BL system for a crt.5 on 2s - RC-Monster Forums

rchippie · 04:31 PM

What is a good system for a crt.5 using a maxamps 2s2p 8000 lipo?. I have two of these packs so i would like to stick with 2s & not have to buy a 3s pack. I will be keeping the stock chassis .

BP-Revo · 11.11.2007, 04:44 PM

Personally, I would just run a MM Motor (5700) or a L can motor with an MM ESC, unless you can dish out the money for a Neu 1509 (then I would do that).

Serum · 11.11.2007, 04:45 PM

perhaps a novak Hvmaxx 4.5.

rchippie · 05:36 PM

BP-REVO
I like the MM combo. so would the 5700 setup be the best for 2s also if i was to use a L motor on 2s which one would be the best to get ?. What would be a good start for the gearing ?.

Rene i thought about the novak system. But i like the probramability of the MM system .

ssspconcepts · 11.11.2007, 05:33 PM

Quote:

Originally Posted by rchippie

I like the MM combo so the 5700 setup would be the best for 2s also if i was to use a L motor on 2s which one would be the best to get ?.

Rene i thought about the novak but i can get a mamba system for less .

Just in case you are interested...

http://search.ebay.com/_W0QQsassZluv2shop530

sleebus.jones · 11.11.2007, 05:42 PM

Yup, I second using the 5700.

rchippie · 10:57 PM

Quote:

Originally Posted by sleebus.jones

Yup, I second using the 5700.

I just did some calculations using brian's calculator & this is what i got. I did the calculations using a 12t pinion & the MM 5700 system.

Differential Ratio: 3.25
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 12
Total Voltage: 7.4
Motor KV: 5700
Tire Diameter (inches): 3.25 kit bow ties
Tire Ballooning (inches): 0
Motor Current Draw: 35
Motor coil Ω: 0
Spur/Pinion Ratio: 3.83 : 1
Total Ratio: 12.45833 : 1
Tire Circumference (inches): 10.21 inches (259.34mm)
Total Motor Speed: 42180 RPM
Vehicle Speed: 32.74 MPH (52.58km/h)
Effective Speed Rate: 4.42mph/V (7.11kmh/V)
Effective KV Value: 5700
Motor Torque: 0.04 ft-lbs
Final Torque: 0.54 ft-lbs

lincpimp · 11.11.2007, 08:20 PM

At that speed it will probably stay cool. I would say go with a feigao 7l, it will run well with those 8k packs and you could gear for more speed than a 5700.

rchippie · 11:11 PM

Quote:

Originally Posted by lincpimp

At that speed it will probably stay cool. I would say go with a feigao 7l, it will run well with those 8k packs and you could gear for more speed than a 5700.

If i use a 7L it will take a very big pinion to get the same speed.

Ratio: 3.25
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 20
Total Voltage: 7.4
Motor KV: 3511
Tire Diameter (inches): 3.25 kit bow ties
Tire Ballooning (inches): 0
Motor Current Draw: 35
Motor coil Ω: 0.0059
Spur/Pinion Ratio: 2.3 : 1
Total Ratio: 7.475 : 1
Tire Circumference (inches): 10.21 inches (259.34mm)
Total Motor Speed: 25256.38 RPM
Vehicle Speed: 32.67 MPH (52.48km/h)
Effective Speed Rate: 4.41mph/V (7.09kmh/V)
Effective KV Value: 3413.02
Motor Torque: 0.07 ft-lbs
Final Torque: 0.52 ft-lbs

Which would be better & would 20t pinion fit if i decided to go with the 7L ?.

I've started my conversion by taking off all the nitro gear & cleaning the car. I have also made my battery box using kydex plastic. I will have to make a new top plate for the center diff & battery box brace. Im going to try to make it all one piece. this will also be used for mounting the ESC & RECIVER.

lincpimp · 11.12.2007, 01:50 AM

Well,

The feigao l can will produce more torque than the 5700 and allow for the higher gearing. You use of 2s batteries does demand a higher kv motor than is optimal. However the batteries you have are capable of 160 amps constant so it will not be too big a deal. Maybe a 6l feigao would be better. TBH you could buy the mm/5700 combo and try it out. If you do not like it, sell the 5700 motor and buy a 6l feigao. The 5700 motors sell well on ebay, so you should be able to get almost enough to buy the feigao motor. The 6l is about 4000kv, so an 18t pinion would put you at 35mph.

dadgummit · 11.12.2007, 11:50 AM

I too just started converting a crt.5 and I am using 1/10th scale truck tires. In my opinion they look better, will last longer and have a flat patch of rubber on the road (as opposed to the rounded buggy tires that come stock) and they are about 4" high which allows you to run a smaller pinion gear. here is the speed calc with a 2s pack and a 3600 kv neu motor:
Differential Ratio: 3.25
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 16
Total Voltage: 7.4
Motor KV: 3600
Tire Diameter (inches): 4
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 2.88 : 1
Total Ratio: 9.34375 : 1
Tire Circumference (inches): 12.57 inches (319.19mm)
Total Motor Speed: 26640 RPM
Vehicle Speed: 33.93 MPH (54.5km/h)
Effective Speed Rate: 4.58mph/V (7.36kmh/V)
Effective KV Value: 3600

rschoi_75 · 11.12.2007, 01:40 PM

yup, a few of us use 2.2 truck tires. I have dirt works on mine right now. They are great for all terrain use. Not too good on the track though... But you can always switch back to the buggy tires for that.

sleebus.jones · 11.12.2007, 09:52 PM

I think a 5700 would be plenty fine for that application. The S can (the 5700) works fine for the smaller 1/10th scale stuff. I've run one in a T4, a B4 and I'm sure it would work fine in my ZX-5 that I'm running a 7700kv in. Something smaller like the 1/12th you are going to run it in shouldn't give you a lick of trouble. In fact, a friend of mine ran a 5700 in his .5 conversion and he was pleased. Besides, if you wanted to go really crazy you could stick a 3S in there, hehe.

lincpimp · 11.12.2007, 11:04 PM

Actually the mm motors have shorter magnet than the s can feigaos. My personal expereince was that my 6900 motor could not keep up on my ls10 on 2s lipo. Way too hot after a 5 min run. Just depends on the gearing. 32mph should be fine. I always gear my stuff for 40mph, cause anything less is boring.

rchippie · 11:15 PM

Quote:

Originally Posted by lincpimp

Actually the mm motors have shorter magnet than the s can feigaos. My personal expereince was that my 6900 motor could not keep up on my ls10 on 2s lipo. Way too hot after a 5 min run. Just depends on the gearing. 32mph should be fine. I always gear my stuff for 40mph, cause anything less is boring.

Would a different mamba system be better or is the 5700 system the better choice ?. also do i need a bore reducer ?.