Took delivery last Monday, Already built my exhaust

[Machine]

Haven't even hit 500 Miles, and barely a week old, but I got the exhaust built on Tues. Now, before everybody freaks out about sound clips, I got to give it a couple weeks to let it break in. Its got a bit of rasp when cold, and a small leak as I forgot to order a new gasket. So it will be a while before I have a clip.

That being said, I have been extremely happy with how the sound turned out. I had ordered an additional resonator, but after listening to the car with a open downpipe, I decided it was not necessary. Its got a deep smooth idle, with just a bit of pulse, Revving is pretty quiet, but put some load and get the turbo moving and its got a great deep roar. 70mph, 6th gear and it all but disappears. Its getting a bit louder as it breaks in, but only sounding better. If this wasn't my Daily Driver, I would have run just straight pipe after hearing the open downpipe. It is not ridiculously loud and has a REALLY cool sound to it.

I had almost all the pipe laying around, left over from doing the exhaust on the X-Runner. I decided on 2.25 as that was the size of the downpipe, and I didnt feel anything was bigger (and I had it laying around) I bought a Magnaflow Muffler, a Summit Racing stainless tip, and a Jones Resonator (which, again, I did not use) Everything is cut and fab from prebent Mandrel.

Tomorrow Im going to check it over and put in a new gasket, along with my first oil change with some DEXOS for 500, then Mobile 1 at 1000 after that. THen ever 5k from there on out.


Pics

 

[silversurfer]

Cool, great write-up

 

[wingman]

I cant wait for the sound clip!!! Hurry up and break it in!!!!!!

 

[dvn]

Nice job!

 

[Watchdoc]

Looks nice. Can't wait to hear it. I'm guessing this is significantly lighter than stock too.

 

[Machine]

Marginal, Factory system is Mandrel Bent 409 Stainless, actually noticable high quality over other GM cars I have serviced. It is however, one piece. And short of dropping the rear axle, I had to cut it out. The pipe is a bit small, but the Resonator and muffler are pretty free flowing. The resonator is straight through, and for the size of that thing, only about 2-3 inches of the core are perforated. It seams to be designed to remove a very specific sound frequency. The rear muffler appears to be a "turbo" style; offset inlets and outlet a "S" path. But there is no baffling or curves, at least from what I could see. Stock system is pretty nice, but pipe diameter would become an issue at some point.

I doubt I lost any significant amount of weight.

 

[AndrewGS]

I've got a Magnaflow replacement muffler and want a little more volume. I'm thinking of going down to the exhaust shop and having the resonator removed. I don't know if it would be worth it though.

 

[BoG233]

man this is great info Machine thank you

 

[Machine]

I've got a Magnaflow replacement muffler and want a little more volume. I'm thinking of going down to the exhaust shop and having the resonator removed. I don't know if it would be worth it though.

Probably not, the resonator doesnt muffle the sound, it removes a specific frequency. Bumping up the pipe diameter, and removing the "california" cat that is after the downpipe. Is the quickest way to more volume.

 

[laborsmith]

I would think Machine has the right of it. The sound the resonator deals with is one you do not want, loud or soft. If I were to go for more exhaust sound, I would consider replacing the second cat. Of course, I already decided to dump the muffler.

Laborsmith

 

[sonicShadow]

i know this is probably a stupid question but wont you be shooting codes if you start taking of the resinators and or catilatic converter

 

[keto06]

Cat - yes
muffler - no
resonator - no

 

[Machine]

there are two Catalyst on this car, one that is right off the turbo, which is the main one, and the Aux or "california CARB" cat that is after the downpipe.

Only the first cat is monitored by the ECM through a 02sensor, the second one is not monitored and can be removed with no adverse affects. ( this is a real "grey-area" for emissions laws though)

My system is fairly broken in, I will post some audio clips soon. I am unfortunately getting a bit of a rattle or rasp when reving at idle, but it comes and goes, usually if Ive been cruizing or got my foot in it for a while, it goes away, so im thinking something might be loose in the muffler, and its tightening up under heat.

 

[Watchdoc]

Would love to hear those audio clips.

So why did you use a muffler clamp after doing all those pretty mandrell bent welds?

Did you have to cut the stock cat back to remove it?