of conversions done using this system including this one, which used an AC51 (just a higher voltage version of the AC50):
http://www.youtube.com/watch?v=BlSb4It9ZdY
(warning- language- and make sure you watch the guy come back around the corner a couple times!)
Should be a fun car when I'm done!
Will be no doubt asking lots of questions here, as well as on a particularly good DIY electric car forum.
As my handle may suggest, one of the things I do for fun is to melt metal. I've built a simple propane-fired box kiln and pour brasses and bronzes mostly, using home-made greensand and more recently oil-bonded sand molds. I make mostly drawer pulls and knobs/handles and even a few chisel planes, all for one of my other passions- my woodworking projects.
But I got bored...so time for something new!
I've owned a 1975 Triumph Spitfire since the late '80s when I was in uni and wanted to learn about cars from my dad, a long-retired auto and diesel mechanic. Oh, and it taught me, the hard way- the Leyland 1500 engine was an utter piece of crap, disappointing me numerous times. I put a Toyota 20R engine and transmission in it in the early '90s, but it never really fit the car. The last sticker on the license plate was the year I moved in with the girl who DIDN'T like this car- we've been married now for 15 years. I kept the car though, with the intention to do something fun with it some day.
My son is 11- old enough to be useful (when he can be pried away from video games), but young enough to still think what his dad does is worth paying attention to. So the two of us have embarked on an electric conversion of the Spitfire. Goal is a daily driver for my commute in the spring, fall, and days in the summer where the lack of A/C won't roast me to death. 60 km one way, with a charge at work to get home.
Current status is that we've pulled the engine, exhaust system, gas tank etc., separated the body from the frame, restored the frame (lots of practice welding!), painted it with surface tolerant epoxy, replaced the brake lines and hoses, and ordered the parts for the conversion. Body is going to take quite a bit of work- floor pans, rocker panels etc.
Going with an AC system- a HPEV AC50 motor and Curtis controller, and LiFePO4 prismatic cell battery pack. I've seen lots of conversions done using this system including this one, which used an AC51 (just a higher voltage version of the AC50):
http://www.youtube.com/watch?v=BlSb4It9ZdY
(warning- language- and make sure you watch the guy come back around the corner a couple times!)
Should be a fun car when I'm done!
Will be no doubt asking lots of questions here, as well as on a particularly good DIY electric car forum.





RE: Electric Car Conversion
RE: Electric Car Conversion
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
RE: Electric Car Conversion
My son is great when there's a task he can tackle on his own, with help available when he needs it. He has no patience for fetching tools, which I could do for my dad for hours. Struggling to find things he can do on his own without mucking things up- was easier when there was stuff to take apart that wasn't needed in the finished car.
RE: Electric Car Conversion
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
My privileges may be suspended for doing this, but..
... look through this other forum: http://www.diyelectriccar.com/forums/ (unless that's the one you're already found, of course)
and this may also provide inspiration: http://www.evalbum.com/
I've been watching those guys for a while, but haven't quite jumped in yet. Maybe I ought to hurry up. My son just turned 13.
STF
RE: Electric Car Conversion
Tough decision though- I'm fundamentally a cheapskate, and just the parts for the conversion have been expensive, beyond what I wanted to spend by at least a factor of two. I was tempted to go the total DIY route, salvaging an old forklift motor, getting a Chevy Volt pack from a wrecker and chop-shopping it, building a kit motor controller etc., but the spend on the battery pack alone was so substantial for my required range that it didn't make sense. I'm too much of a cheapskate still to be spending any of this money twice! That seems to be a common theme with these conversions- people cheaping out, then going back and spending more money to replace something which was unsatisfactory. I'm sure I'll tinker with it forever, but I do hope that the Leyland evil spirits that stranded me repeatedly at the side of the road will be well and truly purged by the time I'm done!
The kid was a big help last night- right in there with me, scraping away the remnants of the carpet underpad while I sliced away rusted bits of the remaining floor pans with the angle grinder- I'm getting to be a surgeon with that thing. I've definitely got nothing to complain about with respect to this kid! He likes painting, which I hate...I think the bodywork is going to be something he'll enjoy and will definitely be able to contribute to. Plus there's still a lot of stuff to disassemble that I didn't get around to yet- he can pull the ignition coil, heater core hoses, starter relay and a bunch of other crap I left attached to the body bucket when we pulled it. I'm sure there's something for him to help with at every stage.
Yeah, get on it! 13's not too old- he'll be able to contribute a lot! And if my experience so far as been any indication, the father-son time working together will be worth whatever it costs.
As to letting him muck things up, I don't mind it at all- I do plenty of it myself. This car's a wreck already so there's really nothing irreparable that he can do to the thing, assuming I'm around to keep him from getting himself hurt of course. But I do need to jump in when he's about to round or snap off a bolt that I'll have to extract from some horrible location etc. The two of us had to fight for two hours with one of the four bolts which held the gas tank in place- the threaded boss tore out of the sheetmetal. It was like the car was clinging on to its fossil fuel addiction...
RE: Electric Car Conversion
Hoping to get the kid involved more in the wiring- he got bored of watching me weld and grind pretty quick.
RE: Electric Car Conversion
I found a MG chassis that's been stripped and re-painted, but the owner hasn't bothered to reassemble. Almost perfect for an EV conversion. I still haven't convinced myself to do one of these so I haven't mentioned anything to the owner yet. He's an old-school type so he might not sell it to me if I let him know my intention of stuffing it full of electrons, not pistons. But I sure am deep in research mode. Found two similar conversions, one thoroughly documented on a website. Looks like a 9" Impulse is all a MG would need, both a good fit in the space and power to hustle it along. I'm not thrilled by the range reported by the builders of the two MG conversions I've seen so far. Not much room for batteries in those 2-seaters. They may have preserved too much trunk space. The entire electrical system would be "carte blanche" so to speak.
STF
RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
STF
RE: Electric Car Conversion
Cheers
Greg Locock
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RE: Electric Car Conversion
Mike McCann, PE, SE
RE: Electric Car Conversion
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RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
Using a simple 200 Wh per mile, or in my case 120 Wh per kilometre, then I'm going to need at least 15 kWhr of charge to do my daily round-trip, 120 kilometres.
Bigger picture: an EV conversion project will take several years to complete, but in the near future I have to demolish my mouldy old garage and build a new one. It really must go. I would much rather spend all that time to build an EV in a garage with a nice shop space, and without the mould. If a new garage is under way, then I ought to arrange the roof to take a few solar panels, too, huh?
STF
RE: Electric Car Conversion
John R. Baker, P.E.
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Siemens PLM:
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RE: Electric Car Conversion
One company (Nissan?) is marketing solar panel installations for your house, so you can recharge you eCar using solar power, presumably at night.
RE: Electric Car Conversion
I went AC, both because I didn't like the thought of brushes and their maintenance, and because I wanted the regenerative braking, not just for the range improvement but because the car has rear drums only and the brakes are 100% mechanical. I have an HPEVS AC50 with a Curtis AC controller- motor's already in, I'm laying out the various parts on a piece of plywood to figure out the best way to fit everything. The car will be capable of pushing 500-650 A forward and 200 A reverse on regenerative braking. The plan right now is for 100 A to come on when I take my foot off the accelerator- kind of like the "drag" you get on an automatic transmission car- and another 100 A to come on with the early travel of the brake pedal. I'll have a pot so I can reduce that to zero in bad weather if I start locking the rear wheels.
Regrettably I'm down another car- fortunately nobody was hurt, but my 2008 Prius is probably a write-off. Ran a stopsign that was completely hidden by tree boughs. Wow, those crumple zones work- neither cars' airbags went off. But mine is likely toast, which is a shame because insurance won't give me what it's worth to the family as transportation...
Yeah, it's summer, but the kid spends his time inside playing video games unless we kick him out...it's both fun and his way of socializing with his friends- tough to compete with it.
RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
Moltenmetal,
Thanks for the extra info about your plans. I too would like to use an AC system but it's still not the norm. I would rely upon some expert advice to choose components and integrate them properly - there are some EV conversions that use AC (on EV Album) that clearly do not perform well.
Sorry to hear about the Prius biting the dust, too.
Curious about something: I've been in some nasty collisions too. When the firefighters arrive, they are pretty aggressive about rendering the car inert. Cutting battery cables and so on. Presumably with an EV this could be very invasive indeed, even counter-productive in a home-built EV. Did anything of the sort happen at your accident scene?
STF
RE: Electric Car Conversion
http://www.csiro.au/Outcomes/Energy/Powering-Trans...
