Ask The Editors: Why No Aluminum Exhaust?

They call this pipe Aluminum Series – but it’s made of stainless.

You didn’t make it up. Aluminum 2-stroke head pipes did exist for a few years in the late 90s but the trend didn’t catch on. Why? Cost. They were nearly double the price of their steel counterparts and, while they did offer some weight shavings, really didn’t offer any other major benefits. And a major downside to backyard tuners is that aluminum is much trickier to weld.

They did exist, though, and because of their rigidity, proved more susceptible to fatigue, especially at the mounting points.

A big part of the reason you don’t see them around much these days is one of physics. Performance 4-stroke exhaust is much hotter than that of a 2-stroke, meaning aluminum (which melts at 1,200 degrees) would turn to mush on a 450. Steel, by comparison, is good until about 2,500°F. Couple this reality to that half the price to purchase concept mentioned above and you understand why the aluminum head pipe stopped making sense.

The muffler, on the other hand, is far enough away from the engine for the exhaust gasses to cool significantly, explaining why aluminum mufflers are fairly common.

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