Hi
I have 2 of these engines, one on a 32" sport mono and a second on a 32" sport hydro. I have tried using several different tuned pipes, Macs and others, .40 size to .60 size, with various lengths measured from the glow plug and have not been able to see any performance gains (i.e., could not get pipe to come on, etc.). The engines seemed to prefer .45 and larger pipes over the .40 size. Do you have any suggestions or has anyone had success using these engines with tuned pipes? They have good torque and are very economical to operate in my applications, running 6 oz. tanks in both boats with reasonable running time. I run 15% nitro fuel which works fine with my .67 and 7.5 K&B marine inboards with pipes.
Thanks