Old Engines are inefficicent at creating power/torque,WHY?
Old Engines are inefficicent at creating power/torque,WHY?
(OP)
Why do old engines produce such little power for their displacement, for example, the 1968 426(7.2L) hemi produced 425HP.The modern 6.1 L hemi produces about 425 HP, the same as the 7.2! Why is this?





RE: Old Engines are inefficicent at creating power/torque,WHY?
Notice the rpm at which max power is developed - that's increased due to better materials, and perhaps better structural design.
The torque at max power has increased because you've got 4 valve heads, or better cams, or better porting, or better header tuning.
Every cylinder actually fires every time. That is a big help. Every cylinder has roughly the same mixture in it. That is a huge help. The cams actually open and close when the designer thought they should. That helps.
Also, no cold spots on the cylinder walls, able to run higher cc temps due to materials again.
But basically, 40 years of competition and hard work.
A cynic might ask why with hundreds of millions of dollars spent is the specific output of the new engine only 16% better than the old one?
That's a much funnier question.
Cheers
Greg Locock
I rarely exceed 1.79 x 10^12 furlongs per fortnight
RE: Old Engines are inefficicent at creating power/torque,WHY?
Better understanding of the mechanicals (rings, bearings, etc) relaxes self-imposed longevity limits.
- Steve
RE: Old Engines are inefficicent at creating power/torque,WHY?
A big gain has been manufacturing technology to greatly improve precision and complexity at lower real cost.
Regards
Pat
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RE: Old Engines are inefficicent at creating power/torque,WHY?
can't vouch for this link, but it seems reasonable.
http
RE: Old Engines are inefficicent at creating power/torque,WHY?
- Steve
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
Modern engines are built to tighter tolerances and have fewer adjustments ... but games can still be played.
The difference between SAE gross "back in the day" and modern SAE net corrected figures makes the difference in specific output from then to now bigger than it first appears.
Improvements in other areas besides peak power are more impressive. Fuel consumption, for one. Back then, anything with 200+ horsepower got 7 mpg. The reduction in emissions is spectacular by comparison. And then there's durability, driveability, cold starting, etc.
As others have noted, engineers have been doing something in the past 40 years.
RE: Old Engines are inefficicent at creating power/torque,WHY?
A blanket statement that old engines make so little power...
Take a peek at some of the early 1920's Indy engines. DOHC, 4 valve, duplex supercharge/turbocharged, methanol fueled, etc. As for machining complexity...try the Jumo 211, DB 601 or, RR PV-12 Merlin. I've seen the internals of all three and they do not lack for any deficiencies in machining. Especially the Jumo...it is like a Swiss watch.
Your right, Greg. WHY aren't we further along the curve?
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
As to the OP, the 426 Hemi Superbird that I had the chance to see run up on a chassis dyno made well in excess of 425hp AT THE WHEELS! You need to brush up on the "politics of the era". Big brother had a BIG influence on published numbers!
Since you specifically ask for advice---From someone who has BTDT---Stick fairly close to the stock setup for your GTO. The closer to absolutely stock you can make it will pay dividends further down the line. You can get by with a mild hydraulic cam setup, maybe a set of headers (keep the original stuff)...dual exhaust with the stock exhaust manifolds works just as well on the street, though...and, a good Pertronics or similar electronic ignition. That's about it. You will have more power than you can ever use on the street.
"Why aren't we further along the curve"? Wow, DG. Perhaps I was being TOO subtle!
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
- Steve
RE: Old Engines are inefficicent at creating power/torque,WHY?
And I agree about keeping the 68 Goat close to stock & keep all original parts if mods are made. Look at the Barrett Jackson auctions, it either has to be a really wild custom or totally original restoration to get top dollar. Typical backyard hot rodder mods will kill value.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Do you really need more power anyway?!
RE: Old Engines are inefficicent at creating power/torque,WHY?
