Impressive numbers. Only problem is that it's a ***** [:@] to keep the header and tuned pipe from falling apart and coming loose.
My flex header cracked twice and you can't even weld these darn things.
I had a DA-50, KS-1060 tuned pipe on an original EF Yak-54 87" and wished I just bought a stock muffler.
Sometimes the extra 400RPM is not worth the additional complexity of a tuned pipe setup IMO.
I know it's a quiter setup, better transition etc. etc. but frankly I got tired of my setup.
ORIGINAL: RC Extreme power
{SNIP...}
Now here is the kicker, All the new Area 51cc engines I have run got from 6950 to 7050 with a Mejzlik 22-10 and go to about 7200 after about 3 tanks and up from there with stock mufflers, This one got 7450 on the first run with about 2 min run time, It was getting late so I will test a 23-8 Mejzlik tomorrow.
Milton