I have installed a pair of MTW cans on My Comp. ARF 2.6 extra with a D.A. 100 and I am experiencing a "pipe effect" in the mid range. I had to cut 2" off the headers to get the assembly to fit due to the blade spar. Has anyone experienced the same problem and if so what did you do to overcome it? When pulling into a hover, there is no throttle response.....plane either falls backward or punches out of the hover with no way to find a happy throttle setting. 28X10 Mejzlik 2 blade and 25X12 Mejzlik 3-blade. The 3-blade softens the effect but I still have no throttle response in the Mid-range.

cutting those 2 inches off changed your powerband. u need to get those inches back the shorter u go the quick you get the on the pipe deal and lose midragne response....

is that typical? the shorter the headpipe, the earlier motor comes on the pipe?

For good midrange, the pipes need to be 10" long (25cm) when combined with MTW td75K mufflers. With TD75, the headers can be 1" shorter
I tuned the carb on a DA100 when at MTW, and had the engine carb set up in about 5 minutes with excellent response at all throttle settings. For carb tuning, see http://www.prme.nl/forum/viewtopic.php?t=54