I'm thinking about going with the GMPP extrude honed manifold (I know, I know, not the best choice but I found one for dirt cheap and I'm going to try to get it ported) and the GMPP touring exhaust for my LSJ. Since there is no GMPP downpipe and the stock one is pretty restrictive I would like to know what my best option is for an aftermarket down pipe that will fit these parts. Oh, and I would like to get one with a cat. Any suggestions?

 

CA's XTC downpipe, will bolt right up to that set up

 

i've got my stock ss/sc dp if you want, complete with cat....idk if it is compatible or not, but it should work? someone around here will know...offer stands if you want, price negogiable

also have the stock headers

and exhaust but its been cut in half so i could remove it...

ha just realized the thread this is under
nvm about the previous

i'll be honest, i went vibrant header/dp combo, with the magnaflow - its a great setup, good sound, and looks nice too. as far as performance goes, depending on what you run on the blower and other engine mods, 2.5 piping should be just the right size. I noticed a slight drop off in psi's (like half a lbs) was only hitting about 14psi's but the 2.9" fixed that up real quick

back to exhaust components thou...imo, if you are going to spend the money, spend it on something worth it. get a good setup, stay away from gmpp imo. wont give you the satisfaction you want and its almost as expensive if not more than other better parts...do some searching around here, there are plenty of threads on this topic btw so you can get a better idea

 

I have the stock downpipe but I'm looking for a less restrictive aftermarket one. Thanks for the offer though.

 

yeah is there any aftermarket header/downpipe that does not cause a check engine light??

 

no problems with my vibrant dp, but it only comes as combo header/dp....I havent had a cel since i got my stg. 2 about a year and a half ago ::knocks on wood:: and i've got full bolt ons, intake header dp exhaust....

anything you go with should be fine as far cel's go...just make sure you don't go for a highflow cat or something like that. from what i understand that could make the o2 sensor go goofy...might cause some problems that and you don't need a highflow cat or to be catless for that matter...our blowers like a little resistance, not enough back pressure means less power, unless you are running something smaller than a 2.8 with a tune and supporting mods, in which case your engine MIGHT be pushing enough air through to benefit from the highflow cat

 

ic so as long as i get a header/downpipe without a highflow cat i shouldnt get a check engine light and dont need to tune anything? or is most downpipes regardless gonna cause a check engine light?

 

I have the zzp downpip with high flow cat. The check engine light is on but the combo sounds great with my touring exhaust. My thought is if you get a downpipe might as well get the high flow cat, why not have the best flow possible. I think you can get a cel delete anyway from arc or some vendor

 

I would imagine a catless downpipe would be more likely to throw a code then one with a high-flow cat.

 

A catless dp will flow better

stock cat for ss/sc is high flow, its just the pinch that needs to be worked. Go to muffler shop and have them weld a pipe in place there

if not, the cobalt addiction one will bolt up

 

honestly guys, unless you are running something smaller than a 2.8" pulley, with the supporting mods - you dont really need a high flow cat, or to even go cat-less - you could stand to lose more power than you would gain. the superchargers need back pressure to be effective....

 

no.. wrong

superchargers do not need back pressure to be effective...

dont listen to that last post, it will screw you up.

reminder, the stock ss/sc cat IS HIGH FLOW.