What fuel are you high compression guys running?

[4000GT]

Hmm im just not getting it lol

Why is lower ethanol better considering more ethanol reduces det?

[bozu]

I think you read his post wrong:
E85 is 85 % ethanol and 15% petrol
E30 is 30% and 70 % petrol

E30 has less ethanol (only 30%) then E85 (85%)

[4000GT]

bozu Wrote:I think you read his post wrong:
E85 is 85 % ethanol and 15% petrol
E30 is 30% and 70 % petrol

E30 has less ethanol (only 30%) then E85 (85%)

Ah thats my problem... I was thinking E85 was 15% Ethanol... all good! Thanks.

[Celica RA45]

if your comp was 11to 1 ,stay with 98 as you go up in comp you would need say 100 octane fuel as you go up to 14 to 1 anything over 110 octane is good. now you are at 15 to 1 race fuels say ELF lms is good but at 10 dollars a litre and is 110 octane or you can use e85 which is 115 octane and is way cheaper

[4000GT]

Yeah E85 might be the way to go, just dont like the fact I cant get some from my local petrol station, which is why I think the 98 plus an octane booster might be a way to go. Though the octane boosters tend to bump it by 5 - 7 points, puts it in the might be ok range.

[IBMFD3S]

dont know it available in your surroundings but maybe LPG is an option?

[Uzelac]

4000GT Wrote:Yeah E85 might be the way to go, just dont like the fact I cant get some from my local petrol station, which is why I think the 98 plus an octane booster might be a way to go. Though the octane boosters tend to bump it by 5 - 7 points, puts it in the might be ok range.

lots of testi g showed that those boosyers aro mostly rubish, just few raise octane value but it is never that much, maximum 1-2.
for 15:1 only race fuels or ethanol.
lpg is good idea but it is hard to rev engine above 6000 rpm on pump lpg. again, some special lpgs will allow easy 9000rpm, but i havent seen they are easy avaliable

[IBMFD3S]

as i see it: the problem is detonation and probably exhaust valve is a hot spot so the fuel ignites on it's own because of the high pressure and/or a hot spot.
if LPG or CNG is not available I think there are 2 options IMO:
either start injecting water or a mix of water and methanol as it lowers the grade of self-igniting surcomstances. in that case you can put pump gas in it.

here some figures:
gasoline, including racegas, auto-ignites at 660 F.
alcohol, (methanol, ethanol and isopropyl) auto-ignites at 858 degrees F.

'of course we know' that the primary deal with lower intake temps is more oxygen molecules per volume. and when you are talking oxygen nothing beats alcohol, or methanol specifically.

meth is 49% oxygen by weight
ethanol is 34% oxygen by weight.
gasoline is zero% oxygen.

as to cooling:

meth is 1.154 MJ/Kg
eth is .913
gasoline is .297

methanol is the winner.... lots of oxygen and lots of cooling. so i would think about injecting methanol or a mix of methanol with water.

/edit: with the above i mean (of course) injecting pump fuel with xx% of a mixture.