E 85 racers, how much compression are you running now?

I'm finishing up a new motor for my bracket car, it is a 400 stroker motor with a set of 440-1 heads that ended up with more mechanical compression than I had originally planned on
What compression ratio are you guys running in your bracket cars now?
Thanks in advance, your help is appreciated

Cab it wasn't that long ago we made 866.. on pumps junk on qmp's dyno.. that motor was around 13 to 1.. and made Power to 8200.. but was always kind of hard on the rod bearings.. I think E85 is the greatest thing since the invention of cheese.. but I think you're better off being on the safe side my opinion only

12 to 1 here. Alum headed smallblock

I was right at 13-1 with my smallblock when I was trying E-85.

13.1 here alum.headed BB.

Guys I race with are running 15:1......on E85.

Cab, if e98 is available locally, a brew with some race gas rather than pump swill might make a big difference. I have seen e98 for sale in nw Minnesota and it was much cheaper (according to a friend) than pump e85, and it was available in 55 gal drums. There would be no fed or state taxes on the e98.
If e85 is made with 86 oct, then a mix of 110 race fuel to make e80 , or 20 percent race gas, might push octane to about 113 ? I am guessing on the facts hear, but using the math for mixing race fuels. If there are local ethenol alcohol plants in the area, that might be a source. Info might be available on an e85 race site.

My Hemi is 13.5:1 and the bearings look like new after 400 runs.

I have friends with big block chevies over 14:1 on pump E85.

12.5 iron heads, big block.

12:1 on a 0.030n jet in my junk.

I believe a big bore chamber will do better on knock.How much duration,overlap will you have?Stroke?[dwell at TDC]

Wouldnt the Cam have something to add to the equation ?.

I was running 14.1:1 on mine.. the cam was too
big on duration but it ran well

14:5 on ours. 3 years now

This motor has between 14.8 and 15.1 compression ratio checking all eight cylinders, the cam is 282@.050 intake(.457 lobe lift on both lobes, I'm using 1.61 ratio rockers) and 292@.050 on the exhaust ground on a 108 LSA installed at 103 to 105 ILC( I check the LSA at three different heights, .200, .100 and at .050 from max lift on both the intake and exhaust lobes
What little info I could find on the internet forums on E85 and calling around to guys I know who race with E85 all basically say 15.0 to 1 is the max compression ratio to use with common pump E85
I am going to check locally to see if I can buy a 55 gallon drum of E98 and use it to help me adjust the local pump swill E85 to get around E90 to race with
Hopefully I won't hurt this new rascal while learning to retune the tune up
Thanks to all for the help

12.8 and I test it before filling my drums. Cam timing will help.
493 ci is being freshened right now. Ray said everything looks good!

Don

The max effective ratio will vary with chamber shape, valve inclination, intake valve location, VE, etc.
A small angle wedge with long stroke will tend to shroud the intake valve with a high CR, and also mask flame travel.

Not arguing with Poly at all here, he cites a very specific case, but IN GENERAL:

Flame travel for a quiescent mixture in a gasoline engine is woefully slow. As the rpm and stroke length increase, the flame travel is even less than the piston speed! That's why squish is so very important, it mixes the flame through the chamber which speeds up the lighting off process.
Because the flame travel is slow, larger diameters give longer time for the flame to travel and give more time for the mixtures out at the ends of the flame path time to form knock-prone compounds.
As a result, with everything else being equal, larger diameter cylinders need more octane.

R.

There are alternatives to pump E85. Torco, VP and I'm sure others sell their versions of E85. We picked up a solid 2 tenths switching from pump to VP. I know others with similar results at your compression ratio as well. Let me add that at the time finding DECENT E85 in Vegas was a challenge which prompted our switch to drums

So what you are saying Al is when racing in Vegas I should bring my own alcohol?

Please let me act in Al behave, anytime you come to Las Vegas make sure and bring all your own drinking alcohol, women and extra money for gambling