HSP short course upgrade

[gothe80]

hi everyone
I've upgraded my hsp short course to a brushless setup with an 80amp esc and 3650 / 3100KV motor. everything else is stock. (Brushed version) after a bash i found the motor to be very hot, the gearing i have in it is a 81T spur and 23T pinion, would that be alright for the setup? I’ve looked around over the net and it seems they both brushed and brushless have the same gearing.
any other info would be much appreciated
thanks

 

[pug]

That's some very high gearing, try gearing down on the pinion a few teeth to see if it helps. Also, check for any binding in the drivetrain.

 

[The_RC_Dude]

hi everyone
I've upgraded my hsp short course to a brushless setup with an 80amp esc and 3650 / 3100KV motor. everything else is stock. (Brushed version) after a bash i found the motor to be very hot, the gearing i have in it is a 81T spur and 23T pinion, would that be alright for the setup? I’ve looked around over the net and it seems they both brushed and brushless have the same gearing.
any other info would be much appreciated
thanks

Do you drive hard, like full throttle a lot of the time, are you using 2s or 3s? Is it hot where you are? Do the electrics have decent airflow? I think the gearing might be a little high, for a 1/10. For smaller scale cars, like 1/14, that gear ratio would be super low, in my 1/14 scale buggy, I have a 15t pinion driving a 44t spur, but my buggy is much lighter than yours, smaller wheels, blah blah, I'm getting off track here. Point is, check the above, and buy some smaller pinions, like one that's 1 tooth smaller, one that's 2, one that 3, and maybe a pinion that's 4 teeth smaller.

Either that, or try a lower kV motor.

And like @pug said, check for drivetrain binding, no worn out bearings, no oversized wheels, ect.

 

[gothe80]

I might try the pinions first which I have plenty of, but it’s is strange that it’s all stock gear, the stock brushless motor is a 3300kv and I have a 3100kv. I didn’t think it would make that much of a difference

 

[The_RC_Dude]

I might try the pinions first which I have plenty of, but it’s is strange that it’s all stock gear, the stock brushless motor is a 3300kv and I have a 3100kv. I didn’t think it would make that much of a difference

I would recommend trying to gear down first, then try the motor swap. The pinion change is easier and faster. Do they make a stock brushless version of your truck? If so, compare the BL setup you have with that stock BL setup, and read/watch some reviews of the stock BL truck and see if people have issues with heat. Basically, compare the results of your BL setup and the stock BL truck, if it exists.

 

[pug]

I would recommend trying to gear down first, then try the motor swap. The pinion change is easier and faster. Do they make a stock brushless version of your truck? If so, compare the BL setup you have with that stock BL setup, and read/watch some reviews of the stock BL truck and see if people have issues with heat. Basically, compare the results of your BL setup and the stock BL truck, if it exists.

Binding in the drivetrain can also cause heat issues due to the extra friction and load on both the motor and ESC.

 

[The_RC_Dude]

Binding in the drivetrain can also cause heat issues due to the extra friction and load on both the motor and ESC.

Uh huh, yes. I edited my previous reply earlier with that. Any kind of binding is bad, be it drivetrain, suspension, or steering binding.

 

[biggman100]

hi everyone
I've upgraded my hsp short course to a brushless setup with an 80amp esc and 3650 / 3100KV motor. everything else is stock. (Brushed version) after a bash i found the motor to be very hot, the gearing i have in it is a 81T spur and 23T pinion, would that be alright for the setup? I’ve looked around over the net and it seems they both brushed and brushless have the same gearing.
any other info would be much appreciated
thanks

A couple questions. Which truck do you have, the SCT or the desert truck with the roll cage under the body, or the storm? Did you upgrade to better bearings, especially in the hubs? HSP cars are notorious for having very crappy metal shielded bearings that seize easily. You said you went from brushed to brushless, does yours have the metal or plastic gears? If it has the plastic diff gears, they wont hold up to brushless very long. As for the pinion size, 23T is way too much for them, unless you have the exact electronics that HSP sells them with. Oddly, with the HSP electronics, 23T and 26T pinions work, but, if you use any other brand of electronics, its better to stay under 20T for the pinion. Since you upgraded to brushless, i would also swap the plastic spur for the metal one. The gearing is listed as 48P metric, but, after a bunch of trial and error, i found it is actually mod 0.6 gear pitch. Unfortunately, you are stuck with that, because noone makes a spur in any other pitch for the HSP cars.

Do you drive hard, like full throttle a lot of the time, are you using 2s or 3s? Is it hot where you are? Do the electrics have decent airflow? I think the gearing might be a little high, for a 1/10. For smaller scale cars, like 1/14, that gear ratio would be super low, in my 1/14 scale buggy, I have a 15t pinion driving a 44t spur, but my buggy is much lighter than yours, smaller wheels, blah blah, I'm getting off track here. Point is, check the above, and buy some smaller pinions, like one that's 1 tooth smaller, one that's 2, one that 3, and maybe a pinion that's 4 teeth smaller.

Either that, or try a lower kV motor.

And like @pug said, check for drivetrain binding, no worn out bearings, no oversized wheels, ect.

