I was looking at exhaust systems for my YFZ450. I notice that a large percentage of systems are aluminum. Some are stainless, some titanium, and others have carbon fiber.

I happen to think that carbon fiber may not be good for the long hall as it reminds me of plastic that may crack or go bad with ruff use or have a problem with longevity. This may or may not be true.

Titanium is very expensive. Why is it worth it?

Aluminum may be just right as it offers cost effectiveness.

I like stainless steel although it may not have the weight saving advantage of other materials.

I do mainly trail riding in what I consider harsh terrain so I'm really leaning to the stainless steel or even aluminum systems.

What's your take on the best material for exhaust systems?

 

I have ceramic-coated mild steel, Ti and al (aluminum) systems on any of (6) bikes. They'll all break/tweak/etc. Personally I like the "works" look of bare mild steel maintained w/ WD-40. I don't like fiber - just a personal think.

 

Titanium is not worth the extra cost unless you have money burning a hole in your pocket. The up side of Titanium is a density of .169 lb/cubic inch with the yield and ultimate strenghth of many steels, (300-400 series Cres about .29 lb/cubic inch). Titanium has a very high operating temperature so it wont degrade as a material for exhausts. On the other hand, aluminum has a density of .098 lb/cubic inch, great for weight and will also handle the temps in a silencer, not a good head pipe material choice. The down side is it is much more brittle with significantly lower yield strengths. Carbon fiber has very high operating temps, has a low density, I think around aluminum, but cost is high and it may delaminate under high vibration environments.

I went with a mild steel head pipe and an aluminum silencer. I should last as long as the quad.

 

The difference in the materials is in the weight. The reason that people who race are concerned with weight is because it is easier for a lighter quad to accelerate than it is for a heavier quad and a lighter quad is easier to control than a heavier quad in a race lasting X amount of minutes.

The things that make certain exhausts perform better than others is the pipe size, length and muffler restriction compared to the flow requirements of the cylinder head. For the money on a mildly modified quad I've found that the Lexx system from Rocky Mountain ATV performs very well and is a bargain for the price IMO. In the testing that I've done it isn't the best system on the market for making power, but it's also not the worst. On a mildly modified trail quad you won't be able to tell the difference in it over a system that costs 3X's as much except in sound.