Originally Posted by
dojj
underdrive pulley should COST you hp because they are doing more work as they are turning much faster than they should as they are smaller
it's just like putting smaller wheels on your car and then driving in one gear
i have a crank underdrive and they are smaller thus slowing the speed of all the ancillaries. the revolutions are unchanged on the crank pulley whatever the size as they can only spin as fast as the crank.. they also weigh a lot less. mine standard was 1.4kg and new one 200g. the weight alone frees up the revving and although small they do make a difference. they have long term drawbacks because you no longer have harmonic balance but on a track car i dont car.
edited cos i got bigger and smaller the wrong ways around earlier