Laust Pedersen

Our cars are rarely used for only one purpose and sometimes we also get tired of the “same old stuff”. One part of the car that can easily be changed to fit either the street or the track is the exhaust system (emissions and noise level). Even when driving on the streets it can get tiring to listen to the same exhaust note (acoustic spectrum) and see the same tail-pipe and muffler.
With the spread of low-cost manufacturing some exhaust components are actually getting cheap. It is possible to purchase polished stainless mufflers on eBay for about $30 and universal cats for about $70.
So in order to switch between (occasional) track and street configuration as well as getting some visual and sound variety, I had my aftermarket exhaust modified with V-bands to easily switch between cat/test-pipe and any of the 5 muffler-tip configurations I have/will come up with.

Pic.1 shows the exhaust system with the test-pipe ready to be switched with the cat and the oval muffler which came with the car now with a V-band.

Pic.2 is the planned 4 extra set of mufflers and tips. Maybe I over-shopped a bit.

Pic.3 shows the two extra muffler-tip sets now available.

My original oval muffler with the typical slightly oval tip is a bit of a “rumble box” with deep resonating sound that can set off a few car alarms, even with the cat in place.

The dual muffler with two round tips is a lot quieter, can only trigger very sensitive alarms, and sounds very smooth. However the two round tips don’t look quite right for the car.

The last round (bullet) muffler can be found here http://www.aeroexhaust.com/ (SKU#: AT2525), which I found at less than half cost at eBay, is actually very interesting and supposedly works with a venturi effect as described on their web-site. When people on the Rennlist on a couple of occasions asked for muffler recommendations, I always suggested this, but nobody seemed interested.
I have just used it for a couple of days and it is as expected a little loud, but sounds awesome. It is actually quiet at idle, but under power it has some welcomed harsh overtones. If it reduces backpressure and increases HP as claimed, then it is less than I can detect without instrumentation (same idle vacuum and maybe a tiny bit better turbo spool-up). The square tip looks good to my eyes.

The other two mufflers have to wait on my otherwise excellent fabricator/welder’s glacier speed.

Laust

cpt_koolbeenz

Very cool... Do you have pics of some installed?

reno808

what kind of muffler is on pic 1

Cory9584

your wastegate ties in really far upstream, i would think it will cause more turbulance there

Laust Pedersen

Thanks, no installed pics readily available, but I'll add them as the various mufflers/tips gets installed.



With only 50% certainty I am guessing Magnaflow. I bought the car 2.5 years ago with that aftermarket (cat-less) stainless exhaust system and for various reasons I am sure, that the muffler with tip was included.



The WG tie-in location seems to be standard for most aftermarket systems. I would guess that the interference mechanism has to do with the resonance length of the dump pipe. So the more costly (to manufacture) Porsche design has a resonance below the rpm's where torque is generated.


A couple of acoustic oddities on the Aero Turbine system in Pic.3 is that it has high directivity, meaning that it is much louder just behind the car than anywhere else and contrary to most systems it gets quieter as the engine warms up.

Btw, I just passed CA smog check with flying colors with the cat in Pic.1. The car had to be “exercised vigorously” before the test though.

Laust

Keithr726

Which testpipe is that? I'm thinking about getting a clamp-in-cat style one and I like yours.

billthe3

Do you have any pics of the square exhaust on the car? One of the PO's of my car put a square/rectangular tip on my stock exhaust, and I like the look enough to potentially keep it over an aftermarket unit.

Laust Pedersen

As mentioned, the car came with the stainless cat-less exhaust, so I brougth a universal cat and 2 V-clamps with 6 fittings to my fabricator/velder, who cut a piece out of the exhaust, which then was used as the test pipe.


Here are also a couple of pics of my current installation:

gt37vgt

WG tie in upstream may cuase a little turbulance trivial really try explaining to the local regersration orthorities that the wastgate pipe goes past the cat in the factory config . as they are to stupid to understand what a wastgate is and if they have ever seen one it has been part of a turbp whil your choping and welding set the waste gate (screamer ) vented for the track as an option too