mrvette

read up on engine operation theory, and then two different cars I put DPFI on......first one was a '70 Lemans/GTO convertible....462" engine.....with carb it got about 12 mpg.....14 or so on the freeway not towing anything.....with the DPFI and a sorry old analogue open loop computer from a '79 Caddy 425 engine, it jumped to an easy 14+ around typical driving, and 18 on the freeway.....not towing, when towing a boat it got about 15-16 or so.....depending on how high it was flying......

Later on my '72 355 vette with muncie was getting ~12 around town 16 on the road...336 rear.....went to DPFI speed density like a '88-91 vette....got 24 on the road with the muncie......since then I have put in a 200 4r trans, and it's better yet on the road, but in fact I dunno how much due to driving habits....overall it's about 18 in mixed bag driving....

now to look at operational theory vs a carb, and it's a easy to see with my results....common sense 101, don't need more tests.....

MX5000

So you have NO real world testing or a control to prove that DPFI is the sole responsibility for cleaner emissions and ETHANOL has nothing to do with it, gotcha. Just some random observations that you achieved a little better MPG with DPFI verses a carburetor.

Milan454

Most mechanics get their information from biased sources. The conventional fuels will not be replaced by ANY ethanol blend higher the E10 in our Lifetime. If anything higher Ethanol alIows higher compression as stated before. I run E85 in my 67 Camaro for 15 years now with Holley 850s I modified on my own WITH NO ENGINE PROBLEMS. There is a lot of misinformation about Ethanol including its corrosiveness. But I distress. As others stated build what you like. Don't worry about what might happen.

jim2527

https://www.pure-gas.org/index.jsp

jim2527

So am I better off running E10 93 or ethanol free 89 in my '70? Cost and mileage are not relevant. Resistance to knock/detonation is.

leadfoot4

An interesting discussion, to be sure. In my area, for a number of years, I could purchase 91 octane, "non-ethanol" gasoline, and that's all I used, both in my cars/trucks, as well as my yard equipment. But recently, the octane rating for this has dropped to 90, and I'm concerned about using it in the cars, now, as they all call for "premium" fuel. I can, however, still purchase 93 octane, 10% ethanol content "gas", and I'm confused as to what would be better for the cars. I know that the slightly lower octane rating won't matter to the garden tractor and lawn mower.

Rescue Rogers

I run 93 E10 with no detonation at 10.5:1, but I havent tried going lower because I'm lazy. You could try the non thanol and see if yo get detonation at your current timing setting, if you doo either drain the tank or back off the timing. If the price is right its worth it.

resdoggie

Here's an article for those who are concerned with using E10 in older cars:

https://www.hotrod.com/articles/mixi...-for-old-cars/