Thread: stock 04 grand prix GTP

All I know is that the 99-03 GTP running on a 3.4" pulley has the same amount of boost as the 04-09 GTP with a stock pulley, which is 3.8"...maybe around 8-9 lbs?

Originally Posted by TheAce144

All I know is that the 97-03 GTP running on a 3.4" pulley has the same amount of boost as the 04-07 GTP with a stock pulley, which is 3.8"...maybe around 8-9 lbs?

fixed it for ya

and no, they produce just about the same boost on the stock pulley.

putting a 3.4 on the gen 3 without anything else(supporting mods) would make it produce prolly up to 10-13psi over the stock psi of 5-7. The smaller pulley makes the SC spin way faster than before, so it makes more boost.

Originally Posted by Fivefingerdeathpunch

fixed it for ya

and no, they produce just about the same boost on the stock pulley.

putting a 3.4 on the gen 3 without anything else(supporting mods) would make it produce prolly up to 10-13psi over the stock psi of 5-7. The smaller pulley makes the SC spin way faster than before, so it makes more boost.

I don't know, got the info from Will @ Overkill...said that the genV supercharger was more efficient than the previous generation and therefore made more boost...here is the mail he sent me :

"If you don't have a downpipe, I would start there first, and then drop the pulley size. You'll probably find you can only drop to a 3.6" pulley size, best to get a modular pulley system so you can swap sizes easily if needed. Remember that 04+ with the GenV superchargers are much more efficient, so when you see a pre-gen running a 3.4" pulley, you have nearly that equivalent boost with a stock pulley."

Originally Posted by TheAce144

I don't know, got the info from Will @ Overkill...said that the genV supercharger was more efficient than the previous generation and therefore made more boost...here is the mail he sent me :

"If you don't have a downpipe, I would start there first, and then drop the pulley size. You'll probably find you can only drop to a 3.6" pulley size, best to get a modular pulley system so you can swap sizes easily if needed. Remember that 04+ with the GenV superchargers are much more efficient, so when you see a pre-gen running a 3.4" pulley, you have nearly that equivalent boost with a stock pulley."

Originally Posted by bluegtp91

Calculations?

Quite a bit.

Considering the GenV makes as much power as a GenIII with a 3.4" slapped on it whilst the GenV is still on a stock or close to stock pulley...there is no ramp up on the GenV...the rotors are better...and coated better for that matter...its also a little bit bigger of a blower as well...so since it is displacing more air, its of course going to make more power...and it can do it without pulling as much power FROM the motor to make it...unlike the GenIII...which needs hogging out...re-coated rotors, the entire inlet ramp smoothed so the air ramp up isn't all screwed like it is from the factory...and the outlet opened up quite a bit...its just a increase in technology really IMO.

Better overall design...but it is still a heaton...and the more you pulley down, the more heat it makes and the more power it is going to TAKE FROM THE MOTOR to make more power.

I always had a nice little scale like this...

Both blowers will make about the same figures from the factory...while the GenV car will still make about 10-20 more horse and torque to the wheels than the GenIII car if they are tossed side by side with the same pulley.

3.8" GenV = 3.5"/3.4" GenIII

3.4" GenV = 3.2" area GenIII

3.2"/3.0" GenV = 2.8"/2.55" GenIII

That's how I always understood it...Steigmeier Performance...who is VERY well known for porting the M112 cases for the 03-04 Cobra's did a GenV M90 and said they gained nearly 20 crank horse from just their porting...I never saw any actual dyno charts...just their claims...but it was ported in a rain drop or tear shaped outlet...just like they do on the M112...something strange like this...

I'm just gonna quote this from my other thread to help you out in understanding the GenV to GenIII...and how the pulley size compares.

Thanks for the support Bluegtp!