My 3d didn't run any hotter than my 2.5d. Also, since the 3d is pulls less amps, I get about a minute or two of extra run time as well. I ran FIVE full packs (20+ minutes each) this weekend on our indoor track and temps never broke 110 on the motor (it was about 45-50. Temps for my 3d usually run below 150 on a hot summer day after 10 to 15 minute main. I also had a 1515 and it always ran at 160-175, but never got any hotter similar to what Rootar is saying. Most of these motors just find a temp that they tend to run at and stay in that range. As long as you aren't getting above 180ish, I wouldn't worry about it but you are definitely running on the high side for that setup. I would break your car down completely (diffs and all) and rebuild it to see if there is any binding or something hidden you can't easily see.