@Gone Elvis
Unfortunately we'll not make Sunday (Eldest son's wedding
![Very Happy :D](./images/smilies/icon_biggrin.gif)
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I think you should change the setup as Skiddins advises - more boost coming in earlier. Depending on the gearing, you will be unlikely to hit 20 000 rpm on the straight. [Non boosted 13.5's top out at around 23 000 to 25 000, with the peak power at around 12 000 - 15 000 - aiming for the boost to end at or around the peak power rpm is a good starting point]
You need to bring in the timing advance early enough so that you get the torque/power boost effect, but not so soon that it just heats the coils up without any effect.
In essence (and I am not an expert!), the stator coils take a finite time (milliseconds !) to build up to maximum magnetism once the ESC fires voltage / current to them. You want the max magnetism to be achieved before the magnetic pole of the rotor passes under it (ideally 90 degrees before). As the revs build, there is less available time for the coil to "charge" - hence you have to fire the coil earlier as the revs rise = timing advance. Firing the coil too early means the peak magnetism is acheived with the rotor pole too early (at 180 degrees to the coil for example) and no torque is gained, just heat.
["blinky mode" or non-boosted ESC's do not have the ability to program the advance of the coil firing by rpm]
HTH