for the USGT "Spec" tires, what are guys doing to enhance the traction?

I've heard simple green, wd40, brake clean and other...

We stuck three Trackstar motors on the Motolyser (sp). At the + sign they were between 44 and 53 degrees of timing. Those are really where the motor produces at about max efficiency. So with that said, adding more timing is probably not beneficial. There lower speed is from a high resistance stator (compared to other motors in the wind). I had a interesting back to back last weekend. I ran one TS 21.5 for 6 minutes and it was 125 deg. I switched to another that showed 4 degrees more timing. After a 6 minute run it was 165 and actually ran slower. I ran the same gearing with each. Next step will be to check the resistance of the stators. The rotors feel similar but I will check them also.

Mine (13.5T) maxes out at 33 degrees, as measured on a GForce motor checker. That's much lower than most other motors. It's nearly identical to an old Novak SS Pro I have (34 degrees), and the KV of these two motors is also very close (3030 vs 3150 RPM/V). Maybe the 21.5T versions have been changed for more timing?

A higher stator resistance (within reason) has little effect on the KV constant of the motor. Rotor size and strength has more effect.

I modified my trackstar motors to get an extra 10 degrees timing out of them. They were definitely much faster with the extra timing. On the dyno, they made 10% more torque than my D4 short stack, but had 10% lower KV, so I had to run a pinion that was 2-3 teeth larger with the trackstar motor. Interestingly enough, I'm consistently faster on my small local track using the trackstar over the D4. Both motors come off at 157-160 degrees.

Howard: I haven't measured it but how do they compare in air gap?
One of those motors was a 17.5 it is the one that was 44.

If the rules set by RobK state Roar motors, how does modifying the motor to get more timing work?

See posts 4075-4078 on the previous page.

Doesn't roar approval mean no modifying the motor? If not then can one cut a turn off the windings since it's not adding a part and is leveling the playing field with the short stack motors?

I think you're opening up a can of worms...

That's an excellent point! I haven't measured the air gap.

Agreed. I'm a mechanical engineer with access to machine shop equipment. It's good to know that as long as I don't add parts, I can freely modify my motors and not be illegal.



Mark

Then let a computer engineer remind you that... you're racing toy cars

Life's too short to grind on $30 motors in (what should be) a fun hobby.

It stuff like this that makes me hate racing sometimes.....

I agree with you 100%. I'm trying to make a point.

I've been racing "rulebooks" for over 35 years. SCCA, NASCAR, and now RC cars. It's what is said 'between' the lines that is often more important. And anytime two guys get together and race, someone will look for an advantage. Toy cars are not exempt from that.

Personally, I just use off-the-shelf stuff and go racing. But if I'm given carte blanche to have at it, it might be fun. Penske is my hero.

Mark

P.S. RobK's left eye is probably starting to twitch right about now...lol.

Yes, because he gave permission to increase the timing range on the Trackstar 21.5 motor so that it will have the same range as other brands, and this now seems to be interpreted by some as "I can modify any motor in any way that I want".

Keep in mind that if any ROAR-approved spec motor is modified like this, then it won't be legal for use in ROAR-sanctioned races. But I haven't seen too many 21.5 classes at ROAR events.

It seems there are those who interpreted my post as I will modify the motor any way I want. Far from it. My point is if you allow one thing others will see it as not following the set rule and they can do other motor mods. Thus my saying "you are opening a can of worms". Those that buy a specific motor should run it as is. If you don't like any part of a motor then don't buy it..