transmission

[GTP2000]

exactly how much horsepower and boost can the stock gtp s handle i ve been told that there supposed "family cars" so exactly how much can they handle and where would i find a tranmission to handle about 350 horses or more if the stock tranny can t

[BNaylor]

Originally Posted by GTP2000

exactly how much horsepower and boost can the stock gtp s handle i ve been told that there supposed "family cars" so exactly how much can they handle and where would i find a tranmission to handle about 350 horses or more if the stock tranny can t

The stock 4T65E-HD tranny in a 1997 - 2003 GTP should be able to handle up to 350 horses but it will probably be unpredictable and will depend on the mileage on it. I read someplace that it was designed to handle mid 13 sec 1/4 mile times under continuous use. I turn 13.62 @ 102 mph and the tranny has never acted up.

As for boost, the stock 3.8 pulley gives around 7.5 to 8 psi boost. A 3.5 pulley will take you up to 11 psi boost. I know a lot of GTP owners that safely run pulleys as small as 3.0.

If you plan on going above 350 horses or into the 12 sec. range ZZPerformance has a modified 4T65E-HD tranny for around $1700.

A transmission oil cooler and switching over to synthetic ATF is highly recommended.




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials