Looking for a perfect muffler!

Moses · 09-12-2002, 09:47 AM

First off, I have a 1983 911 SC with stock exhaust except I have a 1 in 1 out GHL muffler. I love the muffler, but I want to switch to SSI's.

Here's the problem: I want a deep, rumbling exhaust-but I don't want to set off every car alarm in the neighborhood. ( I don't mind setting off alarms in parking garages, though)

Is there such a thing as a 2 in 2 out muffler that sounds aggressive but doesn't rattle windows and send the old folks running for cover?

I've searched the archives, but most people describe 2 in 2 out mufflers as bone-jarring loud.

Even if it's a 2 in 1 out muffler, does anyone have an SSI/muffler combo they are really happy with?

JWest · 09-12-2002, 09:55 AM

How about 2 outlet muffler with the second outlet partially blocked until you get the sound level you desire?

HawgRyder · HawgRyder's Garage

I have been looking at all the different posts on mufflers too.
The one thing that stands out in al the posts...one man's noise is another man's music.
I'm not happy with my original style muff and plan on changing it as soon as I get her on the road as a daily driver (garage queen).
My idea for a muff is to build one myself...this way I can get exactly what I want.
I have done exhaust systems before...and it's not that hard...just selecting the right pipes and materials (stainless)...after all...I only want to build it once.
If you check out high performance cars with similar size engines and look at what sizes of pipe and lengths they used...you should be in the ball park.
I'm playing with chambered cavities right now...but might end up just cutting my old muff in half and measuring everything.
Above all...listen to every type of muff yourself...at cars shows....races..etc. then make a descision.
Bob

82SC · 09-12-2002, 12:07 PM

dansk 2in 2out sounded great...and fit the characteristics you stated...

great build quality...nice fat dual pipes

peopl at N. Hollywod speedo came out to ask what type of engine I had in the car...most thought it was a v-8...

it started getting to me after a while...you can't hold a conversation...and car alrams would go off in every parking garage...

Jack Olsen · 09-12-2002, 01:25 PM

The cheapest way to do it is with a $90 dual in dual out Flowmaster. It's pretty loud, but not like megaphones or supertrapps. And you can cap one side and its suddenly pretty quiet.

I've thought of putting a valve on the second outlet -- either a Porsche heater flapper valve or a flipped and capped exhaust bypass valve like 1/4-mile guys use, so that I could adjust volume with one of the heater levers (or a dedicted cable actuator) in the cockpit.

Greg S · 09-12-2002, 01:32 PM

I have SSIs and the stock-type Dansk 1-out muffler. It has a nice sound and isn't too loud at all. Doesn't set off any alarms except of course the alarm on a car no one would steal anyway.

That seems like it might be what you're looking for.

RoninLB · 09-12-2002, 01:44 PM

I think Moses should visit a DE and listen..a dual out Monty always sounded a little different than the whole 911 muffler world, IMO.....Ron

Bill Douglas · 09-12-2002, 01:47 PM

Moses. Just an idea. I don't really understand the internals of muffers and how the flow works but.... If you like the GHL, why not get a muffler place to cut and weld the 2 in bits onto your existing muffler.

TimT · 09-12-2002, 01:48 PM

The"perfect" muffler doesnt exist!!

RoninLB · 09-12-2002, 02:06 PM

I'm with Tim on this one..it's kinda like sleeping with a big mouth.....Ron

masraum · 09-12-2002, 02:29 PM

I think the perfect muffler is no muffler, but since there are reasons NOT to do that, I think the Flowmaster crossflow is the best for the money.

On a related note, one of the most amazing things that I have ever heard is the sound of the showroom stock Corvette racers from the late 80's. The first time I ever heard them I was on the opposite side of the track from where they started and thought Godzilla was walking throught the city. It was really amazing.

TimT · 09-12-2002, 02:37 PM

someone else had posted this link before, they make what looks like a very cool product

Im thinking of getting a pair for my car

911pcars · 09-12-2002, 02:45 PM

Since everybody's perception of what sounds nice is pretty subjective, here's one way to tune the dBs. This strategy assumes installing a second tailpipe on the other end; a mirror image of the driver side tailpipe. The twin-pipe setup exiting the middle of the muffler is not a good candidate for this.

