Muffler differences???

porsche735 · 10-09-2006, 02:24 PM

I am installing a 1985 3.2 into my 1973 car. I have replaced the exhaust with the old style heat exchangers and have backdated the sheetmetal to the hoses on each side of the fan (removing the "helper" heater blower assembly).
My question is, is there a benefit to using something other than a stock 2-in 1-out muffler for this setup? Are there appreciable gains to be had with one of the higher cost mufflers or a 2-in 2-out setup? If so, which would you recommend. Aesthetics are not so big a deal to me...

Thanks,
Chris

Grady Clay · 10-09-2006, 03:06 PM

Chris,

The two big differences are performance and weight. Pay attention to both.

Best,
Grady

mb911 · mb911's Garage

Quote:

Originally posted by Grady Clay
Chris,

The two big differences are performance and weight. Pay attention to both.

Best,
Grady

very sound advise.

what ever your decision I would stay with a dual in single out

dd74 · 10-09-2006, 05:04 PM

Quote:

Originally posted by mb911

what ever your decision I would stay with a dual in single out

Interesting. Why is that, Ben? I thought the dual-outs were good for a handful of hp.

PM'd you, too.

randywebb · 10-09-2006, 10:33 PM

good for a handful of noise... I have dual outs, cowhorn style

pwd72s · 10-09-2006, 10:36 PM

Quote:

Originally posted by randywebb
good for a handful of noise... I have dual outs, cowhorn style

What??? When you left here, I'd have sworn you had NO muffler.

dd74 · 10-09-2006, 10:39 PM

Dual outs have to be good for something. Or do the only logical choices in mufflers entail full race (megaphones) or a single out (street), with nothing in between?

rdrr · 10-09-2006, 10:50 PM

I'm sure I read a post where someone had dynoed a dual out vs a single out and found a 5hp gain, or something like that. Sure hope it's true as I've just ordered a dual out M&K.

dd74 · 10-09-2006, 10:57 PM

The beauty about the M&K from what I see is the weight. A dual-in/dual-out supposedly weighs 14 lbs. Many others weigh close to twice the M&K's weight.

mb911 · mb911's Garage

Quote:

Originally posted by rdrr
I'm sure I read a post where someone had dynoed a dual out vs a single out and found a 5hp gain, or something like that. Sure hope it's true as I've just ordered a dual out M&K.

I friend in the UK just dynoed one with single out and then dual out he gained 8hp. I did not see the sheets but thats what his email said. Sounds high to me I would think 4 hp max

randywebb · 10-10-2006, 11:01 AM

" I'd have sworn you had NO muffler."

Awwwww... it's a car of moderation. Why won't anybody believe me when I say that?

Folks - I hate to tell you this - but people who have dynoed a lot of mufflers, including Steve W., Bruce A., and a machinist/engine builder for a NW race team -- all say no extra hp with dual outs -- UNLESS by dual outs you mean a sport muffler.

pwd72s · 10-10-2006, 11:10 AM

Quote:

Originally posted by randywebb
" I'd have sworn you had NO muffler."

Awwwww... it's a car of moderation. Why won't anybody believe me when I say that?

Folks - I hate to tell you this - but people who have dynoed a lot of mufflers, including Steve W., Bruce A., and a machinist/engine builder for a NW race team -- all say no extra hp with dual outs -- UNLESS by dual outs you mean a sport muffler.

Aye, that's the rub...especially in the pre smog era 911's. All the easy performance gains like exhaust changes had already been done...at the factory. As they came off the line, these cars had already been "hot rodded". This applied to intake as well...