flyskybri

hi, i recently converted my x2crt to brushless, i used the turnigy 1/8th trackstar motor and 150amp esc combo from hk,
i've been using it for fpv fun, the fastest speed i've seen on my osd is 23mph, this was with the timing set to normal, i've been playing around with the settings and there not making any difference, also using 3s or 4s lipos arn't making any difference, i've got the esc wires around the right way, done the throttle range a number of times..
also the last time i had it out it seemed to be getting slower,
could my esc be faulty?
it sounds like it not reving up high enough..
any ideas??

mkiiina

iTrader: (71)

What KV is the motor and what is your current gearing? Have you checked your drivetrain to make sure its moving freely without binding?

pablo040

A lot of thongs "could" be faulty, or were setup wrong initially - but without more investigation on your part, giving a vague explanation like "it's slow" is not really being of much help.

A huge part of this hobby is working on our own vehicles, and doing most of our own self diagnosis, and my suggestion would be to get out your tools and user manuals (opening to the trouble-shooting section) and start trying to figure out what you did wrong or isn't working quite right.

djiewie

one thing wich worked for me. recalibrate the transmitter with your speedo, neutral , brake, full speed or do the analog digital servo thing, read the manual from the transmitter.

flyskybri

thanks for the replys, the motor is 2650KV and the drivetrain runs freely without the motor on, spur gears 48T and pinions 12T, i've put a 15T on doesn't seem any faster,this is with the wheels off.
sorry for the dumb question didn't mean to offend anyone, just that i'm new to electric been drinking nitro for ages, maybe that's my problem..lol
so thought i'd ask on here in case there was something obvious i'd done wrong.
i've used three different tx's an old dx2.0, turnigy 9x and brought a new gt3b..

mkiiina

iTrader: (71)

Doing some quick math (along with the help from rc-monster) here's what I came up with.

With 12t pinion
Differential Ratio: 3.3076923076923075
Transmission Ratio: 2.215277777777778
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 12
Total Voltage: 16.80
Motor KV: 2650
Tire Diameter (inches): 4.33
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 4 : 1
Total Ratio: 29.30983 : 1
Tire Circumference (inches): 13.6 inches (345.52 mm)
Rollout: 0.46:1
Total Motor Speed: 44520 RPM
Vehicle Speed: 19.57 mph (31.43 km/h)
Effective KV Value: 2650
KT constant: 0.51 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...


With 15t pinion
Differential Ratio: 3.3076923076923075
Transmission Ratio: 2.215277777777778
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 15
Total Voltage: 16.80
Motor KV: 2650
Tire Diameter (inches): 4.33
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 3.2 : 1
Total Ratio: 23.44786 : 1
Tire Circumference (inches): 13.6 inches (345.52 mm)
Rollout: 0.58:1
Total Motor Speed: 44520 RPM
Vehicle Speed: 24.46 mph (39.29 km/h)
Effective KV Value: 2650
KT constant: 0.51 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...


Bottom line is your gearing is off. If you can go to a 45 or so and maybe another tooth on the pinion. Keep an eye on your temps as well.

Keep in mind if you are racing top speed isn't everything. I have my 8ight 2.0t geared for around 33 mph for our track and its about perfect.

sschultz

iTrader: (15)

otherwise, buy a good nitro engine and all problems solved!!!! plus, you get rid of that irratating whining noise!!!!! good luck!

flyskybri

thanks mkiiina for working that out, i'll give the spur gear a change and see what that's like,
sschultz i perfer nitros too (it's the future,lol) , i took out a ninja 21 to fit this electric motor,it's just nitro's no good for fpv, i tryed it first, but seemed to interfer big time with my video, also reverse is good to have..
once again thanks for helping mkiina