Thanks for the quick reply. I'm fairly close to this but will make some tweaks. Because I'm running 10.5 I tried no timing in one of my heats and it felt slow. The straight is fairly long so I added 15 degree timing and used Profile 3. I also had 10 degree top speed timing but used a very small slew rate.

I think I was running 75% punch and 9600mhz. dynamic brakes were disabled and 10% drag brake.

Is "punch" equal to the "expo" on the transmitter?
Also, am I correct that higher PWM gives smoother "feel", but increases ESC temperature?

Punch is not expo. Punch is linear. You are correct about the pwm.

Thanks! What does Punch affect?

I think of punch like a slipper adjustment. It's the torque adjustment for the motor. Run more punch when there is more traction. Running stock though don't run too much.

Would you also keep the motor at its out of the box 30 degree timing? I've never used a motor with end bell adjustment-
Thanks

for lower turn motors yes. for spec motors - 13.5 or 17.5, you will probably want to turn it up.

I turned my boys 7.5 endbell timing down, is that not the way to go? and what would it do if I did?? raise temps? or anything.

I'm really curious about "end bell timing" as well.

Is this a situation of "borrowing from Peter to pay Paul" situation, or does turning the endbell timing up just give more power throughout the power band?

Please help me.

Advancing endbell timing produces more RPM, more overall power, LESS torque, and generates more heat. Mod motors generate enough RPM that you don't need to change the timing. with my 17.5 motor, I will generally run around 45 deg timing depending on the actual motor and conditions. And most cases I am geared 34-36 / 69

17.5 (and 13.5) motors don't turn enough RPM, so you in turn hang more gear on them. In order to get the top end, you hang a huge pinion on. Problem is, the bigger the pinion, the more heat you generate and the more torque you need to turn that gear over. That's why you read about some guys trying High Torque or HT rotors. I tested one at Motorama in my B4.2. Here's the pic of the gearing I ran. after 6 minutes I was at 84 degrees. Granted air temp at the track was mid 60's. But you get the idea.

40/69 with 12.8 Rotor. I did NOT stay with this as the track simply wasn't big enough and I couldn't put any bigger of a pinion on while still adjusting the motor screws

Bob, thanks for the explanation. I kinda' thought there was no "free" power, but, just didn't know what was given up and what was gained.

I'm guessing a little extra end-bell timing is good on my 17.5 buggy and adjust spur/pinion from there. Make sense? (I hope)

just run it for 2 min and check the temps. then run for 4 min, check the temps..... do this until you hit the length of your quals and again for your mains.

Don't practice longer than a qualifier.

keep the temps under 150. Also remember the temp cutoff that's built into the ESC reads the temp from the board, which is higher. So if you set it for 150 deg, you'll likely hit your temp cutoff. 150 internal is closer to 100 on the can from the outside. I personally disable the motor cutoff temp setting on the ESC and just monitor it with an temp gun externally since this is what I'm used too.

Great explanation, Bob. Very much appreciated.

Thanks Bob!!

One point I want to stress especially with 17.5 classes, but it applies to all types of racing. When you gear for performance (or use boost, or motor timing) you have to be mindful of how long your race is. Judge the heat you build up by that. If you want to practice for 10 or 15 minutes - gear down, calm it down - so it lasts. This way you get a balance of performance, and products that last for a while.

At the MN series I race at has 15 minute electric A Mains. You have to gear quite conservative to still have motor at the end, let alone battery. Lol