Thread: 98 GTP Coupe-upgrade questions-exhaust

so how much HP gains would I expect to see from the CAI, 3.4 pulley, and the Plog and downpipe changes( I already have 180 t-stat) and the tune? how much torque changes as well........I am just looking for approximate changes not exact numbers. Thanks.

Originally Posted by bluegtp91

Quit thinking about the pulley. That is why I posted that thread up there...you got a bunch of mods to do before you safely drop a pulley size. CAI, Colder Plugs, Plug Wires, 3" DP, U-Bend Delete, Front Powerlog, OR Headers, and a tune.

Then you can drop to a 3.5" or 3.4".

I am not thinking about doing the pulley until last, but I am thinking about doing it in time. I did read that entire 3800 upgrade thread before I started this thread. Since I did not realize exactly what exhaust components there were totally, and what each aftermarket piece replaced on the stock setup. That is why I started this thread to get more info and do the mods in the "proper order" before finally changing out the pulley and getting the aftermarket tune. I just wanted to know what type of HP gains I could possibly expect when I was all said and done with all of those changes(T-stat 180, PLOG, 3" downpipe w/ubend delete and high flow cat, CAI, Tune, and then pulley) I am just trying to see if it is worth the money to me to spend to get how much HP........Is it twenty HP or fiftyHP or what? I just would like a guesstimate of how much it will help in the HP department. Thank You