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Re: Autobahn thrill-ride!
> In modern cars the redline is monitored electrically, and exceeding
> redline is not a performance option because of fuel and spark cutoffs,
> If an aftermarket performance camshaft is installed factory redlines
> will be to low. Valve float is the normal concern at high RPM.
> Depending on the car limits can be changed various ways.
Valve float will be the concern when the fuel/air system can keep up with
the demands of the rpm. But the sizing of the FI system might have been tied
to the nominal rpm band -- the system in some cars cannot deliver enough fuel
for airflows beyond the designed redline. Running the engine above redline
in this case risks detonation, hence the fuel cutoff at redline. Moral is:
make sure the system can deliver at the higher airflow rates when you adjust
the built-in limits.
Walter Meares Intermetrics, Inc. firstname.lastname@example.org
Information Systems 733 Concord Ave Cambridge MA 02138