Dual Out vs. Single - Noise or hot air?

[Purrybonker]

Ok - it's SSI's and Dansk/Monty time for the 3.2 I guess.

There seems to be lots of opinions on mufflers, but is the decision about dual/single out more about audio esthetics or function?

I would rather keep the single out for that stock look - unless there are meaningful implications to power associated with the dual out. I am quite happy with the sound of the factory muffler (even with the cat) and would prefer not to significantly increase the loudness of the car.

Recommendations?

[1fastredsc]

Since you don't want to increase the noise to much, you may wanna try a single because from what i hear, duals are loud. Or look for an aftermarket universal muffler. Assuming that both outlets are the same size, the flow on the dual out would be better but i couldn't tell if it makes a big performance difference on paper or not.

[JeremyD]

Check out the following

Thread one

Thread Two

Thread Three

From the peanut gallery. This weekend - just finished installing a single in, dual out on my 1987 Cabriolet. Dansk premuffler.

I don;t think it's too loud at all - even in a cab - in fact from a sound standpoint - not much louder than stock - pitch has changed to much throatier - burble burble.

I'll try and isolate a sound file.

THEY'RE ON!!! (Long)

[BGCarrera32]

I heard a guy's SC that I met on this forum. He went with SSI's and a dual in/dual out Dansk. Quite a bit "droanier" and resonant at idle and under 2k rpm (you have to speak up a little)...but whoa what a nice sound when you step on the loud pedal...nice exhaust note. Not any noisier than stock per say, but a nice smooth sound. Plus, from everything I have heard and read, a dual in dual out with SSI's are an easy 15-20 hp gain over the cruddy stock 3.2 exhaust.

I'm planning that mod myself in fact...

-BG

[KTL]

I'm sure i'm in the minority here, but here goes.

I say save yourself some money and get a Dansk premuffler and the Dansk or Monty muffler like Jeremy did.

Seems to me that from what I recall, the stock/unmodified 3.2 motors don't benefit as much from the SSI's. Sure they're nice. I wouldn't mind having them. Not sure about the cost/hp ratio though. But we all know Porsche hp ain't cheap. Maybe when my OE exhaust falls off i'll get them?

Here's my weak reasoning (besided being cheap). A buddy has a well stripped down 86 coupe with the B&B headers & muffler and an Autothority chip tuned for headers. His car is quicker, but it doesn't run away from me. I'm running a Fabspeed premuffler, stock muffler, a stock chip with the fuel enrichment turned up a notch and a little bit of lightening. I keep up with him just fine.

These exhaust debates crack me up because we get diddly squat for the amount of money spent. Like I said, Porsche hp ain't cheap. Kinda funny how many don't find $700 for a muffler unreasonable. I think it's outrageous!

[1fastredsc]

It's biggest gain is in the top end, that's where having equal length headers makes a slight difference.

[BGCarrera32]

We might not be in agreement, but I respect your opinion. All you have to do tho is take a look at the silly crossover pipe arrangment of the 3.2, the unequal length header in the heat exchangers, and it starts to become evident as to where some hp can be gained. Remember, I'm talking about dual in/dual out. Obviously ditching the cat is the first step, which I would have done had Fabiani not sent me a crooked and rewelded premuffler...so now I contemplate the "big" mod.

First things first though, I need to cut 30 lbs. out of myself...

I do agree, however, that $700 is outrageous for a muffler. But if I wanted sane, I would drive an Accord.

[Bill Verburg]

There are 2 big factors that posit against SSIs on 3.2s.

1) they have only 1 3/8" ID which is getting to be on the small side for that displacement

2)the cams do not have a lot of overlap which header tuning feeds on

besides that they are expensive and for proper fitment require replacement of 2 oil lines.

For far less $ almost as big a bang can be had w/ a proper euro resonator in place of the cat and a free flowing final muffler.

w/ a chip of course.

[Randy Webb]

The SSI folks consistently maintain that the tubes are plenty large enough for a 3.2L. There's always bias, but he seems to be a pretty "by the data" guy.

[Steve W]

The whole premuffler exhaust vs SSI debate has been going on for a while now, but here's my take as I've run all those combos. When you run a premuffler and with sport muffler, the power gains are almost the same as a set of SSIs and a sport muffler except SSIs will set you back $2000, parts only when all is said and done and you'll have to figure out how to pass smog if you have to deal with it in your state. With either setup, you'll need more fuel to the motor otherwise it will run lean, bog, and hardly increase your power much through the powerband, except from 5400-6200, because the factory programmed this area overly rich. At full throttle, the dme ignores all sensor inputs and goes by a preprogrammed fuel and ignition map for a stock motor. It doesn't know you did any mods to your motor to increase airflow. When I ran a premuffler setup, with a programmed chip and the proper fuel, my car ran pretty hard, I could chirp my 265 wide rear tires on a first to second gear change, and I have a lsd also. When I put on the SSIs with a Monty single out, I was disappointed that I noticed no difference or increase in power. Subsequently I reprogrammed the fuel maps in the chip for the SSIs, and then noticed some additional power.

As for Monty vs. Dansk on a set of SSIs, a dual out Dansk will get less on your nerves than a single out Monty. The Monty has a annoying drone from 1800 to 2900 that gets real tiring after a couple of months - like a high pressure single note tone in your ear. The 2 out Dansk has it too, but within a narrow window between 1800 to 2200. Both of these are pretty loud, like a hypoed V8, so if you want it quieter, go with a single out Dansk sport. Lots of noise/resonance wary owners have been really happy with them. Now if you go with the premuffler combo, go with a single out Dansk sport, as it's actually not that much louder than a stock muffler inside the car, and has no droning. According to Mike Jensen, the U.S. rep for Dansk, there is no power difference between the single vs dual out other than noise.

