Novak Brushless - fan or no fan? and Gearing?
 

I have just placed an order for two novak brushless systems for my ZX5 and B4.:D
Both systems have the new sintered arms. I know that sintered have stronger brakes, slightly more power and run cooler (is that the motor or speedo as well?).

What i'm keen to know is whether i can chance running the speedo with out the fan in either 2 or 4wd? i'm guessing the 6.5 in a B4 might be ok without the fan as the load shouldn't be too great. but a 4.5 in the ZX5, unlikely? Has anyone placed the fan on it's side next to the speedo so it fits under the shell?

also does anyone have a good starting point for gearing the B4 (6.5) and ZX5 (4.5)?

many thanks

hi jim i run a 6.5 in my x6 so based on a b4 and i run a 19/20 pinion never got really hot but i run my fan on top

i run a 4.5 novak in my lazer with a fan u will need new body either kl002 bullit shel or the azerashi one also gear it at 15 81 its a little quick too quick in fact:D pm me for any wiring help its a hand full

defo run the fan it gets mega hot;)

In your B4 try taking the washers from between the fan and heatsink, it might just fit underneath the shell without any butchering.

If it's a new sintered rotor motor, you might get away with it in your B4, wouldn't like to try that in your ZX5 though...

its fast too fast beyond belief fast in fact go a speed gun in may be fastest off roader ever:D

Sintered runs cooler.

In the B4, I beleive the ESC would stay cool 'enough' without the fan, but if you can get a fan in there - do.

I would recommend, a 25mm fan, mounted from the side on the chassis blowing through the fins. Wired direct to 7.2v so it is blowing even before you are turned on.

6.5R is a good choice for 2wd by the way. :)

cheers for the replies guys.
Chris, when you say sintered is cooler is that the motor or the speedo as well? No one seems to clarify that.
i currently have a 25mm fan in the lazer for the old motor, hence the idea of pointing it at the speedo instead!
i'll see if i can shoehorn the fan into the B4. I'm sure it will be ok now, but come 30 deg heat in July the fan may be needed.

I agree the 4.5 may be a tad overkill on some tracks but the price was too good. i may get a 5.5 motor to use as well, and save the 4.5 for really fast tracks!

i needed a fan at kiddy 9 degrees thermalled without fan no prob with pm for cheap fans ps im not selling them c u will need a fan i use 7.2v fan 30mm hooked up to reciever no probs

Ah sorry.

When I say sintered runs cooler, I mean both the ESC and motor. They thermal at approx 200F, but im reaching just over half of that.

I check it with a digital temp gauga after most runs... worth doing.

cheers mate for the info will put that sintered in for tivvy :D

I've done some back to back tests here so can help. Running sintered over bonded made my speedo and motor run cooler but by different amounts. The motor ran 10deg F cooler, which is nice and helpful. The speedo ran just over 20deg F cooler which is really quite significant. Went from warm to really barely warm at all.

Now, you may be able to get away without the fan in 2wd but it’s a risk. There are several options; firstly in the B4 you can easily run a 25mm fan in front of the speedo taped to the chassis blowing through the speedo. You can I believe just wire it to the fan output on the speedo because it just needs that extra bit of cooling over no fan that you need for safety. I think this will be fine in 2wd however if there is still a problem you can wire it to 7.2V which makes it shift normally about twice as much air and will defo sort the issue. The other way is what Bradders did and milled down the centre fins, you can then mount an 8mm thick 25mm fan down the centre and it will just fit under a B4 shell.

In my X5 I can’t fit the 30mm fan either, I have a 25mm fan wired 7.2V pointing directly at the speedo fins (speedo on side) and on the weekend with a bonded rotor it was coming off less than 100deg F, i.e. VERY cool indeed, this was running a 5.5 motor and the car was very quick.

I do actually have a 4.5 but with decent cells outdoors I think it will get used few and far between. Will be fun though when I do ;)

cheers guys that's pretty useful stuff.
Dan when you say speedo on it's side do you mean as in standing up on it's edge, or just side on to the fan so the air blows through the fins?

i like bradders solution! i have a 25mm fan, and the old man has a milling machine :D

do you reckon this would also work in the 4wd if the 25mm fan was wired to 7.2 volts? i've just had a new shell painted and i don't want to have to get an Arahzi(?) shell with big scoops and beg my friend to paint that as well!!

lastly, what overall gear ratios are you guys running (the X6 has the same ration as the B4?)

On my X5 the speedo it taped on its side so the bottom is on the tranny tunnel and the GTB stickered side faces down, the fan then sits alongside, flowing onto the top of the speedo. I believe (but take no responsibility for) that the 25mm 7.2V fan will work fine as long as it it mounted directly on top as it works perfect for me how I have it. I’ll try to take a pic and host it tonight.

I have noted, even when on bonded my Novak runs much cooler than some of the lads at York with equivalent LRP systems. That said they don’t run fans (or heat sinks some of them) so it’s no surprise. That way I have both cars set up now I expect to be able to run any motor in either car and never even have to think about thermal issues ever again even in the summer (sintered rotors).

On the weekend I ran 19*78, but believe Secret Agent Barton was on either a 17 or 18 84 on his B4 and he won the event! I will experiment with gearing down even further but need to get some other Losi spurs for the X6.

cheers Dan, really helpful. and a pic would be great. anyone have a pic of Bradders speedo?!!!!

Well, i've managed to shoehorn the speedos into both cars, i'll deal with putting the shell on later!

Next questions are what are peoples preferred settings on the speedo. I know Dan and Chris go for minimum drive of 1 and throttle curve of -20% ish. But i can't find any info on the other settings such as drag break and deadband etc.

Can people post up their settings and reasons?
ta

dan do you mean like this??? [paul sinclairs]





http://www.4wdrc.com/images/novak_brushless_1_big.jpg


http://www.4wdrc.com/images/novak_brushless_2_big.jpg

Oops I forgot about this, mine is almost like that, but the speedo closer to the motor and the cap in front. Essentially though that's where it is but with a 25mm fan on the side of the speedo.

Will be running it at Bury on sunday if anyone interested.

hu else is going on sunday?

anyone? some ideal settings for 2 and 4wd? Have the first regional on Sunday so need a good starting point as i haven't had a chance to test it properly on a track!
ta