I believe back in the 60's that the High Priest of Horsepower, Reverend Mr. (Keith) Black stated that "How fast you go is directly proportional to how much money you spend!" As we could not afford one of his drag motors we were not quite as fast as others less fiscally challenged.
Back then, the cost of insurance would go up with the HP rating. So, many were labeled with lower than actual net and way under the gross HP ratings. Part of it was to make it more affordable for the typical young, barely insurable (remember assigned risk?), wanna go fast car buyer. If I recollect, a magic number was 300 HP, which my '69 Z/28 Camaro, with a 290 HP sticker on the air cleaner, just got under. With a '71 Z/28 I gave my insurance guy the 275 net rating instead of the 330 gross and was able to avoid the factory hot rod insurance penalty again.
Mechanicat, it has been said already and I will say it again, if it is totally stock, leave it that way or make only reversible modifications, keeping the original bits.
Yosh
RE: Old Engines are inefficicent at creating power/torque,WHY?
I also agree about those big auto engines of the past being under rated for insurance reasons.
Another reason they would not rate them or make them output more HP is most all manufactures then had a performance parts division, and to sell hot rod parts you don't want to make the stock engine that great, else your performance parts department would not be a needed entity.
And its taken the after market to figure out how to make such things as high flow cylinder heads, that has added greatly to the increase of HP in the auto engines of today.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Two engine types that make an interesting comparision are the small-block Chevys and the modern LS1-type engines. Both are pushrod, both 2-valve but the LS engines make far more power more easily than the old engines.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Something that you have to consider is how much influence the bean counters had on what made it to the showroom. Making more HP out of the same size envelope takes better materials along with more engineering and manufacturing sophistication. There were people at the Big Three that knew how to make plenty of power with smaller packages. How to get it made at a required price point was probably an insurmountable challenge. Now, with fuel economy as a major influnce on design, smaller, lighter engines that can make more power with less fuel are a necessity. Of course, this ups the cost. Oh boy, to remember that a '57 Chevy with a fuel injected 283 was about $2000 new, and now??
Yosh
RE: Old Engines are inefficicent at creating power/torque,WHY?
or you can get a bespoke version:
http
RE: Old Engines are inefficicent at creating power/torque,WHY?
http
Cheers
Greg Locock
I rarely exceed 1.79 x 10^12 furlongs per fortnight
RE: Old Engines are inefficicent at creating power/torque,WHY?
One exception was the Chevy ZL-1, which allegedly did make an honest 435hp. Yet, remove the log exhaust manifolds and install headers, and it would jump to 550-575hp.
Or, how about all of the Quadrajets that had little tabs on them that prevented the secondaries from opening fully?
And then there all of those Japanese market cars that happen to make exactly 276hp, and the same engine in the US makes 300, 320hp.
RE: Old Engines are inefficicent at creating power/torque,WHY?
So, why should I spend $$$$ on a little motor that makes lots of power, when I can spend only $ or $$ on a bigger motor that does the job? That bigger motor will probably be cheaper to fix, and may even live longer. The initial cost of that nifty 'efficient' motor may totally eat the savings in fuel down the road.
Economic/market competition has given us lots of great choices out there...
cheers
Jay
Jay Maechtlen
http://home.covad.net/~jmaechtlen/
RE: Old Engines are inefficicent at creating power/torque,WHY?
It seems pretty much the same stuff of the good old days.
The biggest improvement is induction and exhaust systems from and to the cylinder, accurate ignition, tight control of A/F etc.
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
Surface coatings also aid in this tight clearance technology I think.
The relatively reduced cost of higher precision machining is a major area of improvement
Regards
Pat
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RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
- Steve
RE: Old Engines are inefficicent at creating power/torque,WHY?
We aren't further along the curve because, in my opinion, manufacturers are more interested in meeting fuel economy numbers than having large peak power numbers.