HSP vehicles arent exactly a true 1/10TH scale. They are sized somewhere between a 1/12TH and 1/10TH scale. The only almost 1/10TH scale SCT they made was the Storm, and that is discontinued and hard to find parts for. Every other HSP car they make (SCT, Desert truck, Monster truck, Buggy, Truggy, On road car) sits on the same chassis as the Redcat Volcano, which means no regular 1/10TH SCT body will fit, because they are too long and wide. HSP actually started with two buggies, one electric, one nitro, and every other 1/10TH vehicle they make is based off those two vehicles, and shares a lot of the parts across the entire line.

As for the suggestion for a lower KV motor, i would say go the opposite. In every HSP based vehicle i build, i run either 3900KV or 4370KV 3650 motors with 15-17T pinions. They seem to run best on that set up. Even if you swap to a lower tooth pinion, with a 3100 or 3300KV motor, it will be slow, although, it will get longer run times that way.

 

[gothe80]

Binding in the drivetrain can also cause heat issues due to the extra friction and load on both the motor and ESC.

Uh huh, yes. I edited my previous reply earlier with that. Any kind of binding is bad, be it drivetrain, suspension, or steering binding.

A couple questions. Which truck do you have, the SCT or the desert truck with the roll cage under the body, or the storm? Did you upgrade to better bearings, especially in the hubs? HSP cars are notorious for having very crappy metal shielded bearings that seize easily. You said you went from brushed to brushless, does yours have the metal or plastic gears? If it has the plastic diff gears, they wont hold up to brushless very long. As for the pinion size, 23T is way too much for them, unless you have the exact electronics that HSP sells them with. Oddly, with the HSP electronics, 23T and 26T pinions work, but, if you use any other brand of electronics, its better to stay under 20T for the pinion. Since you upgraded to brushless, i would also swap the plastic spur for the metal one. The gearing is listed as 48P metric, but, after a bunch of trial and error, i found it is actually mod 0.6 gear pitch. Unfortunately, you are stuck with that, because noone makes a spur in any other pitch for the HSP cars.


HSP vehicles arent exactly a true 1/10TH scale. They are sized somewhere between a 1/12TH and 1/10TH scale. The only almost 1/10TH scale SCT they made was the Storm, and that is discontinued and hard to find parts for. Every other HSP car they make (SCT, Desert truck, Monster truck, Buggy, Truggy, On road car) sits on the same chassis as the Redcat Volcano, which means no regular 1/10TH SCT body will fit, because they are too long and wide. HSP actually started with two buggies, one electric, one nitro, and every other 1/10TH vehicle they make is based off those two vehicles, and shares a lot of the parts across the entire line.

As for the suggestion for a lower KV motor, i would say go the opposite. In every HSP based vehicle i build, i run either 3900KV or 4370KV 3650 motors with 15-17T pinions. They seem to run best on that set up. Even if you swap to a lower tooth pinion, with a 3100 or 3300KV motor, it will be slow, although, it will get longer run times that way.

Thanks for that info, I’ll go down on the pinion gear but I thought the lower the kv the more torque you have down low. It’s been years since I have got into the rc

 

[The_RC_Dude]

Thanks for that info, I’ll go down on the pinion gear but I thought the lower the kv the more torque you have down low. It’s been years since I have got into the rc

Yeah, so the HIGHER the kV, the more top end RPM you have, but less top end torque. A longer can length and/or wide can width means more torque, not more speed. So a 3650 3500kV will have the same RPM as a 3660 3500kV motor, but the latter (the 3660) will have more torque than the 3650. What this mean is with the 3660 you'll be able to gear up a little bit, and have the same torque, but a little more speed than the 3650 motor. Basically, you can turn that little extra torque from the 3660 to a little more RPM. This is all theoritical, so in real life, you have friction and all that stuff, but it won't skew the results that much. Hope this makes sense.

In a nutshell, a bigger motor can length/width = more torque, and a higher kV = more top end RPM, but less top end torque.

A couple questions. Which truck do you have, the SCT or the desert truck with the roll cage under the body, or the storm? Did you upgrade to better bearings, especially in the hubs? HSP cars are notorious for having very crappy metal shielded bearings that seize easily. You said you went from brushed to brushless, does yours have the metal or plastic gears? If it has the plastic diff gears, they wont hold up to brushless very long. As for the pinion size, 23T is way too much for them, unless you have the exact electronics that HSP sells them with. Oddly, with the HSP electronics, 23T and 26T pinions work, but, if you use any other brand of electronics, its better to stay under 20T for the pinion. Since you upgraded to brushless, i would also swap the plastic spur for the metal one. The gearing is listed as 48P metric, but, after a bunch of trial and error, i found it is actually mod 0.6 gear pitch. Unfortunately, you are stuck with that, because noone makes a spur in any other pitch for the HSP cars.


