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Emissions note for North Carolina. This May, I went to conduct an annual emissions/car test at Crown BMW in Greensboro, NC. TO MY SUPPRISE, the state inspector, who is a Honda car technician and Crown automobile employee that visits all their facilities to conduct inspection, FAILED MY CAR. He stated that if a muffler does NOT have a tail pipe, it will fail the visual inspection. He informed me that this is a BRAND NEW LAW for NC!!!! WOW, I explained to him that the SuperTrapp is a muffler and an approved spark arrestor. He said that if, you fail the visual, he is bound by law, not to continue the tests. BUMMER!

So that next morning, I went to another garage that had passed my friend's SuperTrapp system on his 5-0 Mustang and guess what, he said the same thing!!!!!!!!!!! Unless the SuperTrapp has a tail pipe, no inspector can test the car's emissions.

Depressed, I started to view the SuperTrapp part's catalog to see what I can do or a way to make an add-on tail pipe to by-pass this silly NC state law. After a brief time I found what I was looking for. It's called the open end endcap for the 5-inch mufflers. Part number SUP504-3052 from the Summit Racing catalog @ $ 6.95. So with the help my friend, he welded on a 3.5-inch pipe on the end and painted it black. (see photo)
I just reverified that SuperTrapp no longer makes the 5" Open End Cap. But if you purchase the 4" SuperTrapp Exhaust, they do make an open end cap for that size.

As soon as I received the part, I bolted on to my car and headed back to the dealership. The inspector looked at it and it passed. BTW it also passed emissions, my car actually burns cleaner than stock!

UPDATE: Early last year, I had my resonator removed by the same muffler shop in Greensboro, NC. The cost was about $50 (including replacement piping). The result was the automatic increase of NOISE. The sound out of my car was mean and purposeful. Unfortunately, I forgot to take a weight of the now scrap metal stainless steel resonator, that had two pipes leading into it and one pipe out. Off hand, by feel, it was close to 20-pounds.
If someone knows the exact weight, please inform me, so that I may note it on this page.
Below are the after shots of the new connector pipes, that replaced the resonator. If you have any questions please contact me any time.

First: I found their limited website at www.SuperTrapp.com 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): Race Seach.com had them, Part number: 543-2519, unfortunately they have gone out of business their website is no longer up and running. So I suggest you check out www.Summit Racing.com.

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.

When 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.

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.

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.

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.

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.

One last thing, after I went home, off went the tail pipe and on when the aluminum, 5-inch Star, machined end cap from SuperTrapp (part number SUP502-1000 @ $ 118.95). I will use my add-on only during emission inspections.

The reason for the aluminum end cap is that I conducted a dyno test and found that my car's engine generates the most horse power and torque WITHOUT any spacers. The only thing I can do to free up more Hp/Tq is to replace the header/catalytic and the resinator. My next plan is to cut out the resinator and replace it with a straight pipe. That will make my car a lot louder and force me to use my spacers to quiet the noise. I will keep everyone posted on the results and other stuff.