JDWCA: You can make lead weights to fit in the triangular sections of the chassis center spine with a spare chassis you dont mind trashing, and some solder. The soldering iron you need to use has to have a small tip to fit down into the triangular sections of the chassis. Take several lengths of solder and nip them into 1/2" sections so you can drop them into the triangular shaped areas of the center spine... heat them being careful to not hit the plastic, and add more solder until you have that triangle full of solder. Move on to the next triangle until you have all of them full. The next part requires careful removal of the chassis from around the "lead weights". They will not drop out because the flux used in the solder will be very sticky and not allow it to come out without forceful removal. A little bit of time with a dremel will split and cut away the plastic, and then you have the weight in your hands. After removal, clean it with motor spray to remove the sticky flux. You may have to file each one to fit just right, but that depends on how well you heated the solder, and didnt warp or deform the chassis. It sounds tedious, but it is well worth it, placing necessary weight nearest the chassis centerline, and adding a bit of strength to boot.
Johnbull: I stayed away from the V2 series motors for the very reasons you mentioned. Good wear characteristics with (generally speaking) less HP. It seems that max HP requires a rebuild after every run. A skim on the comm and new brushes is what TC motors needs to be fast every run. A second run without a rebuild, even on the 10 turn motors nets a lot less HP and efficiency. This is very frustrating, but i guess it is all in the name of speed. I havent done lap time comparisons between 10 and 8 turn motors. But i am always faster with the 10 turn motors. As far as magnet strength, i have access to a magnet zapper, so i dont worry about that. I have noticed a sweet spot in comm size with max power and tire size. Seems a comm size of .273 works best with foams cut down below 57mm. Rubber tires seem to work best with a comm larger than that. (you say 4mm of timing advance, is that almost 20 degrees? Im usually between 20 to 30 degrees of timing) I always run a 100 tooth spur, i tried a 104 but didnt like what i had to do to the car to get it to tweak out. The 104 spur moves the motor further away from the center of the car, compounding this problem is the larger pinion you invariably need to run. There are a lot more variables than what has been mentioned. Are you running single wind? Doubles? I usually run triples on asphalt (low/med bite) and doubles on anything else. I tried single winds, but big wire/low wind motors are hard for me to get a comfortable power band to drive the car. They are much too punchy (IMO). Not to mention they are electron hungry. Whenever i goto a big event, you watch the factory guys, and there is a definite difference in driving styles. Kinwald, Francis, Mike Blackstock, are prime examples of "the car looks slow and smooth" but the lap times are blistering. Then we have Barry Baker, Craig Drescher, and other that arent seemingly as smooth, but net similar if not faster lap times. Seems that both styles affect motor choice and battery usage, as well as setup. I guess i was just frustrated in going to the "motor of the week' that everyone was running, and it made me slower. Maybe i just suck... LOL
- DaveW