Originally Posted by
b20btec
I like this motor in 17.5 TC with 3.7 28 deg. timing, also feels better with a large spur and pinion combo, instead of small spur small pinion. 100/51 in xray seems to keep it in the powerband. 88/47 felt good but the lower rpm of the 51 pinion is fantastic.
Forgot to mention, carpet indoor at rsd Houston.
It's not the big spur big pinion combo that is causing the difference, you just have a different FDR than with the smaller spur and pinion (1.96 V 1.87) times your internal gear ratio.