ATTN: Gar or Bruce..exotic fuel AFR question.

[Phil Rickard]

Hello gentlemen. I have a brief but confusing question. As you may have read in the past, I'm building a 377 SBC, suited to burn a 2%-3% mixture of Nitromethane and 100 octane racing fuel from VP and my question is related as to what I can expect to see for AFR readings, respectively. I have done some research on the subject and have found out that Nitro is approx. 49.6% oxygen by weight/volume and that increased fuel flow is expected, however, what I'm not sure on, is how to determine if I need to concentrate on the already known 12.5 AFR as a tuning benchmark for proper combustion at WOT? This engine is N/A.

The problem of fuel separation has been addressed and is not a factor here, as there are additives to add to the racing fuel to keep the nitro reliably suspended for up to six months; I've found a source for that.

Is my reasoning correct to think that I can tune the engine conventionally on 100 octane race fuel to start out with, so that I give myself a benchmark of correct AFR, then switch to the exotic fuel and see where the addition of it places my AFR in relation to the original tuning curve? I would think that given the relatively small amount of nitro actually in the fuel, that I could still tune the engine's AFR as if it were gasoline only. Afterall, nitro is essentially adding an oxygenant to the fuel the same as N.O.S. would...correct? I don't know if the other by-products of nitro would effect this. Any ideas?

Thanks in advance.

Regards....

Phil Rickard- Engine builder/Tuner, Les Stanford-Pirate Racing Corvette C5R......Formerly with L.P.E.
vettebuilder at skyenet.net
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