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Trekkor |
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I do things... ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 7,809 Joined: 2-December 03 From: Napa, Ca Member No.: 1,413 Region Association: Northern California ![]() |
Bought a five gallon jug of leaded 110 octane "VP" brand racing fuel. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)
My motor seems to have higher than stock compression. Lowest is 160 PSI. My speed shop guy says the valves will like the lead. (IMG:http://www.914world.com/bbs2/html/emoticons/chowtime.gif) Maybe I just like throwing money out my open windows at speed... (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif) KT |
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lapuwali |
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Not another one! ![]() ![]() ![]() ![]() Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 ![]() ![]() |
Like Dave said above, compression pressure measured with a compression tester and compression ratio are only vaguely connected. I have to disagree with sixnotfour's comment. Running more octane than the engine was designed for is pointless. 100 octane gas may very well have been available at the pump in the US in 1967, but that doesn't mean a stock(ish) '67 911 engine would be able to use 100 octane (in fact, I very much doubt it could). My '67 912 requires 98 RON (the European measure), which is very roughly 93 (R+M)/2 (the US measure). Since 98 RON was and is "premium" in Europe, I'd expect the '67 911 required the same grade of fuel. It may actually require less, since a 2.0 six will have smaller cylinders and combustion chambers than a 1.6 four, and smaller combustion chambers are typically more knock resistant. The only way to REALLY work this out is to run the car on a dyno on 91 octane pump gas and a mix of the 110/91 octane, and fiddle with the timing some. I actually doubt you'd notice the difference between timing that would not ping on 91 and timing that would require 93 to not ping. |
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