big hammer

Non oxygenated race fuel can slow down stock engines.

You're not really getting power from the timing with ethanol. Ethanol is full of oxygen which allows you to burn more fuel in a cycle for a net power gain

While its correct that ethanol does have energy per unit than gasoline, the high 02 content allows you to burn more units of it in a cycle than gasoline and that's why poppa can squeak an 11 second pass on it and not on regular gas

2003Cobro

^^ your retarded. Your acting like E85 is another form of BOOOOOOSSSSTTTTTTTT. Its higher octane and you run more timing and prevent detonation and make more power. Stop trying to over think this.

V8EATR

So race fuel and face plated transmissions slow you down, and any weight reduction that isn't on purpose doesn't help the vehicle, check.

big hammer

You're wrong

HioSSilver

iTrader: (8)

You would likely notice it more with a atick. More driver involvement.
Good post....a little research goes a long way
Unless you're this guy
Well 2 of 3 came from your camp.

But yea....if you ain't tuned for it or your engine can not utilize race fuel it can slow you down.

2003Cobro

So you get a tune for E85 with the same timing that you run on 91 and you will gain power from the super oxygen rich E85???

JC316

iTrader: (1)

Yes, you will. Hio and hammer are correct this time. The difference is small, but it is there. From pure power standpoint, the E85 will almost always have more power than race gas of the same octane, with the same compression ratio and timing.

marc97taws6

iTrader: (6)

I love my pump gas

Sticks n Stones

I've personally seen this: first hand. low compression motors with big camshafts and a guy who had a calibration sticker on his seat pants could notice the power loss between high octane race or av gas and 92 octane. I was pretty sure I could tell between 92 and 87 on my Z28... the dyno sure saw it though: 10rwhp loss from 87 to 106 octane as long as I kept same total timing.

Back in the craptastic years (mid 70s to early 90's) average V8 compression ratios where in the 8.0-8.5 range. "High performance" was 9 to maybe 10 to 1. Some crazy guys with amazing heads/intakes/carb/ tuning would get away with up to 11 to 1 on pump gas - but we all thought that they were friggin crazy. In reality those were the guys who had the $$$ to acquire the efficient head designs that everyone takes for granted nowadays. Back in the day, those combustion chamber and int/exh airflow paths were cutting edge and guarded jealously by those few who knew the black magic art that led to those designs.

R6cowboy

iTrader: (3)

This is correct. But, the difference will be so little it wouldn't be noticeable. Literally talking a few hp difference at the same timing and compression, 93 vs E85, N/A wise. It's almost a moot point.

V8EATR

So who is building all these engines and not tuning them for the octane they are running? That's putting long tubes and a larger maf housing in a car and not tuning for it and saying adding those parts made you slower.

marc97taws6

iTrader: (6)

I can recall several started race threads in this section where the fbody owner claimed "untuned" and they were racing like that.

Idiots

R6cowboy

iTrader: (3)

Exactly. Changing fuel and not tuning accordingly for the specific type used is pointless and shouldn't be done in the first place.

big hammer

Looks like you still don't get it man

2003Cobro

This is what i am saying. It would be very insignificant. Hammer is billing it like running E85=nitrous. Thats retarded. Its the octane boost that allows for more aggressive timing curves and no spark retard because of detonation that makes the difference.

big hammer

Actually E85 makes its gains on a stock NA engine in a similar way to nitrous just to a lesser extent man

JC316

iTrader: (1)

It's not insignificant, about 10%. Hot rod did a test of this, identical timing and compression, race gas vs E85. The E85 had gains in the midrange and wasn't as touchy.

It's not like nitrous, but it's not insignificant either.

HioSSilver

iTrader: (8)

MT did a test on a flex fuel silverado. It picked up .3 and 3 mph in the qtr. Not really insignificant.

V8EATR

So lets say on a coyote, how much power do you think e85 would be worth not increasing timing at all? Honestly, how much?

vs a conservative 87 tune, you bet. 93 would be worth some too. Of course its helpful, but its not a huge gain like you claim.

2003Cobro

Lol no changes except fuel and it picked up 3mph. Thats ~30hp gain. Wow. Imagine if it had a TOON!!!!(truth the Car must have been getting some knock timing retard and didnt have any with the E85)

You guys are nuts. Guys add E85 on a NA car with a CORRESPONDING TUNE and arent gaining that much. So 30hp on a silverado no changes. Man when i go E85 i should gain about 250hp!! Sweet i cant wait.