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Savage flux xl Alza differential help please!

Messages
6
Hi, I have been trouble shooting for awhile and have had problems with my motor stopping and overheating. I have the stock flux motor and esc. I have a pretty heavy all aluminum custom savage xl flux with an Alza differential. Any ideas on motors/esc or ways I can stop my motor from over heating after like 5 minutes. Anyone else have these issues with heavy trucks or Alza diff? Thanks so much for your help.
 

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olds97_lss

Well-Known Member
Messages
2,322
Location
Dekalb, IL 60115
Found a comment a while back on another forum regarding running a center diff and gearing:
https://www.msuk-forum.co.uk/forums/topic/205956-savage-flux-alza-center-diff-pinion-and-spur-questions/?do=findComment&comment=2142199

Here's the standard flux gearing. For a CD, change transmission ration to 1. Put your spur at 48 and pinion to 11, change to 2000kv and select 4s, pick your wheel diameter. I'll guess you tyres at 6.3", it's suggested to start with a rollout ratio of 1:1 and see how temps go. So, 11/48 is around 40/60mph on 4/6s, 1.41:1, on the high side. 10/50 is 35/52mph, 1.23:1, better. 9/50 is 31/47, 1.1:1 better still.
http://www.scriptasylum.com/rc_speed/top_speed.html

So, would suggest your running really tall gearing for what the motor/esc is. The stock motor is a 2200kv.

I've had to gear mine down quite a bit to deal with heat when I started running 6S with a super 5SC transmission with center diff. It's got other gears in the transmission, so not direct gearing like a simple center diff would be. I had been running 4S with 20/44 gearing, but now on 6S, I'm running 16/48 and it's still on the high side.
 

lokky

Member
Messages
7
Those tyres/wheels look heavy so perhaps the rotational mass as well as the overall weight is too much for the motor and gearing. Try a smaller pinion. I run a alza cd on 11/50 with 4S with 2000Kv and no major heat issues. Do you know total weight with or without lipos. Try testing with lighter wheels, but i think you need a lower kv motor with 6S to handle the weight of your car. Usually increasing voltage reduces the motor amp draw. Bashing on grass will work the motor more than on road. Are you sure that the stopping is due to the motor overheating and not the esc? Usually it is the esc going into thermal shutdown. Motors will usually continue to run until destruction.
 
Last edited:
Messages
6
Those tyres/wheels look heavy so perhaps the rotational mass as well as the overall weight is too much for the motor and gearing. Try a smaller pinion. I run a alza cd on 11/50 with 4S with 2000Kv and no major heat issues. Do you know total weight with or without lipos. Try testing with lighter wheels, but i think you need a lower kv motor with 6S to handle the weight of your car. Usually increasing voltage reduces the motor amp draw. Bashing on grass will work the motor more than on road. Are you sure that the stopping is due to the motor overheating and not the esc? Usually it is the esc going into thermal shutdown. Motors will usually continue to run until destruction.
I think the weight of the truck is like 18lbs without lipos.
I guess it might be the esc shutting off. I just ordered a 11 and 10 tooth pinion you try. Do you think 4s batteries would give less heat? I was trying to avoid buying another motor but if I need to I will
 
Messages
6
T
Found a comment a while back on another forum regarding running a center diff and gearing:
https://www.msuk-forum.co.uk/forums/topic/205956-savage-flux-alza-center-diff-pinion-and-spur-questions/?do=findComment&comment=2142199

Here's the standard flux gearing. For a CD, change transmission ration to 1. Put your spur at 48 and pinion to 11, change to 2000kv and select 4s, pick your wheel diameter. I'll guess you tyres at 6.3", it's suggested to start with a rollout ratio of 1:1 and see how temps go. So, 11/48 is around 40/60mph on 4/6s, 1.41:1, on the high side. 10/50 is 35/52mph, 1.23:1, better. 9/50 is 31/47, 1.1:1 better still.
http://www.scriptasylum.com/rc_speed/top_speed.html

So, would suggest your running really tall gearing for what the motor/esc is. The stock motor is a 2200kv.

I've had to gear mine down quite a bit to deal with heat when I started running 6S with a super 5SC transmission with center diff. It's got other gears in the transmission, so not direct gearing like a simple center diff would be. I had been running 4S with 20/44 gearing, but now on 6S, I'm running 16/48 and it's still on the high side.
thanks, I will try a smaller pinion gear and see if that helps. I guess getting 4s batteries can help with the heat too? I’m not looking for speed. It is more show than go.
 

olds97_lss

Well-Known Member
Messages
2,322
Location
Dekalb, IL 60115
4S will help some, but it will still pull a lot of amps if geared wrong, which will still heat up the esc. Your just geared too tall and may need a different center diff spur as well as a pinion to drop the gearing enough.

A lower kv motor will run cooler, but will overheat too when geared wrong. I think a 2200kv motor should be able to live on 6S. Perhaps a 2000kv or 1800kv would be less fussy.

Which esc do you have? The really old one that was a Mamba Monster v1 or the later one that I think is a hobbywing rebrand? They used at least 2 in the savage. My flux had the old MMv1 in it. Wasn't waterproof. The later HW one was waterproof.
 
Messages
6
4S will help some, but it will still pull a lot of amps if geared wrong, which will still heat up the esc. Your just geared too tall and may need a different center diff spur as well as a pinion to drop the gearing enough.

A lower kv motor will run cooler, but will overheat too when geared wrong. I think a 2200kv motor should be able to live on 6S. Perhaps a 2000kv or 1800kv would be less fussy.

Which esc do you have? The really old one that was a Mamba Monster v1 or the later one that I think is a hobbywing rebrand? They used at least 2 in the savage. My flux had the old MMv1 in it. Wasn't waterproof. The later HW one was waterproof.
It’s the stock one that came with it. Its pretty old. It’s called ELC-6s by Hpi.
 

lokky

Member
Messages
7
I would be looking at about 1480kv motor on 6S for your heavy car as this will give more torque. Need to cost up motor vs more lipos if don't have any 2S packs.
 

Biddie_fiddler

Well-Known Member
Messages
267
Location
Perth, WA
I'm more than willing to bet that the main cause of the overheating is the weight of the car and the rotational mass of those wheels.

Read up on moments of inertia. I did this during one of my units at uni. Its the same principle a flywheel works on.
Those wheels are gonna be very heavy, and trying to turn those is gonna put a lotta strain on that motor.

I experienced this when my rig was nitro and I put 4" wheels on it. She struggled hard to get moving, destroyed the poor clutch shoes.

Your rig looks extremely heavy and so you'll need to compensate for that with your gearing. This has been mentioned above already so pointless me repeating it again.
 
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