Originally Posted by SinistiR

I bought two 121's right when they came out. One about a week before the other one. I ran a gallon of Byrons 30/11 through the first engine and was never happy with its performance. The bottom end performance was killer, but noting up top. I mean, nothing. I ran P3s and P4s with no change in performance, and a 2035 pipe. I had dirt get past my air filter and roughed the crank up a bit. So I put about half a gallon of the same Byrons fuel through the second engine with the same pipe but only running a P4 now. Then went out ran 3 qualifiers and put her through 22min of a 30 main before my receiver pack died. I can honestly say the performance of this second engine is way better than the first. It has the same bottom end snap, but with alot more top end pull. I am only an hour leaner or so on the hsn and maybe 2 hours leaner on the lsn. I really am happy with how its performing. I have a +1 clutch bell I am going to try. If I can soften the bottom a little more and pick up a little bit more topend, I will be real happy.


With the 8mm insert, I can get 9min in a main with no flame out. I think I can push it to 10min once she has a gallon or so through her. The engine is in a D8.

Andy