l wanna get more horsepower out of my 1999 Pontiac Grand Prix GTP. How can l do this?
can you say how much it would increase by too?
thanks!

Sell it and buy a mustang

screw dirtytri guy! first thing to do is to get a supercharger overdrive pulley. it is a smaller diameter pulley that increases spinning rotation. it is designed to give u boost sooner, & it increases it by about 2 or 3 psi, good for about 5 horse. easy to install with a hardened bolt & bearing, should come in the kit. i've got one on my 2000 Pontiac Boneville SSEi & l LOVE IT!!!!!

other than that, try to keep it stock, because u will retain more horsepower. if u add components, u will only confuse the computer & it will end up hurting you. trust me, i've tried. the only other thing might be a 50 shot of NOS. the supercharged 3.8 used decreased compression & forged aluminum pistons, perfect for NOS.

good luck!

If you get too radical, you will need to beef up the transmission.

The trans barely holds factory given horsepower numbers as it is.

There are several things you can do. You can start simple with something like a pulley and/or exhaust. If you want to get real serious, the 3800sc motor will make a lot of power. It all comes down to how much money you spend. Check out this site for some ideas:

https://zzperformance.com/

Hey take advice from someone who owns a 99 GTP,
ignore everybody but black_67nova. DO NOT INSTALL NOS, l have a heavily
built 400 hp GTP, l install all my performance parts MYSELF. email me for any advice l have been though it all--- [ teamforzalive.com ] here are 3 sites l use for my car parts:

the cheapest thing that you can do is put a smaller supercharger pulley on the car and it will make the super charger spin faster and it will make more boost. But do not put too small a pulley on it cuz it will over rev the super charger and rein it. A fyi you have to change the supercharger oil every year you can get the oil at GM dealerships. they can tell you how to change it.