Sure, Ferrari makes some impressive engines. But then I'd expect nothing less with the price their cars cost. However, looking at the numbers doesn't impress me a huge amount. That engine is just built to rev quite high to get the large HP numbers - HP is proportional to T x rpm. I have a few user modified Corvette's with "crappy old school" pushrod engines which would have fun playing with that Ferrari and those Corvettes didn't give up much drivability or fuel economy to get the big power numbers they have.
RE: Old Engines are inefficicent at creating power/torque,WHY?
When picking a prime mover for a project, the power to mass ratio (watts/gram) is a much more relevant concern than the power/cylinder swept volume.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Cheers
Greg Locock
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RE: Old Engines are inefficicent at creating power/torque,WHY?
YouTube has plenty of videos of these.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Faye Taylor would be spinning in his grave if he could see the directions we've developed down in the last 10 years.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Mass specific output is fine for comparing engines "in a vacuum" (figuratively, of course). But output per unit engine mass indicates little about how any given engine will be perceived when in service.
Ignoring forced induction applications, specific torque (peak) doesn't vary a whole lot either way from a little over 70 ft-lb/liter. Meaning that a first-cut estimate of acceleration based on torque, gearing, and vehicle mass isn't going to yield comparative results all that different from what you'd get using engine displacement, gearing, and mass instead. Gearing can be dropped out if the vehicles being compared are reasonably similar in that respect.
Norm
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
10-14 bar BMEP is the rule of thumb I use. The 70ft*lbs gets tricky, I've dealt with 2-stroke motocross engines that when set-up properly make nearly 4 times that.
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
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: Old Engines are inefficicent at creating power/torque,WHY?
I'd be curious to see what a decent modern DIS system by itself would do to those dyno figures!
RE: Old Engines are inefficicent at creating power/torque,WHY?
Imaginary or computer?
I'm with you, Ross. I saw a crate motor 426 run up and, while impressive, it only made a bit over 500 hp. At the time everyone was jumping for joy...Most did not do that well.
Did get to see an 800 plus on a dyno...looong time ago. One of the Pitman bros. 390 blown Chrysler's.
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
Just as an interesting side note, the 8000 hp mark has been breached by an aftermarket hemi (496 cubes) running nitromethane, and obviously tweaked a bit more than what you would have gotten in '64 or '65. I'll see if I can dig up my references on it.
But anyway, 2 hp/in3 is not rocket science, and easily obtainable in a streetable motor.
RE: Old Engines are inefficicent at creating power/torque,WHY?
True, that's on the wimpy end of rocket science. ;)
RE: Old Engines are inefficicent at creating power/torque,WHY?
On pump gas? Totally stock in the late '60's/early '70's, with (single or dual?) carbs, and point ignition? Factory exhaust manifolds? "Totally stock" I take to mean "as delivered to Joe Average by the corner Plymouth/Dodge dealer". Not some skunk works factory blueprinted and tweaked drag engine. Totally stock as I've described, 2 HP/ci was indeed rocket science back then for a normally aspirated OHV engine with pushrods a foot long.
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
It was a big deal when HRM ran an article on a small-journal SBC build-up that made 572 HP (early 1970's). Around 5.4 liters.
I think there was one tiny V8 (OHC) that claimed 240 HP from 2 liters at some time in the 1960's. In the context that Italian dynos of the time were commonly suspected of being calibrated using small horses.
None of those engines would be considered daily-driveable, and the pushrod ones still fell short of 1.75 HP/in^3.
Norm
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
Largest dyno I have seen was testing a RR Merlin race engine for a P-51, about 4000 hp. I don't recall anyone publishing data on fuel diggers. I know that the claims are all in the big numbers and, I agree with some...I just don't agree with 8000 unless I see some supporting data.
Two...On pump gas? 91 octane pump gas? 600hp from 360 cu.in.? Several 600+ hp street cars out there, I agree. However, NOT 360's. Most are 500+ cubic inch monsters.
Perhaps I have been on the left coast too long and have missed out on the automotive revolution back east.
