That was my next question about what size pylon course you are flying. What are the times you are turning? What RPM are you getting and what prop. We just got done with a Club 40 race today using the TT.40 with APC 9X6 prop also the 10.5X4.5 "toothpick" seems to give equal performance. Because the TT.40 had been discontinued the NMPRA tested a bunch of engines and came up with the EVO.46 as an equivalent engine. To match the TT to the EVO .46 it must run the APC 9X6 due to the disparity in performance. (Club 40 rules). In NMPRA /AMA 424 class everyone runs the APC9x6. Both of those engines have been discontinued so we will run out of engines eventually. They now allow the JETT .40 with a restricted intake and exhaust and it doesn't have a throttle and about 3 times the price of the EVO or TT but at least its available.
The EVO .46 is a real POS. Major engine failures are frequent due to poor materials and MFG standards. Some run real well but most encounter difficulties sooner or later. Today we had one EVO broke a nipple on the Carb and then we had one break the Crankshaft! Both very unusual failures for a model engine.
Sparky