Matt,

Is the 7500 rpm number with your CF-lam Xoar 18-5/8 x 13?

I don't think mine needs a nose ring, but if it adds to the quietness and efficiency I will give it a shot. Although this plane is the quietest gasser I've seen, there are still a few bumping and knocking things I have to track down, and the 18x10PN prop is pretty noisy when the tips start ripping over 8k rpm.

There is also something I noted the other day, the engine permormance dropped significantly when doing an outside loop. I don't believe it was a fuel delivery issue (i.e. fuel clunk not following fuel), but rather the change in air pressure on the little static plate (or whatever it is you call it... the plate on the carb with the small hole in it). I know this is sometimes solved by soldering a nipple on that plate and running a piece of fuel tube back into the fuse. But first I will make absolutely sure it isn't a problem with the clunk. It was cold, and Tygon does stiffen up quite a bit.