DF-03RA OVERHEATING :( Gearing Ideas?

[fb5b]

Hey guys just picked up a DF-03RA, running the largest stock spur and smallest stock pinion (29/78) for a FDR of 8.22 on standard TC tyres (waiting inserts for the rally blocks) using a Traxxas XL5 ESC and a Kyosho X-Speed 20 turn motor, after 4-5 minutes it just gets uber hot, and the motor makes some pretty funky noises

Any ideas on how to gear for this and a 15 turn motor I have? Puzzled how it'd be with Rally blocks which I'd assume would need higher gearing as they are slightly taller tyres, effecting rollout etc etc.

Running using a 6 cell IB4200 pack, haven't even thrown my Lipo at it yet!

Any help mucho appreciated!

[DCM]

you are undergeared........

[fb5b]

undergeared? I only run a 27t stocker (Trinity CO27) at 7.3 in a TA05, and I run a sports tuned at 6.56 both for a tight track in racing.


We also run 8 singles in the 9-10 range so I would have thought a FDR of 8.2 for a 20 turn was spot on!?!

[sosidge]

Perhaps it is the motor that is the problem, not the gear ratio. Try a different motor. Also check the transmission rolls freely.

And I'd love to know how the car handles the rough-ish stuff when you get it going!

[fb5b]

Originally Posted by sosidge

Perhaps it is the motor that is the problem, not the gear ratio. Try a different motor. Also check the transmission rolls freely.

And I'd love to know how the car handles the rough-ish stuff when you get it going!

Tranny is nice n free, just installed the slipper and heatsink bars, figure I'll thrash the s#it out of this motor, as I dunno how old it is it was in the bottom of a box, but I did take it out and motorspray it, oil the bushings etc.

What kinda FDR do you suggest for say a 15 turn?

Stock it comes with a 29 and 32 t pinions and a 75 and 78t spur, same IDR as the Dark Impact obviously.

I have the 82t spur from the slipper but it's too big for either of these pinions.

[fb5b]

PS Kudos on ur TA-05R guide sosidge, I race a TA-05IFSR with a 10.5 BL so ur set up guide was my bible for a while.

This bugger will be running novice offroad amongst some Minis and kids with cheapy Duratrax Evaders so with any joy, I can get it set up nice!

[DCM]

if it is an old motor, then chances are, it is the motor, but it would of been handy to tell us that you had dug it out the bottom of your box though.

[Supergreg]

Once I had a DF03 (Dark Impact buggy) I also ran into overheat problems in no time. I ran a 17t LRP Challenge motor with shortest possible gearing, heatsink bars and additional fan (mounted on top of the motor), but still too hot in there. I think it's a general problem of chassis construction having too little heat absorption.

[sosidge]

Originally Posted by fb5b

PS Kudos on ur TA-05R guide sosidge, I race a TA-05IFSR with a 10.5 BL so ur set up guide was my bible for a while.

This bugger will be running novice offroad amongst some Minis and kids with cheapy Duratrax Evaders so with any joy, I can get it set up nice!

Thanks, glad I could help. Can't answer your gearing question for a 15T motor really, probably 7:1 will be OK to start with, same as what I start a 19T with.

[DCM]

I run about 6.8 in the TA05 on a 10.5/19t

[sim]

Internal ratio for the DF-03 is 55/18 = 3.056, if that helps.
Doesn't sound like you geared it too tall though.

[fb5b]

Surely if I go from 8.22 now to the 7's, with a higher turn motor, it'd get hotter? I would assume I'd have to get the gearing lower. I know brushless motors can heat up if undergeared but not brushed? Also with the Rally blocks I'd need more conservative gearing as my rollout is more isn't it?

I run a 10.5 Trinity BL in my TA05 for racing geared at 5.32 and it's under 40 celcius every time after a 5 minute race but I doubt I could run any sort of brushed motor in the DF03RA at that ratio.

[DCM]

undergearing can cause as much heat as overgearing.

[fb5b]

Well I tried the 15t motor at 8.22 and it struggled on accelleration which tells me that at 8.22 it's overgeared?

Any thoughts?

[fb5b]

I just checked the last Tamiya Rally car (TB-01 Lancer) manual and the stock gearing on that was 9.91 (16/61) in a car with better air flow.

Perhaps the DF03 needs to be geared in that area to counter the lack of air flow in the car?

[tom_chang79]

It's not an apples-to-apples comparison, but I'm running a DF-03MS buggy, with a Mamba Max + 4600kV with a final ratio of 10.3. Overheating isn't an issue with mine.

The motor has the same if not more airflow then the motor in my B44.

I am running the 78T (0.5 pitch) spur with 23T (48 pitch) pinion. Yeah, the 48 pitch pinion mated with the 0.5 pitch spur is kinda loud, but it's hardly noticeable next to the 1/8-scale buggy conversion that are doing metal-to-metal gear mating...

With a 15 turn, I would try a gear ratio of 11 or so. Again, gear ratios really depends on what kind of track you are running it.

If your car is brand new, I would run the car with at least a pack or two on your bench, while the car is on a stand or jacks with the wheels off of it to break in your drivetrain and make sure that it's seating correctly. Often times, when a car is brand spanking new, the drivetrain and suspension components may feel tight.

If your drivetrain still doesn't free up after a pack or two, try to figure out where it's coming from in your drivetrain by removing a gear here or there to isolate which one is too tight...

It could just be that your motors just doesn't have enough punch to run the car at a lower gear ratio. Excessive RPMs will heat up your motor, but so is excessive loading. Electric motors draws the most current as the shaft is loaded down more and more. For example, if you stall your electric motor (say it was jammed) and you still gunned it, the motor is drawing the maximum amount of current it can (therefore most likely releasing smoke that you can't put back ;P)