OEM Muffler Flow Rates? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

edevlin · 01-07-2007, 03:35 AM

Does anyone know if the flow rates are the same for an OEM Non-S and a S muffler. I was searching on the site and could not find any information. I would think that the 3.2 motor would require a higher flow rate than the 2.7.

The reason I am asking is that I would like to have a higher flow rate on my 2.7L exhaust system which is running headers and high-flow cats, but with my stock muffler.

I have tried two aftermarket mufflers so far, the Dansk had a resonance I did not like and the Gemballa was LOUD.

I have had my Boxster in the shop for a week, I will be picking it up tomorrow. It is having Bilstein PSS9 suspension installed, I cannt wait....

Ed

j.fro · 01-07-2007, 06:41 PM

The internals on both mufflers are identical. I would assme that the flow rates are the same. On another board folks have posted pics of the mufflers cut open.

MNBoxster · 01-07-2007, 08:33 PM

Hi,

You're assuming that the Base muffler is max'd out, which I doubt, and if it is, probably only at WOT, again which I doubt.

There's likely no real benefit to a switch, except the aesthetics of the Tail Pipes. Aftermarket pieces may be improved, but the OEMs are probably same-same...

Happy Motoring!... Jim'99

TriGem2k · 01-07-2007, 10:34 PM

Hey Ed what did you end up doing with the Gemballa exhaust that was too loud for you? If you still have it I might have a buddy interested in purchasing it from you.

BTW you are going to LOVE the PSS9 setup. We had 80degree weather today I racked on about 200 miles in the twistiiiis. Just can't seem to get enough of it.

James

edevlin · 01-08-2007, 03:23 AM

Thanks all for the feedback on flow rates and internals on the stock 2.7L OEM muffler. I not really interested in the look of the muffler, just wanted to be sure that the intake/exhaust system was breathing optimally, as I am trying to squeek out all the performance I can.

I had wondered about the stock muffler flow rate because some have reported a modest increase in HP by only replacing the stock muffler. BTW, the exhaust sounds very nice currently with intake, headers and 100-cell cats into the stock muffler, so I am not looking for louder sound.

I have had all the exhaust work done by the folks at Auththority Pitstop in DC. They are the ones that stuck on the Gemballa muffler for me to try. It is still sitting on the floor of their showroom. It is in as new shape, but is a used muffler, they may even have around on consignment, I am not sure. If anyone is interested in it, just drop them a line.

Ed

RandallNeighbour · 01-08-2007, 10:30 AM

Ed, what kind of 100 cell cats did you put in, and how much were they?

The Dansk version I found for my 2.5 were something like $1300... ouch!

Houston C4S · 01-08-2007, 03:41 PM

The only comparison I can help with here is one between an
'01 Box and an '04 Box S.

Theses mufflers are not, let me repeat that, not the same.

You can look right through the '04, end to end (off the car,
of course). If you put a lens in it you could use it as a telescope
(albeit a rather heavy and bulky one).

You cannot do that with the non-S '01.

And the sound is not the same. The '04S has a very noticeable
sound increase (Which goes away at road speeds above about 50
or so on really smooth pavement).

That's not to say that the flow is better. These automotive exhaust
engineers are pretty crafty these days. It's my opinion that the
reason they can make these new cars quiet (or loud, if they choose)
is the large size and chamber design. They can be quiet and still flow
lots of air.

So there is sort of a non answer for you. They are different, they
do sound different, but do they flow differently? Ya got me, bub.

I suspect, however, that they flow just fine as they are and while
some might sound better or look better, it'll take a dynomometer
test to really know.

Ask Randall -- he knows.

All the best,

- Mark

RandallNeighbour · 01-08-2007, 03:56 PM

I only know a lot about nuthin'!

Boxtaboy · 01-08-2007, 04:08 PM

Quote:

Originally Posted by Houston C4S

Theses mufflers are not, let me repeat that, not the same.

You can look right through the '04, end to end (off the car,
of course). If you put a lens in it you could use it as a telescope
(albeit a rather heavy and bulky one).

You cannot do that with the non-S '01.

- Mark

That's weird. On my 01 base, I pulled my OEM muffler before installing my Dansk pressed sport exhaust, and the OEM unit was exactly as you described the 04 muffler - ie. that you could look right thru it from one side to the other. With my Dansk, I noticed that you couldn't do that, as it had tapering tubes with holes in it that formed a cone.

I do think the 04 muffler does sound different from the 01 though, as it was engineered to produce a more raspy growl than the earlier models, but still not loud. As for flow characteristics, I have no clue. I just like the sound of my Dansk better than my OEM one.

edevlin · 01-09-2007, 02:53 PM

"Ed, what kind of 100 cell cats did you put in, and how much were they?

The Dansk version I found for my 2.5 were something like $1300... ouch!"

Ouch is right, I paid 1200.00 for the 100-cell cats that are on the car now. They were used and came off a 3.2 with a supercharger. I am not sure if they were Dansk or custom made. It turns out the the CEL I have been getting after putting the cats on is because one of the cats is bad, so I am taking them back to the shop for credit and getting the TTP cats. I am not sure of the final price, but I think the TTP 100-cell performance cats cost, are you ready..... 1800.00 (http://www.t-t-p.de/english/catalytic.php), big ouch.

Ed