A 'different' muffler question...

Quicksilver · 02-11-2003, 01:24 PM

I am wondering if anyone has seen a serious comparison between mufflers / exhaust systems and their sound output vs. power output. Specifically I am looking to free up the exhaust on my 87 Carrera but I want it as quiet as possible. (jeeze, I know I am going to get flamed on this one

) I drive the hell out of the car and I don't want the cops looking up their donuts and I don't want the rice burners to think that they need to race me.

I have been thinking of putting the euro pre-muffler in place of the cat and then a quieter stainless muffler. Another idea would be a 74 style header with 1-5/8 or 1-3/4 primaries and then some sort of quieter style muffler behind it. (Something like an SSI but with larger pipes.)

Anybody tried anything like this?

Wayne

Superman · 02-11-2003, 01:30 PM

We don't know how to make them quieter. We also don't know how to reduce horsepower, make them handle more unpredictably in corners or require longer braking distances. (just being a smart@ss)

boyo · 02-11-2003, 01:39 PM

Saw a show ("Trucks on TNN") the other day, showing a switch actuated valve that switches between muffler and no muffler. Someone pulls up to you at a stop light, and the coast is clear... Flick! Vroom! Flick! Purr....

-Boyo

ChrisBennet · ChrisBennet's Garage

'74 Style headers make things louder all by themselves I think.
-Chris

Quicksilver · 02-11-2003, 01:54 PM

(I think I stopped putting cards in the spokes when I was 12...)

I think I asked the wrong question. Has anyone ever tried a muffler and found that it was too quiet and refined? (That way you can hear the guy next to you when he asks for the Grey Poupon!)

Wayne

stealthn · 02-11-2003, 01:55 PM

Boyo,
I saw that too and I'm surprised no one here has tried something like that. Have a two out muffler, but one out is mechanically closed for street driving then opened up for track. I too want a quiet or slightly louder than stock muffler, but would like more HP.

makaio · 02-11-2003, 01:58 PM

Quiet and free flowing don't usually go together. You sorta have to pick one or the other. Just by installing a Euro style pre-muffler or test pipe will increase the noise level.

72 four door · 02-11-2003, 02:03 PM

I saw that too on trucks

__________________
72 911
82 911
70 GTO

97 GT Ragtop
74/76 Jeep cj's

72 four door · 02-11-2003, 02:04 PM

and my question would be wouldnt you have to adjust the mixture?

Jim Garfield · 03:03 PM

stealthn:

How did you make the open/close flap for the muffler?

I have a dual in/dual out BB system and I would like to be able to close the right
side when I don't need it as the resonance between 2 & 3k rpm makes my teeth
hurt. It also rattles the neighbors windows when I pull out of the driveway.

edit: stealth, I just reread the thread and see that you didn't actually do this yet.
Has anyone ever done a cutout flap for the right exhaust?

gumba · 02-11-2003, 02:17 PM

I use Supertrapps bolted to the SSI's on my 2.4. Will do the same setup on my 3.2 in my '73 targa. By varying the plates you can change the noise level. It also has an effect on the power band. I've seen some racing 993's using headers with Supertrapps.

jhugh · 02:23 PM

My uncle has been into Porsches forever. He time-trialed (and ruined, on a mis-shift) a 912 when I was a little kid. Now he has a 993 cabriolet tip. He is definitely of the "caviar" Porsche set. Only Andial touches his car. He would probably object completely to the basic premise of this bulletin board, if he even knew it existed.

When I first pulled up to his place with my Carrera with a dual-out B&B muffler and cat bypass, he said, "Nice car, but your muffler's broken." Then he said, "Soon you'll take that piece of ***** off and put the stock one back." He also said, "Power doesn't equate with volume. If you want more power, you should call Andial and get a 'tuned system.'" I talked to Andial. They said they do SSI and Dansk for the street. They said they didn't know anything about the other vendors. They probably don't approve of them, even though they make more peak hp, because they're too loud for the street.

I think that as long as you assume that you're using some kind of dual-out headers, and that you'll chip the car appropriately, volume will equate with power - in other words, disregarding the single-in setups, the louder you car is, the more power it will make. I think we know that SSI and Dansk is nice on a Carrera. That's probably what you ought to do. It'll be louder than stock, and too loud for my uncle, I'm sure. But not too loud for most of us. I don't think it would make quite as much peak hp as my new GHL headers & dual out muffler. My new system is louder than SSI and Dansk, but less loud and less boomy than my previous stock headers and B&B dual-out setup. And it sounds much better! More "Porsche" and very like a leopard.

I can't wait to hand my uncle his caviar tiptronic a$$ on the street. It will happen!

