Some deep thinking on getting Best MPG in a VAN

[racprops]

OK I jumped in to another thread that was about cams and engine, but it was hinted I was high jacking the tread SO I am starting one of my own, (sorry guys..was so impressed by the thread I though you would help me...)

So let me try this as my own thread.

I wanted to throw my plans and ideas out for feed back, as much as I THINK I have a good plan and idea, rather than waste time and money, this is the first place where I think I will get good feed back and good info rather than the knee jerk reaction I get from every hot rodder..."It will not work and you NEED RPMS and HP...."

I regret to inform everyone that my 93 G20 Full Size Custom Chevy Van suffered a major lost of oil because of a failed hose clamp connecting my 15 year old oil cooler. The engine has totally seized.

BUT she will be back, as this means I have to and can do my super drive train, something I just could not justified with a good running engine.

Here is my thinking and a fairly old plan:

From all I have read about MPG I come up with two ways SMALL and LIGHT with small motor, to make them work they run higher RPM.

But I am driving a BIG van, big in wind resistance (pushing a box though the air) and heavy.

The trick seems to be a big TORQUE motor. There is a reason diesels are used on big rigs, TORQUE.

Diesels make torque and at low RPMs, they can barely get over 3500RPMs. The only thing that makes better torque is an electric motor which has all its torque at 1RPM…

IF there was a replaceable power supply I would be going to electric motors BUT there are none so far. Not for nonstop long road trips anyway.

So I am building a gas engine as close to a diesel as possible.

It is not too farfetched as some might think, a 1990 Cadillac came with a Chevy 350 with a low RPM cam that had its torque peek at 2200, and the earlier Chevy 400 in a big station wagon had a cam that peeked at 2000. The Olds 403 has similar cam timings.

Torque is what gets you down the road.

So here is my lay out: A 385 Chevy with 192 Swirl port heads, max RPMS with them stock 6000, they have been cleaned, no polish as the ruff walls are better for low RPM power…3 angle valve seats, Perfect Circle valve seals (Chevy has a history of bad valve seals) like new guilds or replacements as needed, stock valve springs, new keepers, and roller tip rockers to minimize pushing the valves back and forth.

The stock Chevy/Cadillac cam, or a 400 aftermarket cam IF it can be had With Stock timing and built for a roller) as is the cam I have as a roller cam.

The block is cleaned and ready to go, I have Keith Black “D” Shaped disc pistons (allows running low Octane gas) with a stock 350 crank so all I need is a 400 crank fitted.

Feeding it will be a 85 to 92 Chevy TPI intake. Again these intakes are said to produce 30 to 35% MORE torque, HP and MPG over the same engine running a carb.

Running the PCM will be a add on computer card that give me almost total control of the fuel system.. http://www.dynamicefi.com/EBL_P4_Flash.php

Once all of that is done I will test drive it and see how things work.

Then I plan on putting in an 8L90 transmission which has some very nice low first gears and then rebuilding the rear end with a possi and a set of 243 gears.

My numbers show it will be able to do 80MPH at 1700RPMs.

My 2000 Mercury with a similar setup got 27 to 30 MPG at 65 MPH. And 25/26 MPG at 80 MPH. It has a Ford version of a tune port intake and running 343 gears.

The big problem is running an engine too far below from its torque peek, doing so can cause bucking (lugging) and poor MPG.

By building a high torque low RPM motor I should be right on the money. I expect to get MPG in the 20s.

I wish I could find someone whom has built such a set up but so far everyone builds for HP and higher RPMs and running in higher RPMs just seems to mean more fuel to keep it happy.

I am posting this to see if I can get either confirmation or real proof I am wrong.

PS Here is a few reasons why I want to save the Van: https://www.facebook.com/richardacoy...X9e4B82CGvS3pA

I love this van as a high way road machine BUT as other van owners say, She has a drinking problem...

More: A few of the questions I have not been able to find answers: The 1990 Cadillac cam: was it straight up or as I have heard tweaked, either advance or retarded?? Every time I look into replacement cams they always push the torque peek upward, anyone know of a good (or) better roller cam??

Or the specs or numbers of the Peanut Cam??

And is the any problem running it any of the lower gears for a long time such as I figure I will be doing with he 8L90??

I also am aware that a number of engines like the OLDs 403, and the Chevy 400 ran torque peeks at 2000 RPMs, so I am not so "out there."


Thanks for reading.

[racprops]

And a few more notes;

I have tried a couple of changes in the past, at one point being totally fed up with the high wearing out of Chevy engines, mainly valve guilds and seals plus the cylinder wear. I had a friend whom was totally surprised by the Chevy’s need for a ridge cutter to remove pistons, he was a Cadillac and OLDs fan and with those engines such cylinder wear was unknown…I learned it was due to the use of high nickel in the engine block…and have learned how to spot some Chevy engines with higher nickel.

