How can i get a downpipe that with fit up with the GMPP Performance Exhaust? All the Downpipes i been looking at are 2.5 piping, and the GMPP piping is 2.25. So how can this work?

 

2.25

 

All the Downpipes i been looking at are 2.5 piping, and the GMPP piping is 2.25. So how can this work?

 

they should still bolt up assuming they are the 3bolt system

 

I just got my gmpp exhuast..does it increase horsepower?

if so does anyone know how much?

 

Pick up a SS/SC downpipe, they're 2.25" and cheap.

 

it should gain around 12 hp gain. Thats what i was thinking Reign SS. At my flange point from my cat back its only 2 bolts but in the front where the exhaust mani hooks up its 3 bolt. Im wondering if it will fit up with both my stock mani and my catback because the downpipe diameter is 2.5 and my exhaust is 2.25.

yea i kno there cheap, but i want to get a highflow cat and a new downpipe. so i might just buy it and if it dont fit send it back or sell it.

 

ONE, i repeat ONE person got a 12 whp gain, and that was like 2 years ago. i wouldn't expect more than about 5 or so horesepower realistically.

any downpipe should bolt up to your exhaust.

 

ok thanks man. I just read what CED says under the description when you click on the exhaust

 

yea, it's pretty misleading. i would NEVER go by a companies dyno #'s, remember that they're always going to give the hihgest number that they have seen, not what the average person will see.

 

It all depends on what supporting mods you have. If your completly stock and then do the GMPP exhaust, you will get like 3-5HP. If you have an aftermarket intake/header/downpipe with stock exhaust and then upgrade to the GMPP exhaust you might gain 10HP. It all depends on the other mods.

 

Yea, true on that i plan on bying a highflow cat on the downpipe off on cobalt addiction and the GMPP exhaust manifold so the headers and downpipe should add around 10 and the exhaust so hopefull maybe around 15 to 20 gain. i hope

 

If you do an intake, header, DP and exhaust you will gain around 15HP. It all depends on what brand parts you use, the diameter of the pipes you run and wether you run a short ram or cold air intake. You will probably gain more power with a real header rather then a GMPP manifold. Also look into the 2.4 intake ani swap.

 

If I remember right XM15 did the 2.4 mani swap and lost tq but gained 2 hp...