Can we loose rwhp??
04-06-2004, 03:31 PM
#3
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Absolutely. The automatic's hydraulics consume
flywheel horsepower in running the pump, pushing
volume@pressure through the innards. Slip in the
converter turbine and lockup clutch is power that
never makes it to the driveshaft.
Most performance converters are only equal to
the stock at best; at the high end efficiency drops
a lot (unlocked). Some vendors claim to beat GM's
converter efficiency but I'm a bit suspicious; GM
is the only one "on the hook" for CAFE mileage
and emissions regs.
But, there is more to delivered power than the
converter's efficiency. Because of the relation
of torque and horsepower to RPM, the peakiness
of powerband, you may get a lot more driveshaft
power/torque out of a converter that lets the
motor wind up to 4000RPM, despite a percent or
three more (in)efficiency losses, than on a stock
converter whose low slip dogs you down at 2500.
This is where it's really at, getting a converter
that keeps you straddling the horsepower peak
when you want it. And trading away as little as
possible for that.
flywheel horsepower in running the pump, pushing
volume@pressure through the innards. Slip in the
converter turbine and lockup clutch is power that
never makes it to the driveshaft.
Most performance converters are only equal to
the stock at best; at the high end efficiency drops
a lot (unlocked). Some vendors claim to beat GM's
converter efficiency but I'm a bit suspicious; GM
is the only one "on the hook" for CAFE mileage
and emissions regs.
But, there is more to delivered power than the
converter's efficiency. Because of the relation
of torque and horsepower to RPM, the peakiness
of powerband, you may get a lot more driveshaft
power/torque out of a converter that lets the
motor wind up to 4000RPM, despite a percent or
three more (in)efficiency losses, than on a stock
converter whose low slip dogs you down at 2500.
This is where it's really at, getting a converter
that keeps you straddling the horsepower peak
when you want it. And trading away as little as
possible for that.