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Matt
18-11-2004, 07:31 PM
so check it. today (thursday) its 30+ degrees in sydney, a real scorcher. so i grab my car and 2 batterys and head for the track for some practice and tune laps.

run the first battery - all good. i let the car cool for 5 or so mins and fire up battery #2. i get about 2 laps run time and on the third lap the motor completely stops.

SHIT

i get it home for diagnosis. speed control light works and responds to throttle on the controller but no motor movement. voltmeter shows current to the motor. i disassemble the motor and clean thoroughly. put back together and _still_ no go.

SHIT.

this was not good and i remember breaking into a real bad sweat (did i mention it was 30+ degrees).

to cut a lot of panic short, the motor plate that the motor screws into had gotten so hot it warped (!) and the motor was on a servere angle that would not allow it to freely turn with the spur gear.

ive spent 3+ hours pulling the rear end to bits, and used trial and error to get the metal plate straight again (only tool i had was a pair of plyers).

a test drive tonight proved positive. she was flying up and down the street but i learnt that my pinion gear is way too large because the car needs a good 10 - 15 meters to wind up to full RPM and this is half the length of the straight on the track. the car would only be at full speed for the last half of the straight and on no other part of the track! i am running a 22 teeth pinion, im going to take a dive down to an 18 on sunday for race day.

tuning is such an "on-going" process, isnt it.

azzachaz
19-11-2004, 06:22 AM
I actually thinking of going the other way with my Alpha 3. It gets up to full speed too early. Heaps of torque and acceleration which is cool but it would be annhialated down at the track becasue of its low top speed.

With the nitro's you need to buy a new clutch bell to do this ($15-50). It has a 13 tooth gear at the moment. Might change to a 14 or 15 tooth and see what thata does.

The more expensive option is to go 2 speed.

Matt
20-11-2004, 10:57 AM
a bit of an update...

i messed with pinions friday night (i was up until 3am tinkering with the car - soooo adictive) and i went from a 22 to an 18 tooth pinion and OMFG she lost speed something cruel. accelleration was on tap but no top end at all.

i switched to a 20 tooth pinion and she gained speed and didnt loose too much accelleration.

so, although it may only be 2 teeth that ive dropped, the difference is there. so much so that dropping 4 teeth destroyed the speed and it was quite slow.

amazing how a little change can make a big difference.

Matt
23-11-2004, 08:45 PM
ha. due to an oval shapped spur that caused tight spots on each revolution, ive had to go back to the [larger] factory kyosho spur and also upgrade the pinion to compensate. im now on the 22 tooth pinion again.

thanks for reading :p