Very interesting and comprehensive presentation Dave, lots of good
thoughts there, worth saving.
The item about some degree of detonation in highly stressed
blown/nitrous engines is a good point, undoubtedly true, and it must not
become excessive or damage will result.
Another interesting point is that the fuel octane must suit the
compression ratio, the very high octane gases do not work well with low
compression ratios. This was demonstrated at Bonneville a few years
ago, when Marty Dickerson brought his Vincent out to run in Vintage
Pushrod class, in exactly the same form as in '53 (probably most if not
all the same parts!) when he took the AMA 1000cc Class C gas "naked" (no
fairing) record at 147 mph. Class C at the time restricted you to 8 to
1 compression (this is real ancient history). Same bike, same man (and
this is a lion of a man), now he has to use ERC spec gas at Bonneville,
and the bike would only do a little over 125 mph. He told me it was the
spec gas, the octane was too high for the compression ratio, it burned
too slow, didn't push hard enough on the pistons. No matter how much he
advanced the ignition timing, he couldn't get it to detonate audibly,
which told him the tale. The old-timers, in the pre-data-collection
days, tuned their bikes by advancing the timing until they got
detonation, then backed off a tick.
I'm going to send your paper to a few of my off-List friends. Cheers
Bill
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