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Unit 5302 · 05-07-2001, 06:27 PM

For 17% driveline loss you cannot multiply by 1.17 to come up with an accurate number.

You must either multiply by .17 and add that number to the rwhp, or divide by .83 (1-.17).

In this case you're stating 18% loss, which would equate to 412hp at the flywheel.

398 x 1.18 is not the same as 338 / (1-.18). When taken in that context adding and subtracting within a product is not communicative.

Regardless, the solid post fix Cobra's were dynoing at 280rwhp, which equates to about 337hp at the flywheel. That's 70hp less than this Cobra dynoed at. I'm not gonna call BS on this, just cause I want it to be true, I really really doubt it, but hey, I can dream!!!!

You cannot use a flat rate for approximate loss of power at the wheels for all cars.

Here's why, the friction is directly related to the amount of force put onto the transitional surfaces within the driveline. The faster it accelerates and the more power exerted on it, the less net gain you'll have. So adding 100 crank hp will net you about 83hp at the wheels with a 5spd. The AOD is not nearly so forgiving, at 22% driveline loss you only add 78hp at the wheels per 100hp at the crank, the C4 should be around 19% loss.

If the Cobra R really dyno's at 370rwhp, it's got 450hp at the crank with the 6spd. In a stripped lightend chassis it should run 11's no problems with traction.

Let's not forget some dyno's allow for changing parameters within the software, when you do that, you wind up with a less accurate hp measuring. Like the Superflow Dyno's for Motorcyles vs the Dynojet models.

05-07-2001, 06:27 PM	#18
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	For 17% driveline loss you cannot multiply by 1.17 to come up with an accurate number. You must either multiply by .17 and add that number to the rwhp, or divide by .83 (1-.17). In this case you're stating 18% loss, which would equate to 412hp at the flywheel. 398 x 1.18 is not the same as 338 / (1-.18). When taken in that context adding and subtracting within a product is not communicative. Regardless, the solid post fix Cobra's were dynoing at 280rwhp, which equates to about 337hp at the flywheel. That's 70hp less than this Cobra dynoed at. I'm not gonna call BS on this, just cause I want it to be true, I really really doubt it, but hey, I can dream!!!! You cannot use a flat rate for approximate loss of power at the wheels for all cars. Here's why, the friction is directly related to the amount of force put onto the transitional surfaces within the driveline. The faster it accelerates and the more power exerted on it, the less net gain you'll have. So adding 100 crank hp will net you about 83hp at the wheels with a 5spd. The AOD is not nearly so forgiving, at 22% driveline loss you only add 78hp at the wheels per 100hp at the crank, the C4 should be around 19% loss. If the Cobra R really dyno's at 370rwhp, it's got 450hp at the crank with the 6spd. In a stripped lightend chassis it should run 11's no problems with traction. Let's not forget some dyno's allow for changing parameters within the software, when you do that, you wind up with a less accurate hp measuring. Like the Superflow Dyno's for Motorcyles vs the Dynojet models.