For our N* GXP'*?

No cat-backs. Yea I could probably hack up a Seville STS system from Corsa. But I am not paying that much to hack it up. There are no CAI'* out there either.

As such, I was left to my own devious methods.

I have two Magnaflow Mufflers (part# 12225)


and tips


on order, and I already mocked up a CAI system. I don't have pics yet, but I will try.

There are no CAI'* or Cat-Backs for ANY year of Bonneville.

For the most part, you don't want a cat-back. Our exhaust is free-flowing mandrel-bent stainless steel. Change the mufflers alone for a change in sound, they won't provide any power gains.

Yep, 409 stainless. Not quite as good as 304 but it won't do much more than surface rust.

Ever cut apart an OEM muffler? I have. There is plenty of restriction in there. Most are a minimum of 4 chambers. Some of the GM trucks are 6. OEM mufflers (as well as most componentry throughout the car) is designed with multiple objectives in mind. They include power, economy, sound deadening, durability, serviceability, etc. This jack of all trades, master of none approach leads to some obvious areas of improvement.

The plumbing in our car is ok and free flowing as you mentioned (I was actually pleasantly surprised by this when I had it up on the rack) which is why I'm not touching it. If I were to do a blower or internal engine mods, that'd be a different story and I'd go 2.5" at a minimum. It'* not so much about them "making horespower", but rather them allowing better volumetric efficiency which when combined with the "uncorking" of the intake side also, works as a system allowing that big air pump under your hood to be more efficient. This translates into easier acceleration from less RPM'* needed to obtain that same level of acceleration. This results in better economy as well as allowing the engine to spool up quicker when needed which allows the engine to be more efficient in power making. It'* not about the individual pieces, rather the system as a whole.

Trust me, I've learned a few things over the years as a technician and modding a few vehicles!

But sound is the other reason I'm doing it.

Trust us on our experiences here, stock mufflers are usually kept until the car is in the 13'* on the quarter on this Forum. I cut open my OEM muffler when I replaced it 4 years ago, and it wasn't very restrictive at all.

Umm, OK!

You don't sound very convinced. I can show you on the top-25 list which cars broke into the 13'* on the quarter with stock mufflers if you like.

I'm not talking out my arse here. I'm speaking from the experiences of the members of this Forum for the last 5 years.

Well im going to jump in here and say...

the Stock Bosal'* om my GXP were very restrictive beside my Solo-Performance straight through design. Not that the power gained was enough to notice but i bet there was a gain of a few HP also I think with a little work the pipe could be straightened out a little

I went 12.7 on stock exhaust system

338 wheel horsepower (422 Crank HP)

^^ yeah but your car is on crack lol