Heat problems!

[tobbe]

Aaah the sun i shining and it is about 10 degrees Celsius outside. A time for me to take out my B4 for a ride after a loong nasty cold winter! Put in a charged battery and off it go! Damn it was fun driving it:thumbsup:. But after about 10 mins. it suddenly shut down. The ESC (Novak GTB) was extremely hot (I burned myself on the heatsink) the temp-shut down probably got on because after while it worked fine again. I don't have any fan because the original one broke and it's a very tight fit under the body! What should I do to prevent heat building up? A fan may work but it's as I said really a tight fit! I have a 6.5R motor geared 17/81 so it should be fine. Should I cut some holes in the body to make a better air-flow? Any ideas? I must do something because it would probably don't even work in the summer when it's around 20-25 degrees Celsius:bored:

[Wraggy]

gearing seems a little off ?? normally run around a 22-23 on that motor myself , maybe why its getting hot ?? for a starter

[Richard Lowe]

Depending on how old it is it might be a bonded rotor, so the gearing will be different to the current sintered rotors :)

It's always good to have some air moving past brushless ESC's, especially the Novaks that run a touch warmer than the Nosram/LRP units. If you are having issues with space you could always mount a smaller fan in front of the ESC blowing at it, the fan doesn't have to be mounted on the ESC it just needs to blow at the heatsink on top.

Another alternative is the JConcepts Hi-Flow B4 shell - the sidepods are higher so it's easier to fit large brushless ESC's in ;)

[Wraggy]

Depending on how old it is it might be a bonded rotor, so the gearing will be different to the current sintered rotors.
ah yes Thanks Rich forgot about that

[tobbe]

Yes it's the old bonded one. But I'm going to change to a sintered rotor soon. I heard that they run cooler too.

I tried to have the original fan mounted on the side of the ESC. Unfortunately it's a bit too big on the side too, but a new smaller fan is on the way home. But thanks about the tip about Jconcept Hi-Flow body. Must check it out! :)

[super__dan]

Good advice here. On most 2wd cars the body fits really well and so can create a pocket of very still air which gets hot. Personally I try to run my car with as few holes as possible due to potential water ingress, so a fan will really help. In a B4 I think your best bets are a 25mm fan (Novak sell one but other are available) which you can mount offset towards the middle of the car or more easily mount it taped direct to the chassis in front of the speedo, this moves just enough air over it to keep it cool.

However, the sintered rotor as well as increasing performance, allowing you to gear up more and having MUCH better brakes (you'll need to turn your drag brake down), the speedo runs MUCH cooler and this single change might actually fix your problem straight away.

Do both and you'll have no probs. Last year I ran a practice day at Burry and 2 packs of 4200's back to back full to flat and while motor and speedo were warm, I temp gunned them and they were no where near thermal shutdown.

[josh_smaxx]

I went for a bash last night, drove it rather hard till the cells were flat (no fan, GTB and an orion 6.5) and it was stone cold after every run, geared 22/81 (sintered rotor) so it would probably be worth getting a sintered rotor and see how it goes from there.