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
The 475 number is about what Traco was supposed to have been getting out of their Trans-Am 302 CSB according to what I remember. A well tuned in-the-car stock Z/28 would be around 375, sometimes a bit more. The Penske cars were another matter. A combination of motor, drivetrain, chassis, body and mystery(??) modifications.
Could be that those Italian dynos were calibrated with a team of AGIP, Ferrari's fuel sponsor before Shell, six-legged dog from their logo.
Yosh
RE: Old Engines are inefficicent at creating power/torque,WHY?
I've been trying to find a link on the web for you, no luck just yet. The 8000 hp monster I mentioned is being measured/extrapolated with torque sensors, and I don't know that the data has been certified third party yet. I have just bits and pieces myself, but I've heard that they're running in the neighborhood of 50+ psi of boost from a roots blower, force feeding a gallon per second of fuel (injectors in the blower hat, intake runners, and cylinders) at some over 8000 rpm.
In regard to the 600 hp 360's. We have twisted driveshafts, snapped u-joints, and exploded transmissions with these things. We had a 72 Satellite (big and heavy) that would toast anything less than a fueller from a dead start. The hardware is all mostly straightforward, it's the timing, mixture and ignition that is critical. Can't do it every day either, the weather plays a huge factor. There are days when we're down 50 hp or more.
RE: Old Engines are inefficicent at creating power/torque,WHY?
I can make an engine from an idea...I cannot make this infernal machine do anything without help.
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
A bolt together in your garage parts kit to get a 600hp 360 that runs on pump gas? This could be possible but it would be very difficult. Even "new school" engine technology does not make this a easy feat for a naturally aspirated engine.
Can I borrow your dyno to do some testing? Or do you only allow the "big HP" Chrysler products....
RE: Old Engines are inefficicent at creating power/torque,WHY?
So... Agreed that time marches on and things change. However,I'm sorry, but 1.7hp/cu.in. in a NA, two valve, pushrod domestic V8 running on 91 octane gasoline is just more than I can accept without some REAL numbers from a reputable, believable source. I'm sure you are convinced in your belief...So be it. I choose to remain skeptical until proven otherwise.
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
I was involved in one build of a 351 CI Ford Cleveland for a street/race car that was a weekend driver and street class race car.
The guy asked us to build a dual purpose engine and gave us a budget that in the day, allowed stock head and block casting, considerable head work, big SS valves, roller cam, forged pistons, stock crank casting and stock rod forgings with good prep and good bolts etc, after market inlet, big single carby, MSD ignition, avgas 115/145 fuel and a good tubular 4 into 1 exhaust.
It dynoed at 400hp at somewhere around 6500rpm.
The owner was furious at only 400hp, said he already had over 500hp from his back yard built current engine and would not even consider installing the engine.
About 6 months later he blew his old engine and needed to make a race meet next day and make a pass to qualify for some prize money, so he reluctantly fitted it as it was the only possibility to be there with a running engine.
He ran at 1/2 second under his previous best ever time with the worthless 400hp POS.
Moral of the story. There are dynos and there are dynos. There are dyno operators and there dyno operators and there are salesman and there are spin doctors and there are plain BS artists.
Magazines tend to quote numbers from the most self serving BS artists around.
In the day and age, 400 real fair dinkum hp was a very stout street/race American push rod V8 that could regularly beat engines claimed to be 50% more powerful.
Regards
Pat
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RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
I said that for amateur part time racers, big power numbers are often unrealistic or even fraudulent.
I said that for a street drivable Ford Cleveland with stock castings back when, that 400hp was a lot.
V8 Supercars are not street driven and do not use stock castings, do not use a cast iron crank nor stock rod forgings and certainly do not use a single carby for fuel metering.
650hp is quite believable for them.
Regards
Pat
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RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
Ya, I've a few dyno numbers for Vette's with around 450 to 500 crank hp from stock displacment LS1's (350 cu-in) that would still run on Sunoco 94, but I don't recall ever seeing anything at 600hp without a displacement increase.
