The S4 I am looking at getting is a 2001.5 with GIAC chip and APR catback. What is the difference in crank HP and/or WHP between the $400 piggy pipes and the $1500 APR downpipes? Thanks

 

ok.. First of all, piggy pipes are basically a stock exhaust just gutted to free up air. Its a good mod for the money but prob not quite as effective as a full exhaust. I believe you can get the piggies from vast performance.

Your difference in crank horsepower and wheel horsepower is simple. Crank hp means the amount of power your putting at the crank, and whp is the amount of power that is being put down by the wheels after loss through the drivetrain.. Being that we are awd, we lose a bit more power through the drivetrain then our rwd counterparts. To figure whp, its usually about a 20-25% drop off of crank hp.

 

I think he meant what the difference was between the piggies and downpipes in HP.

 

haha.. my bad. yeah, i reread that and i see.. I have no idea.. a couple..