So, what is the most compression anybody here has 1st hand knowledge of in a blow thru E85 application and how much boost?
Oh and did it live.....lol.
I have a 12:1 571" big block Chevy and was told by an E85 carb builder that I can keep my compression and still run a pretty fair amount of boost on top of it with E85.

Thanks

 

There are E85 guys on here running 12.5:1 and 27 psi boost. You do have to run a good intercooler and watch IATs though. At that boost you would have to be right on with the tune. Aluminum heads would help keep the detonation down also.

 

To run that much C/R you would have to run a lot of cam duration to keep the effective compression ratio reasonable. This will make for a rough idle, and push the usable RPM band upwards. Good for racing, not necessarily great for the street.

 

might have a harder time dialing in the tune also, but I'm sure it can be done

 

Here is the engine specs:
4.625 bore GM Pro Stock Bow Tie block
4.25 stroke callies crank
6.385 callies rods
JE pistons
Total seal gapless top steel rings
World Products Merlin X 16* conventional port heads 426/320 @ .800 w/80cc chambers
12:1 compression
Cam .808/.808 276/294 @ .050 112* lsa
So,I'd say I've got a fair amount of duration, and a very efficient chamber
Aeromotive belt pump
2.25" headers
Precision 76mm turbos (a little smaller than I wanted but i got a smoking deal)
Dominator flange intake

Now, I have the choice of going carb or efi, after talking to matt at diy autotune, I'm leaning towards MS3 with 2 sets of 160lb injectors and a couple of the cx racing intercoolers in the engine bay. Tough to decide between that or a Crutch. Argh!

 

To give you an idea. I know of a few local guys running 13.5 to 14:1 compression with E85 builds.


JR

 

Doesn't E85 have an effective octane of like 110+?

 

105 - 109

 

running that high compression with any fuel, will require a high bsfc...
if you run it, get a good tuner...