Quote:
Originally Posted by ss3gt
The first thing you need to do for your car is this. Divide its weight 1250 kg by its HP 190. This shows that each HP is pulling 6.5kg of weight..or for every 6.5kg of weight you shed 1 HP is freed up
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Interesting "rule of thumb" but far from scientific.
The fact is that the car will accelerate (on level ground) exactly the same if you removed the same weight from anywhere else on the car.
The 'rotational mass' of the system is FAR outweighed by the 'total mass' of the car.
The total mass is by far the dominant factor in calculating acceleration based on hp. The rotational mass difference is in the noise.
Based on this link:
http://www.w8ji.com/rotating_mass_acceleration.htm
If you could take off the 30 lbs driveshaft, and replace it with one that weighs ZERO, you get a whopping 1/4 hp equivalent difference.
Edit: Now when talking about reduction in rotating mass, removing it from the flywheel, or around the perimeter of the wheels (rims/tires) makes the biggest difference in rotational mass.
In fact worn tires versus new tires makes a MUCH larger difference in rotational inertia than the great "Pulley upgrade".
SO if you want to feel a bigger difference on the butt dyno than a LWCP, just have your tires shaved.