The point is back in the early 90s I put a used OLDs 350 into my then 1998 Chevy van. It worked fine until it lost a rocker arm on a trip to Chicago. It limped home and I asked for another OLDs 350, but my friend was sold out and he offered me a 305 OLDs.

WOW was THAT a mistake….MPG dropped big time and on trips I was getting honked at by big rigs climbing mountains as I had to use second gear to get up the hills and was slower than them and I was in the way so had to pull over to let them pass.

AT this point I was planning on a 403 OLDs when I discovered a site called 3rd Gen. Camaros and about TPI and how great these fuel injection systems are, and sadly there were no TPI for the OLDs engine and I don’t think even fuel injection system for these old engines.

So I then bought my 93 TBI 350 with a four speed auto with OD and planed on swapping in a TPI someday. That someday did not happen until now.

So I came up about the same thing you were talking about a large engine running slow. And I felt a 350 might be a little small so feel a stroked 350 with a 400 crank making a 383 would work better.

[redneck]

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https://ecomodder.com/forum/showthre...tml#post579506


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[racprops]

Thanks, I am looking into that BUT a program like it still may not show odd defects in my plans, like what I have ran on a program covering the gear rations, rear end, and tire size.

It shows that the 8L90 gears will be great, it does not show if you can run in those gears for long times. I can see that I might be running in 4th though 6th gear a lot and only get into 7th and 8th rarely.

So how does automatics handle using lower gears for long times??

Rich

[iikhod]

If you want a diesel-like engine, why not put an actual diesel engine in the van?

[racprops]

Won't work...high cost of the engine, high cost of installing it, high cost of service and repairs, the only smart way would be dump current van and buy a Van with a stock diesel.

I want to both save my current Van and improve it.

I already have the 350 as described above so the only step is to fit a 400 crank. And then assemble it.

I am then left with only one remaining question: The cam, is the peanut cam too small for the 383??

Rich

[rmay635703]

Originally Posted by racprops

Won't work...high cost of the engine, high cost of installing it, high cost of service and repairs, the only smart way would be dump current van and buy a Van with a stock diesel.

I want to both save my current Van and improve it.

I already have the 350 as described above so the only step is to fit a 400 crank. And then assemble it.

I am then left with only one remaining question: The cam, is the peanut cam too small for the 383??

Rich

You can purchase crate Military 6.2 diesels for $50 on up and they use the same transmissions as the 350

As long as you use a C code 6.2 they last a long time, have minimal maintenance and are quite simple.

Another option is to talk to the guy below
https://ecomodder.com/forum/showthre...mpg-33961.html

A 5 speed stick is usually quite helpful

[Ecky]

Food for thought: In gasoline engined vehicles with multiple engine choices, the smallest engine variant (in the US) virtually always has the highest fuel economy. It's an exception when going bigger helps anything.

It is possible to go too small, and cause the engine to run out of its optimal BSFC range, but there are vans in Europe with sub-2L engines, which deliver in excess of 30 and sometimes in excess of 40mpg.

[racprops]

Tried it and it failed badly: The point is back in the early 90s I put a used OLDs 350 into my then 1998 Chevy van. It worked fine until it lost a rocker arm on a trip to Chicago. It limped home and I asked for another OLDs 350, but my friend was sold out and he offered me a 305 OLDs.

WOW was THAT a mistake….MPG dropped big time and on trips I was getting honked at by big rigs climbing mountains as I had to use second gear to get up the hills and was slower than them and I was in the way so had to pull over to let them pass.

I believe it is a power to weight thing.

[racprops]

Gentlemen, PLEASE as much as I am into major swapping, as in I have done a bunch of them in the past: a 350 Cleveland into a 1968 Cougar XR7, a OLDs 350 and later a OLDs 304 into a 78 Chevy Van, and a TH200R4 into said Chevy Van and into a 79 Camaro, AND both a 74 Chevy Van and the 79 Camaro got Cadillac tilt/telescopic columns, and there have been a bunch of stuff done to the 93 Van and my 2000 Mercury which as I have a failing motor I am going to do a FULL engine, transmission and FRAME swap…I am putting a 2004 Crown Vic Ex-Police Frame with all the improvements Ford did in 2003 (as well as the tighter P71 stuff) so my 2000 will have 2004 running gear.

I am not at all interested in Diesel in any way.

I do ask for help on my planed project as outlined above.

Help with the questions I have asked.

Thanks for your suggestions they just are not in my plans.

Rich