Formula42

My research tells me that 10 psi,9:5:1cr, and 93 octane is safe for the street......anyone know how much more cr I could run safely on E85(104 octane) ?

gennex

iTrader: (1)

im at 10:1 with 20psi on E85, no issue

Formula42

That is great info thank you! I looked around but could not find much on this subject. Can anyone else share there experience with compression, E85 and boost?

MaxxMitchell

iTrader: (15)

9.3:1 with 26psi, and a few hits with 30-31psi on 22 deg. Another car with 10:1 has seen 18-19lbs several times with 20 degs, stock bottom end. I haven't seen the limit to what E85 can't support.

Formula42

Excellent info! My problem is that I was originally building an NA motor and I had my heads milled down to 65cc. They are cnc ported and nasty to tell you the truth. I dont want to buy another set of heads but I also don't want to run -23cc reliefs to get compression where it should be for 93 octane. I learned about e85 and just happen to have a station here in town.

Would I be better off with -11cc reliefs which would yield a cr of 9:7

or -3.2cc which yields 10.5:1 cr (is this to much for 10lbs on e85 for street use?)

or does anyone know if somebody out there makes a turbo ls piston with reliefs between -3.2cc and -11cc? I got my info from the wiseco site and there is no piston offered between these two sizes....10.1 sounds great how do I get there?

4.005bore, 3.622stroke, 65cc heads, 6.125rod ls2

open to your opinions thanks

gennex

iTrader: (1)

10:5 is not too high, just keep the boost under 20 and check the plugs, keep the timing modest. i noticed that at 10:1 instead of 9:1 the throttle response was much quick and boost came in like a steam roller.

also can you go with a 70cc chambered head, that would drop you down a little. lsx ls3 are 70cc, thats what i use.

mulletnotch

iTrader: (2)

My new motor is 11:1CR and E85 fueled.

Hit's hard and comes in QUICK in comparison to similar setups with less compression. I was a bit nervous what we'd be able to do with the higher compression but so far I've only seen positive results all around!

Luke Skyjacker

iTrader: (1)

how much more hp/torque does adding say 1pt of compression add to the same amount of boost? lets say moving from 9.3 to 10.3 both @ 16lbs?

A friend of mine is considering running e85 in his straight 6 datsun motor. looking for 40+ lbs here. he has been at over 28 on Q16/116. Any issues with this much boost and e85?

t-1

iTrader: (20)

10 to 1 at 17lbs. but im at 6600 ft of elevation

S2VYSS

This might be a stupid question but is that on a forged bottom end?

gallo-lo

iTrader: (11)

What did -3.2 cc bring to with 317heads? Gasket?

Formula42

Anyone else playing with boost and e-85 experimenting with higher compression?

Formula42

I suspect the answer to this is unknown? Or this is to many variables to predict....

Look at the potential of E-85! It's like the high compression days of the 60's with leaded gas! Time to mill your heads!

Also its better and cleaner all around for your engine(zero emissions?), the environment and cheaper at the pump than a gallon of gasoline. However.....on paper you get more mpg on gas than E-85. In real world driving I have read of others who actually get more mpg with E-85 because the engine is just that much more efficient on it.


Unfortunately E-85 stations are few and far between. There are only four in my entire state. Luckily for me one is in my home town. That said....I think user Frost makes dual tune pcm's if im not mistaken. So you could have a gasoline tune and an E-85 tune that you could switch between in case you couldnt get to any E-85. Awesome right? Hell yea it is.

There is more....somebody correct me if im mistaken but I believe the newer pcm's for our cars 00-02 have the ability to work with sensors that can monitor and adjust to exactly how much gas/E-85 is in your tank. So you could mix the two fuels and the pcm can tune for it real time.

maxgee

iTrader: (5)

I've been runnin e85 on 10ps1 11:1 CR with T70 and love it. Previous set up was on 9:5 CR which was ok but my new set up comes in quicker and feels stronger. Dynoed 573/607 on my current set up with stock bottom.

Working on forged set up right now.

hellbents10

iTrader: (10)

We ran 10.5:1 on stock bottom at 19psi for a long time and it was great. A2A intercooler on that one.

It depends on many things but this is what I tell people....higher compression helps get the turbo spinning but there is a point where the tuning window gets very narrow.

We have run 10:1 on E98 non-intercooled to 40psi.

maxgee

iTrader: (5)

Nice!!
I was going to drop down to 9:5.1 with my forged build but have now decided to drop it around 10:5.1 as I'm only going to push 14.7psi on track and 12 or below on the street.

forgedlt4

this is a dyno graph of my lt1. 11.3:1 on 7 lbs of boost, with E85. it should be higher, something happens at 4500 RPMs.


the power curve is great. it spools crazy fast.