Schizo Posted March 17, 2004 Report Share Posted March 17, 2004 How much octane is needed for 180 compression? Quote Link to comment Share on other sites More sharing options...
dlnoss Posted March 17, 2004 Report Share Posted March 17, 2004 I'd probably run 110 with that compression and the timing advanced Quote Link to comment Share on other sites More sharing options...
Schizo Posted March 17, 2004 Author Report Share Posted March 17, 2004 So a 50/50 mix of 110 and 92 would be out of the question? would i have to go with 110 straight up? Quote Link to comment Share on other sites More sharing options...
dlnoss Posted March 17, 2004 Report Share Posted March 17, 2004 I wouldn't say it's out of the question. I tend to be conservative. You might ask Jim. Quote Link to comment Share on other sites More sharing options...
duneslinger Posted March 17, 2004 Report Share Posted March 17, 2004 I've been running 175 comp on a ported motor 100 over bored 66.5= 385 +4 timing with 22cc domes on J&S 130race gas 1/2 92 octane & mobil 1 oil for more than a year with no problems, Runs hard on the dunes Quote Link to comment Share on other sites More sharing options...
Brian G Posted March 17, 2004 Report Share Posted March 17, 2004 Please run 110 straight!! Quote Link to comment Share on other sites More sharing options...
brock_fuzzy_69 Posted March 17, 2004 Report Share Posted March 17, 2004 well my thoughts on it are that 92 octane gas is around a 1.90 lets jsut say 2 bucks evan for comparison standards and i can go out and buy the race gas for 4.00 a gal in 112 so half and half is 3 bucks a gal and straight 112 is 4 bucks a gal so i might as well jsut runn the 112 the shee doesnt burn that much gas really Quote Link to comment Share on other sites More sharing options...
Ducman Posted March 17, 2004 Report Share Posted March 17, 2004 I don't know this for a fact, maybe somebody else does. I've been told that when blending fuels if you take lets say 92 and mis it 1/2 & 1/2 with 110 you cant always say the result will be 101 octane once blended. It could be significantly less. Thats what the petrolium dealer told me when I asked him about mixing say 114 and 91 pump. It may have something to do with the fact that most race fuels use lead to bump up the octane rating, so when you blend it with a pump gas that is unleaded it dilutes the lead significantly and changes things in ways so that can not be calculated as a linear result. There was no significant gain or loss in the amount of money I would spend at the petrolium distributor since the 114 cost 2x as much as the 100 octane that I buy there so there was no sales motive for the guy to sell me one or the other fuels. He just recommended that I should buy and use straight race fuel that had the octane requirement I wanted because with blending you might not be getting what you think you are. Any thoughts on that? Quote Link to comment Share on other sites More sharing options...
fixitrod Posted March 18, 2004 Report Share Posted March 18, 2004 I've been running 175 comp on a ported motor 100 over bored 66.5= 385 +4 timing with 22cc domes on J&S 130race gas 1/2 92 octane & mobil 1 oil for more than a year with no problems, Runs hard on the dunes That depends on a lot of factors. Quote Link to comment Share on other sites More sharing options...
bkabina Posted March 18, 2004 Report Share Posted March 18, 2004 Your exhaust duration has alot to do with it.If you have Jims motor I would say you need to run it straight. Quote Link to comment Share on other sites More sharing options...
Schizo Posted March 19, 2004 Author Report Share Posted March 19, 2004 Just installed 19cc domes and went to 76 competition 110 straight up Quote Link to comment Share on other sites More sharing options...
theeechozen1 Posted March 19, 2004 Report Share Posted March 19, 2004 I have also herd that you can lower the octane rating alot more when mixing fuels Quote Link to comment Share on other sites More sharing options...
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