Hello, I have a Viper 10.5t that I run in a sct22 2.0 in a open class and recently changed the rotor to a 12.8 high torque, should I expect a large drop in top speed?

I've also noticed with the standard rotor using 30 degrees of can timing and geared 86/19 the motor would come off the track significantly hotter than when I ran 86/22 for gears and I'm baffled as to why, any thoughts?

Thanks

Going from the stock rotor to high torque will give you more bottom end power, yes there will be a reduction in rpm. You might gear up a tooth - depending on the temps you get.

With the gearing question - are we still talking about the same 10.5 motor? Its possible to gear too low, just like you can gear too high. If your too low, the motor is at full RPM more (all the time), making it work harder - which equals more heat.