In general the 4-slot motors feel as though they have weaker magnets, thus more RPMs and less drag brake in the corners. They are good for drivers who can carry momentum through the corners, but I personally find they lack torque for those of us that drive more with throttle than finesse. I've had my best luck with 4-slots in Mini where you don't need torque. But there are plenty of 2-slot motors out there that can blow my doors off down the straight.
I don't believe the 4-slots are 23 turns as others have said, but they will sound as though they spin up faster with little or no load due to the weaker magnetic field. But then again, I've had dog 4-slot motors too. I think everyone is correct in saying you have to go through a lot of motors before you pick the cherries out and give them and your car a little TLC.
Correct, Bill. 4-slot motors have 27 turn arms and are fully legal, but were made in a land long ago and far away when they balanced the arms by hand one at a time and did a much better job. Since good arm balance is one of the primary reasons one Johnson motor will spin faster than another, statistically you have a better chance of getting high rpm with a 4-slot.
But, as you said, 4-slot motors also have weaker magnets and thus generally produce less torque, which is why I normally run a 4-slot in Mini and use a 2 slot in GT3. Having said that, my Mini race motor right now (and the fastest one I own) is a 2-slot, and I ran a 4-slot in GT3 in Memphis to a 2nd place finish. So it all depends.
Like Bill and Jeff said- you gotta buy a lot of motors and break 'em in to find the fast ones.
Later
Doc
__________________
I've never lost.
I've just been a little bit behind when time ran out...
I don't really have a for real dyno. I was using a APS motor dyno, running at 5 volts with no load. the numbers are what read out. and the figures are just to show the point of how I came up with a few more rpms and more amp draw, buy applying a little tuning. I continue the search into the black hole of silver can tuning.
I have a feeling these numbers are realistic as these motors properly tuned will turn in lap times at the Tamiya test tract as fast if not faster than stock motor times. and I saw them lap me several times at the Tamiya TCS finals.
BTW after breaking in the motor for 1 hour on the APS motor dyno Motor Break in Mode, the brushes appear to be almost fully seated. I will go out to tamiya next month for testing for the TCS qualifier in July. I will report if I can tell any real improvement in motor performance.
also I will test my best IB 3800s vs. my best 3300s to see if the weight will make that big a difference in performance. Last year the 3300's appear to be as good as my gp 3700s. probably because of the weigh saving over the minimal voltage increase.
Please continue to post up anything else that improves the motor.
Last edited by nagatahawk; 05-18-2006 at 07:50 AM.
regarding the 2 slot vs. 4 slot, fyi at the Tamiya finals you have to purchase motors there,and the cans are marked. so any tuning tips other than buy a couple of dozen motors would be helpful.
I was threatening myself to move up to gt1 and gt2 rather than attempt to find the anwser to these motors, but finances will limit me this year. I hope my horsies come in this week end at the Preakness.
The motors last year at the Nats were Johnson 2-slots, and they had some seriously HARD brushes. It took hours upon hours of water dipping at 3V to get them to seat.......or at least that's what I experienced.
This year I've read the hand-out motor for GT2 and Mini will be black can Sport Tuned Mabuchis, and my limited experience has found that they have much softer brushes that require minutes instead of hours to fully seat. Beyond that, I haven't a clue!
And before you get too excited about battery choices, don't forget that GT2 and Mini will also be required to run a SPEC battery purchased at the Nats.
i heard you had a land missile at the last TCS! 
dont worry. 
i think the Hickmans will be out in at Fremont TCS in June.... i can ask there 
Similar Threads