on a 99-04 gt, if i put a full exhaust on it how much of a HP gain should i expect?

 

damn man, youre pumped about this 99-04 GT business (how can you afford insurance if youre paying 3 arms and 2 toes for insurance on the fox now?)

aside from that
everything else stock, youre looking in teh following vicinity

LT Headers-15-20 rwhp (maybe a tad high, someone else will follow up on me)
Catted Pipe- 2-4rwhp
O/H Pipe- 3-6 rwhp or so
C/B- 4-6 or so,

those are all really rough estimates, but dont worry about different brands of midpipes and catbacks giving different numbers, they're all witin 1-3, nothing you'll be able to feel

 

ive always thought of exhaust more for potential and sound than HP gains, its really extremely minimal on a stock engine.

 

I agree,those numbers are going to be pretty close.

 

they seem high to me, true hp on a stock motor maybe 15-20 tops.

but the sound makes it all worth it.

 

hp doesn't add like people think 20 would be pretty much max thats with lt's

 

well, it sounds like i was right

most of the numbers were right, headers were a little high though

but thats why i said he shouldnt worry about the differeneces in power gains, go strictly on sound preference

 

i wasn't trying to flame you i was just backing up bob

a lot of people think that advertised hp is what you get

20 hp form headers
15 form mid pipe
15 form cat back

thats 50 hp. its just not gonna happen.

 

what about getting a custom exhaust system from a local muffler shop. my friends have had good success with their tuners, and save a good bit of money going that route. plus the sound is killer. would anyone suggest him going that route?

 

the biggest restriction on the 99+ cars are all the cats and pre cats. LTs are always good for freeing up a few HP but I think the midpipe is where you will really see the difference.

Still, it's not a HUGE difference like you see advertised. In my experience, Tim is correct and the whole setup will only net you about 20 RWHP......but only if the engine can breathe IN as well.

It's a combination of mods that makes an engine come to life but exhaust is probably a really good place to start.




Custom exhaust systems can be good or bad. Depends on the shop and what materials they use and how they bend the pipes. If you get a custom exhaust made out of 2.25" steel pipe that is bent on a crimp bender, you are better off with the stock equipment.