What is the pipe diameter going into and out of the big resonator under my 2007 MCSS? It looks like 3" OD but it's hard for me to get under there and I don't have any calipers. I'm going to cut it out and replace it with a straight piece of pipe. Thanks guys.

And I did search the forums. Tons of 6th gen stuff but less 7th gen.

 

is this what would be considering adding a downpipe? cause i added magnaflow muffs and deleted my res. but still want more sound. if this is what your are trying to do as well id like to know also. ty,joe

 

I don't think so. I consider a downpipe that which connects the exhaust manifolds to the cat. This pipe, that I will order from Summit, will replace the resonator. I just need to know the stock pipe diameter for a 2007 SS.

exh manifold--->downpipe--->cat--->resonator--->2 mufflers out the back

 

i believe it is 2.25

 

Thanks but it seems way bigger than that. They wouldn't run 2.25 behind the LS4. It's closer to 3". It's big pipe.

 

2.5" to the Y, 2" to each muffler and 2.25" to the tips.

 

For the 2007? Great, thanks!

 

For all LS4's - Monte and Impala.

 

Great, thanks again!

 

it is the size they have for the ss and the v6 for the 7th gen i was talking to that speed custom shop they do work on alot of chevy's engins and exaughst. they said sertain setup on sertan vehicals like fwd runs better with 2.5 to pushing 3 if there is alot of mods but loose a lot when goes bigger to 3. with rwd runs great with 3 inch and runds good with 2.5. it was explaned to me when they were testing a car on there dyno that was rwd getting a 3 inch exaughst put on do to some thing not running right. i would go to 2.5 from 2.25 setup wich most have. and i think you would be happy with the set up