Message text written by Don Kerr
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Hi Joe. I have run any number of forced induction engines in my half
century on this rock and without exception
the car/bus/semi/m-cycle et al all used a factory cam. Exceptions to the
rule, sure ,how about drag vehicles or off shore power boats etc.The
idea is to keep your chug around drivability but to have the benefits of
a larger engine at positive boost .Always run a stock cam, or copy of
same,with a performance cam the blow through will hurt your mileage and
so waste fuel.Why do it?Diesel engines do not use long duration cams to
make power, they are boost pressurized up in the 20's lbs psi,(admittedy
intercooled.)OTR semi's develop 4 to 600 hp at 1800 rpm.My motorcycle
750cc was 180 hp + at 11500rpm.My old VW bus churns out 150 or so at
5000rpm.
Try your local library on turbocharging or forced induction. Regards
DK
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Folks,
Don't forget that we are now dealing with a denser fluid here and all the
calculations change. A camshaft optimised for airflow at 14.7 PSIA will be
not be optomised when the air is at 30 PSIA. The air is now denser and
responds differently.
Dave Massey
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