Hi @ all !

I have a 77 Mvvs with Mvvs-header and KS-silence-muffler (4chamber).
It turns a 14x4 W @ 11200 rpms peak and ca 10800-11000rpms in flight .
It runs with 15% synthetic oil and no nitro , very reliable . I use it on my Diablotin .
Don't use Mvvs-muffler ,they chokes the engine down and it won't be reliable.
My 77 Mvvs runs very reliable at all rpms .