recommend a torque engine for towing and high MPG
recommend a torque engine for towing and high MPG
(OP)
Howdy all. I am currently back to the question that always seems to provide unsatisfactory answers for me. I've decided that maybe I am asking the wrong people so I'll give this forum a try... I am building a 1967 1 ton chevy dually flatbed 2wd truck for towing a gooseneck trailer and can't decide which engine combo to go with. The idea is maximum low speed torque across a low to flat rpm range that pulls and pulls yet still offers decent fuel efficiancy. I realize that this could be relative so I'll add that 6 to 9 mpg is not acceptable. I'll run 4.11 gears and 31 inch tires which should put rpm's at 65 mph at the 3100 rpm mark and with a manual overdrive providing a .73 or so 5th gear should bring this down to a decent 2263 rpm. Hence my desire for a low rpm flat torque curve. Every one wants to tell me their 500 ci Cadillac tow truck gives 18mpg or that their 454 Chevy does even better than that. I've never gotten better than 8 with these kinds of motors. I'll add that I am looking for a FI gasoline or propane fueled motor (as Diesel makes me physically ill to be around, unfortunately). An industrial motor seems best as higher speed cruising is not an issue. Thanks...





RE: recommend a torque engine for towing and high MPG
In the unlikely event that you /need/ more than 70 hp, then:
Please specify what fuel consumption at what speed you need, also exactly the real towing performance that you need (ie weight, grade,speed), and the weight of the truck and the weight of the trailer.
What top speed on the flat do you need?
Cheers
Greg Locock
RE: recommend a torque engine for towing and high MPG
RE: recommend a torque engine for towing and high MPG
If you must use gasoline, try to rent or borrow (or a long test drive) a Chevy/GMC with the 8.2 and see how you like it. If it is acceptable, try to find one in a salvage yard. The no load/heavy load, 3 mountain passes/costal driving situation is about the worst possible for a carburated engine. Add in -40F to 100F yearly temperature extremes and it gets even worse.
As for final gearing, try to get the RPM as low as possible and still pull the load. This may require a 6 speed manual, and you may have to "row" the truck for best efficiency.
IMHO, you will spend much money and time searching for a gasoline combo that will, at best, only be as good as a poor factory diesel combination.
RE: recommend a torque engine for towing and high MPG
I am very handy with the fabrication issues and have no problem converting this older truck to Fuel Injection that is computer controlled -- this should take care of these problems you've brought up, somewhat anyway.
"As for final gearing, try to get the RPM as low as possible and still pull the load. This may require a 6 speed manual, and you may have to "row" the truck for best efficiency."
I have an old Spicer 8138 auxilliary industrial transmission which is essentially an over *and* under drive in one (3 more speeds --under, 1:1, over) this does add the extra gears but means alot more shifting which can be ok if it keeps me in the right range.
I really just don't know which motor to start with -- a test drive is always a good start although I was thinking of something more interesting like turbocharging a Ford IL 6 300 ci with boost in the 6 to 8 lbs range. Any turbo guys out there?
Also, as a last resort how can I make that Cummins diesel near complete burn so as to reduce particulates, tailpipe chemistry, etc. I've heard about propane injected enhanced burn -- anybody done this? They claim better burn and more power.
Thanks again!
RE: recommend a torque engine for towing and high MPG
There is plenty info on the web.
Improving performance:
Checkout the last post by optimum:
Thread71-108825
http://www.sturmanindustries.com/main/index.htm
RE: recommend a torque engine for towing and high MPG
RE: recommend a torque engine for towing and high MPG
http://msdignition.com/2005/2005_13.htm.
They were claiming 75 hp average increase! "Nitrous for your diesel without the dangers" was the comment, I think. I have no idea what sort of milage you get for a gallon of propane "boost" so I'm not sure how cost effective it is.
RE: recommend a torque engine for towing and high MPG
You are asking for something tha can not be done with gasoline. You want to turbo charge a 300 six? Can we say EGTS!!!! If you are interested in fuel mileage you need a diesel. The bigger the better. Gear the truck down to 2.50's-2.73's and atleast a 6 speed manual. I would go up to a 33-35 tire if you can get them to fit. I would go with a C7 Cat. RPM is directly proportional to fuel mileage. By installing a large diesel you can run down the road at 1400 and return excellent mileage. The idea is to 'lug' the heck out of it. The engine will pull all the gear you can stuff in it. If that scares you too much drop a cummins 5.9, 7.3-6.0 Power Stroke or the 6.5 GM diesel.
If you must go with gas, dont be concerned with mileage but I would build a stroker BB chevy. 500 Cubes, 10:1 flat tops aluminum heads with air flow optimized for idle to 3500 rpms. A cam with fast opening rates and as little overlap as possible. You will have an engine capable of pulling a steep gear will not melting the exhaust off of it. It will be more efficient because it will run close to idle.
RE: recommend a torque engine for towing and high MPG
Oh well, I wish it were that simple. What I mean by "physically ill" is that I am chemically sensitive to Diesel fuel and the exhaust these motors make. Simple. I trailer my horse trailer and other trailers often. I get in and out of my cab back and forth to locate hitches and balls and chains, making sure the lights work and all that is related to hooking up a trailer, loading and unloading a trailer. Guess what? With little imagination I think you can see that one stands in a cloud of exhaust fumes before long. Also if one hasn't figured it out I work on my own rigs. Diesel fuel, again, makes me ill to be around. Soaks into the skin and clothing and shop floor etc. I DO wish it were that simple. Oh yeah, self service stations in Two Dot, Montana? Right. Anyway. I am curious what you ment by "EGTS" in regards to a turbo charged 300 six? I have read more than a few articles on propane powered turbo aplications of low reving truck motors that are normally gasoline carbeurater aspirated. Unfortunately these are articles and not technically constructive. Keep in mind that propane boasts 106 octane, enters the manifold already fully vaporized and I am talking about low boost at low rpms. Seems like an idea worth contructively and objectively pursuing perhaps. Now, on to your VERY HELPFUL, thank you, diesel power ideas. It does bring me back to diesel though, something this exercise was trying to avoid. Inevitably, that is probably where I will end up it looks like...
PS What do you roughly estimate "Excellent Mileage" to be with your C7 Cat scenario?
RE: recommend a torque engine for towing and high MPG
A slightly smaller, lighter, more aerodynamic truck would also help. Look at some Japanese or European designed light to medium turbo diesel trucks if you want good economy while towing 6 horses. Something like a 3 tonne Isuzu springs to mind.
Regards
pat pprimmer@acay.com.au
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RE: recommend a torque engine for towing and high MPG
RE: recommend a torque engine for towing and high MPG
A turbocharged gasoline engine towing will be in boost for long periods of time, in the mountains which will create lots of exhaust temp. Propane is a nice option but you would need dual fuel unless you know where all the propane refill stations are. A big diesel (Used Cat for Example) would get you well into the 20's for mileage unless of course you enjoy the torque to much. Your best bet would be a big gas engine built to be very eff. at low rpm.
RE: recommend a torque engine for towing and high MPG
Oh yes, empty my old 91 Dodge still gets something like 20/21 max and my 454 BBC gets about 12. My son's later Dodge electronic Cummins gets 24+ most of the time---all have 4.10 or4.11 final and same size tires.
Rod
RE: recommend a torque engine for towing and high MPG
RE: recommend a torque engine for towing and high MPG