Any change Exhaust on 3.5L

[ND4SP]

Has anyone changed exhaust on a 3.5? I am wondering how it would sound. I was thinking of getting bigger exhaust tips, however would be better to get whole exhaust done at the same time if I am going to do it.. I know that the 3800 would sound great with louder exhaust.

[LittleHoov]

I think there are a few people here who have changed the muffler, but im not positive.

I would recommend at least removing the u-bend (look behind the cat, youll seen what I mean) and possibly getting a high-flow cat, those are two restrictions in the exhaust, but im sure the biggest is the manifolds themselves, although there isnt much that can be done about that for the 3.5, unless you wanted to pick up a spare set and attempt some DIY ported manifolds.

I strongly advise against changing the piping size, bigger is not always better and the stock pipe will flow very well and you wont outflow it, changing the pipe size will only sacrifice what little low-end torque you already have.

Ive been somewhat leary of changing out my muffler, mostly because Im afraid it will sound like crap, and secondly because I dont like the fact that the Intrigue is only set up for one exhaust tip. Id rather have no tips, or duals, and you cant cosmeticallly pull off either with the Intrigue.

[ND4SP]

Originally Posted by LittleHoov

I think there are a few people here who have changed the muffler, but im not positive.

I would recommend at least removing the u-bend (look behind the cat, youll seen what I mean) and possibly getting a high-flow cat, those are two restrictions in the exhaust, but im sure the biggest is the manifolds themselves, although there isnt much that can be done about that for the 3.5, unless you wanted to pick up a spare set and attempt some DIY ported manifolds.

I strongly advise against changing the piping size, bigger is not always better and the stock pipe will flow very well and you won't outflow it, changing the pipe size will only sacrifice what little low-end torque you already have.

I've been somewhat leery of changing out my muffler, mostly because I'm afraid it will sound like crap, and secondly because I don't like the fact that the Intrigue is only set up for one exhaust tip. I'd rather have no tips, or duals, and you can't cosmeticallly pull off either with the Intrigue.

I don't want to change exhaust pipe size just the tip size. I definitely don't want to sacrifice low end torque, as the 3.5 doesn't have enough as it is. Can't do dual exhaust very easily, I would be happy with bigger exhaust tips. I just don't want to change my muffler, I fear it will sound like crap. I took my car to a friends exhaust shop, he had never done the u-bend delete. He told me about 60 bucks, I didn't think that sounded too bad. He is an exhaust artist, if there is such a thing, he is VERY picky on how everything looks when it is done. I won't go any where else...

[LittleHoov]

Youll need to do something with the 02 sensor or it will throw a constant code, it will lay sideways, parallel to the ground....or you can do away with it altogether and get an 02 simulator for around 25 bucks. Or you can have the check engine light permanently on, but I dont like that idea.

I know its considered a pretty big restriction in the 3800 Supercharged world, people claim differences in just removing the u-bend and keeping the stock cat. I dont know how big of a restriction it is in a NAed car, but I would think it would have to hold it back some.

[ND4SP]

Originally Posted by LittleHoov

Youll need to do something with the 02 sensor or it will throw a constant code, it will lay sideways, parallel to the ground....or you can do away with it altogether and get an 02 simulator for around 25 bucks. Or you can have the check engine light permanently on, but I dont like that idea.

I know its considered a pretty big restriction in the 3800 Supercharged world, people claim differences in just removing the u-bend and keeping the stock cat. I dont know how big of a restriction it is in a NAed car, but I would think it would have to hold it back some.

Thank you for the information, however I am a son to an auto mechanic. I do appreciate the information though. Up until the last few years, I would do all my own maint.. Now oil changes are so cheap, (if you bring your own oil and filter. I use Mobil One) that it isn't worth it for me to do it myself. They also check tire pressure, front end components etc.... I just recently had the first O2 replaced, to see if my mileage would improve, I do see some, not much... I would have changed it myself, however I couldn't see it very well.

[aghopkins]

Originally Posted by LittleHoov

Youll need to do something with the 02 sensor or it will throw a constant code, it will lay sideways, parallel to the ground....or you can do away with it altogether and get an 02 simulator for around 25 bucks. Or you can have the check engine light permanently on, but I dont like that idea.

