Charley B

Any one have thoughts or experience with a Flow Master Muffler on an OB with cats only, no mid muffler?

BeerFish

Charley - I have a 3" aftermarket Y back to a Flowmaster 40 without any midpipe. Love it!

Jadz928

I like mine. No mid muffler, though I have 2 resonators on the y-pipe before the merge. 10db per. I like it much better now. It is possible your cats may create a similar noise reduction.

hacker-pschorr

My 79 has no mufflers - love it
The 81 has a small straight through Borla - almost as nice as the 79

I agree with Jadz, if you still have the cats, running wide open after the cats will not be that loud (I tried that first). Problem is, if you are going for more power, dumping the factory Y pipe and the cats is priority #1. Number 2 is changing out the manifolds for 85/86 SS units.

Andrew Schauer

I have a Flowmaster 40 on my 1980, no cats, no mid muffler. I get compliments all the time on the sound. With the windows up, in town you can barely hear the exhaust. On the highway, wind noise more than covers up the sound.

BeerFish

Andrew! Send me some pics of your YSR 50!!!

As for noise, my 84 is MUCH louder now. But I love it, reminds me of a Harley on crack!

The Old systome delete - new system install gave 11 HP on the Dyno for me.

SMTCapeCod

There is a car with custom flowmaster or similar mufflers on the 928OC website, I think the most recent Wilbraham tech session, if you just want to look at the routing and fitment.

bcdavis

I found it sounds a little raspy without a resonated exhaust tip.

Charley B

Thanks guys. I appreciate the responses. I made an appointment for Tuesday to have a Flowmaster installed. They suggested a 2 in, 1 out, to make room without having to lower the routing, and then a twin tip out the stock position.

Eric, I already have the '86 manifolds.

bc, or anyone, what is a resonated tip?

Jadz928

A resonator anything related to exhaust is essentially a thru-pipe with a bunch of holes in it to catch certain sound frequencies. Therefore decreasing decibles and certain pitch. Of course the pipe with holes is encased by something.

My oval tip is a resonator as well, just not a very effective one. The Dynomax bullet resonators really did the trick and acheived an effect similar to what Bcdavis did with his Monza tip... removed the raspiness.

Looks something like this...

SMTCapeCod

I've got straight through exhaust aft of the cats on my Audi's 300HP V8. I went with aeroturbine resonators in the center section because my desktop search seemed to indicate that they were particularly good at handling midrange drone. The rears are Stebro, and I had a custom stainless dual in/out straight through muffler up front. Still hear it at idle and on the road but without drone or intrusivenss, and it's downright ornery when provoked.
I think there are some pics on the forum of a Mufflex install that also used a rear mounted flowmaster-- if I'm remembering correctly. I"ve seen a couple end of system installs- it's good because any backpressure will have less effect at the very end of the system (whether that's noticeable or not is up for debate)...but I have not come across such an install that really looks tidy from the aft end, except that mufflex example.

SMTCapeCod

Found it, my mistake it was magnaflow rather than flowmaster (and note use of center resonators), but they did do a nice job finishing the install at the rear fascia, imho. Not much room there.
https://rennlist.com/forums/showthre...hlight=mufflex