My recent guide on upgrading the 144001, 124018 and 124019 with a drop in 2445 5400kv made for a very fast car but also generated a lot of heat for the motor and ESC. In this guide I have a brief look on the impact of adjusting ESC timing on power output as measured by speed and the resulting change in heat of motor and ESC plus efficiency.
Most cheap ESCs, notably the Surpass/Racerstar are impressive in that there is some basic ability to programme the ESC for throttle punch, dead band, low voltage cut off plus braking and reverse as you can see in this guide. Step up to a more premium ESC like the hobbywing 16BL30 and 10BL120 as recommended in my brushless guide and amongst other items you also have the ability to adjust motor timing.
Basic timing theory
In your internal combustion engined car the motor timing can be adjusted - the point that the sparkplug ignites the fuel in the ignition chamber relative to the piston location. The advance that is applied here compensates for the delay between spark and combustion (related to the octane rating of the fuel). I am oversimplifying things here but advancing timing can benefit power at the cost of efficiency. This relies on engine design fuel, rpm, throttle and other factors so as you can imagine there is no one generic timing ideal.
Much the same is true with your brushless motor but instead of a spark we are talking about the magnetic coil of the motor energising to create a magnetic field to rotate the stator - advancing timing can increase power but typically generating more heat and dropping efficiency. The difference is that this can be managed by ESC programming rather than physical angle adjustment on the motor (although this is true for brushed motors)
So although it is super fast (78kph on 2s), my 2445 5400kv drop in brushless upgrade runs hot and has been known to trigger esc thermal cutout. On any other car I'd look to drop the gear ratio (smaller pinion) but on this car the 15t is already the smallest pinion available. Although cooling solutions like venting, heatsinks and fans can improve I wanted to see if this could be helped with adjusting timing down based on the overly simplified theory that:
Well I have more speed than I know what to do with which means everything in the right column sounds ideal.
How to Decrease Timing
I decreased timing on my Hobbywing 16BL30 using the programming button next to the power switch but if you are not confident counting beeps and LED flashes then the programming card is much easier and not expensive. Note: this is different to the surpass/racerstar one.
If you wish to use the programming instructions the manual can be found here but specially here are the programming details and parameters available for this ESC:
As you can see it is 11.25 degrees advanced from the factory meaning this is plenty of room to drop (or increase if that is your thing). Because I wanted to see a reasonable impact I went with reducing timing advance to 3.75 degrees. Read on for my results
Results for reducing ESC timing
Good news is that motor and ESC temp have definitely come back. I gave this car a good 10-12 minutes of hard street bashing in a large area meaning decent speed pulls, spinning out and accelerating hard again from standstill. After this the motor and ESC was hot but I could keep my finger on either for more than 3 seconds. At no point did I hit thermal cut off which did tend to be a feature of this setup in my earlier runs at 11.25 degrees advance. The 1800mah 2s battery I was using was just under 3.8v per cell at 12 minutes which is a 10-20% improvement in runtime on the previous setting so this is a nice little gain in efficiency as expected - less energy being wasted as heat.
It is worth noting that the ambient temperature has dropped about 5 degrees from when I ran with stock timing and I am enjoying the additional venting mods that I outlined in my original drop in brushless article.
Decreasing the esc timing advance from 11.25 degrees to 3.75 degrees has definitely reduced the top speed to a more manageable level with the 2445 5400kv motor but has more importantly reduced motor and ESC temp. The difference is noticeable and was enough for me to have confidence that I would not overheat the motor and not hit ESC thermal cutoff along with the improvements I made to the poorly ventilated 124018. This simple change to programming on this excellent ESC means I can now run my car the way I want it without worrying about damage. I will test other options in the future but for now, this is exactly what I was looking for.
Next up I'll be looking at 2s vs 3s and bringing in a lower speed 3600kv motor to compare.
Hopefully you have found this article useful, I'm focusing on making my guides and testing more technical and exhaustive so the choice is made easier for you. If you purchase via the links here or on any of my pages I receive a small commission at no cost to you which is enough to help my cover my hosting fees and other expenses related to quadifyrc.com - thanks!
21/4/2021 03:23:59 am
Very interesting stuff, thanks quad.
21/4/2021 08:48:04 am
Nice. If you have the 16BL30 then at least you have the option to adjust if you ever want to further down the track
21/4/2021 10:58:50 am
Yes I will definitely play around with it. Since of the settings sound fun, level 9 punch 😉
4/5/2021 12:28:07 am
Hiya, I haven't done too many other tests with timing as I've been working on motor kV and cell count but the same theory applies for reducing and increasing advance at other increments.
23/4/2021 09:30:23 am
I may try this on a slower motor i have with an rpm meter see what they do
23/4/2021 01:47:57 pm
1/5/2021 05:27:32 pm
Hey how do you know if your motor will accept the timing change I have a. Bunch of different motors but I don’t think the timing works
4/5/2021 12:29:48 am
With brushed motors the only timing you can change is on the motor itself. With Brushless systems you have the option of both but ESC is the preferred route as you can control by programming rather than physical/mechanical changes
24/5/2021 08:26:42 pm
As I understand the 10BL120 already has the lower timing?
26/5/2021 01:41:26 pm
Yes, looks like default timing is zero degrees on that one.
25/5/2021 05:24:17 am
Hobby Wing states that the 10bl120 is not designed for a racing application.
26/5/2021 01:42:29 pm
Only thing I can think of is that they have other models with fixed timing for specific classes. I think you can ignore that statement.
18/6/2022 06:33:27 am
Does anyone know what the typical timing is for the surpass hobby 35A esc?
29/6/2022 05:40:56 pm
Good question that I can't answer sorry, I've never seen them published.
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