ORIGINAL: f3a05
I can confirm that the Aeroslave pipe is very good with the OS 160 in pattern applications.
The top revs you mention(8--8-1/2K) are what we get with pattern props(APC17*12,15.5*12 4blade,Engel 18*11carbon),with a good transition.
Not quite as quiet as the Greve Ali. pipe, but more top end and a faster spool up.
I think your problem might arise in selecting a3D prop to load the motor to the top revs you want.
An alternative approach might be to check out what Weston UK have in the way of mini, "torque" pipes.
I don't have personal experience of them in this size of motor, but they have a big range, and they certainly work well in the smaller sizes.
I like a faster spool, that usually means that the mixture is correct throughout the range.
For a 3D prop I am looking at a 19x7. I can go with a 19 x8, or 20 x6 or 7 if I need to as well. I don't think there will be any problem loading the motor where I want to? Am I missing something here?
I did look around for more of a tuned power pipe, but did not find anything larger than a .91 size. Jett makes an in cowl muffler that is supposed to give a mild boost at around 8000, but some people have been having problems with the 1.6FX and that muffler.
Another option is a tuned KS can, but that weighs 7oz plus header so 10.5oz, I think.
Thanks for your help guys. I will follow all leads.