I'm not a huge fan of wheel motors for production cars, but I think the advantages of that location are so great that it will become inevitable down the track as cars get (hopefully) smaller.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
STF
RE: Electric Car Conversion
I'm not too worried about the ride issues from them, I just don't like relatively expensive/fragile electronic bits out on the wheels.
Ride issues were investigated by Lotus and Damian Harty they didn't seem very worried.
http://www.proteanelectric.com/en/wp-content/uploa...
Mr Hurdwell and the younger of the Andersons also had a look
http://www2.eng.cam.ac.uk/~djc13/vehicledynamics/d...
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
Rule of thumb that the EV conversion crowd use is that the Wh/mile correlates well with the weight of the vehicle in pounds/10. A Chevy Volt apparently has a range of 61 km on a 16.5 kWh pack which is used to something less than 70% DOD before the IC engine is switched on- almost dead on 300 Wh/mile, but that car is both greatly heavier and more aerodynamic than mine, so there are factors both ways. I figure on highway speeds all the way in the morning so I went with 300 Wh/mile to be conservative.
The AC systems that have sucked are either chopshop combinations of industrial induction motors and VFDs or transmissionless/clutchless conversions unless I'm missing something. Here's an example of a VW Beetle conversion done with an AC51, which is the same motor operating at higher voltage- same torque, modestly more peak horsepower than what I'm using. Make sure you watch him come back around the corner and do a burn-out start- well into the video, and warning, the language gets a little "excited" when they see how well the car performs...
http://www.youtube.com/watch?v=BlSb4It9ZdY
I'm not expecting mine to behave like that, but having up to 120 ft-lbs of torque available at near zero RPM should make for a fun drive! Even that 2.2L Toyota 20R that I had in it didn't generate that kind of torque until you were well up in RPM.
RE: Electric Car Conversion
AC motors are typically very rugged, so I would see no reason to be concerned about them as wheel motors. Except if you have non-electric issues like too much force on the bearings, or vented motors.
If you don't like brushes, don't AC motors have brushes? Maybe not all of them but some types do. The ones that don't have brushes (assuming you need slip in one or more wheels and you only have one AC controler, and not one for each motor) is an induction motor, which won't allow dynamic breaking. So I assume they aren't induction motors. Therefore you most likely have a controller for each motor, which is why AC controllers cost more.
RE: Electric Car Conversion
RE: Electric Car Conversion
Glad to know that everyone is okay.
Does this accident perhaps offer up any useful e-car parts for your project? Depending on how insurance works in your area, you might be able to buy the written-off car from the designated junk yard for a slight markup (e.g. $400) over some agreed fraction (e.g. 40%) of the Write Off value (i.e. what the junk yard pays the insurance company).
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
.
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RE: Electric Car Conversion
"AC motors have brushes..." Some do, but many don't. The vast majority don't, in fact.
Correct me if I'm wrong, but the only AC motors with brushes are field-excited types (whose speed can be controlled by adjusting the current in a winding on the rotor). That style of motor has been on the decline for decades.
When discussing AC motors now, I believe most people assume you are talking about an induction motor, with no brushes or magnets or field windings at all. Just those induction bars encased in the rotor core. If talking about varying the speed, this can be done with an induction motor, but I believe it is limited. If I'm not mistaken, the "AC50" motor in the OP's project is an induction motor, and he is expecting regeneration braking.
There are also AC motors with permanent magnets in them. They are either called synchronous motors (because they don't slip like induction motors do) or BLDC (brushless DC) motors. Despite the reference to "DC" in the name, they are wound with poly-phase stators so that the electronic drive can control their direction with alternating phase rotation, like any other AC drive. I don't know if these are available or affordable for homebuilt EV projects yet, but they are in the Prius and the in-wheel motors that GregLocock has mentioned (or perhaps more correctly "Electronically commutated").
STF
RE: Electric Car Conversion
Excited- batteries just arrived!
The motor is indeed a brushless 3 phase induction motor with a quadrature encoder on it which apparently helps the controller greatly with low speed regulation, though it's also used to limit maximum speed of the motor. Here are a couple links:
http://hpevs.com/catalog-ac-50.htm
http://hpevs.com/Site/power_graphs/imperial/peak/p...
The motor is paired with a Curtis controller:
http://curtisinstruments.com/index.cfm?fuseaction=...
The motor is open drip proof, i.e. internally fan ventilated rather than TEFC. That helps it develop the short term peak power it needs, without frying, while also being lighter weight and less bulky. Service life on these is reported to be excellent, properly protected by a properly programmed controller of course.
RE: Electric Car Conversion
That motor and drive should control well pretty much right down to zero speed. Regenerative braking really doesn't recover much energy at very slow speeds so using the brakes vs regenerative braking when close to zero speed wouldn't make any significant difference in the battery life.
RE: Electric Car Conversion
RE: Electric Car Conversion
The motors usually used in DIY vehicle applications are used DC forklift motors- series wound- that the users have advanced/rotated the brushes on so they can run at higher speeds. The DC vehicle motors are pretty much the same, but with some of the work done for you and with a bit of extra reliability over an over-volted forklift motor. With series wound, regenerative braking is possible but not easy. The DC controllers which do DC regeneration are a little sketchy from the perspective of the DIY conversion community if I've taken their pulse correctly, whereas with AC it's pretty easy.
RE: Electric Car Conversion
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
It's interesting that you bring it up because there is no real size limit in universal motors - they've even been used in electric trains, so technically universal motors have been used in EV's already. Not in those nifty linear-induction drive trains that Vancouver's got, though! (I rode that train every day for a week during the Olympics).
STF
RE: Electric Car Conversion
The LIMs regenerate and the recovered power is fed back into the DC bus bars. Usually the total power used is more than the total power regenerated. There may be infrequent times when the regenerated power exceeds the total power used. If the bus voltage rises too high, resistor banks are switched in at the sub stations to waste the excess power.
This has to rate as one of the world's largest VFDs with one of the physically longest DC buses.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
I do agree that the AC induction motor has advantages compared to a DC motor that make it worth the extra cost.
RE: Electric Car Conversion
When seeking regenerative braking, on either an AC or a DC motor drive system, the motor can probably do it, whether DC series wound, AC induction, AC synchronous or any similar type. It's the drive electronics that must be capable of the necessary switching/frequency adjustments, and be able to direct the reversed current to the batteries under some control (because some batteries cannot accept recharging at the same rate they give it out, less of a concern with Lithiums). The neat thing is that the drive can switch to regeneration mode without changing the speed of the motor immediately. The controllers are different but the effect may appear the same to the driver of the vehicle. The AC motor torque will reduce immediately when the AC drive frequency is changed, but as long as the frequency control stays ahead of the vehicle driver's input and the deceleration under the car's inertia, then the response can follow the driver's inputs with gradual changes in speed not abrupt ones. On the other hand, the DC drive only needs to switch the polarity of the motor's field coil and (again) without changing speed it has already entered regeneration mode. When the applied voltage is reduced now, the current is induced to the supply, which recharges the batteries. So, clearly in both cases, regeneration can be available as soon as deceleration is requested by the vehicle driver, at any speed. The high kinetic energy of the vehicle's inertia at high speed can be regenerated, as long as the controller and the batteries can handle the current. Otherwise the energy might have to be dissipated by a resistor or something equivalent (can't see anything like that in the Curtis datasheet though, so maybe I've guessed wrong about this).
As a side note, I see that a DC drive varies voltage as a PWM of the battery supply (knew that) but the AC drive must vary the AC voltage in proportion to the frequency as it changes the speed of the motor. That's news to me and very interesting. Must read more!
Seems like an EV can't rely entirely on regeneration for its braking. Not at slow speed, as LH pointed out, but also just as a safety measure - what if the controller fails while rolling? Looks like MoltenMetal has re-done his entire mechanical brake system and the lines, so he should be good to go. What percent of the kinetic energy can be recovered in a typical braking action?
