[badasslx13]

i hear alot of ppl saying how to gain hp is to get underdrive pulleys what is it an what do they do an how much hp will u get?

[EagleAutosports]

Underdrives work by slowing down the accessories which in turn put more horsepower to the rear wheels. Typically the crank pulley is smaller, the water pump and alternator pulleys are bigger. There's both street and race versions and the two will be obvious if put side by side.
Usually an underdrive kit will put 5-7 hp to the rear over stock.

[hellrazr94]

r they realy worth the money