What is the highest temperature you can go for a stock motor (17.5T)?

In addition, what is a good temperature to get racing optimum performance?

There will be some variance from motor to motor but generally they will run best when kept in the 150-160f range as a max and under 190-200f to prevent damage.

Ditto what he said..I noticed that after installing an r1 wurks 30mm fan my motor temps were 30 degrees cooler! It doesn't have to be hot to make power, that's not how motors work as far as I know. People will gear up... Meaning they will go to a 33t from a 32t if the temp is cool enough and allows it. The lower the fdr is the harder the motor has to work and will generate heat.

thank you guys.