I know its considered a pretty big restriction in the 3800 Supercharged world, people claim differences in just removing the u-bend and keeping the stock cat. I dont know how big of a restriction it is in a NAed car, but I would think it would have to hold it back some.

I am considering doing the u-bend delete on my Intrigue. I am just wondering how you went about solving the O2 sensor dillemma and about how much it costs to have it done?

[LittleHoov]

I had actually brought all of my own parts to my exhaust guy, one of which was a reducer of proper size that had an 02 sensor bung already welded into the side of it. You can also just add a bung in separately, and then the sensor will just screw right back in behind the cat as it normally would.

It will lay sideways, parallel to the ground, as opposed to straight up and down like it is in stock form.
http://www.pfyc.com/pc/WB5001/GPEXH/...placement.html That shows what im talking about to some degree, mine is actually tilted a little more toward the body of the car than the ground, but I think even positioned like that there is little risk of ever hitting it on the ground.


As for pricing, that will vary pretty widely, I would stick to the mom and pop shops if at all possible, or someone like your friend who is good at welding and such. Mine only cost 35 bucks to have installed. But I had already purchased everything necessary for the install, all he had to do was cut and weld. He didnt use any piping, 02 sensor bungs, reducers, etc that were his own.

It might actually be more cost effective to do away with the rear 02 sensor entirely and just run straight pipe after the cat and get an 02 simulator from somewhere like Intense Racing.

My rear 02 sensor randomly throws a code from time to time, I have no idea why, but I havent bothered replacing it, as I know the cat is fine, and even if it wasnt we dont have emissions testing here so I dont really care. I think the problem is with my sensor though, and not with the setup.

[aghopkins]

Thanks for the reply. I will print out the link on the u-bend delete and take it to the local exhaust shop that I used to have dual exhaust put on my old truck. Maybe they can fabricate something like that.

[ND4SP]

Originally Posted by LittleHoov

I had actually brought all of my own parts to my exhaust guy, one of which was a reducer of proper size that had an 02 sensor bung already welded into the side of it. You can also just add a bung in separately, and then the sensor will just screw right back in behind the cat as it normally would.

It will lay sideways, parallel to the ground, as opposed to straight up and down like it is in stock form.
http://www.pfyc.com/pc/WB5001/GPEXH/...placement.html That shows what im talking about to some degree, mine is actually tilted a little more toward the body of the car than the ground, but I think even positioned like that there is little risk of ever hitting it on the ground.


As for pricing, that will vary pretty widely, I would stick to the mom and pop shops if at all possible, or someone like your friend who is good at welding and such. Mine only cost 35 bucks to have installed. But I had already purchased everything necessary for the install, all he had to do was cut and weld. He didnt use any piping, 02 sensor bungs, reducers, etc that were his own.

It might actually be more cost effective to do away with the rear 02 sensor entirely and just run straight pipe after the cat and get an 02 simulator from somewhere like Intense Racing.

My rear 02 sensor randomly throws a code from time to time, I have no idea why, but I havent bothered replacing it, as I know the cat is fine, and even if it wasnt we dont have emissions testing here so I dont really care. I think the problem is with my sensor though, and not with the setup.

Did the wiring have to be extended? The only thing that is making me wait is that I want the pipe to be stainless. I don't want, aluminized steel, not good. I will have to call my buddy to see if he can get stainless, if so, that will be done soon.......

[LittleHoov]

In my application the stock wiring worked just fine, my high-flow cat was actually a little shorter than the stock one, so it moved the sensor back towards the engine a bit so the wiring actually had to be tucked away a little bit. Im not sure how much room for growth the wiring has, but if you keep the sensor in the same location or closer, then you shouldnt have any problems.

I think some of my exhaust may be aluminized, and I know all the piping is stainless. Both have surface rust, but other than that....but we dont have overly harsh winters here in Missouri, at least not usually.

[phewop118]

I had a hole in my resonator and had the resonator replaced with a straight pipe. That actually made my exhaust sound better. It is a little bit louder, with a slightly deeper sound at idle that turns more towards a whoosh around 3000 rpm.

I would like to eventually put in a high-flow cat and get an 02 simulator and remove the u-bend, but I don't have the time or the money at the moment to do so. I also thought about getting some Borla's for the 3800 supercharged in the Grand Prix and dual tips, but I know they aren't worth the money.