I see a lot of people who go "I remember back in the day..." and describe how awesome the old American muscle cars were. It's mostly looking back at those times with rose colored glasses. For the most part, the muscle cars from the 60's and 70's had poor chassis and suspension technology and crappy tire technology with engines that needed high octane fuel and badly polluted and constantly went out of tune and tended to quickly wear out, typically needing a rebuild before the 100k mile mark.
To compare, many of todays engines will easily run 200k miles plus with only oil changes and a couple of spark plug changes.
At a car show last summer, I saw a old Charger (probably about 69-70 vintage) that had the whole floor cut out and then the body was welded over a new Charger chassis. That's certainly one way to make an old muscle car perform as well as many people remember they do.
As already stated, every aspect of building a new engine from design to finished product has been improved. Time does march on and better does happen. It'd be naive to think an old engine design will perform as well as a new design. The old design can be updated using the new technology but that's a different arguement.
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
No sir, I do not doubt that the numbers they quote are actually numbers they may have seen on their dynos. Mainly because I recently watched a NASCAR 358 Ford running at 750hp on a Superflow...it was totally strung out, too.
Was what I saw accurate? Is what the Supercar guys claim accurate? Are the numbers I just got today on our Lotus/Cosworth accurate? Probably NOT. Leave the high hp numbers to the salesmen and the dorks that believe all this crap. A dyno is only good for comparison. Anything else is subject to interpretation.
Does all this change my mind about an old school domestic iron block 360 @ 600hp on 91 octane? Nope.
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
I've been involved in the development and homologation of some high performance modern engines. I've recently moved to the USA and have been getting into old American Muscle- looking really deeply into the engines- trying to build GT power simulation models of my 440 R/T DOdge and a 426 Hemi, I also know the new twin plug Hemi very well.
For starters the homologation back then when the 440 6 pack was rated at 390 Bhp and the Hemi at 425 bhp- was optimistic. It's true that the 425 Bhp Hemi was 'under rated' by contemporary standards but if it were re-homologated by todays SAE J1349 or DIN standards it would still be lower than the rated 425 Bhp. (My colleague worked at Chrsyler and has the VE and fueling figures to hand- this is what I'm basing my GT power model on).
back to topic- the reason why things have progressed:
First of- engines breath alot better. 4 valve heads is an obvious one- but even if you compare a modern 2 valver with an older one- the flow for a given port size is alot better so the port mean gas velocity/flow compromise is better optimised.
The next is runner lengths- alot of these cars were running carburetteurs- with an intake manifold compromised for fuel flow distribution AND air flow distribution and no room for tuning. Even in the 80s Chevy ran fuel injected cars with no tuned intake lengths for the normal engine operating range.
Back pressures for alot of the more mundane Buicks and Oldmobiles were high compared to modern high performance machinary. The Aston Martin Vantage V8 has a peak power back pressure of only 350 mbar, an E39 BMW M5 has a back pressure of 250 mbar, looking at an LT1 engined 1996 camaro- I've measured the back pressure at 600 mbar. I know people WITHIN the big three that think that's a Good figure. The intake losses were high on many american domestic cars- the same Checvy LT1 engines thing has an intake losses of 80 mbar. A Jaguar XJ8 has an intake loss of around 33 mbar.
Sophisticated engine management systems have allowed higher compression ratios to be specified with fine knock control.
Cam profile design has come a long way- even staying with the pushrod configurartion- the new LS7 engine has a light valve system mass- a very high rocker arm ratio (1.8:1)- compare that with a 440 RB big block of 1.5:1, allowing a peak valve lift of 15 mm!! Piston masses have gone down- which in league with valve train design improvements--sees peak power speeds on V8s going up from the norm of 4800-5200 rpm to 5800- over 6500 rpm. If we start looking at Hondas and BMW M engines- MUCH much higher!
In cylinder charge motion has finely developed tumble motion optimisation which allows more ignition advance FOR A FAST BURN before the onset of knock.
