How much timing is too much?

[WraithCrawler]

Hello. I am wondering if advancing the timing on my setup is in some way inherently bad for the motor, or if the only issue to be aware of is motor temperature?

I checked Novak's website, which said that the factory neutral timing position on my motor is 30* of advance. I have set it as they indicated. More recently, I've been playing around with my MMP settings, and added as much as 10-15 additional degrees of timing in the top end. This made the truck much more fun as it will now do little power-slides, wheelies and "burnouts," to a degree, but still retains the ability to crawl VERY slow since the advance only phases in over 10,000rpm.

• Without the extra advance (STOCK 30*), I was seeing about 14,500rpm max.
• With the extra 10 (STOCK 30* + 10* via MMP) I am seeing around 17,700rpm.
• With 15* (STOCK 30* + 15* via MMP), I believe it gets to just shy to 20k rpm.

Even with all that, the highest motor temp I have ever seen is around 85*. This is WELL shy of the 160* that Novak warns is a safe temp to stop at.

Initially I played with gearing to add some top-end, but I hated how it ruined the ability to crawl with precision. Fiddling with the motor advance above 10k has given me the best of both worlds. I'm just hoping I'm not about to melt anything. So, again, is the timing itself in someway harmful, or is temp is all I need to be concerned about?

Relevant info:

• Axial Wraith
• Novak 21.5 Crawler Ballistic
• MMP
• 16/87 gearing (smallest/biggest my shop had in stock; worked out well)
• 4000mah Traxxas 3s lipo
• RPM/TEMP via DX3S Telemetry receiver

[EddieO]

If you are not exceeding the heat max, and its performing the way you like....you can keep adding timing until it doesn't meet the above.

Later EddieO

[Charlie-III]

Originally Posted by EddieO

If you are not exceeding the heat max, and its performing the way you like....you can keep adding timing until it doesn't meet the above.

Later EddieO

+1.

While advance timing can produce power, your reverse will SUCK!
I'm not sure on brushless, but in general, you will start to generate heat with timing which is really bad for the magnets and then the insulation on the windings.
Lots of timing also can kill battery runtime.

You can also gear the motor for more speed (larger tooth count on the pinion or lower tooth count on the spur).

Keep an eye on motor & ESC temps, if you can lay (not just a quick touch) your fingers on each and NOT burn them you are likely within acceptable temp limits.

Maybe your better bet is to get a "hotter" motor, one with less turns (brushed) or a higher KV (brushless).

[2500hdon37s]

personaly I dont like to run more than about 18* of timing on a brushed motor. keeps temps down, you still have good wheel speed in reverse, and longer motor life.

[AreCee]

You'll know if you have the timing set too high when you smell something burning. Like Eddie O said as long as the temps stay below 160* you should be OK. However, runtime and motor life will be shortened.

[WraithCrawler]

Originally Posted by 2500hdon37s

personaly I dont like to run more than about 18* of timing on a brushed motor. keeps temps down, you still have good wheel speed in reverse, and longer motor life.

I should have been more specific. The motor I listed is a sensored brushless motor. Because the timing advance is via the ESC, I have it set to only advance above, say, 12krpm. My reverse was already set at 50% power, so it wasn't actually effected by the digital advance.

Also, as I've been playing with it more, with 30* base timing (what the factory specified as "neutral") plus an extra 15* via the ESC, the highest temp I saw on an entire 3s pack was 121*F measured on the motors surface. I'll probably keep it set this way for a while and just watch the temps.

Also, I have the temp probe taped to the surface of the motor with a dab of thermal paste between the two. Should this be sufficiently accurate?

Originally Posted by 2500hdon37s

personaly I dont like to run more than about 18* of timing on a brushed motor. keeps temps down, you still have good wheel speed in reverse, and longer motor life.

When you say 18*, are you saying in addition to how the manufacturer set the motor? Novak says that the motor I was uses 30* as the "neutral" position. The manual goes on to explain the pro/cons of advancing or retarding the timing from there.

[Manning]

You have a nice "best of both worlds" setup going. Mellow motor, easy gearing, and throw a ton of timing at the motor with the esc to get the speed.

I wouldn't go above 40 degrees advance in the esc. But make a nice gentle ramp. Your 10k start is fine, or even a little high. Might try a 8k to 25K ramp with 40 degrees max. You'll be amazed at the rpm's the thing will turn. It'll balloon the tires, maybe even fling them off the rims. Have fun.

I think the hall effect sensors are reading 30 degrees "ahead" of the physical sensor alignment, and that's where the "30 degrees at neutral" is coming from. Supposedly brushless motors don't like to run with much less timing. JRH probably knows the full technical scoop.

[Erik D_lux]

When running my Losi with a MMP and a Novak motor I would run 50* of cheat above 9k rpm and I would leave the motor at the stock timing that it came with. I had to run a fan on my motor but I think every LLC should. After running the fan on the motor I never had a problem. Before that it would overheat and ruin the motor (did that before cheat too).

[WraithCrawler]

I went ahead and programmed it for 30* from 10k-30k. It never saw 30,000 RPM, and thus never saw the full 30*, but holy crap did that thing get moving. It reminded me of the powerband in a large turbo drag car. It just kept getting stronger. Just for kicks I took the front drive-shaft out and went sliding around the driveway. It made me miss the old Nitro Stampede I had when I was 14.

After about a minute I ended up ripping some of the suspension to bits, so I replaced everything and went back to "Smart Sense" mode. It was fun for a bit, but it was just too fast for a vehicle with fully locked 4WD and solid axles.

Also, I'd say I used about half of a battery pack, but never got over 140*F.