Colin wrote: >If you do not use vacuum advance , then you will have to recurve your distributor like WW does, and watch your temps closely. You will not be able to allow your engine to get as hot as the car did due to the effect on pre-ignition and detonation that this has, and you will almost assuredly have to use 100LL.<
I'm burning pure 93 octane auto fuel from the BP station, and I have 9.3:1 compression ratio. Dan Weseman is also running 93 octane in his 9.5:1 cr Corvair. Neither of us has vacuum advance, but WW did recurve our distributors. One other difference between us and most Corvairs is that we've paid particular attention to keeping our quench distance down under .040", which lends a lot of detonation resistance to a squish type combustion chamber. I'll be the first to admit that 100LL will give you more margin before detonation sets in, but I wouldn't call it imperative. Besides the obvious cost benefit, the main reason I use 93 auto fuel is to keep my oxygen sensor from being lead contaminated. The O2 sensor drives the air/fuel mixture meter, which I do consider to be essential when you're flying a non-auto-altitude compensating "aircraft" carb. The air/fuel meter tells the "brain" (that would be me) when to move the mixture lever back and forth. Someday I'll work on flying behind something that is automatically altitude compensating. I applaud your efforts at bringing any "aircraft" engine closer to the automotive world. I've tried to keep mine as simple as possible, just like the automotive variety... Mark Langford, Huntsville, Alabama see KR2S project N56ML at http://home.hiwaay.net/~langford email to N56ML "at" hiwaay.net --------------------------------------------------------------
