I spent the day yesterday swapping pipes & manifolds on the JL.21 CRE Mod. The pipes tested were. (Tested on HB D8T) M2C Clutch w/ (2) 1.0's & (2) 1.05's with a half loaded flywheel. Track is med size with 50% loam & 50% hard clay.

Werks 2057
Werks 2013
Jp-4
Jp-3
Jp-2
Jp-1
Dym 086
Dym 053

Out of those pipes the Jp-2 was hands down the best pipe. It makes the most power everywhere and it was very noticeable. Run times @ 10 Mins temped @ 203.

I love this motor!! I prefer it over my B5 CRE Mod, Speed, and Reedy. Can't say enough about this motor.