STF
RE: Electric Car Conversion
Reducing the supplied voltage below the back EMF is another way to regenerate.When a DC machine is running there is only a couple of Volts or a couple of RPM difference between motoring and generating.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
STF
RE: Electric Car Conversion
perhaps 50% in a typical 0.3g stop from 30 mph, depending on about 10 different things, the most important of which is how much friction braking you are using. A google search is not especially productive, the definitive studies are paywalled.
http://www.ecrostech.com/prius/QandA/Brake.htm is useful, graham davies is a very cluey guy
Cheers
Greg Locock
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RE: Electric Car Conversion
I've definitely put some focus on repairing the brakes- no point in being able to accelerate quick if you can't decelerate quick! My brakes on the Spitfire are all direct hydraulic without assist, and I've already put a lot of effort into repairing/restoring them. New lines and hoses throughout already, and it'll have freshly machined or new rotors and properly adjusted rear drums before it goes on the road. Surprisingly, everything in the hydraulic system has been pristine inside so far- nothing rusted or badly seized- but fittings in some cases have been very reluctant to come out. Have had to resort to the wonderful Ridgid long rip stud extractor set more than once, and it's usually successful after the fitting or bolt has snapped off and the resulting cursing has died down. If you haven't seen these before and are still trying to use those useless "easy outs", throw those away and buy one of these sets- worth their weight in gold actually:
http://www.ebay.com/sch/i.html?_kw=ridgid+10+Screw...
It's a set of drills, drill guides, splined shafts you drive into the hole, and matching splined nuts with double hexes on them so you can use two wrenches for balanced torque. The splines are incredibly tough and strong- don't know what they made them from, but it certainly was clever metallurgy.
RE: Electric Car Conversion
http://www.engineering.com/ElectronicsDesign/Elect...
The solar cells on it boast an efficiency of 22%!
STF
RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
RE: Electric Car Conversion
From a different thread: "I have a 2008 Prius base model which has averaged 5.77 L/100 km (40.8 mi/US gal) over 190,000 km, taking all fill-ups and dividing by the odo reading. My current Prius C averages around 4.5 L/100 km (52 mi/US gal) in the summer- worst tank in the worst of the winter was 6.1."
5.77 + 30% = 7.5 (your intent?). 7.5 L/100km is perhaps towards the high end of fuel consumption for similar economy cars. Many of my colleagues are getting more like 6.5 L/100km +/- on their daily commute in similar size and vintage economy cars. Those with VW TDI (turbo diesel) Jetta are in the 5s, easily matching the hybrids. So the 'more than 30%' might be just a bit generous for the dear-departed Prius. 10% is certainly an understatement.
On the other hand, your new Prius C is there, easily.
Fuel economy seems to be improving across the board year-on-year.
RE: Electric Car Conversion
Never made since to me to drive a car when I have to pay extra to have things delivered to my house.
RE: Electric Car Conversion
VE1BLL- I did overestimate that a bit. My '99 5 speed Civic hatchback without A/C did that commute for roughly 7 L/100 km year-round average. 7.5 would be pretty high for the Civic, so that's a little less than 30% improvement with the '08 Prius. But to be fair, the Civic hatchback was a much smaller car- much closer to my Prius C than to the '08 which was a base model, larger, had A/C etc. The C is better than the Civic was by more than 30%, which easily pays off the capital premium of the hybrid versus the ordinary car at current Canadian gas prices. You get the environmental benefits of the lower emissions essentially for free, which in my mind makes it pretty much an obligation rather than a choice. Much harder sell on the Prius base model though- it's a much more expensive car. We bought the '08 Prius when we had two kids in child seats or boosters at the same time- you could do that in the Civic but it was a very tight squeeze especially with only 2 doors. As to the 6.5 L/100 km figure for your friends' performance, I'm not sure how or what they're driving. Most people exceed the EPA mileage estimates by around 20% in real world driving, and I'm no exception. There are morning drives where I manage to get my Prius C to do 3.8 L/100 km which is the EPA combined fuel economy rating for that car, but on average it's closer to 4.5 tank to tank. For comparison the Yaris (Echo in the US I think) with auto transmission is about 5.5 L/100km EPA highway/6.8 city with no combined figure given on Toyota Canada's website- so, a real-world combined economy might be around 7.4 L/100 km (20% more than the mean of city and highway EPA). I'd take the hybrid benefit therefore as at least 30%- certainly a great deal more than 10% which is all you should get from regen braking alone. Yes, fuel economy of all vehicles is improving, and that's great. But people still don't care all that much about it, judging by the size of single-driver vehicles I see day in and day out on my commute.
The electric car project isn't about money for me- if it was, I'd be an idiot. The Spitfire's a totally impractical car- but pretty and really fun to drive, which I think is only going to improve with the conversion. But I'm buying parts retail for the most part, and you'd never think of building a car from retail replacement parts if you cared about money. The batteries will almost, in theory, but never really, pay me back in gas saved if I drive them until they're over 3000 charge/discharge cycles. While there is an environmental angle to this for me for sure, the main driver on this is a learning opportunity for both me and my son, and a chance to rescue a classic car that I fell in love with over 25 years ago.
RE: Electric Car Conversion
Renting a vehicle on a weekly basis for me isen't very efficent, in terms of money spent.
RE: Electric Car Conversion
RE: Electric Car Conversion
I think with an electric motor of reasonable reliability (as compared to the original power plant) it could prove to be a very practical car. But "pretty and fun to drive" are both good reasons for the project too, as is getting your kid out from behind a screen from time to time. Hope you can post some pictures one of these days - good luck and have fun in the meantime, molten.
RE: Electric Car Conversion
A little less efficent, and useful for other things is a balance. But still my PU get above 25 MPG, which isen't bad. But the other PU is 4WD for winter needs, and dosen't get as good of milage.
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
To pass a safety here I need a defrost/defog heater, even though it will never be winter driven and it's a convertible, so the plan is a ceramic element out of one of those little fan-driven space heaters to be kludged into the place of the old heater core.
Rear brake bleeders are rusted solid. Suspect I may be spending some quality time with those rear brakes before I can test drive the thing, even after sorting through all that 12V wiring. And the differential, the only bit of Leyland drivetrain left in the car, is leaking oil from both of the wheel shaft oilseals. Fortunately I have a spare which doesn't appear to be leaking, but unfortunately the bolts which connect the rear leaf spring to the differential are underneath my rear battery pack- what used to be the gastank. Fortunately the rea pack is not completely in place yet, so I guess I have to tackle the differential in the next little while too.
RE: Electric Car Conversion
Yesterday I got clarification on a few wiring issues from the guy I bought most of my parts from- he's been doing conversions and then building his own EVs for over 20 yrs now so he knows his stuff and is very helpful. I also found the programming manual for the controller, which I'd downloaded months ago and forgotten about. The issue was that the controller was set up for the wrong throttle type. Took about 5 minutes to figure out how to set that, and I was up and running!
I opted to use the zinc-in-grease paste on the aluminum + terminals of the batteries and a fluorocarbon grease on the - copper terminals and everywhere else the unplated copper lugs were used. I may buy some Belleville washers or Nordlock washers for the connections later. Right now it has the dreaded split helical spring washers that were supplied with the batteries.
I also commissioned my DC/DC converter and my "fuel gauge" last night- no issues. The BMS was commissioned first and tested and works great. Just the charger yet to test, and the first charge has to be monitored manually with me brooding over the thing with a voltmeter checking it all cell by cell, pulling the low cells up with a 6V charger and dragging the prematurely filled ones down a bit with a headlight to get them to an initial state of balance. The BMS shunts about 2A of charge around the high cells to top off the rest, but the pack has to be pretty close already for it to work.
Now it's full speed ahead on the dash and re-wiring the rat's nest of 12V original car wiring left under the dash. At least all the dead IC engine-related crap has been pulled out so it'll be an easier job.
RE: Electric Car Conversion
Sounds like the result of careful research on the terminal grease. As for the split washers, well, you know what I think of those already!
STF
RE: Electric Car Conversion
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
RE: Electric Car Conversion
I've reading about numbers that electric car homes consume about 56% more electricity.
I'd just like to know if this is accurite.
RE: Electric Car Conversion
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RE: Electric Car Conversion
RE: Electric Car Conversion
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RE: Electric Car Conversion
I would be charging once at home, once at the office, about 35 days in that 60 day period- assuming the car isn't broken down or it isn't so hot that I'll melt without A/C. My charging would be off-peak at $0.075/kWh, and I'm expecting about 300 Wh/mile and 40 miles per trip, so about 12 kWh/trip each way, or $0.90 per trip. There's also a "delivery" charge which is pretty complex (part fixed, part related to peak kW draw in the day) plus tax, which will bump that up to perhaps $1.10-$1.20/trip. For reference, my Prius C is costing me $3.50 each way in gas in the summer, ignoring oil changes etc. My charge at work will cost about the same, or maybe slightly more, since although it's not off-peak, we're buying electricity wholesale at industrial rates. So I save what, $4-$5/day? On a straight economic basis, the payback on the electric car versus the Prius C is basically never, mostly because the Prius C is so awesome. Whatever I might save on gas, I'll spend on replacement batteries eventually. But as I said before, this project isn't about that at all.
