Originally Posted by
gigaplex
I don't have a dyno but I've seen the numbers from other people testing it. I'd be interested if you could confirm on yours. The motor screws aren't wrapped in the stator coils so shouldn't be able to contribute to torque. If simply having ferromagnetic materials outside the stator produced more torque, we'd be seeing aftermarket sleeves that you could install on the outside of the motor.
If the touring spec motor has more power but is struggling due to insufficient torque, that just means it's over geared. The torque curve in our motors is pretty much a straight line with peak torque at 0 RPM, and no torque at peak no-load RPM. Power is torque times RPM, so the power curve ends up being a parabola with the peak power at the half way point. If you gear the motor such that the average RPM in the midfield part of the track aligns with the peak power RPM, you shouldn't be lacking in punch.
There are some GT12 tracks that allow either motor to be used. You are correct that the gearing has to change and by a lot. This is what I tell people (and it is from testing) All of our motors are fixed timing during a test. Torque is our magic number and every fixed timing motor has peak torque at stall and zero torque at max rpm. That is why peak power is at the center of the rpm range. The motors stator design and rotor strength cause a designed in torque peak. Note the stator design. When I test a motor I find that very low timing shows that max initial torque. As you advance the timing you will get to a spot where that number starts to drop. The magic number in timing is getting the peak rpm up without hurting that initial torque thus generating the best power number and efficiency. I tell anyone using a acceleration dyno (of any brand) that the first second of the pull will tell you all you need to know. Now not being a electrical motor engineer I can only offer some conjecture, the non magnetic screws do affect the field and that is seen in the rpm boost. Team Scream noted that no screws in the stator and no slot for them made a huge difference in that field (it was computer modeled) their motors of that design and others that copied it, time completely different.
Now what does that have to do with the USGT TOUR spec motor. That higher power point is too high to be usable it appears. Gearing low moves the working rpm up out of the torque range. It is like trying to make a diesel rev at 8k. Nothing much there when a load hits. That part is my opinion on why but it based on my torque curve findings on the affect of timing.
Maybe I will see the same thing on screws. Interesting test for sure..