Just wondered if anyone has heard of, or tried an Aeroturbine Exhaust System? They supposedly increase mileage and horsepower. At nearly $200, plus installation, they'd have to save a lot of gas to be worth it.
I've heard of people going to straight pipes, or having their muffer converted to a "muffler" (Ie having the baffles taken out of it). Supposedly it doesn't make the car very much louder, and removes the muffler restriction.
I looked at their website, and I don't think that would fit an insight. I haven't measured it, but I don't think the exhaust system is anywhere near the 2 1/4" in/out size of the car version of this.
Also, (and I'm speculating here), that whatever is happening in that thing requires a lot of heat and exhaust flow to do its magic, neither of which you'd get from an insight. Most of their tests are on high performance or high displacement cars.
One thing I'd call shenanigans on is that they ran the tests at 5000 feet of elevation http://www.aero-turbine.com/benefits/. That seems rather odd to me, as most cars are leaned out at that altitude. They ran another test on methanol fuel.
Also, typically increased hp and torque = less mpg. I wasn't able to find any charts on mpg, just hp and torque.
Looks like a variation on the straight through "glass pack" style. I didn't see anything that resembled a turbine and I could not decipher the theory of operation. Too bad, perhaps if I could understand the logic of the design I'd be impressed. I am considering a stainless steel "glass pack" for my Insight, rather than reaming out the existing muffler. Replacing the restrictive stock muffler should improve power or efficiency slightly.
I've studied this type of "muffler" and they are apparently using the "extraction" method for removing or speeding up the exhaust gas flow.
This is the same method used in the design of Exhaust pipes on 2 stroke motorcycles and engines.
You can "tailor" an exhaust system to develop it's horsepower at a specific rpm. The higher the rpm, the narrower the "power curve".
The stock muffler is not that restrictive. I changed mine because of the additional heat generated by the "turbocharger".
Unless you are running the Insight engine in it's "power curve" most of the time, I see no benefit on removing the muffler. (Except for the reduction in weight, app. 22 pounds).......My opinion........ :wink: