Going to take the plunge and convert my XB8EC

[Patrick]

Use this site made by BrianG http://www.scriptasylum.com/rc_speed/_top_speed.html
For racing 35-40mph is a good speed, depending on the size of the track, and the length of the races.

[jhautz]

I ran my buggy on the exact setup you listed with the exception of the motor. I was useing a Neu 1515/2.5/D finned or a 1512/2.5/D smooth motor and it ran fine on both. FOr the 1515/25.D I was able to run 18 pinion gears with no issue in the heat of summer, and with the 1512/2.5D I ran 15-16 pinions. That gave around 45mph for either setup. Giong down on the pinion size wasnt a problem on either setup if you wanted to slow it down a little for the track. Both setups ran fine heat wise and performace wise, but if you are truly worried about heat go for the 1515 it will run just a tad cooler but you will be able to make up the speed with the taller gearing.

The Neus are great motors, they run great unless you put them way outside their comfort zone. They arent like the feigaos that run ok if you get the gearing and load just right but if you move off of that perfect setup they just heat up like crazy.

The 160/18 runs cool and you shouldnt have any problems and 5s also helps keep the temps down. You should be very happy with that setup.

Thats my opinion anyway.