Two charges per day at home, if I did them both at home, would amount to 35*12*2 = 840 extra kWh per 60 day period, or an increase in my household electrical demand of almost 50%. Note that my charger is very efficient- >93%, and the Wh/mi figures include all losses from the batteries to the wheels. But that's not the whole story either. My trip in the Prius would use 2.7 L of gasoline, or about 0.71 US gal, which has a chemical potential energy of about 93 000 BTU (about 27.5 kWh, not that you could produce anything close to 27.5 kWh of electricity from that much gasoline!). The energy used to refine that gasoline is about another 4.2 kWh with the same caveat, since most of that is fuel gas used as heat rather than electricity used as work. I'm ignoring transport etc. for both gasoline and the electrical grid. On that basis, I'm replacing about 31.7 kWh worth of chemical potential energy with about 12 kWh of electricity to do the same job, i.e. to get me to work.
Our electricity here on average is about 40% fossil (100% gas except for whatever we import), 60% nuclear and renewables, so on that basis I'll be shifting my consumption dramatically away from fossil fuels. Taking public transit would of course take less still, but doubles the amount of time I spend on my commute so isn't really a practical option for me more than perhaps a day per week.
The estimate of refinery efficiency and energy content of gasoline is from this reference, which of course answers a question totally different than the one asked because chemical potential and electrical energy aren't directly comparable.
http://gatewayev.org/how-much-electricity-is-used-...
RE: Electric Car Conversion
If that's for a month, then it's 24/7 of an average of just 260 watts. That would be just about enough to power up my satellite TV receivers.
@ moltenmetal - I'm enjoying this vicariously. Thank you.
RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
buried in the specs of most diesel generators is fuel consumption data including the specific gravity of the test fuel.
(One manufacturer who shall remain nameless, posted 10% better fuel efficiency than any of the competition. Buried in the fine print was the SG of the test fuel. Yup, 10% heavier SG than the competitions test fuel.)
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
Bill: diesel is about 35-36 MJ/L or about 10 kWh/L or 38 kWh/L chem potential. 13 kWh/L from a diesel generator would put it at a thermo efficiency of 34% which sounds about right.
VE1BLL- you're welcome! I'm having a good time with this too- most of the time. I'm very much a cheapskate at heart so spending the money on the parts nearly killed me, but it's been a blast- think I might like this "spending money" thing a bit, but hopefully it doesn't become a habit! The rust repair sucks though- wish the "donor" was in better shape! All these guys on www.diyelectriccar.com who get nice Arizona, California or New Mexico cars with zero rust are making me pretty jealous.
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Yes Otto cycle engines are not very efficent, and adding the modern conviences like A/C, radio, automatic transmission, heated seats, etc. just adds to the energy consumption.
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RE: Electric Car Conversion
http://www.triumphspitfire.com/Size.html for weights and things.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
RE: Electric Car Conversion
http://youtu.be/KkOyihRqsJ4
http://youtu.be/_96AYv73IEA
Brakes took a while- rear cylinders and adjusters are aluminum with steel parts, so galvanic corrosion took its toll. But everything holds solid now.
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and...
CONGRATULATIONS
Thank you for sharing your awesome project with us.
STF
RE: Electric Car Conversion
A couple issues to deal with:
1) When you tromp on the accelerator, now you can pull 500+ amps at will- the acceleration is very enjoyable! But the stick shift moves noticeably- the rear transmission mounts are too soft for the job and need some additional stiffening or limit stops
2) At the end of the 2nd charge, I'd put 17 fewer Ah of current into the pack than my Ah meter said I'd taken out of it. Can't really drive the car much until I have it road legal (in the spring) but will see if this measurement problem persists. Suspect the Ah meter had a bit of a hard time with the +400/-100 A current spikes which result from driving the car floored for a block and then taking my foot off the accelerator (triggering 100A of off-pedal regeneration). The pack condition seems perfect. I have a dash-mounted analog ammeter in parallel with the Ah meter (which presumably is a high impedance input so it shouldn't care), and there is about 5 W of leakage out of the pack into various parasitic losses when the car is just sitting there not being driven with the ignition off, so bad measurement of that leakage could be the reason for the mismatch. We'll see if it persists once I'm into more or less steady driving.
So far, so good- the car is a riot to drive!
RE: Electric Car Conversion
RE: Electric Car Conversion
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Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
The Ah meter is still not automatically detecting a "full" pack, but it's another setting I have wrong. The BMS is working perfectly and my pack is pretty close to being top balanced after only a few charges.
Regrettably it's getting cold here rapidly and after all those rust repairs the last thing I want to do is expose the car to more salt- so it's off the road for the winter. Quality time again with yet more rust repairs. It appears that the previous owner had done some very skillful and artistic patching of the old body panels in the vulnerable lower portion of the body. Regrettably he very neatly brazed in the repairs, and the braze has resulted in both the adjacent original panel and his repair pieces being rusted to ratsh*t. Hopefully my fluxcore MIG patches will last longer.
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Except for your life and marriage. I inherited Spitfire 1500 in 1983. It was fun to drive but it consumed many hours in repairs a tuning. Spending all "intimate" that time with it did lead to a sort of emotional attachment (have you seen the movie "Her"?) . When it finally died by throwing a connecting rod through the engine bock, it was somewhat of a relief to get rid of it.
RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
As an electric conversion candidate, being so simple, it's pretty much a perfect donor- so simple. Once I get the rust repairs done and take care of the oilseals in the differential, it's my hope that I'll have a reasonably reliable daily driver for the summer. Oh I'm sure I'll have the odd thing go wrong, probably some of my own handiwork included. But with the original Leyland engine in there? Forget about it...I see the effort put in by these enthusiasts over at the Triumph Experience and just shake my head in wonder and disbelief. A TR6 might be worth the effort, but a Spitfire?
I do exaggerate a bit about my wife's concern with the project. It seems that she's actually come to peace with the car, though she's not what I'd call enthusiastic about it ever. She's a runner- I most certainly am not a runner- and I spend about as much time on the car at present as she spends on training from her perspective. Everybody needs something to keep them going.
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Then I worked at a shop that had a TIG welding and it was easier than gas welding. Did a number of projects on the TIG at work. Still, the work was slow and I was constantly fussing with the settings on the unit, which made the work even slower.
Then I tried MIG welding. 5 seconds later I was convinced. I bought a new MIG welding set and I have enjoyed welding ever since. Miller 180
STF
RE: Electric Car Conversion
RE: Electric Car Conversion
My welds using a cheap Harbor Freight fluxcore welder are beginning to look pretty decent.
For the critical stuff, I am only tacking things together. I'm kind of planning to have a real welder go over it prior to commissioning.
It would certainly be nice to have a better rig. For now, like much of my car, it is "good enough".
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
The main struggle is with the hood (bonnet, I guess!), which is half the car on this thing from a visual perspective. From the time I bought the car it was a mess- wavy rather than dented, well beyond my skills to straighten in the metal itself. It's such a big, awkward panel that the option of taking it to someone (what I did when I bought the car) isn't really practical this time around- and all he did is flatten it with filler anyway. So I've been learning how to flatten a panel with filler and block sanding, with the block being used more like a plane. And I totally lack the patience to do this well!
The rest of the car has filler in random places, so the option of going down to bare steel isn't an appealing one. That means a lot of sanding out knicks and scratches in the finish- tons of them, all over the place. Then it's on to high build primer and blocking that...I keep telling myself I'm nearly there.
I managed to get short-hair fibreglass or brushable seam sealant on all the holes and seams in my floor pan steelwork, and two coats of rubberized rocker guard on the whole interior of the floor pans, footwells and space behind the seats. It ties things together nicely, and with a coat of primer on it I think that may just serve as my finished surface. Carpet did so much rust damage to the car that I'm reluctant to re-carpet it- any time you forget to put up the soft top and it rains even a bit, that carpet seems to hold the water against the steel until doomsday.
I also remodelled and then fibreglassed the original fibreboard transmission cover to fit the Toyota transmission. I still have some work to do on that- it's a damned awkward business.
I have a plan for the heater, which I am required to pass a safety inspection here. It's a Frankenstein of a little AC ceramic space heater with a 12V 7 blade muffin fan. The ceramic elements are nice in that they are at least a little self-regulating so they're safer than a Ni-Cr wire arrangement like you'd find in a hair dryer etc., but their geometry makes a poor fit with a blower, and a fan like this has a very steep head/flow curve so it's terrible with ducting. Fortunately the 7 blade muffin fan I had laying around generates just enough head to stuff a reasonable amount of air through the frictional loss of the two duct hoses, or so it seemed during my initial test. Space under the dash is awkward and at a premium for sure.
