hey guys, a buddy of mine at the field today said that a pitts muffler robs power from the engine. if this is true, how so and is there any way to gain the power back? [>:]

In my opinion, yes, they do take away some power. They are also usually noisier and sometimes make it harder to get yuor engine to run right - many time because they do not provide enought back pressure. You can usually make up for this by plugging one of the two exhaust pipes. I use the stock muffler whenever possible -

Depends on the engine and size. A stock muffler with the baffle plate installed will rob about 200 - 300 rpm. A pitts usually only robs about 150 - 200 rpm.

Pitts are USUALLY noiser than a stock muffler.

The "robbing" of the power is attributed to the lack of back pressure, which in turn means less pressure to the fuel tank. 46 size engines USUALLY do not have a problem with this. Larger engines MAY have a problem (usually ). On my OS 160 FX I had to plug one of the tubes in order to get adequate back pressure to the tank.

I've never had a problem with a pitts muffler from .46 to .91 engines. I don't run anything bigger than a .91 so far.

Gibbs

thanks guys, intsead of plugging one of the tubes i pinched both of them slightly. this created more back pressure and it ran alot smoother in the low end RPM's. i compared it to the stock muffler and at most it lost 50-100 RPM's

james