[KTL]

Bill and Steve have much more hands on experience with this and therefore said it better than I ever could. Great info. as always fellas. And nice of you to spend the time to type what i'm sure has been said many times before!

All I can add is that I had the somewhat equivalent of the SSI's in a B&B header setup and I honestly cannot say that the headers were very much stronger than the factory heat exchangers equipped with a premuffler. Seems to me that the added power is not super-noticeable to my scrawny butt. Or maybe my car is just a dog and i'm a kinda dense when it comes to seat-of-the-pants stuff. Dunno.

Another thing I guess I can add is the smog test experience i've had. I was able to pass smog (and it was a quick pass/shortened test) here in IL with the premuffler in place. It passed solidly and not by the skin of its teeth.

Granted, I have a stock chip and I turned the rotary switch on the DME to the -3% fuel position just for extra measure. Dunno if changing the position of the switch makes a difference, but I figured it couldn't hurt just to do it for the test and then head right home to put it back to the original position. I gotta give Steve a call and get one of his chips i've been procrastinating about for so long. Hate to be running too lean this time of year!

Cutting weight is certainly a way to go faster. Especially if the driver could use a little paring of weight. Just gotta decide what's sacrificeable (is that a word?). I kinda like my makeshift stereo system and don't mind the extra 30 or so pounds. But the A/C? See ya!

[Bill Verburg]

Steve W has nicely summarized what happens, here's why. The SSI headers were designed for the 2.4 and, big at the time, 2.7 liter engines they are outstanding products for these engines because of the size and considerable valve overlap that they use. Modern smog motors have so little overlap that the exhaust flow volume is the primary advantage of one exhaust over another.

The SSI w/ 1 3/8" ID primary pipes flows 9180 l/min optimally. When they are put on a 3.0 they perform well but not as well as on the 2.7, in this app they are asked to flow 10200 l/min. To do so the exhaust gas speed must go up, this is good as it provides a boost in torque lower in the rev range than w/ the 2.7 but begins to back up a tiny bit at the top.

W/ a 3.2 and a bit lower rev limit they are asked to flow 10400 l/min, again at the bottom of the rev range gas flow speed is increased, increasing torque, but again as the revs build the gas speed increase is restricted and cannot keep up w/ the flow. This is a small effect only happening at the top of the rev range. There is a nice increase in torque lower down and since most folks drive 98% of the time in the lower part of the rev range, this is the increase that they feel.

The SSI can also be used on 3.6 where they are asked to flow 11700 l/min and the effect outlined above becomes even more apparant.

When compared w/ a stock exhaust system, where the cat is the biggest restriction to flow, the SSI have the edge throughout the rev range, doing better at the bottom but w/ the margin narrowing to only a few ftlbs at the top. If the cat is replaced by a properly shaped resonator/premuffler that does not disrupt the gas flow and can in fact enhance it, the gap is further decreased.

So while the SSI are better, are they a cost effective solution? It's your decision.

If happier cams are introduced then the additional advantage of a tuned equal length exhaust system can come into play, further enhancing the SSI torque advantage over stock.

The objective in the selection of primary pipe ID is to have the maximum gas speed at maximum revs w/o restriction. Too big will slow gas speed throughout the rev range, more so at the bottom, this is bad for torque.

[dickster]

i dont think you'll sway either camp on this but my vote goes to the euro premuff/sport muffler.

i went for the two out dansk, but would probably go with the single out sport that steve suggested if i did it over. getting old i guess.

[NoLift911]

I'll chime in on this also since I recently went through this as well and got lots fo great advice from Steve and others.

I wanted a stock look with more power so I went with a RUF sport muffler which is basically a modified stock muffler...one in two out. Sound is good, deep but not obnoxious. I also added a fabby pre-muffler that added some extra hp and a little more burble. Then I told Steve my setup and he burned a chip for my specific setup. The result was pretty dramatic...the car pulls, idles and generally drives all around better. All said and done I am probably 15-20hp richer. A real wake up for the 3.2.

Drawbacks are a stinky exhaust with the windows down and stoplights and the girly whining about the smell.

-Jeff
nolift911@hotmail.com

[KTL]

What kind of smell Jeff?

Unburned fuel?

Rotten eggs/farty?

Burning oil?

[NoLift911]

The smell would be good old fashioned internal combustion engine exhaust smells...which the cat does an amazing job of keeping at bay(when isntalled).

As for farty smells that comes from me after too much dairy...but that is another story...she is not fond of that either.

-Jeff
nolift911@hotmail.com

[PeteBrown]

First, this is the perfect thread I was looking for today. Second, being cheap, I agree with Kevin on the insanity of paying $700 for a simple sausage muffler when entire systems for the American and Japanese crowd are in the $400-500 range by the same manufactures.

Along the cheap thought, how does a Flaumeister compare to a Dansk sport muffler in terms of performance? Is there a Flowmaster that has a single-in, single-out design on the same side of the can similarly to a stock Corvette C5 muffler?

My catbypass/Edelbrock system is getting a little too loud and I'm thinking of building flowmaster system but would rather not take off my valence or cut it.

Thanks

[PeteBrown]

Never mind. I found it.

# 52580 for single in/out same side
#42583 for single in/ dual out.