stanleyw808

Hello jfl11,

Runtime is dependent to the track size, traction, tire choice, and even suspension set-up I guess..

But as far as what I found out is as below,

B2102 - Longest Runtime
B2101 - 15 ~ 30 seconds Less
Spec II - 30 ~ 45 seconds Less
Spec II - 60+ seconds Less

As for the 2060 for Spec III, I honestly just go by "Feel" and and felt better with mating Spec III with 2060. With 2090 the top-end seems to be a bit restricted. And also if You refer to the Original OS Factory engine Combo, XZ-B case will mate with 2060 and B2101/2 case will mate with 2090.

Cheers..