HSP vehicles arent exactly a true 1/10TH scale. They are sized somewhere between a 1/12TH and 1/10TH scale. The only almost 1/10TH scale SCT they made was the Storm, and that is discontinued and hard to find parts for. Every other HSP car they make (SCT, Desert truck, Monster truck, Buggy, Truggy, On road car) sits on the same chassis as the Redcat Volcano, which means no regular 1/10TH SCT body will fit, because they are too long and wide. HSP actually started with two buggies, one electric, one nitro, and every other 1/10TH vehicle they make is based off those two vehicles, and shares a lot of the parts across the entire line.

As for the suggestion for a lower KV motor, i would say go the opposite. In every HSP based vehicle i build, i run either 3900KV or 4370KV 3650 motors with 15-17T pinions. They seem to run best on that set up. Even if you swap to a lower tooth pinion, with a 3100 or 3300KV motor, it will be slow, although, it will get longer run times that way.

Maybe they're....1/11 scale! Don't you have some HSP vehicles, I think it was you who has a Storm? How about a middling kV, so Noah can gear up or down easily?

 

[biggman100]

Yeah, so the HIGHER the kV, the more top end RPM you have, but less top end torque. A longer can length and/or wide can width means more torque, not more speed. So a 3650 3500kV will have the same RPM as a 3660 3500kV motor, but the latter (the 3660) will have more torque than the 3650. What this mean is with the 3660 you'll be able to gear up a little bit, and have the same torque, but a little more speed than the 3650 motor. Basically, you can turn that little extra torque from the 3660 to a little more RPM. This is all theoritical, so in real life, you have friction and all that stuff, but it won't skew the results that much. Hope this makes sense.

In a nutshell, a bigger motor can length/width = more torque, and a higher kV = more top end RPM, but less top end torque.

Maybe they're....1/11 scale! Don't you have some HSP vehicles, I think it was you who has a Storm? How about a middling kV, so Noah can gear up or down easily?

I dont have a Storm anymore, but i do have several of the HSP vehicles. A 3660 is a tight fit in that chassis, and, a drawback to the HSP stuff, the more torque they have, the harder they can be to control. One of the first "stunt" vehicles i built, quite by accident, was an HSP Infinitive with a 3660 3800KV motor. It would do standing flips from a dead stop, so i tend to stick with 3650 motors for those cars, and, just pick the motor based on whether i want more speed or more power. My buggies run a 3650 3500KV or a 3650 3900KV paired with a HW 10BL60, and with the 3500, i run between a 17 and 19T pinion, and, with the 3900, i run between a 15 and 17T pinion. My on road stuff runs a 3900KV 3650 with a 17T pinion, and so do my rally cars, but they have a 19T pinion. My one and only drift car runs a 3900KV with a 26T pinion. All of them run a HW 10BL60 ESC (i buy a lot of those).

EDIT: If you look through my HSP post: https://www.rctalk.com/forum/threads/my-hsp-based-collection.133625/#post-1326076 you will see just how tight a 3650 is in those cars.

 

[gothe80]

Thanks guys sort of getting it now, as I said the last time I was into the rc buggy’s they were all brushed, no brushless motors. A lot faster and more fun and for the kids
I’ll give you all an update when I change them around and see what setup is the best

 

[The_RC_Dude]

I dont have a Storm anymore, but i do have several of the HSP vehicles. A 3660 is a tight fit in that chassis, and, a drawback to the HSP stuff, the more torque they have, the harder they can be to control. One of the first "stunt" vehicles i built, quite by accident, was an HSP Infinitive with a 3660 3800KV motor. It would do standing flips from a dead stop, so i tend to stick with 3650 motors for those cars, and, just pick the motor based on whether i want more speed or more power. My buggies run a 3650 3500KV or a 3650 3900KV paired with a HW 10BL60, and with the 3500, i run between a 17 and 19T pinion, and, with the 3900, i run between a 15 and 17T pinion. My on road stuff runs a 3900KV 3650 with a 17T pinion, and so do my rally cars, but they have a 19T pinion. My one and only drift car runs a 3900KV with a 26T pinion. All of them run a HW 10BL60 ESC (i buy a lot of those).

EDIT: If you look through my HSP post: https://www.rctalk.com/forum/threads/my-hsp-based-collection.133625/#post-1326076 you will see just how tight a 3650 is in those cars.

Yeah, looking through that thread, a 540 or 3650 fits with a little wiggle room, and with a 3660 you run the risk of squashing wires So they just aren't built to handle too much power/speed? Standing backflips...wow! You have a LOT of HSP and HSP based vehicles, you're the guru on that stuff!

 

[biggman100]

Yeah, looking through that thread, a 540 or 3650 fits with a little wiggle room, and with a 3660 you run the risk of squashing wires So they just aren't built to handle too much power/speed? Standing backflips...wow! You have a LOT of HSP and HSP based vehicles, you're the guru on that stuff!

To give a better idea of the size difference, this is a 1/10TH HSP Touring car, and 1/10TH HSP Buggy next to a Traxxas Bandit.

As you can see, the touring car and the buggy are both smaller than the Bandit, and, every HSP 1/10TH scale, whether it is from HSP, Redcat Racing, or Exceed RC are all that same size, no matter what style of vehicle it is. Even the HSP based SCT and desert truck are that same size.