Cheers,

masraum · 02-11-2003, 02:26 PM

pretty much what everyone else has says. If you get rid of the cat or go to headers/ssi's then you will get more noise. You can probably stay relatively quiet, but hey, I just took the muffler off of my '88 and bolted a pipe/tip to the cat. No muffler, sounds good, less backpressure (but still got the cat), and less weight. It is pretty loud, but primarily outside of the car. It's actually quieter inside the car than when I had the dual out flowmaster.

Randy Webb · 02-11-2003, 02:28 PM

I never seen any data showing that a louder muffler beats the (original) stock muffler. Also true for the Boxster. Take a look at Bruce Anderson's book and various columns in Pano and Excellence.

jhugh · 02-11-2003, 02:36 PM

Bruce also says something to the effect that "the best chip change is an exhaust change," right? And then he goes on to talk about SSIs and custom headers. I believe the basic premise of gettin more power and improving the exhaust on these cars is GET RID OF THE STOCK HEADERS & CAT. After that, the quieter whatever muffler you put on, the more it will be causing turbulence and impeding the flow of gases out of the engine. Freeflow and louder will mean more peak hp. A little more backpressure and a little less volume may put the hp peak lower on the tach. I sure don't have the data to back myself up, but I just feel & intuit (!) that if you go as quiet and restrictive as the stock muffler is, you will have just wasted a serious amount of $$ putting the better headers on there.

There are data (dyno charts) in Bruce's book showing significant hp increases in 3.2 power with various non-stock header setups.

dd74 · 02-11-2003, 02:54 PM

Why use them on the street?

1) Moron drivers will hear you coming...

2) Moron drivers will move the hell outta' the way...

Early_S_Man · 02-11-2003, 03:01 PM

The only direct correlation I have ever seen between a 'sport' muffler with higher noise level ... and additional power output is with the 'original' 'sport' muffler with narow-spaced small pipes, as sold by Stoddard's and AJ-USA for many years. That muffler is reported by many sources as being good for an additional 10 - 12 hp, at significantly higher noise levels, perhaps as much as 15 dBA! The Phase 9 'silencer' featured in several of BA's charts and tests on 3.2 engines ... were not designed for the street, but, rather to allow race cars to meet more stringent noise limits at tracks. They looked more like 2-stroke motorcycle expansion chambers than automotive mufflers!

Although I have seen many users of Bursch, B&B, Flowmaster, and SuperTrapp's claim higher power than stock ... I have yet to see any noise test numbers coupled with dyno test numbers that support such claims!!!

One switchable 'muffler' that looks like one ... but hardly provides any suppression at all ... was the 1970 racing 'silencer' provided as part of a 'rallye' power kit. and which had very large outlets directly inline with the inlets, and much larger than normal inlets designed to mate with a racing header/megaphone set I have never seen one of those mufflers, or a duplicate/copy ... for sale anywhere, but it is shown in both editions of BA's Handbook.

Jim Garfield · 04:25 PM

My setup is B&B headers, no cat, and a B&B dual in dual out muffler on a 3.2.

Their (B&B) dyno results show an 18 hp +/- gain with a slight dropoff if the right
muffler outlet is closed. With the right side blocked off the sound level
is perfect inside and out, but I would like the option of being able to open
or close the right outlet from inside the car for DE or just general obnoxious-
ness.

I remember seeing some hot rod setups from the fifties with a setup like this...
maybe I'm trying to relive my childhood?

Quicksilver · 02-11-2003, 03:39 PM

From my experiances with various drivers in various cars that when the sound level is increased that the driver will always report an improvement in power. I have also found that when you break out the stopwatch or put it on a dyno that they are wrong about half the time. I'm kind of inclined towards Randy Webb's point of view.

I realize that you aren't going to get any real power improvement out of the 3.2 with out spinning it faster, increasing the displacement or pressurizing the intake. I really just want to be able to use all of the power without calling attention to myself. On my average drive to work I will see the up side of 100 and I don't have any tickets in the last 6 years. I like it that way.

Of the common single outlet mufflers is there one that is close to the stock sound level?

Wayne

Quicksilver · 02-11-2003, 03:47 PM

Quote:

Originally posted by Jim Garfield
My setup is B&B headers, no cat, and a B&B dual in dual out muffler.

Their dyno results show an 18 hp +/- gain with a slight dropoff if the right
muffler outlet is closed. With the right side blocked off the sound level
is perfect inside and out, but I would like the option of being able to open
or close the right outlet from inside the car for DE or just general obnoxious-
ness.

I remember seeing some hot rod setups from the fifties with a setup like this...
maybe I'm trying to relive my childhood?

I would just search the Internet looking for "exhaust cutout" or "electrical exhaust cutout". years ago I talked to a guy who had done something like this on a big block Chevelle and he said the the cutouts tended to rattle when closed and he took them off. He also said that when he opened them up that it made every nut and bolt on the car rattle!

maybe I'm trying to relive my childhood?
Why relive it? It is easier to just skip that whole 'growing up' thing.

Wayne