Thread: Magnaflow VS. Flowmaster???

On my last Grand Prix, I removed the cat and resonator, and kept the stock mufflers. I replaced those with a 3" pipe from downpipe to Y. I liked how this sounded.

On my current GP, I was looking to go a little louder, so I went with the Borla Pro XS mufflers, magnaflow high flow cat (for emissions purposes), 3" from dp to Y, and 2.5" back to mufflers. I really like the sound of this, but I have a little drone that I want to get a resonator to take care of.

Personally, I don't like either flowmaster or magnaflow mufflers on our cars.

I get compliments often on my Magnaflows. Even from some LS4 owners.

Custom 2.5" piping, no res, dual Magnaflow XL 3-chamber mufflers. (pretty similar to GMPP exhaust kit's mufflers)

Originally Posted by Gearhed42

I thought the Magnaflow XL was suposed to compete with the Flowmaster 40 series???

I've never heard that, and they definitely don't sound alike. Not sure what difference it would make anyway.

Originally Posted by Gearhed42

So does that mean they are relatively quiet?

With no res, they're somewhat loud with throttle (or during warm up), but not loud at idle (once at operating temp). With the DP they've gotten a bit louder. And yes, GMPP is GM Performance Parts

Originally Posted by Gearhed42

Everyone keeps saying raspy or fart can sounding?

Like I said, I get compliments from LS4 owners so it can't be that bad.

Originally Posted by archemedes

borla is great but expensive

Borla are not expensive, as far as I am concerned. I took the following prices from Wicked Nicky exhaust. The only site you will ever need for low prices on high performance exhaust systems and more.


Flowmaster 40 Series Delta Flow Muffler, 2.50" IN (O) / OUT (C): Nicky's Price: ea $82.39 PN 942541 Retail Price: $109.85


Borla Pro XS Muffler - 2 1/2" offset inlet / 2 1/2" center outlet (a)2 1/2" inlet dia (b) 2 1/2" outlet dia (c)14" shell length (d)4" shell height (e)9 1/2" shell width PN 40358 Nicky's Price: $74.00



Oh, and Flowmaster are made of regular steel. Borla are stainless steel and are warrantied for 1 million miles. And I think my Borla's sound nicer than every Grand Prix with flowmaster.

But just a note. Sound is something subjective. Meaning, I may like the sound of my car. You may not. Ricers evidently like the sound of fart cans. I do not. Some people like 22" rims, some don't. So take everything FWIW and with a grain of salt....even my advice.

I just replaced the mufflers on my GMPP (Magnaflow) catback with the Borla's Zef link to. And I love them. Seems like the pair were right at $169 shipped and they arrived pretty quick.

Originally Posted by Gearhed42

Zef and indeed are you running them with or without the resonator?

My exhaust system TOG's>>Hogan 3" catted DP>> GMPP catback plumbiing>>MBRP resonator>>Borla XS Pro's>>Magnaflow 15* rolled edge tips.

The resonator helped slightly with drone but the Borla's were a night and day difference in killing drone and V6 fartiness.

Mine is a hybrid, because the resonator went bad and it seemed as if the sound deadening of the mufflers burned out like glasspacks do. IMO, leave your resonator in place and add the borla muffler(s). It's good to have the Ubend removed but not the resonator. On a V6, the quieter the exhaust system the better.

Originally Posted by Gearhed42

Once i decide on a muffler (now im all confused) ill probably just leave the resonator in and if after a while i feel it should be louder ill remove it then. Now to decide between mufflers.....

If you are going to BGPM, wait and listen to as many systems as you can. One thing though, some mods will effect the sound. SO what you hear may not be exactly what your car wids up sounding like.