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How many HP's

W

wrfdff4

New member
Ive always wanted to know how many HP's my 1999 GP GT coupe has with a K&N air intake and a 2.5 downpipe (cat, u-bend delete). Tell me what you guys think
-Thanks,
Bobby
(PS my chrome 18's hold me back alot)
 


that would be a toss up. every 3800 car reacts differently to mods. stock factory rating is 200hp at the crank. I am guessing maybe 220? but you have 18's...so I am guessing that will put you back down to stock rating through parasitic drag.
 
if it is 200HP at the crank though the loss with the transmission even with the mods, probably putting maybe 175 to the wheels
 
Wow that seams low since Edmunds rated the 3.4 at 210hp and the and the 3100 at 165hp. They rate the 3800 at 200hp. Weird
 
has nothing to do with engine ratings. Most of them are rated at the flywheel. A car makes more hp when it doesnt have to move the car. You have to take off some for the transmission everything else that makes the car move. so yeah the engine is rated for that, but what you put down to the wheels is another story.
 
Also those ratings are engine without cat, mufflers exhaust restrictions or air cleaners airbox restrictions
 


if u multiply the horsepower of the car at the crank/flywheel by 20% then take that value and subtract it from the inital horsepower number, that'll give u what the actual horsepower is at the wheels; plus or minus a few hp since every car is different.
for example, a GPGT is rated at 200HP, so 200*0.20=40, now take that value and subtract it from 200. so it'd be 200-40=~160fwhp. savvy? lol
 
I always heard a 25% loss through the drivetrain. But that may be old school stuff. And with new oils and what not, the number may be different. But none the less, the drivetrain does take a lot of HP away.

And even still, an air filter, down pipe, cat removed, etc isn't going to help all that much. My guess is around 175 HP at the wheel as your car sits.
 


so with a completely stock ,2007 base model gp ,3.8 series III , factory says 200hp / 230tq. so what would i be truely getting at the wheels > hp + tq....

with my stock 2000 GAGT sedan 34.L ram air ,factory says 175hp/205tq..... guys say actually likely only getting 145 hp + actual tq ??. i ran 3 passes at 1/4 mile ran factory 15.9 with extra body in car ,then 15.8 next 2 times no passenger .

i am also guessing my GAGT is faster then my GP
 
on average for FWD and drivetrain loss. multiply the hp and tq numbers by 20% then take that total and subtract from the hp and tq. for example the 97-03 has 240hp/260tq. 20% drivetrain loss equates to 48/52 and finally the cars actual fwhp is approximately 192fwhp/208fwtq
 
GAGT+GP-OWNER said:
so with a completely stock ,2007 base model gp ,3.8 series III , factory says 200hp / 230tq. so what would i be truely getting at the wheels > hp + tq....

with my stock 2000 GAGT sedan 34.L ram air ,factory says 175hp/205tq..... guys say actually likely only getting 145 hp + actual tq ??. i ran 3 passes at 1/4 mile ran factory 15.9 with extra body in car ,then 15.8 next 2 times no passenger .

i am also guessing my GAGT is faster then my GP
Click to expand...

I ran 15.89 with my stock 99 4 door GP GT w/125k miles. Car has a sunroof with aftermarket 16" chrome rims. I left the headlight in, didn't change tire pressure, no weight reduction, 3/4 tank of gas. I figure the way my car was setup that it should be on the slower side for a stock 3800, so i'm not sure that your GAGT would be faster than your 3.8, although it would be extremely close.
 
fst said:
on average for FWD and drivetrain loss. multiply the hp and tq numbers by 20% then take that total and subtract from the hp and tq.
Click to expand...

Or, to make the math simpler, just multiply by 0.8 and there is your answer... :th_thumbsup-wink:

johnnyj773 said:
i heard the most hp u can get out of a gt is 300.anybody else heard this?
Click to expand...

If you're talking about a 97-03 GT (no supercharger, since 04+ GTs have superchargers), then the most you can get without forced induction is around 300cHP. Which is about 240wHP.
 


how do u think i can accomplish this?am i close with the future mods in my sig?or i'll have to do more like cam or rr?
 
johnnyj773 said:
how do u think i can accomplish this?am i close with the future mods in my sig?or i'll have to do more like cam or rr?
Click to expand...

To get close to 300? You need a pretty aggressive cam and some head work at the very least, in addition to what you have listed. A PCM won't do it either as you'd need a custom tune. And probably headers instead of the Plog/x-over/dp combo.
 
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