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I wouldn't count on it.
No sure about how much But, your going to probably
also be changeing the timing. Nitro needs like a 2 day head start on
ignition. Then again a 2% charge might not matter much, but I wouldn't
asume anything. If max HP is at 12.5 then I would also get a EGT there,
and be damn sure to get best atmospheric data available, and use all that when
tring even a *short* load of Nitro.
Folks really tend to forget gasoline is about like
playing with dynamite, and when you get to Nitrometh, nitro propane, hydrazine,
and this other stuff your in the world of nuclear
devises.
Watch a top fuel or funny car in early season
testing, them boys been at it for years, and start way down on the base
cals when cranking up a new combo / season.
Personally, after having the EGT, AFR, and climate
stuff, I'd probably start out with 4 degrees les timing, and at least 5% rich on
fuel, and short shift it, and see what things are like (plug
wise).
Then see what the AFR read, and start tuning
from there, again, that's what I'd do, no quantie, or waranty implied
ot expressed, racin inheitanty dangerous yada yada
Bruce
----- Original Message -----
Sent: Tuesday, September 26, 2000 1:31
PM
Subject: ATTN: Gar or Bruce..exotic fuel
AFR question.
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@skyenet.net
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