Engine bearing friction has come down- if you look at the size of the bearings of an old Mopar- they're way oversized for the IMEP the engines made. The "RB" big block especially so- the 'B" Big block Mopar sizes would have been just fine.
So we've covered port flow, manifold design, CR, combustion, friction and ECU control of it all.
And that about sums it all up
www.auto-scape.com
RE: Old Engines are inefficicent at creating power/torque,WHY?
Now with Euro V coming our way I imagine that number has increased, just due to the extra cats, but I don't do engines or noise any more, so that may be misleading.
Cheers
Greg Locock
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RE: Old Engines are inefficicent at creating power/torque,WHY?
I had some personal expereicne wiwth a pump gas 425" 360 that made ~540hp NA. That motor had a conservative cam choice as it was slated for EFI use. 600 is certaintly not out the question for an NA mopar small block on pump gas. 600hp with 360 cubes- I have not heard of, but I wouldn't mind being wrong.
RE: Old Engines are inefficicent at creating power/torque,WHY?
In Japan the 276HP LAW was inacted because there government thought that the 300ZX Twin Turbo was fast enough and governed that no car in Japan could be rated at any more so skylines, Supras, and NSXs all got down rated in japan though they were capable of much more, stock skylines and supras are capable of over 400 HP with a twist of a boost controller.
In America they underrated from the factory for insurance but the way they measure HP is different from how it used to be. What we think of as 505 from the new corvette would be much higher to them back then, a stock Z06 2010 vette would smoke any old stock muscle car.
This sorta relates to OP's question as to power, Cars have made huge leaps and bounds in technology and people are working on it more and more everyday, the next BIG tech to hit cars will be solenoids for there valves, the valve train sucks up to 25% of the engines true power output just to turn. But before that we will have DISI injection (direct injection similar to a diesel but much lower pressure). DISI allows for much leaner mixtures to be used at higher boost/compression to lower knock and increase fuel mileage.
So to answer the question: Humans got smarter and built better machines.
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
And, Fiat's Multiair system appears to be a practical way of getting almost infinitely variable valve timing and lift. It still uses a camshaft, but uses a solenoid to regulate a hydraulic circuit between the cam and the valve. It's in production.
Direct solenoid actuation of the valves is not likely to see mass production in the foreseeable future. Multiair and other similar systems achieve the majority of the benefit at a fraction of the cost and electrical power demand.
RE: Old Engines are inefficicent at creating power/torque,WHY?
- Steve
RE: Old Engines are inefficicent at creating power/torque,WHY?
http
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
It shouldn't be considered a blanket condemnation of that engine concept. Your comments on the 2011 Hyundai Sonata, please.
- Best in class power output
- Best in class (gasoline non-hybrid) fuel consumption, and it was possible without too much difficulty for road testers to beat the US EPA estimates.
No doubt some is due to good aerodynamics and attention paid to weight reduction, but it's also the only direct-injection engine in its class in the North American market.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Fitting rather untorquey engines into fat cars is always going to be a bit of a gamble. 40 years of experience says you won't be particularly happy with the result, but the pimply faced youth managers will know better. Although of course the front-line engineers will get the blame when it only achieves two out of three program goals.
Cheers
Greg Locock
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RE: Old Engines are inefficicent at creating power/torque,WHY?
They was also some comment about never going more than 60kph during the testing.
Take both out on a freeway and set the cruise at say 80kph or 100kph for a good run and see where the economy is.
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
Learn to read...
RE: Old Engines are inefficicent at creating power/torque,WHY?
Regards
Pat
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RE: Old Engines are inefficicent at creating power/torque,WHY?
Seems like for lots of projects The focus is on measureable hard parts. Rod bearing clearances controlled within 0.0002 inch, etc.
My old twostroke dirt bikes have patiently explained to me several times there is exciting HP and excellent throttle response still hidden in the small suitcase full of brass jets and aluminum needles.
When Bill "Grumpy" Jenkins first achieved prominence in drag racing it was as a tuner.
RE: Old Engines are inefficicent at creating power/torque,WHY?
