HI... I'm Jaime.. and I need exhaust

[lastonemade02]

Hi guys. I just bought the last 2 door GP/GT ever made from the original owner who worked at the Fairfax plant in KCK. It has 68k miles on it and is in just like new stock condition. The first thing I wanna do is upgrade the exhaust system. I'd like to lose the cat., and resonator (no smog check here in Mo.) and add 2 new Flowmasters. What do I do about the sensor behind the cat.? Will I get a check engine light or experience any perf. problems? Any ideas will be helpful. Thanks in advance. Glad to be a member of the GP family!

[MizzBecca]

welcome =)

[carl06GT]

welcome. your gunna wanna keep your res. other wise it is gunna be real raspy. your best bet would do the mufflers and a 2.5 catless down pipe

[lastonemade02]

Thanks! Does the catless downpipe have the fitting for the o2 sensor? Jaime

[carl06GT]

https://www.zzperformance.com/grand_...=551&catid=110

thats whats your looking at right there.

in option 2 add the 02 bung
leave option 3 alone
option 4 do the prepaid label for your stock cat to get some more money for parts on there website

[lastonemade02]

Thanks Carl! Will going catless WITH the o2 sensor installed cause any check engine light to come on, or change the performance of the vehicle?

[Bio248]

Thanks Carl! Will going catless WITH the o2 sensor installed cause any check engine light to come on, or change the performance of the vehicle?

yes, your check engine light will go on and you wont be able to pass emissions. nothing performance wise will be effected though. run a cat. it makes the exhaust less crappy sounding, doesnt get the rear bumper all dirty, and saves the world (if youre into that sort of thing).

no need to go catless as it is not a restriction. if you think that deleting the cat and resonator and adding in flowmasters is going to sound good then i have bad news for you. it will sound mega crappy. you like ricer rasp? you got it. keep the cat, keep the resonator, and replace JUST the mufflers. get a 3" downpipe WITH a cat and bolt that in there. im already telling you that if you do what you described that youre going to regret it unless you like loud ugly v6 sound. these cars are meant to be quick and quiet, not loud and obnoxious. leave that to the hondas that think they get more power from running a straight exhaust on a 4 cylinder that makes less power than my lawn mower.

[Swash]

yes, your check engine light will go on and you wont be able to pass emissions. nothing performance wise will be effected though. run a cat. it makes the exhaust less crappy sounding, doesnt get the rear bumper all dirty, and saves the world (if youre into that sort of thing).

no need to go catless as it is not a restriction. if you think that deleting the cat and resonator and adding in flowmasters is going to sound good then i have bad news for you. it will sound mega crappy. you like ricer rasp? you got it. keep the cat, keep the resonator, and replace JUST the mufflers. get a 3" downpipe WITH a cat and bolt that in there. im already telling you that if you do what you described that youre going to regret it unless you like loud ugly v6 sound.

Welcome aboard Jaime! I hope you've checked out the local board Kansas City Pontiac Motorsports Club

Bio...is a cat lover - I don't mean feline. You'll get differing opinions on the restricion of the stock cat - personally, I would remove it and either go with a hi-flow version, or none at all. He did however answer the rest of the questions correctly.

-Swash

[carl06GT]

im not sure about that cuz i have an 04+ body style. but im sure blue91gtp will chime in before long on that and be able to help you out

[lastonemade02]

LOL how bout it blue?

[Bio248]

oh, well..i have a 2.5" high flow cat on mine if youre going to be like that.

[Swash]

oh, well..i have a 2.5" high flow cat on mine if youre going to be like that.

AHA! I knew it!



-Swash

[Liquifire]

if you go with the zzp downpipe you will have a hi flow cat built in if you wish and you can add the rear 02 bung so that you are not throwing any codes. Leave the res.......I agree with basically everything bio said and I can vouch for the v6 sounding bad if the exhaust is modified too much(it was like it when I bought it) so I put on different mufflers, tips, and put in a glasspack where the res was supposed to be. Sounds much better now. For best results post your questions in the General Tech sections, or specific motor areas for the most viewers. Of course if it doesnt apply to those areas, please pick the area that the thread applies to. Good luck. Yes, and I would also recommend that you get a 3" downpipe and not the 2.5 zzp has them both bolt in or weld on fyi.......

[Liquifire]

Please read the thread "safely modding your 3800" before modifying your vehicle at all. This should help you get started on modifying your car and just some good overall knowledge about our cars.......

[lastonemade02]

Thanks for all your help guys. I'm gonna go with the 2.5 downpipe since I'm not gonna do any perf. mods to the engine, and run the hi flo cat and o2 sensor. Do you guys like the magnaflo's or the flowmasters best for these cars?

[Swash]

Thanks for all your help guys. I'm gonna go with the 2.5 downpipe since I'm not gonna do any perf. mods to the engine, and run the hi flo cat and o2 sensor. Do you guys like the magnaflo's or the flowmasters best for these cars?

It's a preference thing. The best I've heard is actually Dynomax with a 3" DP (he is cammed) and glasspack replacing the stock resonator. Sounds good. As I always say - a GP will never sound like a Mustang GT. Ever.

-Swash

[TheOtherNick]

You could still throw a code with the high flow cat, since they do not work as well as the factory cat.

[lastonemade02]

Maybe the best thing for me to do is just replace the u pipe only, and add the new mufflers then.

[TheOtherNick]

You can get an 02 sim to fix the ses light.

[Liquifire]

or you could get it tuned out as well if it does throw the code........