Still hoping to have this thing reasonably pretty and road legal by spring!
RE: Electric Car Conversion
STF
RE: Electric Car Conversion
That will be fun to blast around in. No, of course it doesn't save money - it is for 'fun'.
(sanity maintenance!)
Regarding the summer and keeping cool - the mesh top on mine has worked out super well.
Mine is the mesh from a defunct trampoline, but the 'shade cloth' used for gardens would probably work fine.
It blocks enough of the sun (winter or summer) for comfort, but still lets some air through and you can still see the sky.
So, it's open-air with a bit of protection.
Boy, that was a rusty sucker. Oh, well - unless you intend to show it, it doesn't have to be perfect.
It just has to be good enough for you.
Regards
Jay
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
Gawd I HATE painting and bodywork! It's all good fun in the context of the overall project, but I sure as hell will NOT take up auto restoration as a hobby when I retire...you need a totally different temperament than mine to make that any fun!
Today I'll pick up my quart of tinted primer/surfacer and my precious 2 quarts of expensive single stage solid colour urethane finish coat material. The colour is topaz orange- which brought howls of delight from my orange-obsessed son and partner in the project, and "eww- it looks like puke!" from my beloved wife...still not very supportive, the dear! It's a real '70s car colour- pretty lurid, highly visible, and definitely not red. Given that probably 80% of the Spits still on the road are some shade of red to the point of it being pretty much a cliche, and that I already have two red cars AND a red brick house, repainting it the original "pimento" orangey red was not really an option!
Despite my experience now with a whole gallon of paint through a HVLP gun, I'll never be a painter for the same reason as I'll never be a welder- you need better depth perception and hand-eye coordination than I've got to have a hope of being good at it. So I'll try my best to paint it, let it cure hard, then colour sand and polish it in the spring when I can do that outdoors. There's bound to be a lot of flaws when I'm done, and I'll probably scratch something reassembling it all in the confined space of my shop, so that tedious job can be put off until I really need to do it!
RE: Electric Car Conversion
...the lawyer looking over my shoulder would like to point out that Endura is good for auto body projects like yours, and not for aerospace projects, as my "aerospace" handle would imply.
STF
RE: Electric Car Conversion
The guy who sold me the topcoat also sold me an acrylic-epoxy hybrid tinted primer. We'll see how this stuff sprays and sands. The acrylic-urethane primer surfacer I used (damned autocorrect keeps changing surfacer to surface!) was a bit of a bear to figure out, but now that I am done, I know how to use it! It's a DREAM to sand- easy as can be, never loads up the paper. Goes on thick without sagging too.
The tinted primer is tinted "yellowish", or so it says on the can. I hope it's a decent colour as I'd like to use it over my floor pans and inside the trunk and bonnet lids etc.
RE: Electric Car Conversion
Good pressure, and enough volume that they'd probably actually defrost the windshield.
oh, well.
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
Mine will look pretty rough right after spraying, but hopefully after colour sanding and polishing in the spring it will look pretty sharp! Sharper than the car has looked since I've owned it, that's for certain. Here's hoping, anyway- the coloured primer looks pretty good on it already!
RE: Electric Car Conversion
Very glad this bodywork is more or less behind me- from this point onward, parts should be going back onto the car!
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STF
RE: Electric Car Conversion
Mike Halloran
Pembroke Pines, FL, USA
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Worried now about polishing it, as that will probably bring out some of my bodywork flaws! And it's orange, so the orange peel is appropriate! And it's pretty uniform- though there are a few places where I got perfect finish, but they're few and far between. Gun settings...still a mystery. It appears that you need to spray this stuff as thin as the mfg recommends (I did- more reducer than 4:1:1 and you might end up with mud cracking), and then lay it on heavy enough for it to flatten itself- which is just ever so much less than it takes for the paint to sag... If it wasn't such a dead ringer for amateur work, I'd leave the orange peel- the gloss is spectacular right now!
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STF
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Any chance of getting a more detailed set of pictures showing placement and mounting of the battery packs, motors and regenerators?
I hope the inspection goes well, and you might be limited to liability insurance on this road queen. You are definitely going to turn some heads!
RE: Electric Car Conversion
http://www.diyelectriccar.com/forums/showthread.ph...
There are no "regenerators"- the inverter generates DC from the 3 phase AC motor to recharge the batteries whenever you take your foot off the accelerator. Totally seamless drive-by-wire. You can also use a pot on your mechanical brake pressure or your brake pedal position to adjust how much regeneration you have.
RE: Electric Car Conversion
It's a Triumph Spitfire.
Just like my car is a '61 Corvair.
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
And... there's this MGB just sitting in the garage of a guy I know... Totally stripped and body already patched... He hasn't touched it in 10 years... It would be a shame not to, right?
STF
RE: Electric Car Conversion
SparWeb: yes, the garage comes first, but the car comes immediately AFTER! My garage/shop has been in service for about 8 years and paid for itself building my custom kitchen and bathroom cabinetry. Regrettably there was usually an old wrecky car in the way, making me wonder why I was keeping it. I think now that it was a good decision!
RE: Electric Car Conversion
The frame is, as I said, stripped and patched, but not re-painted, so it may have developed new rust spots in his garage over the years.
He has the transmission out on a pallet but I've never looked closely to see if it's still in working order.
I would probably get stuck with the engine if I was to buy the frame. Can that be re-sold? I doubt it's in good condition.
He is unmarried, so I am unable to approach the Director of Finance on the matter.
STF
RE: Electric Car Conversion
I'd way prefer a Spitfire as a donor because unlike the B it has a full frame rather than unibody/semiframe construction. But the B is arguably a nicer car overall.
According to Hagerty/Silver Wheels, they figure a 1972 MGB in #4 (fair condition) is worth about $5-6,000 CDN. A quick web search gave that as the asking price, but a lot of those cars sit and rot on the market for ages and don't sell. Per Hagerty's website: "#4 cars are daily drivers, with flaws visible to the naked eye. The chrome might have pitting or scratches, the windshield might be chipped. Paintwork is imperfect, and perhaps the fender has a minor dent. The interior could have split seams or a cracked dash. No major parts are missing, but the wheels could differ from the originals, or the interior might not be stock. A #4 car can also be a deteriorated restoration. "Fair" is the one word that describes a #4"
RE: Electric Car Conversion
Maybe he's ready to pass it along cheap to a new home.
If he's not, stay in touch. He may know of others, or he may think about it and decide to unload it.
As for my car - pics on the website in my sig.
And, I'm pretty easy to find on other sites, by reason of name.
Regards
Jay
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
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Are you still pushing it back home?
STF
RE: Electric Car Conversion
Now I'm worried that some evil Leyland demon has managed to survive the restoration and is waiting to jump out and get me. I had the car up on axle stands again and checked all the U joints etc.- everything is fine. I do need heavier front springs because my ride height is still too low at the front, but otherwise the car is running like a champ.
I did a few more calcs, for those interested in the efficiency and GHG emissions. Sources of information are in {}
Ontario power grid: 9.24% natural gas, balance nuclear and renewables. Zero coal. That's a year round average- spring through fall is better at 7.85% fossil. {IESO Mar 2014-Mar 2015}. CO2 emissions are 40 g per kWh at 9.2% nat gas {Gridwatch}
Efficiency chain, power plant to stored energy available from battery: 82%
(6% grid loss {IESO}, which is only charged for at 3.6% of delivered kWh {Toronto Hydro} x 93% charger efficiency {ElCon, verified by my kill-a-watt and ammeter} x 94% battery efficiency {thousands of measurements by Darren Sims, P. E., on his own LiFePO4 pack in his converted Jetta- this is the average in my temperature range}
Conventional gasoline efficiency chain: 81.4% well to tank on an equal BTU basis (I'll call this EBB), treating a BTU thermal as equal to a BTU electric when used in production (98% production, 84.5% refining, 98.4% distribution/transport {all from the GM/Argonne well to wheels (WTW) study 2001} 99.86% evaporation ie. 0.14 % uncaptured evaporative losses at all points in distribution{Env Canada}. Compare with European estimate of 82% {EU JRC WTW Study 2014}
2583 g CO2 per U.S. Gal from above losses {GM/ANL WTW 2001}. 8887 g CO2 emitted per gal by combustion only {USEPA/USDOT Joint figure, groundtruthed by calc using C8H18}. CO2 equivalent efficiency well to gas tank is therefore really only 77.5%- I'll call this an equal CO2 basis efficiency or ECB
100 km trip basis:
Original Spitfire- 8L/100 km {EPA- I got worse because I drove it fast, burning up both gasoline AND main bearing thrust washers...}, 24.3 kg CO2 WTW, 253 MJ energy from tank 312 MJ WTW EBB, 327 MJ ECB
Prius C: 4.5 L/100 km summer {my measurements}, 13.6 kg CO2 WTW, 142 MJ from tank, 175 MJ EBB, 184 MJ ECB
E-Fire: 250 battery Wh/mile (my measurements), 0.76 kg CO2 plant to wheels, 55.9 MJ from battery, 68 MJ plant to wheels
The E-Fire reduces CO2 emissions by 96.9% relative to pre conversion and by 94.5% relative to my awesome Prius C hybrid. It produces negligible toxic emissions relative to either.
