2.8 SuperTrapp Exhaust

Subject: Muffler system upgrade for a 2000 2.8 Z3 Roadster
Cost: $150 for the exhaust plus installation (approx $75), I just checked the website and the price increased to $160.
Good: Customizable sound & performance, low cost AND lightweight
Bad: Non-that I am aware of at this time.

Why do this: As the immortal Tim Allen said “MORE POWER”. One of the first things I did to get more power out of my 2.8 was to Fogg the cold air intake (CAI). Even though Shawn never did a 2000 2.8, I took his ideas and suggestions from both his instruction on the 1.9 and from communications with the immortal himself and I was able to modify my CAI to work similar to his.

Of course this was not enough. So the hunt was on for a more affordable power upgrades. So I started looking into exhaust system replacements. I looked at every type possible, even asking about replacing the exhaust manifold and/or catalytic converter, not without screwing up my emissions & computer. So I concentrated my search to muffler replacement only. I looked at Bola, Dinan, Supersprint, etc. I searched for all types of information (horsepower increase, cost, material type, etc.) that would help me decide what muffler to purchase. I read all the articles from the MZ3 website on exhaust/muffler systems.

To my surprise, I found that all the stainless steel mufflers’ costs were in excess of $300 to $600!!!! Not including installation. Plus I was not convinced that the performance versus cost ratio was worth the money spent. I then remembered about the SuperTrapp system. They were primary an aftermarket motorcycle muffler. But, I saw them on cars in the past, about the late 70s. Plus I knew that they made systems that were stainless steel and lightweight. So the hunt was on.

First: I found their limited website http://www.supertrapp.com/default/atv_splash.htm not a great site to see what was available. But it did explain on how their system works.

Second: I found a supplier (there were not many in my area): http://www.racesearch.com, Part number: 543-2519, http://www.racesearch.com/CGI/mhp?mode=sbpn&pn=543-2519

Third: I found the one I wanted Stainless steel 5″, now granted if you called SuperTrapp & view the Z3 Coupe message board, they recommend that I use a 4″ system for horsepower up to 250 Hp. The 5″ system is rated up to 400 Hp. The reasons for the 5″ is simple with the wider inner diameter, the exhaust gasses would flow easier, less noisy and the 5″ outer diameter fills the factory muffler exhaust cutout nicer.

Arrow points to the location where the stock exhaust tube was cutWhen I had my muffler installed I had the installer hack off the original muffler and it’s supply piping back to the rear axle. If you look at the picture, you will see that the bend to the muffler has been reduced. He then made some custom hangers to hang the muffler at the stock points. Due to the heat generated from the exhaust gasses and the many discussions on the message board on melted bumper fascias due to the muffler. I instructed the installer to have the muffler hang a little lower and poke out more than normal. Giving it less of a chance of the muffler from melting the bumper fascia.

What is with the metal disks and cover???? The SuperTrapp muffler is basically a “glass pack”, where you have an inner tube that has holes and an outer tube that has insulation between the two tubes. Since there is no bends or baffles within the muffler, the gasses are unrestricted to flow toward the end of the pipe. Now the glass pack system has been around for a long time, if you had a hotrod or muscle car, you will know what I mean. Now for the metal disks and cover. The disks that you see on the side of the muffler are really spacers that have been stamped to allow the exhaust gasses to pass between two spacers. The metal cap is to help tune the performance of the muffler and car. Now the easiest way to explain this is to imagine that you have a large bucket with some holes in it. Now fill the bucket up with water, you will see that the water takes a long time to empty out. Now add more holes to the bucket and add water, you will now see that the water will empty out quicker than before. So the more holes you add the faster the water exits. Now there is more to the SuperTrapp system, which deals with vanturies that help pull the exhaust gases from the car. View the SuperTrapp website for more information.

Basically this is how this works with the car: The less spacers you install on the muffler, will produce more backpressure on to the system. Thus, increasing your torque, decreasing overall horsepower and a more quiet sound. With (6) spacers, the noise was a similar to my stock system. The more spacers you install on the muffler, it will reduce backpressure. Thus, decreasing your torque, increasing overall horsepower and a more robust sound. I ran both (12), (18) & (24-max) spacers. I normally run (24) spacers as a daily driver. Which is has a nice growl during idle and a cool roar during hard acceleration plus, I have had no complaints from my neighbors. I did try the system with NO spacers and it was too loud for normal driving.

I have raced my new exhaust with only (12) and no spacers, only to find that no spacers worked best. I will try my (24) spacer setup to see how it fares. Since the installation, I have not conducted a horsepower comparison, my fault. It will be hard to see if my new muffler has done anything, because I have done a ton of things to get this car quicker than stock. Check out my website for details: http://www.z3power.net

Summery: I am happy with the purchase of this muffler and I would do it again. In addition, if I did not have any performance gains in torque or horsepower, I have reduced the overall weight of the car. Which is always a good thing for our heavy cars.