I want it to whoop some @$$ (TC4/Mamba/Lipo)
 

Team Kit TC4
Mamba 5700K
20T Titanium Pinion
72T stock Spur
Current FDR: 9.00

I'm currently running a 3600mah Nicad 6Cell, but i have some 3s 3000mah Lipo's on the way.
I know the 3s Lipo is going to be a world of differences but what else can i do?

Castle Creations "recommends" a Pinion of 13-18T and the largest spur i can get.

1) Should i go to the 18t pinion like recommend, (which would make my top end slower)
Or since i'm looking for top speed leave the 20t
2) If go with a 76t or 77t spur gear like recommend that will also hurt my top end.

So... Right now my gearing is not what Castle Creations recommends.. But it will be faster.. (giving that something doesn't break)
I'm thinking, i will leave the current gearing, and just install the heat sink and fans i have and watch the temps.

Just looking for opinions.

Thanks,
Tom.

Are you SURE that a 76 or 77 spur really IS what Castle is recommending?

First thing I'd do would be to find out if Castle is talking 64 pitch or 48 pitch gears... In a TC4, with 48 pitch gears, an 18 tooth pinion with "the biggest spur you can get" is going to be a LOT different than with 64 pitch gears.

If Castle is thinking 64 pitch with their recommendation, you will NOT be able to get a big enough 48 pitch spur in the car to avoid cooking your motor.

Here is the link: Remove the X and put a "." (dot)
castlecreationsXcom/support/documents/speed_and_gearing_chart.pdf

All Castle says is "Use the LARGEST Spur available" with a 13-18t Pinion gear. And at the bottom of that first page, it does say 48pitch.

Lets say heat is not a problem with the current 72/20. Should i go up on the pinion (21-22p +) or go smaller on the Spur? (68-70 -)

Thanks!

I can't see the chart, the link works, but the document itself seems to crash my pdf reader.

If heat doesn't seem to be an issue with 72/20, then my choice would be bigger pinions instead of a smaller spur. Once you get down to small pinion sizes, there are fewer teeth in engagment with the spur... with a powerful motor, the more teeth in engagement the better to avoid wiping the teeth off the spur.

I'd watch the temps closely at first...

I was running 23/72 (48P) with the 5700 in my TC4 and everything ran cool. Your way under geared. The 5700 also makes more power with low timing or med. timing. I wouldn't go 3 cell lipo, but rather a good 2 cell lipo (SMC5200 or 5000) geared 24/72. This is assuming you are running rubber tires and foam would be a tooth higher.

Well with a 2s battery the motor is spinning at 42180RPM, where with the 3s its spinning at 63270RPM. So my 20/72 is alot more harsh with the 3s then it would have been with a 2s. Obviously.

I'm going to do some passes and then check the temp with my friends lazer temp sensor gun soon. And see if it's alright. It feels fine to the touch, so I'm thinking i am fine.