Quote:
Originally Posted by oil pan 4
With the perfect, ideal gear ratio only expect about +2 maybe +3 mpg highway.
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I am very aware of the fine line between the correct torque range and lugging an engine. These are my starting point for testing.
This is the best I can do and plan with the vans current stock 3.42 rear end gears. There is the possibility that my engine may make great torque at 1000RPMs, but I am not counting on it. The ideal is to gear everything at the engines torque peak, under or over by much and she will start drinking.
SO you cannot gear a stock engine with a torque peak of 2800/3000 to pull at 1500RPMs and get good MPG. So I am building an engine that peak at 2000 RPM and gear close to that.
Once it is built I will do as careful testing at all available speeds, RPMs with all the gears I have to test. THEN as I have a howling rear end will then rebuild it with what will seem to be the best gear ratio, with a range of 2.73 to 4.11 I can choose a gear that may be ideal.
So I start with a best build I can do, a 383, 9.5 compression, everything built for MPG, ceramic coated heads and pistons, telfon coated pistons skirts gapless rings, Rhoads Roller lifters giving me a variable cam, a cam selected to allow a torque peak at 2000 or less, but thanks to the lifters will then turn into a power engine at 2500 to its max RPMS of 5000RPMs, fed by a 1987 Chevy TPI intake system.
Then to add to all of that I have a chip for the PCM to engage Lean Burn Mode which in the 80s Camaros allow them to go from 20/25 TO 30/35MPG.
To that I will be adding water injection, and extra EGR.
Lastly my van is very great in wind.
This is what I have said concerning high profile vans with high roof and how they are blow around by wind and big rigs:
I bought my 93 Star Craft Custom Van after having stock Chevy vans for decades I was concerned that with the raised roof and side ground effects would make winds worst for driving.
I drove a 74 Chevy van full time during the 80s and crossed the US on many times, in the 90s and into the 2000s it was then a 78 van. Again we did a lot of road trips all over.
I was very used to fighting for control with cross winds and when passing or being passed by BIG RIGS. The bow wake of air would buffer and push my vans all over the road; I am sure near every Van owner knows what I am talking about.
My first road trip showed me that was NOT a problem. Cruising at 75 MPH I was over taking a Big Rig and I braced for the fight as I over took the cab…and..and WTH no fight, I breezed by this big truck….
Must have been a trick cross wind that stopped the bow wake of the big rig, BUT it happened again and again, almost no effects of passing trucks, and even when I was over took by even faster big rigs.
OMG The stream lining ground effects of the Star Craft panels which I loved for their LOOKS really works. I have had the van for 15 years and LOVE this effect.
I believe these ground effects keep air from under the van and I believe this nearly stops the effects of bow wakes and losers the effects of cross wind on my G20 van.
Here are a few suppliers of like ground effects systems. Note they need to be streamlining, running boards seem to do not work.
Starcraft is no longer in business parts can be found here:
Starcraft Conversions - Unique Concepts
https://customvan.com/catalog/
https://www.bodykits.com/c-1234295-b...ts-side-skirts...
My Van
https://www.facebook.com/media/set/...
The only thing that I cannot remember is was my first road trip made in the 93 was done on the Stock wheels and tires OR had I already swapped to the 18 inch wheels with load and speed rated low profile tires. The over height IS the same as the stock wheels and tires just more wheel and less tire.
I have proven over and over again and again running these types of wheels and tires improve handling greatly. At least with the softer wheels and TIREs on a G20, the one ton 8 bolt wheels and HEAVY duty tires run of those trucks feel as hard as does my 18s.
My latest proof is my 02 Ford Explorer which was so badly handling that even a land change felt like she might tip over, it had FAT stock balloon tires I was about to sell her off when I bought 20 Wheels with lower profile tires and again the over height IS the same as the stock wheels and tires just more wheel and less tire.
The floppy Explorer NOW handles like a good big car, not a race car but MUCH better.
And PLUS with the 18 inch wheels and tires on my 93 Van is I had a blowout at 80MPH with the front right side…and unlike a common blow out there was NO fight to maintain control, in fact I only knew I had a problem by how she started pulling to the right, once I crossed 4 lanes of highway slowing down was a little surprised to find a blowout….
I have not driven a new custom van with the same look like the newer Express vans, There seems to be only one company doing these conversions, Explorer, It looks like Explorer Conversions run with greater ground clearance and I think that defeats the ground effects.
Lastly there are two Express vans documented to get 29/30MPG with stock bodies…so it is NOT the box causing crappy MPG.
And there are a bunch of changes and improvements I have made as well.
Rich