Took me a minute to figure it out. lol Check my engines Forum and it mentioned using a larger expansinon chamber increases horse power some. My engine should performe better with the pitts Muffler which i'm considering will have to make mods to the plane to fit it but will get better performance. My tuning is Probably off and that why i'm not getting optimum performance. i tuned the engine in the winter when it was cold and today it was 70 out and it was 40 when i tuned it. So its running a tad on the rich side.

Going to retune and try it out again tommarrow Should be better hopefully.