Well been waiting to get my membership approved so I could post. Anyway heres my question.

From the best I can tell from reading what I could the 2.4 autos have a different downpipe.


So my question is this. What would i need to run the gmpp exhaust manifold (yes I know theres better but theres warranty at work here lol) with an xtc 2.5 downpipe and the SLP catback?

The car is an 08 2.4 auto sport model. Would like a bit more power and this seems like one of the cheaper setups to go with while retaining my warranty.

Though any advice input or different options are always welcome.

 

I think the DP needs to be about 1.5" longer or something like that. Just take it to a muffler shop and have them cut the XTC in two near the exit and weld in an extension so its length matches the stock DP (that's probably what I'll be doing once I find one for my M62 build). They'll probably charge you only 30 or 40 bucks so it's not a huge deal.

Here's a link to a good write-up about it: https://www.cobaltss.net/forums/2-4l-le5-performance-tech-46/2-4l-auto-dp-vs-lsj-dp-150651/

 

I think that only applies to the LSJ dp because the cat rests on the sway bar or something

 

well guess this could be interesting. Was going to buy the gmpp header (manifold) and have them put it on so I retain warranty guess I will go to an exhaust shop right after that for the downpipe. Wonder how loud the xtc 2.5 dp will be with the gmpp header and the loudmouth (obviously pretty loud). Anyone throw a check engine light with the xtc dp? Any rough ballpark numbers for the hp gain?

 

you are dead wrong.

the only downpipe that won't fit perfect is the LSJ dp, reason being that the cat is fairly large and sits ON the sway bar. believe me. i had the LSJ on for 3 weeks and it rattled every minute of it.

i threw the xtc on and now at traffic lights im always wondering if my car is even on, cause before it would rattle at low rpm and at idle.

so OP that setup would be perfect.

and BTW if you did what he was saying your exhaust would end up being too long. mine sticks out a good bit past the rear fascia as it is now. if you added two inches? hooooooly ****.

 

that might work fine then since its the 2.4 sport model so it has the larger rear bumper. just curious how loud this setup will be lol

 

im just saying you wont need to add any tubing onto the XTC. it will just make it look retarded.

and all i can tell you is that with a LSJ header, XTC dp, and a Corsa catback the **** is loud when you get over 4k, kinda like vtak.

but as lower rpm it sounds ****.

 

Any chance the Xtc downpipe might cause a cel? The only reason I am asking is that the 08 E37 ecm is not supported by HPT, and it may be difficult to permanently cancel a cel.

 

i wouldn't be able to tell you. i got Trifecta to tune out my rear o2 sensor's codes cause i was expecting codes. so now i'll never get them.

 

Ya, I forgot. You guys that live south of the 49th, got it sweet. Trifecta looks good, but I am not crazy about the cross border crap.

 

lol we had a guy from Quebec drive down to the Trifecta tune meet.

cause it was 200 bucks at the meet and shipping prices would have been outrageous.

 

would tune but am nervous about voiding the warranty as I only have 16k on an 08 model.

 

my best suggestion would be to try finding a stock 2.4 PCM and then tune on that. swap in the stock one when you go in for work.

 

I wouldn't worry too much about a basic tune.

First of all, if the engine breaks, they (the dealer and GM,) have to determine that the tune caused the malfunction. Not likely.

Secondly, perception is nine tens of reality. If your car is done up like a "rice-mobile" with lots of tacky performance parts, then you might have a problem. They are going to think you are a moron, and treat you accordingly. I suggest that if they think your car is a well balanced performance vehicle, they may be less inclined to tar and feather you.

On the other hand, if you go for a "***** out, all the way, 93 octane tune", you may have a problem at some point in time.

 

thats exactly what i have.

no appearance mods. just a black bowtie and no rear bowtie.

AND there is a TSB or whatever out for GM techs to hook up the cars coming in with Tech2 and check for aftermarket tunes, in which case warranty is instantly voided.

 

Is it instantly voided? I was under the assumption that GM/dealer had to link the problem to the tune. (i.e. if you spin the connecting rod bearings, that can hardly be linked to a tune.)

 

https://www.cobaltss.net/forums/show...termarket+tune

check that thread.

 

guess I will just do the gmpp header xtc downpipe slp loudmouth catback and cai and be done with performance upgrades. Hopefully thats enough to at least break into the 15's