I can read plugs, tailpipes...
I can hear what the "heartbeat" is telling me.
I can "sense" what the engine is doing.
Yes sir, I CAN do all these things. I've always been able to do all these things. I have NOT been able to teach others how I do it, not for not trying.
My oldest boy, the painter/artist/mechanic is fair, but misses the little stuff.
My youngest son is a "reader". If it's in a book, he knows all about it. He is, however a very talented race car driver.
My daughter loves cars. She also loves computers, Ipods, cell phones and, is for the most part very intelligent...she is also a space cadet when it comes to cars.
Even my wife, just after we were married enrolled in a basic automotive maintenance course after she graduated high school.
If you want to follow me around, maybe it will rub off a bit. The last of the "black arts"?
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
ht
This, despite benefit of such proven power boosting brochure bullet points as:
- 13.5-1 compression ratio
- Fuel injection
- 4 valves per cylinder
- DOHC
- cHaIn DrIveN cams
- Variable valve timing
And, the popular torque enhancing "long stoke."
Might have >>something<< to do with those interesting valve timings.
Pretty good BSFC though.
RE: Old Engines are inefficicent at creating power/torque,WHY?
Cheers
Greg Locock
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RE: Old Engines are inefficicent at creating power/torque,WHY?
Yeah, I was just being contrary, providing a new, high tech sounding example of "crumby" HP and torque. Probably cause I'm pretty old and inefficient myself.
I wonder what operating condition triggers The intake closing at 120 ABDC. 50 degrees BTDC. Start compressing when the glass is nearly empty. Just take a quick sip of air.
I used to have some info on Crower's "more complete expansion" kit for Chevy V8s. High compression, skewed valve events. That had to function with a carburetor though.
Dan T
RE: Old Engines are inefficicent at creating power/torque,WHY?
SIDI or GDi delays the onset of knock at high loads- which means a higher compression ratio can be specified. May be 1-2 ratios higher than a conventional SI engine. For every ratio increase- assume about 3% fuel economy benefit. When you're already at 10:1 it may be less- say 2.5 %. This is a benefit in terms of BMEP and BSFC. GDi alone gives between 3-5 % benefit in terms of Volumetric efficiency and therefore torque. However some of the fuel economy benefit of GDi alone is lost due to the pump drive torque required to inject at 200 bar or so. So the net gain is about the benefit of the CR change alone with a handy BMEP benefit- due to charge cooling and due to the CR change itself.
If the engine is down sized to compensate for the power/torque increase- - while targeting a certain torque/power curve you can get a further slight benefit in fuel efficiency due to lower pumping losses.
The biggest gain with GDi comes when you boost the engine in league with variable cam phasing. You can specify BIG valve overlaps at low engine speeds- for great scavenging- and boost the engine hard, and not worry about short circuting of the injected fuel because being DI you can inject whenever you want in the cycle and thus avoid short circuiting. This gives a HUGE wall of torque at low speeds- and you can therefore, in theory down size your engine further to chase slightly better fuel efficiency.
www.auto-scape.com
RE: Old Engines are inefficicent at creating power/torque,WHY?
is she looking for a husband?
www.auto-scape.com
RE: Old Engines are inefficicent at creating power/torque,WHY?
Rod
RE: Old Engines are inefficicent at creating power/torque,WHY?
RE: Old Engines are inefficicent at creating power/torque,WHY?
Rod -
Practioner of a Black Art indeed. There have always been lots of parts selector/assemblers out there. Some working to very precise tolerances and clean to a fault. But, not many have been able to make every motor they touch the one to beat.
I thought that I was OK at tuning, but would have my partner touch it up before we made a run. Not just to make sure as a lot of times he would make a minor adjustment which made a real difference. Typically, it would be me in the seat fired up and ready to stage, he would nod his head when it felt and sounded right to him. Found it was best not to ask him to explain how he knew what to adjust, just drive the car.
Yosh
RE: Old Engines are inefficicent at creating power/torque,WHY?