Thread: slp gtx exhaust on a 2004 gtp? Upgrade?

hey everyone found an slp gtx Catback exhaust 2.5 inches for pretty cheap on craigslist and wondering if this would fit my 2004 GTP and would it be worth the upgrade. I don't care too much about sound just looking for the weight reduction and hp benefits. I dynoed at 255 whp back when I got a tune from zzp. since then I've done a fuel pump and plan on installing 1.95 rockers I have sitting on a shelf. I assume after the pulley drop I should be between 270 and 290 to the wheels? so would this exhaust free up and hp currently have the stock 04 gtp dual tip exhaust and speed daddy headers.
any input would be great dont know much about exhausts.

Lol I dont have just a tune I have basically the same build as you except I have 60# injectors and a fenderwell intake and i can't imagine its that loud its not an aftermarket slp exhaust its the exhaust that comes stock on the gtx made by slp

Same reason you have a 450 lph pump pretty sure thats more overkill lol than #60 injectors with rockers e85 and headers

I'm am 20 not going to lie but I am a sleeper type guy. loud exhausts just seem dumb to me except on like a huge turbo Evo bulid or something haha I think I still have the dyno sheet in my trunk dont know if that will show the gear never actually asked him kinda just was like cool thanks

Sorry I thought you were the other guy but I plan on doing rockers and run e85 so I just wanted to play it safe especially since the #60 are only like $15 more

I say if its cheap enough go for it,(whats cheap?) Getting hard to find and never really reasonable either. It should fit. Tips alone are about 80 each I think if you can still find them. Add a resonator for sure.

Originally Posted by tzerilli

Lol I dont have just a tune I have basically the same build as you except I have 60# injectors and a fenderwell intake and i can't imagine its that loud its not an aftermarket slp exhaust its the exhaust that comes stock on the gtx made by slp

The only power mod you have is the tune. The rest are just support mods that gain no HP. With SpeedDaddy headers, the SLP won't be a direct fit, you'll have to cut a flange and a bit of tube off the front, basically ruining it once you decide you don't like it. If you plan on daily driving it, don't get it, but for a toy, go for it.

My 420 lph pump isn't that much overkill, it's rated like 360hp on E85, and it's the only pump I found that was E85 ready and was also OEM fit without any modding. I also have a couple smaller pullys and 1.9s to put on, just gotta get a new MAF, so it was future proofing.

Originally Posted by rottonj

I say if its cheap enough go for it,(whats cheap?) Getting hard to find and never really reasonable either. It should fit. Tips alone are about 80 each I think if you can still find them. Add a resonator for sure.

from downpipe back for $200 obviously I would have to cut the down pipe section off though since the headers would be superior but yea I did ask the guy and he said there isn't a resonator which kinda turned me down since im in my apartment and cant weld or cut much adding the resonator would probably cost as much as the exhaust haha and I hate paying the shop lol plus lots are saying no hp gain so I might skip out plus I still gotta install my rockers should probably focus on that instead of spending more money haha

Originally Posted by industrialfish

The only power mod you have is the tune. The rest are just support mods that gain no HP. With SpeedDaddy headers, the SLP won't be a direct fit, you'll have to cut a flange and a bit of tube off the front, basically ruining it once you decide you don't like it. If you plan on daily driving it, don't get it, but for a toy, go for it.

My 420 lph pump isn't that much overkill, it's rated like 360hp on E85, and it's the only pump I found that was E85 ready and was also OEM fit without any modding. I also have a couple smaller pullys and 1.9s to put on, just gotta get a new MAF, so it was future proofing.

hey I 100 percent agree with the over kill theory I've learned better to pay $20 to $50 extra bucks for "overkill" than possibly $100s for "underkill" breaking **** haha I just mixed you up with the same guy that said my injectors were overkill my apologizes. and the seller did tell me It wouldn't be a direct fit which as I said did turned me down since im limited to tools I can use in my apartment parking lot plus this will probably be my daily for a long time as im finishing my build and honestly kinda love the car now so I should probably just avoid it especially since I don't have a problem with it now and actually just got done fixing a crack near the resonator.

This past summer I put an slp powerflo from intense on my gtp. Let me just summarize by saying it was on my car a day before I decided to add as long a resonator as I could.

It was on my car two more days after that before I ripped it off, put the stock catback back on, and wept for my $530.

It sounded nice at idle, but any level of throttle made me wanna blow my brains out, and going up hill or pulling out from a stop light made me feel like a douche. The drone and volume really is that bad.

I’ve been around here for like 10 years listening to these guys tell everyone who asks to leave the exhaust stock because they did it and it was bad, and I still thought I’d give it a shot. Well, at least I know now.

Headers, rockers, cam, downpipe, highflow/no cat... all of that will deepen the exhaust and make it louder. Don’t mess with the mufflers.