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Old 06-18-2013, 04:40 PM   #52
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Join Date: Apr 2012
Chapter/Region: NESIC
Location: Portland, ME
2012 WRB WRX Hatch
TP Stage III & ELH


Originally Posted by GrumpyPitbull View Post
Most of us know the differences between the cars I stated above, yet these threads continue to fester because some people think that red STi badge adds 40hp .... It doesn't. Its been proven several times that the two models dyno the same, and have an almost identical power curve. Some attribute it to more drivetrain loss in the STi, others to the WRX being under rated. Either way, they are about the same in the power department.
So because they have the same whp on a dyno, you think they have the same whp on the street in all scenarios, even when the drivetrain inertia, which influences whp, isn't a factor?

The STI just magically can hit 158mph, while the WRX can only muster 142mph, but they 'must' have the same whp on the highway because they have the same whp on a dyno.

Maybe this is a better anology, picture a bucket loader on a dyno... the whp will be read waaay lower than crank because what you're measuring is the acceleration of the rollers, which is being hindered by the acceleration of the masssssively heavy wheels, flywheel & entire drivetrain.

Now picture that bucket loader towing something, steady state drivetrain, power passing straight through. HUGE power making it out the wheels, doing work, because it's not being robbed by /invested into the dynamics of the system.

These scenarios exist in cars, like overcoming wind resistance, increasing elevation, etc and crank hp will play a bigger factor because drivetrian loss is playing less of a factor. And dynos cannot account for it. Crank horsepower is real power in the right scenario.
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Last edited by blehhh; 06-18-2013 at 04:59 PM.
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