Questions about a Novak 7.5R Brushless

[godale03]

Hey Guys,

I have a few questions about the Novak 7.5R Brushless. First question is how many turns is it? I have not been able to find any info on it. Even on Novak's website all I can get is an electronic version of what documentation comes in the box. Nowing how many turns will help me with my pinion selection. Right now I am running an 18T pinion. I know that the ESC and motor are sensitive to heat so I do not want to run the wrong pinion. I am looking for a middle of the road setup... meaning I am looking for good low end grunt, with decent top speed. The track I run is short and windy so masive top end does me no good. Also I am having some problems setting the drag brake..... what percentage do you guys recomend? Thanks

Tom

 

[sweetdiesel]

The 7.5R is a 7.5 turn motor.

http://www.teamnovak.com/products/brushless/06motor_chart_web.gif

Proper gearing depends on many factors, such as vehicle weight, tire diameter, # and type of cells used. Ambient temps can also come into play when finding that sweet spot. What car is this setup in?

As for drag brakes, I like to have mine set to 3% on the ESC and then turn the EPA down to 20% on the transmitter. Use that as a baseline set-up and adjust to your driving style.

 

[godale03]

Hey Sweet D... thanks for the info... I swear I looked on Novak's site and they only had the info for the 5.5 and the 6.5. Ok... well I do know now. Thank you for helping me with that info. I was pretty sure that is what the 7.5 meant... but you know what they say about assuming. lol

The truck that this is setup in is an Associated T4 FT. I am running 6 cells (SMC 4200). The tires that I am running now are 2.2 size Proline Road Hawgs.... but come racing season I am going with Edge in the front and bowties in the back. Hope this helps.

Is there anythig I will need to change with the ESC if I set an EPA? Thanks

Tom

 

[sweetdiesel]

The EPA on the brakes sets the maximum braking power, with these brushless motors you will not likely need 100%. The EPA setting will not effect the drag brake setting.

A good indicator of the sweet spot for your track and gearing setup is to measure the temps of the batteries, ESC, and motor after a run.

Taken from another site

Hot motor, cool controller, cool batteries = undergeared
Cool motor, hot controller, hot batteries = overgeared
Warm motor, warm controller, warm batteries = happy components

Hot, warm, and cool vary as well, so here's another general rule:
Hot for a motor = generally over 160F (71C)
Hot for a controller = generally over 150F (66C)(or "thermal" range for the controller)
Hot for batteries = generally over 150F (66C) for nimh, 130F (54C) for lipo
Warm for a motor = generally 100F (38C) through 150F (66C)
Warm for a controller = generally 100F (38C) through 130F (54C)
Warm for batteries = generally 100F (38C) through 130F (54C) for nimh, ambient temp through 120F (49C) for lipo
Cool for all components = generally ambient temp and up to 10 degrees F (5.6C) more

The reasons the above are not always true are numerous, but may include:
Sticky drivetrain - will put un-necessary strain on electronics whether geared correctly or not.
Poor quality batteries - batteries will heat up regardless of gearing.
Wrong motor for the application - will put un-necessary strain on electronics whether geared correctly or not.
Wrong controller for the application - will put un-necessary strain on electronics whether geared correctly or not.

I would start with the stock gearing and go up or down from there.

 

[godale03]

Well that is the thing.... it came with no gears stock other than the 87 tooth spur... The pinion was not included in the kit.

Thanks for the temp info... I never really thought I would need my temp gun for my electrics... but I will have it on hand next time I have it out.

By the way..... that 7.5 really makes that T4 scoot! LOL

Tom

 

[sweetdiesel]

Well that is the thing.... it came with no gears stock other than the 87 tooth spur... The pinion was not included in the kit.

Tom

The T4RS RTR truck comes with a 20T pinion. I'd start from there.

 

[godale03]

The T4RS RTR truck comes with a 20T pinion. I'd start from there.

Ok... cool. Thanks my friend. Sorry for the string of dumb questions... but I do have a better understanding now. Thanks

Tom