It uses 21% of the source energy (ECB) of the preconversion car and 37% of the ECB source energy of the Prius C.
Assuming one daily on peak charge at work and one at home off peak at night, including all fees and taxes, cost of electricity is $0.19/kWh - yes, those renewable FIT contracts are costing us on our hydro bills... Including all losses that's $3.66/100 km. At last fill up price of $1.14/L including taxes, gasoline would be $9.12 for preconversion and $5.13 for the Prius C, both per 100 km. prices here hit an all time peak of about $1.40/L for comparison.
Battery replacement loses the day for the conversion though, on a purely financial basis. My 18.5 kWh LiFePO4 pack cost $8000 CDN and will last 3000 cycles at 70% DOD if Sinopoly's data sheet is to be believed. Even assuming full distance (83 km at 70% DOD) between charges, that's $3.20 per 100 km, all paid up front. Payback against the preconversion car is very long, and against the Prius C is never. Put a $150 / tonne carbon tax on gasoline though and now we're talking- that would add $3.53/100 km to the original car's consumption. It also gets cheaper if you get a Chevy Volt pack for the reported replacement price of $3,000 (presumably subsidized by GM) for 16 kWh of stored energy- or one out of a wreck for $2,0000. But still not an economic slam dunk- until a substantial carbon tax feeds a cost back to using gasoline. Until then, gasoline remains king.
Much is made of embodied energy in these analyses, but in this case you've got to consider that I reused a car which was otherwise ready for the scrapyard- that's bound to have more internal energy associated with it than my battery pack does.
RE: Electric Car Conversion
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Electric Car Conversion
Right now I have only off-pedal regen, set at a peak of 100 A (the controller can do 200 A of regen vs 500 A of forward current). Training myself to drive it right isn't easy- when you want to coast, you need to watch the ammeter and back off the accelerator until you null the current- or put your foot on the clutch. Neither is automatic to me as a driving instinct. What I may eventually do is to map another pedal over the brake pedal with a brake pot to control regen, or to put a brake pot on the linkage slop in my brake pedal (adding some heavier springs to the pedal to give at least some feedback as you're applying the brake). Others have used hand controls but I want both hands on the wheel when I'm braking! Once I learn to drive it better, my stop and go Wh performance should improve quite a bit.
Merging or crossing several lanes on a major highway to a left exit, absent all the mod cons and safety features, is positively terrifying in such a small car! I used to think nothing of it- I drove this car on highways with no concerns at all, but now I'm older and wiser I guess! I get more comfortable the more I drive it, so it's gradually transitioning from terror to thrill. On city streets, it's a positive joy!
I did put spacers under the spring/shock assemblies after the new spring/shock combinations lowered my ride height, but the 1/2" of spacers I added are the most I can manage without drilling out and replacing the three little 1/4-28 studs which hold the spring cap to the spring mount on the frame. I'd been hoping the spring/shock replacement would INCREASE my ride height a bit! I complained to the local parts guy I bought the stuff from and he's looking for heavier replacement springs, but knowing him, he's not looking too hard. I'll have to do the research- there must be a GT6 spring which will fit and which suited the heavier 6cyl engine, so that would be my first choice. I do seem to have sufficient suspension travel, at least when I'm driving- when I'm cornering tight to park etc. there's still a risk of rubbing the tires on the outer lip of the fenders if I turn too tight. I've rolled them a bit with a ball peen hammer, for the rub points in the forward direction at least. Can't bring myself to do the baseball bat thing...not to mention, we have no baseball bat! I certainly would like a bit more suspension travel too, but the ride height is the bigger issue. Right now it's so low that I have to use an old crank scissor jack under the frame to get enough clearance to get my hydraulic jack under the car!
RE: Electric Car Conversion
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
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RE: Electric Car Conversion
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
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STF
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The regen at throttle lift sounds like the effect of a big gas engine when you lift - compression braking.
(in terms of feel) If you want to coast with a big motor, you'd probably clutch.
cheers
Jay
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
Did some big kid show and tell last Friday- I took the car into my son's gr. 7 science class and did a little talk on forms of energy, the history of engines, energy efficiency, and where the electric car fits into all of this. The kid figures that about 25% of the class was really interested, but when I got to the show and tell part I think I had way more than 25% interest for sure! I think I'll be doing a few more of those show and tell sessions next school year.
Also finally got around to playing with the Curtis controller's settings, and discovered that although my throttle pot lever was being cycled through its full range of motion, or nearly so, by the accelerator cable, it was not actually adjusting the input voltage beyond 2.6 V at full throttle- and the input was spanned for 0-5 V. Fixed that by re-spanning the input in the software...wow, the car really was fun BEFORE I did that, and now it's positively breathtaking! I also adjusted the acceleration parameter by a very small amount beyond the factory default- any more and I'd be squawking the tires when I didn't want to. I also upped the off-pedal regen current, but I'm doing that in small steps until I get around to installing a regen pedal with a pot on the dash to limit the maximum regen current- otherwise, instincts being what they are, the tendency to pop your foot off the accelerator will be too strong and might get me in trouble in wet weather. Regrettably the standard settings don't allow for a pot input to set off-pedal regen current limit, and the one-button programming using the Curtis Spyglass display is functional but not what you'd call convenient. The settings do allow for an "econo" mode switch, so that might be a way to "cheat" it to do what I want. Doubt I'll get around to the regen pedal until the winter.
RE: Electric Car Conversion
Said overlay comprising, say, a carbon pile resistor surrounded by a mechanical stop, such that the first 1/2" or so of brake pedal travel, normally clearance and working just against the pedal return spring, would bring in the regen, and then the normal service brakes would apply?
That might make the car less intimidating for drivers who are not expecting anything weird. (My friend Mark rigged his otherwise traditional kart so that you had to push down on the gas pedal to close the throttle; it was counterintuitive, and scary.)
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
STF
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
(yes, a non-trivial effort)
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
RE: Electric Car Conversion
Rear wheels have maybe 20% of the stopping power of front wheels. You need to take that into account when tuning the brakes, whether revenue or mechanical, or else you will frequently be locking the rear wheels.
RE: Electric Car Conversion
Allowing a car to coast was a feature know as freewheeling. That last car I saw with free wheeling was a 1948 Rover. The feel of freewheeling was so counter intuitive that it was almost never engaged. Travel was a series of coast and accelerate cycles. A very unnatural feeling.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
I suspect it was included to make them less dangerous in snow.
Having the center of applied engine braking between the two front tires, and the CG several feet behind that, can snap yaw the car 180 deg in the time it takes to release the throttle and move your foot to the brake pedal.
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
RE: Electric Car Conversion
In an electric car the throttle pedal should not be doing any braking.
RE: Electric Car Conversion
At cruise speed, lots of vehicles are running the engine slow enough, that a bit of converter slip returns the enging pretty close to idle anyway.
Plus, some transmission gear stages are clutch + sprag, and will overrun unless you manually lock it in a gear.
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Electric Car Conversion
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
Steve
RE: Electric Car Conversion
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
I can now drive the car legitimately to work or wherever else I want, with a reasonable number of km per year that I am unlikely to exceed. Of course if anyone else comes to them to insure an electric conversion, they have now primed their call centre staff to say "no, no HELL no!". In fact they made it clear that they will not insure another car if I migrate the parts to it. So here's hoping the old Spitty stays in fine form!
230 Wh/mile on the way to work today- now that I have the right springs in it and the front geometry is a bit better. Both sets of springs I got from my parts guy were wrong- the pair I put in was an old "swap meet" pair I had laying around- covered with 25 yrs worth of grime, but once I had them cleaned up it was apparent that they'd never been in a car- still had the paint marks on them to indicate which springs they were.
