RC-Monster Forums - 1512 2.5D vs 3D on 5S?

RC-Monster Forums (https://www.rc-monster.com/forum/index.php)

- Brushless (https://www.rc-monster.com/forum/forumdisplay.php?f=12)

- - 1512 2.5D vs 3D on 5S? (https://www.rc-monster.com/forum/showthread.php?t=16468)

Quote:

Originally Posted by rootar (Post 231255)

and for drift, try your start power at medium and see if you notice any difference. but it could be a ton of things, including your drivetrain, and you wouldnt even know it, your gear mesh effects it, the gear mesh of your diffs is important also, take the pinion off and push your buggy on a hard floor, if it doesnt roll 4-5 feet "Silently" with a very light push then id be checking there first. did you check your motor bearings for any play?

my gear mesh was too tight on my front diff awhile back after i redid (too many shims on the wrong side, and my motor was running a good 20* hotter than normal after i fixed that my temps went back to normal.

another thing to look at is it really doesnt matter that the neu is up 170-180 they told me their motors would run fine all day long at these temps, so check your temps and sceduled stops through out your run and after it gets up to 170 see if it goes anyhigher as you continue to run and find out where it tops out, in our 30 minutes july 4th a main my 1515 was running 175 at 15 minutes and at the end of the race it was 173, they will top out like this, and nue told me as long as its below 190 its fine to run them at that temp as long as needed.

Well I checked over the drivetrain today and it all seems normal. I put a 12T pinion in and changed the start power to medium but won't have a chance to give it a proper run till tomorrow. I took it for a quick run in the street and it doesn't to long to get to top speed. Probably be under geared now for the track. I do notice how ever that when the motor is connected to the spur the buggy is alot harder to push and when driving it sort of feels like I am running drag brake but I have that dissabled

on our track the HIGHER i geared my buggy, the lower the motor temp was (it wasnt running at full throttle in alot of places but only 3/4, and had alot of letting off due to the extra speed, but in turn the esc would be hotter, and so would my batteries and my little proteks couldnt handle the really high gearing (46 mph) but my 5s 5000 FP could but now im geared for 41 and the proteks can keep up with that and the motor never runs full throttle except on about 200 feet of the track. which is much better than 600 or so feet it would run at full throttle when geared for 35, gearing down never helped my temps..... so if the 12 is a bust gear up.

Quote:

Originally Posted by DRIFT_BUGGY (Post 231613)

Quote:

Just anyother tip... I run my Medusa v2 60mm 2000kv with a 15t on 4s lipo racing at 41mph at about 130 all day.. I'm sure your Neu could do the same! No nitro can even come close to me.. unless I screw up and my 4s 5k packs get 17-20minutes of non-stop racing :) LOL Just move down to 4s lipo and keep your 15t and be golden :) 4s lipo is the typical max in most sanctioned racing events anwyay (at least for now). You can usually get away with higher voltage at league races though.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 11
Total Voltage: 18
Motor KV: 2050
Tire Diameter (inches): 4.5
Tire Ballooning (inches): .5
Motor Current Draw: 80
Motor coil Ω: 0
Spur/Pinion Ratio: 4.36 : 1
Total Ratio: 14.43357 : 1
Tire Circumference (inches): 17.28 inches (438.88 mm)
Total Motor Speed: 36900 RPM
Vehicle Speed: 41.83 mph (67.2 km/h)
Estimated Adjusted Speed: 40 mph (64 km/h) - 5% loss
Effective KV Value: 2050
KT constant: 0.66 oz-in/A
Motor Torque: 0.27 ft-lbs
Final Torque: 3.97 ft-lbs
Final Power: 1440 watts (1.9 HP)

12t-43mph
13t-46mph
14t-49mph

Quote:

Originally Posted by stum (Post 231640)

That maybe your issue.. you are calculating your speed wrong.. use 43/13 (3.30:1) for the 8ight buggy. At 12t you are at 44mph that is the top you would ever want that motor at iMO. To be honest 11t is a better starting point here is the calc. Looking at it the 3d would be a lot better for you on 5s as it would allow more gearing options, I don't even know if you can do an 11t pinion, at least with the Tekno v3 conversion I'm limited to a 12t as the bottom and it bearly meshes up. The 3d on a 14t is 40mph, then you can tweak up or down some... but I wouldn't buy another motor myself I would make do with the 2.5d at 12t and be happy, gearing down from what you had should reduce temps worst case run a fan on it during high heat summer. Just my2c

