2WD SCT motor KV question.

[biggman100]

I'm starting to think i have this wrong. I thought the lower the KV for a given motor size, the faster the vehicle would be, but, i picked up a 2WD Slash with a 4370KV 3650 eBay motor, and, using the same ESC that is in my Arrma Fury (HW 10BL60), the Slash is a ton faster than my Fury, which has a 3500KV 3650, so, am i looking at this backwards, and higher KV is faster if the motor size is the same? I know gearing plays a part, but, the Slash and the Fury are both running the gearing that the manufacturer recommends. The Fury runs a 32P spur, with a 15T pinion, and the slash has a 16/83 setup.

 

[Chubaka]

The lower the turn the faster it is. The higher the kv the faster it is.

 

[RustyUs]

Just a heads up on those 4370kv 3650 sized motors... anytime I read that particular kV number I think of those F540 motors. The "F" stands for finned. You can see the deeper grooves used on the outside of the motor to form the larger fins. In order to have those larger fins, you give up some size of the stator, and rotor... slightly less power/torque.

 

[biggman100]

Just a heads up on those 4370kv 3650 sized motors... anytime I read that particular kV number I think of those F540 motors. The "F" stands for finned. You can see the deeper grooves used on the outside of the motor to form the larger fins. In order to have those larger fins, you give up some size of the stator, and rotor... slightly less power/torque.

What is the difference between an F540 and a 3650? In the Slash, the 4370 is faster than the 3500KV 3650 i have in my Arrma Fury. Just to see if there was any real difference in speed, i put the 3500KV 3650 from my Fury in the Slash today, and it was noticeably slower than when it has the 4370KV in it. The 4370 i have does have fins on it.

 

[pug]

What is the difference between an F540 and a 3650? In the Slash, the 4370 is faster than the 3500KV 3650 i have in my Arrma Fury. Just to see if there was any real difference in speed, i put the 3500KV 3650 from my Fury in the Slash today, and it was noticeably slower than when it has the 4370KV in it. The 4370 i have does have fins on it.

It will probably overheat easier, and have less torque. It’s a 380 motor in a 540 can.

 

[RustyUs]

What is the difference between an F540 and a 3650? In the Slash, the 4370 is faster than the 3500KV 3650 i have in my Arrma Fury. Just to see if there was any real difference in speed, i put the 3500KV 3650 from my Fury in the Slash today, and it was noticeably slower than when it has the 4370KV in it. The 4370 i have does have fins on it.

I have no doubt the 4370kv motor is faster than a 3500kv motor. It's just that the finned motor basically has less room inside for magnets. Less magnets... less power.

I had one of Hobbywing's first (2010?) surface EZRun ESC/motor combos... 35A ESC/4370kv motor. It was my second brushless motor purchase. I was impressed with the "zip" the motor had in a stadium truck. I was so impressed with that combo, Hobbywing became a favorite of mine. Jump ahead a couple of years, and that same great finned motor got stuck into a SC platform. In order to get the most run time from motor/battery, I had to drop down on the pinion gear size.

540 & 3650 are basically two different ways to say the same thing about a motor size.
Brushless Motor Tech: Everything You Need to Know

 

[biggman100]

I have no doubt the 4370kv motor is faster than a 3500kv motor. It's just that the finned motor basically has less room inside for magnets. Less magnets... less power.

I had one of Hobbywing's first (2010?) surface EZRun ESC/motor combos... 35A ESC/4370kv motor. It was my second brushless motor purchase. I was impressed with the "zip" the motor had in a stadium truck. I was so impressed with that combo, Hobbywing became a favorite of mine. Jump ahead a couple of years, and that same great finned motor got stuck into a SC platform. In order to get the most run time from motor/battery, I had to drop down on the pinion gear size.

540 & 3650 are basically two different ways to say the same thing about a motor size.
Brushless Motor Tech: Everything You Need to Know

Almost every truck i own is an SCT. I typically run 3300 to 3500KV 3650's, whichever one is cheaper at the time. I tried 3800KV motors, but those were 3660's, and they didnt work out so well with the HW 10BL60 i typically use.

 

[RustyUs]

Almost every truck i own is an SCT. I typically run 3300 to 3500KV 3650's, whichever one is cheaper at the time. I tried 3800KV motors, but those were 3660's, and they didnt work out so well with the HW 10BL60 i typically use.

I'm guessing the need for a longer 3660 motor was because of a 4wd SCT? If that was the case, then I think I would use a 100~120A speed control for a greater margin.

What went wrong with your 10BL60 ESC?

 

[biggman100]

I'm guessing the need for a longer 3660 motor was because of a 4wd SCT? If that was the case, then I think I would use a 100~120A speed control for a greater margin.

What went wrong with your 10BL60 ESC?

Actually, the 3660 i only got because i picked up one of those eBay GoolRC 3800KV and 60A ESC combos. When i ran the 3660 on my 10BL60, it would get hot and cut out. Now, I'm running a 3650 3500KV with that 10BL60, in a DHK Hunter 4WD SCT, and, so far, i havent had any issues with it. I picked up an Arrma BLX100 and put that and the 3660 3800KV in my 3S Arrma hybrid I'm building, but i havent ran it yet.