What Kinds of Differences Does a Performance Exhaust Make?

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Engineering Explained installs a cat-back on their AP2 S2000 and gives a before-and-after look the aspects of performance that changed (or didn’t).

By now, most S2Ki readers should be familiar with Jason Fenske of Engineering Explained and his AP2 Honda S2000. He’s used it to test many tuning concepts over the last couple years, and in this episode of EE, Fenske examines the performance difference made by an aftermarket cat-back exhaust.

Fenske installs the Amuse Euro S single-muffler system on his car. With a price tag well north of $2,000, it should make the car perform much better, right? Well, maybe a bit. The biggest advantage comes from the cat-back’s titanium construction. With a single muffler and lighter metal, it reduces weight by 34 pounds alone.

Honda S2000 Cat-Back Exhaust

As for other performance gains, well, things don’t always pan out. Many exhaust companies tout marketing copy like “power gains up to 10 percent.” In some cases where stock exhausts restrict flow greatly, that may very well be the case. However, this cat-back features the same pipe diameter. The straight-through muffler adds a grand total of 2.5 horsepower, largely after VTEC kicks in (yo). That’s about 1-percent.

That translates, however, into about a 5 percent gain in time from 10 to 60 mph. That seems relatively significant from a small power bump.

The exhaust also doesn’t make huge gains in sound levels either, although Fenske wanted a mild aftermarket exhaust. It does change the overtones a bit to add some lower-frequency growl, but the change is otherwise small. Many exhaust companies offer a variety of exhausts systems, however. Some feature less sound deadening — although not necessarily better flow — to generate harsher exhaust sounds.

Ultimately, your reasons for selecting an exhaust system should correlate with your goals. If you want to save weight, particularly for a competition car, a cat-back can make sense. If you want to improve power, you may need to reconsider your options unless you’re only looking to make minor gains.

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