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 11
Total Voltage: 18
Motor KV: 2050
Tire Diameter (inches): 4.5
Tire Ballooning (inches): .5
Motor Current Draw: 80
Motor coil Ω: 0
Spur/Pinion Ratio: 4.36 : 1
Total Ratio: 14.43357 : 1
Tire Circumference (inches): 17.28 inches (438.88 mm)
Total Motor Speed: 36900 RPM
Vehicle Speed: 41.83 mph (67.2 km/h)
Estimated Adjusted Speed: 40 mph (64 km/h) - 5% loss
Effective KV Value: 2050
KT constant: 0.66 oz-in/A
Motor Torque: 0.27 ft-lbs
Final Torque: 3.97 ft-lbs
Final Power: 1440 watts (1.9 HP)

12t-43mph
13t-46mph
14t-49mph

Im running a 46T Spur. I checked the manual for the Losi ESC/Motor and they recommend a 12T Pinion when running a 45T Spur on 5S with the 2100KV motor.
My ESC temp is 130F and battery is 120F

Quote:

Originally Posted by DRIFT_BUGGY (Post 231796)

Im running a 46T Spur. I checked the manual for the Losi ESC/Motor and they recommend a 12T Pinion when running a 45T Spur on 5S with the 2100KV motor.
My ESC temp is 130F and battery is 120F

What were you geared before? A 12t on a 46t spur is about 46mph on the 8ight buggy with a 5s lipo.

13T/46T. Where did you get those calculations from? On easy-rc.com, rcgearchart.com and some other one it says 38.6mph on 37925rpm, 110mm tires, 3.3077 ratio?

http://i33.tinypic.com/a5jcjo.jpg

??????????????????????????????????????

Quote:

Originally Posted by DRIFT_BUGGY (Post 231990)

13T/46T. Where did you get those calculations from? On easy-rc.com, rcgearchart.com and some other one it says 38.6mph on 37925rpm, 110mm tires, 3.3077 ratio?

You have to calculate top speed with a .5 balloon on your tires, expecially at 40mph range you will get at least that much balloon effect... then re-run your numbers :)

Ok, well due to me having tonsillitis i haven't managed to take it down to the track to test it out

Tried the 12T pinion today and medium settings and no good, temp went up to 180F again, then tried it with the 11T pinion and back to low timing, no good temp went to 190F. Has to be something in the drivetrain somewhere. Going to have to strip the whole thing down and check. Before I changed to the new firmware on the MMM and no longer run the ext bec and also changed the diff fluids (5/10/2 to 7/10/3) the motor was running 165F on 13T. I do remember though that I had to rebuild the center diff becuase it was leaking and when I opened the diff there was a washer/shim on the oring and seemed to be the reason why as the washer wore out the oring and I checked the Losi manual and they didn't mention nothing about a washer

Drift;

Double check the motor wires just inside the can where they connect to the windings. You may have to look real hard, but see if there is any fraying or if a few of the strands are broken. If you don't secure the motor wires very tightly so there is zero movement, the vibrations can cause a few of the strands to break at the base of the winding. only a couple of broken strands can cause the motor to overheat and eventually it will just smoke itself. it is not something that you can easily see with the naked eye, but I have had this happen on a cuople of my Neu motors until I figured out I wasn't securing the wires tight enough.

See how I have the motor wires basically ziptied solid to the chassis brace?

http://i240.photobucket.com/albums/f...to/photo-1.jpg

if its in good condition and you can verify it hasnt been over 200 ever i may be interested in buying it. depending on the price of course. how does it run on 4s? (cooler or not?)
thanks,
ryan

Quote:

Originally Posted by tc3_racer_001 (Post 232745)

if its in good condition and you can verify it hasnt been over 200 ever i may be interested in buying it. depending on the price of course. how does it run on 4s? (cooler or not?)
thanks,
ryan

I think I found the problem, the sun gear in the centre diff hosing was rubbing which was where I removed the shim from (rebuilt the diff and it probably hasn't had more than 2 hours running and the diff fluid was black). Haven't been able to test it as I noticed that my front shock shaft is bent and I cracked the hinge bin brace cover. Wont be able to go back to the track till 5 - 6 days (already got news parts on way). Hottest I think I remember was 188F. No way it has been at 200F