aaron_douglas

Newbie question here. I recently bought my first LS1 (2001 M6 Trans Am), and aside from absolutely loving it (previous car was a 4-cylinder crapalier...), I think I want to go with something a little quieter. The previous owner installed BBK LTs with the ORY (looks like 2.5") and the 80 series Flowmaster American Thunder catbacks along with looks like some aftermarket exhaust tips, and he cut the cats out.

I've read a lot about the Flowmaster muffler being very restrictive for the LS1, and also the car just seems a little loud for me, so I was thinking about replacing the Flowmaster muffler with a Magnaflow (Magnaflow 12267 muffler).

Is there anything I should consider before I buy one, or any other recommendations? Like I said, quite a newbie here; I've only really gotten into performance cars in the past year or two. I planned to find a local shop that could install it for me.

Thanks!

99Bluz28

iTrader: (35)

Are you sure of the outlet pipes being 2.5"?
I believe their 3" exit pipes on the FM. Magnaflow doesn't make one with 3" exits so i would suggest the Dynomax#17536, it's very similar to the Magnaflow.

aaron_douglas

I checked the flowmaster website and all were 2.5" outs and 3" or 2.5" ins. I looked at the muffler just now and the in is slightly larger than outs so it's gotta be 3" in and dual 2.5" outs, which the 12267 magnaflow would fit.

I appreciate the response though.

Avaric3

iTrader: (3)

i had a flowmaster catback and it was DEF single 3"in/dual 3"out

im about to put a single magnaflow bullet wit a turndown off of my fm catback tho. im using magnaflow part #14419

99Bluz28

iTrader: (35)

Yeah I had FM cat-back and it had 3" outlets, and I just did some checking and all their F-body LS1 cat-backs have 3" exits, only the 93-97 LT1 F-body cat-back have the 2.5" exits, so maybe that's what's on it.

aaron_douglas

That's strange, the inlet was definitely larger than the dual outs though.

I did read about these supposed to be 3" outs. Maybe he did get the LT1 catback or something.

aaron_douglas

I think I figured it out. It looks like for god knows why he had the 3" outlet cut and replaced with 2.5". Maybe to make it fit the tips or something. But you can definitely tell where it was cut and a smaller pipe was put in. That's awesome...

RevGTO

iTrader: (12)

To answer your original question, yes, I have a friend who replaced the FM muffler after it crapped out with a Magnaflow. Everything welded up fine and he's been very happy with it.

aaron_douglas

I decided to go with the 12266 magnaflow the muffler place had in stock (they matched the price I found online). The inlet and outlets were a little smaller, but honestly it feels significantly better on the low end. I think with the way the exhaust was (no cats, etc.), I had super low back pressure and was losing torque down low.

In any case, it feels and sounds a lot better. Got it installed with tax for 155$ total.

poloaa009

That's strange, the inlet was definitely larger than the dual outs though.