Muffler?????

**misterman** · 04-30-2011

are these good mufflers? if so what size would i get? Magnaflow Universal Satin Stainless Muffler - JCWhitney

also does changing the mufflers add any performance or is all about the sound?

**TheOtherNick** · 04-30-2011

Muffler does nothing for performance. Stock pipe to the muffler is 2". Go on to youtube and pick what you like.

**misterman** · 04-30-2011

so what part of a catback provides the performance?

**TheOtherNick** · 04-30-2011

none.

**misterman** · 04-30-2011

really lol??? so y do people buy them for? also i call these cat backs SLP PowerFlo Cat-Back Exhaust for Grand Prix - 04EXH - PFYC.com

y do i feel like u are messing with me lol

**01gpgt01** · 04-30-2011

its true, the stock exhaust isnt a restriction until your making well over 300whp

**misterman** · 04-30-2011

and the only way to get to that point is to add

thermo
headers
smaller pully
cai
pcm
????????

**01gpgt01** · 04-30-2011

cam, intercooler, colder spark plugs, built trans. DOnt forget those

**TheOtherNick** · 04-30-2011

intercooler cam great tune.

**L36pro** · 04-30-2011

the gains you would see from a muffler would be minimal at best. more air out = more air in so if theres a drop in backpressure you should see a small gain, but mostly it would be placebo effect. ubend delete and resonator delete have seen dyno results of up to 7hp. im running stock exhaust with those two mods and a magnaflow cat. i love the sound, and the performance certainly didnt decrease.

**misterman** · 04-30-2011

arent ubend deletes for 03 and under gp's?

**L36pro** · 04-30-2011

not sure to be honest. i thought GM commonly did the ubend to protect the rear o2 sensor.

**matt5112** · 04-30-2011

lol backpressure.

I agree though.

Minus the resonator part.

That can't do anything unless its falling apart like mine was.

1.5" exhaust FTW?

**misterman** · 04-30-2011

ill check and see if i have one when i change my exhaust clamps

**L36pro** · 04-30-2011

yeah, theyre easy to spot. and i did my resonator because i loaned the car to a buddy and he backed into a parking block, crumpling the resonator and bending the y pipe. its definately louder at idle than my other 2 stock gt's. i like it.

**misterman** · 04-30-2011

so i would need a muffler that is 2inch inlet and 2 inch outlet? there are like 20 freaking size options on the jc whitney page for the magnaflow muffler

**L36pro** · 04-30-2011

2.25 (2 1/4) inch diameter...... actually im not sure of the diameter after the y pipe. i know the main tube is 2.25 in.
the use of basic geometry comes in handy here. measure the outside circumference of the pipe, then divide by pie (3.14) and that will give you your outside diameter, or you could buy an electronic caliper and just measure it that way.

and they are offset mufflers. not sure how your gonna remount the hangars.