RE: Electric Car Conversion
RE: Electric Car Conversion
The shop guys shellacked a guy's car with it because he hit-an-ran a buddy of ours and his girlfriend who was riding with him on a motorcycle. The police just shrugged even when shown the car and the motorcycle paint on it. (high school vigilantism)
Keith Cress
kcress - http://www.flaminsystems.com
RE: Electric Car Conversion
RE: Electric Car Conversion
Fortunately I have a spare- I was always suspicious that the diff, which is the only major piece of Leyland drivetrain left in the car, would bite me in the rear end (pun intended) at some point! Unfortunately, my plan to put all new oil seals in that spare diff while I had it on the bench will not be possible, as the car and I have a date on Saturday- a buddy of mine is including us in a video he's making. Another few minutes off my 15 minutes of fame allotment in life...
RE: Electric Car Conversion
Keith Cress
kcress - http://www.flaminsystems.com
RE: Electric Car Conversion
The spare diff is in, and runs way quieter than the old one did. We'll see if there's a pool of 80W90 under the car tomorrow morning, but I'm hoping the thing seals well enough to last out the rest of the nice weather.
The old diff fought me every step of the way- it was rust-welded to the bottom of the leaf spring to the point that it took a hammer and cold chisel to free the spring from the diff. Had to remove my rear battery pack- If I had done that right off, I would have saved myself hours of suffering. My Haynes manual led me to believe that the spring retainer construction was different than what is actually in the car, which didn't help much- there were four studs that HAD to come out come hell or high water, and they were not fun to say the least. Positively kicking myself for not swapping in the spare when I had the body off the frame- but I didn't know the pedigree of the old diff so it was too much of a gamble to take one which was known to work and replace it with a potential dunner. Hindsight is of course 20/20!
My son, who turns 13 in a week or so, was a GREAT help- he was with me the whole day, undoing bolts, fetching tools, operating the jack as we tried to get the old diff out and to guide the new one in- he was a constant help. His skills have really come along, and his confidence too. He did a trades-related camp this summer for a week and had a riot- he was showing the other kids what to do. Seeing him come along was worth the price of the car conversion parts!
RE: Electric Car Conversion
And much more!
Keith Cress
kcress - http://www.flaminsystems.com
RE: Electric Car Conversion
Bad news is that apparently my dad and I didn't fully understand the design of the Leyland driveshaft...when we swapped in the Toyota motor and tranny, we cut the Toyota driveshaft off at the tranny end, keeping its U joint- and we chopped the front U joint off the Leyland driveshaft, machined both pieces in the lathe, fit them together and even welded them in the lathe- perfect. Only one wee problem, or at least it seems that way from what I understand now. The Toyota transmission has a sliding joint between the front U joint and the tranny- a splined collar slides in and out of the transmission to provide some axial "give" in the assembly, which is really handy for giving clearance for work on the drivetrain. But the Leyland driveshaft has an arrangement of flat strips of spring steel between the rear 2-bolt flange of the driveshaft and the front 2-bolt flange of the rear U joint, which I think were intended to serve the same purpose- not much axial give is required in the Spitfire because both the tranny and diff are fixed to the frame with rubber mounts and the rear wheels are independently suspended, and I guess this was a cheap and probably pretty reliable way to provide it.
Each 2-bolt flange bolts to diagonal corners of a square formed by two straps, and there are two layers of straps for a total of eight.
At least one of those spring-steel straps is cracked through and, I hope, that's the source of a new noise I hear whenever I take my foot off the accelerator and the motor goes into regenerative braking.
New straps are on order, from Spitbits in California (my wallet is stinging from the importation charges already), but I'm thinking I should make some thicker ones out of say 1/8" thick mild steel plate and make the assembly more rigid and resistant to the sudden torque reversals. I'd need longer bolts, and would want those pieces to be identical so the assembly stays balanced- but that should be about it. Having the driveshaft free to move axially at both ends is bound to be hard on the U joints over time.
Any thoughts from you folks who have forgotten about cars more than I'll ever know about them?
RE: Electric Car Conversion
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
My plan is to replace them with straps which are 1/8" thick and wider. The plan is to keep them from yielding OR flexing in the first place, and if they're thick enough it would seem logical that the driveshaft would transmit any axial force to the front end where there's already a sliding joint to take up the movement. In other versions of the Spitfire drivetrain, these rear straps are eliminated in favour of a four-bolt flange on each piece, and there is a sliding joint at the transmission similar to what I have on my Toyota tranny. Trying to replicate that design without having to replace the rear U joint itself and the end of the driveshaft, both of which are in good shape right now.
RE: Electric Car Conversion
RE: Electric Car Conversion
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
RE: Electric Car Conversion
RE: Electric Car Conversion
Fatigue from cyclic loading will crack them.
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
If this was a helicopter, I'd call it a "Kaflex" coupling.
Since the spitfire already has a set of U-joints and a spline, I'm not absolutely certain what the Kaflex joint is in there for, either. Does the body of the car flex so much that later models of car needed extra flex built into the transmission?
Umm, I think it's item #6 on your parts list scan, right? Does that diagram show parts from only one car, or is it two configurations from two different cars, in the same diagram? Is there an intermediate hanger bearing, not shown?
So it must be overlapping metal straps, drilled on the ends, the combination of which in a square makes a coupling between two bolts on one fitting to two bolts on the other fitting. I guess we can ignore, for the moment, there there already are 3 things in your tranny that are supposed to do the same thing as the Kaflex. The fact that the Kaflex is broken is proof, in a strange way, that it was actually doing something. The bars cracked because they were already subjected to excessive misalignment (or maybe the spline's freedom of motion bottoms out?). Replacing the bars with something thicker will change the allowable misalignment and displacement equation. Replacing them with something softer will change the stress equation. Neither in your favour.
STF
RE: Electric Car Conversion
Both the transmission and the differential are fixed in place.
Old designs used the plates to allow for slight end play.
New designs use a spline to allow for end play.
You are stuck between old design and new design.
The spline will absorb any end play. The new plates will transmit torque but will not be flexed by end play.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Electric Car Conversion
Yes the picture shows two different versions of the same driveshaft from different model year Spitfires. Mine is the one with the square part 6 which consists of eight 0.030" thick spring steel straps stacked up, which connect the 2 bolt flange on the driveshaft to the 2 bolt flange on the differential end u joint. In that design, in the original Spitfire 1500, the flange bolting the front u joint to the transmission is solid, with no splined joint.
The transmission and differential are both bolted to the frame with rubber shock mounts. My electric motor holds the front of the transmission more or less rigid, with very limited rubber slop- I did not reuse the original engine mounts- my motor mount is much more solidly connected to the frame as it doesn't dance around like an IC engine does.
The axial flex provided by the straps was presumably there to compensate for small amounts of axial movement of either part within the perhaps 1/4" of total relative movement in the axial direction afforded by the tranny and diff rubber mounts, plus any frame flex etc. The u joints themselves should take care of axial misalignment- all the straps handle in the Spitfire is any motion requiring the shaft to be a minor amount longer or shorter.
My version of this assembly has a splined joint at the front connection between the transmission and the front u joint, which should accomplish the same thing, only more reliably. A splined joint like that was used both on earlier and later model year Spitfirss.
It seems obvious even to a chemical engineer that you don't want axial flex at both ends of a shaft with two u joints. The tendency for the assembly to squirm like a rubber band being twisted would seem to be a major problem under large torques. You want a thrust bearing at one end of the assembly- in my case that would be the front bearing in the differential, which no doubt wasn't designed for much thrust, but should be able to handle at least some.
So my thicker straps are intended to make the rear joint axially rigid, or at least more rigid than it was. As close to a solid 4 bolt circular flanged joint like the one between the rear u joint and differential as I can manage.
Since there's a splined joint at the front which won't permit the assembly to push on my new straps in the axial direction with a force greater than the friction in that splined joint plus the inertia of the shaft, it's tough for me to see what force would be cycling my new straps to the point of fatigue. I know that a little force through millions of cycles can be enough, and I know they're not made of a springy material, but the material they are made of is greatly thicker so it should be stiffer and should not allow much strain. The stack of straps is about as thick as each two bolt flange at each bolting face, and those flange/yokes aren't made of spring steel either.
I put the initial failure down to the material being forty years old, and the assembly being free to squirm. Obviously we should have eliminated this flex joint when we made the new shortened driveshaft in 1992, but changing it now would be a huge effort. I could be wrong of course- maybe those straps will fatigue, or worse still, the yokes will fatigue. If my new straps don't last long, I will replace them with the set of spring steel replacements I have on order. This is relatively easy to work on and inspect from under the car- and it does seem to get noisy enough as a warning that I'm not worried about a sudden failure. And right now it's silent, which is a good sign.