Start with a 2 in-1 out muffler attached to your new SSIs. The factory muffler is a good place to start. However, a stainless factory muffler may be lighter and last longer too. Obtain some exhaust tubing from your favorite source. A 180º bend setup from JC Whitney, Summit Racing or Jegs in your favorite diameter should provide enough material for two tail pipes. You could also install another factory chrome tailpipe if you want to match the driver's side.

You're going to create a hole in the right end of the muffler right where the new tailpipe will be (drill, torch). Start with a 1" hole. Start engine and listen. Loud enough? Stop engine, cut and fabricate the 180º pipe, then weld in place. Not loud enough? Increase the size of the muffler hole until you're pleased with the tone. BTW, as the size of the hole increases, you can make it even louder by accessing the internal bafffle closest to this end and cut a hole through it with a cutting torch. Can't hear yourself think? Patch a portion of the hole, then install the new tailpipe using the "hammer to shape, file to fit, paint to match" procedure.

In any case, you'll also have to provide some sheet metal clearance for the new pipe. You can also start off with the sport muffler modifications to the internal baffles as a baseline listening test before installing any additional pipes. Somewhere in the archives is a drawing of the internal mods to arrive at a sport muffler.

Another way to do it would be to listen to someone's installed sport muffler, Dansk, GHL, B&B, or other aftermarket muffler. Set aside budget and proceed from there.

Just a thought,
Sherwood Lee
http://members.rennlist.org/911pcars

TimT · 09-12-2002, 02:53 PM

I have a bischoff sport muffler, as well as straight pipes and megaphones. ( bischoff, leistritz,dansk and others are all oem suppliers).

the twin in twin out sport muffler is a good choice, the flowmaster is marginally better but you have to have someone weld all the pieces to make it fit. I can do that . other have to pay so the costs somehow negatel.

But the twin in twin out factory muffler bolts right to the SSI's or factory 3 in 1 out

emcon5 · emcon5's Garage

Quote:

Originally posted by 911pcars
Start with a 1" hole. Start engine and listen. Loud enough?

Good plan Sherwood, but I would start smaller, probably 1/4". You can always drill a small hole larger, you can't drill a big hole smaller.

Tom

09-12-2002, 03:09 PM

Moses,
Here is Jack's Flowmaster 1 in 2 out idea(and muffler) on an otherwise stock 79SC.

click for an mpeg

911pcars · 09-12-2002, 03:15 PM

Tom,
A 1/4" hole is not being ballsy (sp) enough. I actually wrote 1/2" hole, then changed it to 1". I thought I'd be a risk taker with someone else's muffler. Oversize holes can be repaired using the "hammer-to-shape, file-to-fit, paint-to-match procedure outlined earlier. Measure twice, cut once only applies to wimps.

Sherwood

emcon5 · emcon5's Garage

Quote:

Originally posted by 911pcars
Tom,
A 1/4" hole is not being ballsy (sp) enough. I actually wrote 1/2" hole, then changed it to 1". I thought I'd be a risk taker with someone else's muffler.

True, but from looking at this cutaway, there are no baffles at all between the right header and the right outlet. A 1" hole will be pretty damn loud.

Tom

911pcars · 09-12-2002, 03:46 PM

Tom,
The drawing shows a "full bulkhead" that supports two pipes which diverts the exhaust flow toward the middle area. Careful, with hole sizes here. Piercing this bulkhead should provide a vastly shorter path from muffler inlet to the right end opening ... as well as more noise. I haven't ventured too much beyond a 1" equiv. hole to the muffler shell (not loud, BTW) due to my stalled attempt at fitting a *!X$#@ RS FG bumper. I temporarily installed a right side pipe to fit within the confines of the stock rear bumper until the next attempt at FG sculpting.

Sherwood

Bill Verburg · Bill Verburg's Garage

Quote:

someone else had posted this link before, they make what looks like a very cool product

That would be me. The Coast Fabrication mufflers sound great and aren't as loud as my Flaumeister. They are good enough to be used on several east coast RSRs that run at Limerock w/o any problems sound wise or power wise.

By the way, here's a Flaumeistered 3.6 hooked up to a dyno, close miked w/ a very poor mike.Dyno run

and heres one in my garage,

garage