----- Original Message -----
From: "Mark Haynes" <haynes386@netzero.net>
To: "Vintage Race Mailing List" <vintage-race@autox.team.net>
Sent: Saturday, April 14, 2001 4:22 PM
Subject: Engine limits?
> I have a question for those of you who have experience with testing an
> engine's limits (hopefully I can avoid finding the upper limits for
> mine).
Little late to think right.
I alluded to it, but didn't finish.
Piston speed can be critical, as some pistons crack if going too fast.
Check the manufacturer for max on piston speed. Then figure piston speed by
Feet per minute times 6 divided by stroke in inches = rpm. Also, FPM = RPM
x Stroke / 6.
Also related is that piston speed relates to air flow and you can calculate
that as cubic feet per minute (look familiar, CFM? every American carb is
rated that way).
If you go too fast, you can demand more CFM than the carb(s) can give and
you lean out. Not real bad, but could result in burnt pistons. Also, you
could demand more CFM than the intake can deliver, in which case your air
density in the intake drops so low you get insufficient A/F charge in the
cylinders and drop power. Not critical, but not desirable, either.
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