RE: Electric Car Conversion
If the shaft is installed with equal articulation angles at each end, as it should be, and the angles are large enough that the needles' tracks overlap so the needle lubricant circulates, then the U-joints will be okay, but then your straps are subject to tension/compression cyclic load variations just from transmitting torque while the joints articulate and the shaft accelerates and decelerates relative to the ends over every rotation. That load case has nothing to do with axial force. ... and should be mitigated some by the extra cross section.
... but the extra cross section and soft material become problematic when the spline doesn't slide easily under load. Keep it well greased with sturdy stuff.
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
Will definitely keep that sliding joint lubed!
RE: Electric Car Conversion
In a normal automotive installation, the pinion shaft axis is level, and the driveshaft slopes up say 3 degrees going forward, and the engine slopes up another 3 degrees going forward, putting the crank at 6 degrees from horizontal. Actually, the pinion may point down 3 degrees so the driveshaft is level, but the situation is the same; the U-joints have equal angles, and the angles are of the same 'sign'.
In that case, the driveshaft should be 'straight', which means that when you look at the end of the shaft itself, the U-joint yokes on each end of the shaft proper should be parallel. ... just as you see them in the shop manual.
In your new case, the pinion is horizontal, and the 'engine' is horizontal, drive and driven shaft are parallel, so you need a 'crossed' driveshaft, i.e. when viewed from the end, the u-joint yokes attached to the shaft proper should be crossed at 90 degrees to each other. The reason why has to do with the sinusoidal transfer function of a single u-joint. Any competent driveshaft shop should be able to rotate one of your yokes for you.
I went looking on the net for a picture to reinforce my point, and pretty much all of the information out there, especially from the driveshaft experts, especially the stuff with nice illustrations, is completely wrong.
So find a picture of a 'double Cardan' joint. They are typically equipped with a small ball and socket in the center, so that the ends physically can be angulated, but cannot be displaced in a lateral direction and remain parallel. The center 'driveshaft', short as it is, has parallel yokes, as it must for minimal NVH. If you built one with crossed yokes in the center piece, you would be able to move the end shafts radially, but you would need some mechanism to hold them parallel, or the center section would be subject to torques with a large cyclic component, just as yours has been since you removed the gasoline engine and substituted an electric motor with a level axis. Did you notice the slope of the engine's crankshaft?
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
I didn't realize the geometry was that touchy...!
I was looking at the CV joint wiki a while ago which has a picture of a double Cardan joint. Will need to think about what you've said and look at that little animation to understand it...I do know that a single u joint has a nonconstant velocity, but thought that two joints paired in reverse or out of phase so to speak spat back out a constant velocity. Didn't know that you needed them to be at particular angles relative to one another to work though...
I had this reversed before- your point was that the crankshaft normally slopes upward toward the front of the vehicle. I could raise my motor to make this angle closer to what Mike says it should be, but it would be a lot of work- as would removing and rotating one of the u joint yokes. But bolting the two 2 bolt flanges together without any straps would give me the 90 degree rotation I need too, would it not? I just don't like the hinge point that would be created where they bolt together....
RE: Electric Car Conversion
If this drawing is correct, I thought I had the top geometry- or close enough to it.
Mike felt that the middle geometry was likely what the Spitfire had originally (did I get that right Mike?)
I have the bottom geometry- and therefore I guess a problem with cyclic loading on the driveshaft. If I were to bolt the two 2bolt flanges together without straps, the yoke ears fixed to the driveshaft at each end would be aligned, as shown in the Triumph parts drawing and the top picture in the image above- but with the straps in place, the ears are rotated by 90 degrees to one another.
Impressive that the assembly as it stands is actually working without giving me excessive vibration- or maybe i'm just used to vibration...
RE: Electric Car Conversion
Mike, please correct me if I'm wrong, again...!
RE: Electric Car Conversion
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
I wonder if someone has a motion model of these somewhere so you can play with the angles and see the results!
I certainly didn't know this, and I'm sure my Dad didn't either. But I'm surprised that he didn't match the orientation that the Spitfire shaft had before we cut it- that he set the yokes 90 degrees apart was a fluke I'm sure. I have no idea what the orientation of the Toyota's shaft was originally.
Mike, even though it appears that blind luck won for me in this case, you deserve more LPS than I can award for clearing this up for me. Thanks a lot!
RE: Electric Car Conversion
First point, the motion equation of the u-joint uses 1/cos(joint angle) so the sign of the angle doesn't matter, just that the absolute value of the angle at each end is the same.
Now, consider the motion of the U-joint. A U-joint puts 2 cycles of sinusoidal oscillation into the output shaft rotating speed for every rotation the input shaft makes. In other words, for every 90* of input shaft rotation there is a peak or valley in the output shaft rotating speed. So, this means the next u-joint needs to be rotated 90* to put each peak or valley it creates opposite to the peaks or valleys the first joint creates.
Well, the output u-joint is already turned 90* compared to the input u-joint when the drive shaft has both yokes in line.
Besides, I've owned a few vehicles that were produced by the millions and they used the top configuration and they worked fine without any drive shaft vibrations. I've yet to see a drive shaft with the yokes 90* to each other.
There is a reason you think every expert on the internet got it wrong and is showing the wrong info.....
RE: Electric Car Conversion
LionelHutz said "Well, the output u-joint is already turned 90* compared to the input u-joint when the drive shaft has both yokes in line."
Is that right? Irrespective of the angles of the joints relative to the driveshaft axis? Damn, I'm having a very hard time getting my head around this moving geometry to understand who is right here! I wish I had a simple double Cardan joint here that I could play with, bending it in the two configurations and spinning it to observe the output shaft rotation!
I have two potential arrangements which are easy to implement:
1) With the u joint yokes on the driveshaft aligned, and the straps eliminated and the two 2-bolt flanges (between the rear u joint yoke and the rear of the driveshaft) bolted to one another. That would give me u joint yokes aligned with one another.
2) The one I have in the car right now, like the Triumph picture but with thicker straps- except the u-joint yokes are definitely at 90 degrees to one another rather than the way the Triumph drawing shows them (aligned).
...and right now I'm not sure which one is best!
The present arrangement doesn't seem to be generating undue vibration, but I might just be used to the vibration it is generating. I did have the thinner, springier, 40 yr old straps fail in this configuration. I put that down to the fact that both ends of the shaft were free to flex axially, which I know to be bad news when using U joints, and to the age/cycle history of the material.
I do find it hard to believe that the original Spitfire engine had a driveshaft angle as steeply inclined toward the rear of the car as what it would need to be to give the squashed U configuration (middle drawing above), and its u joint yokes were definintely aligned. The hood of the car is just too low to make that geometry work out.
RE: Electric Car Conversion
Here, watch this video.
https://www.youtube.com/watch?v=gmV4qwLfOMY
RE: Electric Car Conversion
Engines with downdraft carbs typically had a 'wedge' shape in the intake manifold, so that the carb bottoms were parallel to the ground at design height. Take a close look at the manifold on any random old sedan you can find.
The 'crank nose up' attitude also pushes the front u-joint down, to minimize the tunnel height, while maintaining a reasonable distance between the flywheel ring gear and the ground. It also provides clearance under the front of the crank for the usual front crossmember and steering links. There was also the earliest Pontiac Tempest that used no u-joints, but the driveshaft was thin and heat treated to a spring temper, so it actually ran while continuously bent in the squashed-U shape.
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
Guess I need to take my straps out and bolt the two 2-bolt flanges together and see what happens!
RE: Electric Car Conversion
I don't know where I got the idea that crossed yokes were useful or advisable, but it appears that I was completely wrong about that.
To summarize, the illustration is correct as shown, and I have had some brain fade.
Mike Halloran
Pembroke Pines, FL, USA
RE: Electric Car Conversion
Even if one UJ completely "undoes" the effect of the other (constant speed in -> constant speed out), surely the connecting shaft will still have the torsional speed variation. So the system as a whole will have a variable rotational inertia, which will manifest itself as a source of (2nd order) torsional excitation.
Steve
RE: Electric Car Conversion
I'll try to video both arrangements on the car on stands to see if there's a perceptible difference, but the video has me convinced that my best bet is to bolt the two 2 bolt flanges together without the straps.
SomptingGuy, I do think you might have a point there- it seems there is still something going on which could excite vibrations, even when they are minimized by correct geometry.
RE: Electric Car Conversion
RE: Electric Car Conversion
Thanks all for your help!