It’s no secret that a well-designed exhaust is an important piece of any performance car. In designing an exhaust for my Stealth turbo, I outlined several characteristics which I considered to be essential: a turbo exhaust should be free-flowing, reasonably quiet, lightweight, and robust. A deficiency in any of these categories is unacceptable when performance is the goal, so I set out to design and build the best possible exhaust system.

Noise:

One of the primary methods of reducing noise is restriction, and free-flowing mufflers are often not good at muffling. I selected a Magnaflow 3″ round perforated core muffler for a combination of cost and performance. The body of this muffler is almost three feet long, which gives it excellent noise-cancelling ability, despite minimal restriction to flow. The drawbacks are that it’s a bit heavy and made of cheap 400-series stainless steel — but hey, that’s a lot of muffler for $100. It really gets the job done.

Minimum Restriction:

In making the exhaust flow well there were no compromises to be made. My exhaust uses a single bend between the downpipe and the tip of the tailpipe — that’s right, one 30-degree bend. More on this in a minute. Elsewhere in the exhaust (like the O2 housing pictured below), there are bends to navigate the engine bay and merge with the downpipe. These bends are minimized, but the cat-back is the show stopper in simplicity and free flow.

Weight:

To keep cost low and noise cancellation high, my muffler is a bit heavier than some “race” mufflers (which are loud as hell). Despite the large muffler, weight is much lower than a stock exhaust by the very direct routing and using .049″ thick stainless tubing for the long 3″ pipe under the car. Simplicity is what makes it light; instead of having two exits to four tips and thick, heavy piping with multiple assembly joints, the entire exhaust installs as one piece with three hangers, and exits to a simple, single 3″ hole at the rear. As a bonus, the vast majority of the weight is mounted as low and as far back as possible.

On Style:

You’ve probably seen one-bend exhausts on Supras, or maybe even a Honda. Most of the companies making them may not even know the advantages, never mind the average buyer. Many people buy angle-exit exhauts because they “look hot”, while other people think an angle exit is “ricey”, and that four exhaust tips look much better. Ironically, judging exhaust on appearance instead of functionality is exactly what we’re trying to avoid.

Fact of the matter is, air doesn’t like to turn corners, and the fewer bends you force it to move past, the less restriction there is. Also the fewer total degrees of bend, the more easily air passes. Finally (and almost everyone overlooks this), the larger the radius of bend, the more conducive it is to flow. The bend I’m using has a 3″ inside diameter like the rest of the exhaust, but instead of using a normal 6-7″ center line radius (CLR), I’m using a bend with a 30″ CLR. Judge for yourself how it looks, but the fact of the matter is: this thing works.