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Old 08-31-2007, 08:43 AM
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Dammmittt Dammmittt is offline
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Join Date: Jun 2007
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Mein Auto: 07 M Coupe
Originally Posted by Luminor View Post
OK, so I honestly thought you were kidding. You'll have to excuse my ignorance on the subject, I know next to nothing about physics and the formula for determining a vehicle's torque...but are you honestly saying that you believe removing 8lbs from the roof of an M Coupe will generate any where near 32lb/ft of torque? That means this roof mod would have the same, if not greater, affect on torque production as the 4.10 I just installed...

...if that's the case, I'm ordering one today.
Luminor, I'm talking about torque on the chassis of the car, which produces roll, not engine torque which produces pull on the car. Torque = Force * length. Torque is why a wrench helps you loosen bolts and nuts and such...

Originally Posted by Mo Kalali View Post
Interesting logic! That logic would remotely (underline remotely) make sense if you were rotating the car on an axis running through the car from the back to the front. Sort of like shoving a telephone pole into the rear glass and come out of the windshield and then rotate the car around the pole. Now extending this notion to the torque at rear wheels is one hell of a stretch!
OK, well Force = Mass * acceleration right? (I feel like I'm teaching high school physics here)

Anyway...8 lbs is rough estimate of the weight difference anyway, probably more like 10-12 lbs. Well the point of this is that that 8 lbs directed down, is the mass of the object times gravity...lets call that g. The mass difference of the roof is always going to be the same...but the acceleration will change.

Now, you remove that 10-12 lbs. You figure the center of mass of the roof is about 4 ft off the ground...estimate...

So...if you are pulling one g of lateral acceleration of the car, you would LOSE about 40 ft lbs of torque (twist) on the chassis just by virtue of where you lost the weight on the car because that 1 g laterally is like aiming the weight of roof at a 90 degree angle to the normal direction of gravity (like turning the car on its side). All this means for you is when you turn hard, it puts less stress on the car because you where you lost the weight.

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