What experience do you guys have on mixing high octane fuel with "regular" 93 octane? I have been able to locate some 100 octane fuel and some 115. My comp ratio is around 11.5:1. I just can't seem to lose the detonation running 104 boost. When I retard the timing my performace really suffers. By doing a search here it appears as though you can't just average your octane. i.e. 1 gal of 93 and 1 gal of 100 doesn't give you 96.5. The 100 octane is around 4.25 per gal. I don't know what the 115 is but I think $6-7. Would I be able to use alot less of the 115 in my mixture. HELP!!! What works for you guys?

Originally posted by freshayr:
What experience do you guys have on mixing high octane fuel with "regular" 93 octane? I have been able to locate some 100 octane fuel and some 115. My comp ratio is around 11.5:1. I just can't seem to lose the detonation running 104 boost. When I retard the timing my performace really suffers. By doing a search here it appears as though you can't just average your octane. i.e. 1 gal of 93 and 1 gal of 100 doesn't give you 96.5. The 100 octane is around 4.25 per gal. I don't know what the 115 is but I think $6-7. Would I be able to use alot less of the 115 in my mixture. HELP!!! What works for you guys? You CAN average the two octanes; that is the way to do it. Another option I've used is Xylene or Toluene; octane rating is 117 (Xylene) and 114 (Toluene) so it takes far less to get your octane up versus mixing in 100 octane. I've bought it for $3.40 per gallon in a 55 gallon drum, but the shipping got it up to nearly $5. per gallon. Still cheaper than race gas around here.

You don't want to run more than 20% or so and at that mix you should add in a little valve lubricant like top oil. It and Toluene are the main ingredients in octane boost. Problem with the canned booster is that you get so little it has virtually no effect.

Jody

where do you buy toulene or xylene?

Toluene from a paint store. Xylene, I don't know. By the gallon, toluene is about $7 a gallon around here.

Over here you can't buy the Toulene or Xylene in large quantities because they think you'll be running a meth lab. I've called so many places it makes me sick. Because of that, a gallon of that stuff run about $20. I've found it to be far cheaper to buy 110 race gas ($4.85/gal) and mix it with 92 octane to get 101 octane. If I buy the 110 in 55 gallon drums, the price goes down to $4.35/gal. So, the price averages out to be $3.30/gal, which isn't too bad. I'd rather run the race gas myself.

In my prostreet nova,I used to run a mixture of about 11 gallons of 110 and 5 gal of sunoco 94,and I had about 36 degrees of total timing.In a motor that was 11.4-1,and made 600 HP,with no problems.

The leaded race gas is a simpler way to go. Much easier to find. Around here locally Sherwin-Williams paint stores sell Xylene in 5 gallon buckets for $5.90 per gallon. The advantage for me on the Xylene is it is catalytic converter friendly; I was using it in my 03 Lightning. On an older car without cats I'd probably do the leaded race gas deal, buying the highest octane for the money.

Jody

update....I purchase some 110 today and put 5 gals in my tank on top of 14 gal of 93 that was already there. (5 gals was all I had room for) Problem solved!!! Just that little bit and it really made a difference. Not only was the detonation gone but I noticed an increase in performance that I wasn't expecting cutting it that much. I think i might have to try straight 110 just to see if that will snap my head off. :D