Exhaust Mods for K&B 3.5?

[Flying Pilgrim]

Exhaust Mods for K&B 3.5?

I spoke to a fellow who said he ground out the exhaust outlet holes on his lower unit of his K&B 3.5 and gained some power/speed. Rather than having the small outlet holes, he had one long open slot. Obviously this would make it louder, and less back-pressure (less pressure for fuel tank as well). Has anyone tried this, and did it work?

 

[mark james]

Re:Exhaust Mods for K&B 3.5?

pilgrim, I have done the mod and did not notice any differance in speed ,only a bit louder

(to notice small changes in speed you need a good radar gun.

If you want more out of your mtr,put a nice pipe on it,and a little more pitch on your prop .

hope this helps. mark

 

[lohring]

Re:Exhaust Mods for K&B 3.5?

The NAMBA record holding (at 58 mph) 3.5 tunnel had an exhaust that was cut away somewhat like you describe. The main other modification was a red carb. It was very noisy.

Lohring Miller