Cox Muffler RPM Reduction

Hi Cribbs
Thanks yes I have a tach. I could of course test them. I was just curious to see if there might be some recorded data regarding performance reduction or combo that is already in print about the use or not of mufflers.

So if you used an SPI cylinder with a muffler what might be the effect I wonder?

Thanks
Ice

Ive also had good high rpm in tests with the factory RC cylinder muffler/throttle control if you shim up the cylinder and add a high compression head to eliminate most of the SPI..
Bob

Hi Bob
Interesting. So by shimming the cylinder up to just cover the SPI it can run pretty good then. It isn't bad to have the mosquito sound if the muffler is on as long as we can keep performance up.

Thank you
Iceberg

Define what performance your looking for. I have at least 6 Cox QZ's from the 60's. I don't use any of them with the mufflers. The QZ has a dual bypass, and a high comp head. Using a stock 325 head the engine offers turd like performance.  With the muffler and 35% nitro it makes as much power as a strong Babe Bee which is pretty poor in my opinion.  It's certainly not Black Widow performance from any of them. These have the mill finish aluminum muffler with the hex base and the spring clip that rotates around it's circumference. It's a pain in the rear to start with the clip blocking the exhaust port, with the clip open it still offers enough noise to be problematic. There's a shim under the cylinder which lifts it up enough to block the SPI. As mentioned it came with a high comp head. Using higher nitro really jeopardizes the plugs and they're certainly not getting cheaper.  In my honest opinion, if your in search of a muffled .049, Cox products are not the avenue to go down. A Norvel .049 using 10% nitro offers much more power and a more pleasurable exhaust note.