R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 11-30-2006, 04:50 PM   #271
Tech Elite
 
Turbo Joe's Avatar
 
Join Date: Nov 2003
Location: Corona, CA
Posts: 4,878
Trader Rating: 41 (100%+)
Default

Quote:
Originally Posted by PeteB

you are definately overgeared, forget gear ratios, as they are inherantly inaccurate as different cars have different internal gearbox ratios/ diff sizes, aim for a rollout of about 40mm as a starting point.
Final drive ratio is just as accurate as doing rollout, it just doesn't take tire diameter into account. It's saying "I run a 17T pinion" as a substitute for final drive or rollout that's very inaccurate.

I think it's fair to say that rubber-tire guys use FDR more than rollout, because everyone has essentially the same tire diameter, while foam-tire guys use rollout more often to account for variances in diameter due to truing.

Final drive is the pinion/spur ratio AND the internal (gearbox) ratio combined.
Turbo Joe is offline   Reply With Quote
Old 11-30-2006, 06:25 PM   #272
tc4
Tech Addict
 
tc4's Avatar
 
Join Date: Nov 2005
Location: Australia
Posts: 511
Trader Rating: 5 (100%+)
Default

When you say that 4.1 is overgearing it too much everyone at my club is running between 4.4- 4.1 and i was even told by some mod racers that they used to run 3.9 when they raced with the 540 motors.

Also what is Brasso?
__________________
-Corally RDX PHI
-Johnson 540!
tc4 is offline   Reply With Quote
Old 11-30-2006, 06:27 PM   #273
Tech Regular
 
PeteB's Avatar
 
Join Date: Feb 2006
Posts: 477
Default

Quote:
Originally Posted by Turbo Joe
Final drive ratio is just as accurate as doing rollout, it just doesn't take tire diameter into account. It's saying "I run a 17T pinion" as a substitute for final drive or rollout that's very inaccurate.

I think it's fair to say that rubber-tire guys use FDR more than rollout, because everyone has essentially the same tire diameter, while foam-tire guys use rollout more often to account for variances in diameter due to truing.

Final drive is the pinion/spur ratio AND the internal (gearbox) ratio combined.

I see your point and would agree in principle, but he didnt say "FDR", he said "gear ratio of 4.1".

I run rubber on some tracks and foam on others, thats why I dont calculate FDR at all, rollout is so much more accurate, it takes ALL variables into consideration...

if I were to say "aim for a FDR of x.x" and hes using foams at 59mm, and my statement was based on rubbers of 63mm I would be giving wrong info, hence why rollout is more accurate than quoting FDRs.

maybe the root cause of his problems is that he is calcluating FDRs on the wrong tire size... who knows


whatever...

Peace
__________________
JRXS-R
GTB SS + 13.5 & 10.5
Trakpower 4900
Supernova
Nomadio

Last edited by PeteB; 11-30-2006 at 07:04 PM.
PeteB is offline   Reply With Quote
Old 11-30-2006, 06:29 PM   #274
Tech Regular
 
PeteB's Avatar
 
Join Date: Feb 2006
Posts: 477
Default

Quote:
Originally Posted by tc4
Also what is Brasso?
its metal polish, a brown milky liquid. about $8 in any supermarket

did you figure out your rollout yet?
__________________
JRXS-R
GTB SS + 13.5 & 10.5
Trakpower 4900
Supernova
Nomadio
PeteB is offline   Reply With Quote
Old 11-30-2006, 06:43 PM   #275
tc4
Tech Addict
 
tc4's Avatar
 
Join Date: Nov 2005
Location: Australia
Posts: 511
Trader Rating: 5 (100%+)
Default

Forgot to mention 4.1 is my Final Drive Ratio.

It says my rollout is 45mm.
__________________
-Corally RDX PHI
-Johnson 540!
tc4 is offline   Reply With Quote
Old 11-30-2006, 06:52 PM   #276
Tech Regular
 
PeteB's Avatar
 
Join Date: Feb 2006
Posts: 477
Default

45mm is a bit high, unless it is a huge track with no hairpins, i usually run a rollout of 38-40 depending on track size.

try it and let me know how it goes, and try the brasso thing aswell...

remember that the straight is ususally only about 25% of the track and if you are geared to high, you only get up to speed on the second half of it, and you end up with less acceleration for the remaining 75% of the track, which is where acceleration is required more than top speed.

Also the excessive heat will kill the magnets in the motor.

are you on rubbers or foams?

Hope this helps...
__________________
JRXS-R
GTB SS + 13.5 & 10.5
Trakpower 4900
Supernova
Nomadio
PeteB is offline   Reply With Quote
Old 11-30-2006, 06:56 PM   #277
tc4
Tech Addict
 
tc4's Avatar
 
Join Date: Nov 2005
Location: Australia
Posts: 511
Trader Rating: 5 (100%+)
Default

I dont have any other pinion gears and we only have 1 race meet left this year so yeah.

I will try the brasso thing thought and i'll let you know how that goes.
__________________
-Corally RDX PHI
-Johnson 540!
tc4 is offline   Reply With Quote
Old 11-30-2006, 07:17 PM   #278
Tech Regular
 
PeteB's Avatar
 
Join Date: Feb 2006
Posts: 477
Default

Quote:
Originally Posted by tc4
I dont have any other pinion gears
great! see if you can borrow one that puts you in the 40mm range, that way you can try it out before buying more pinions...
__________________
JRXS-R
GTB SS + 13.5 & 10.5
Trakpower 4900
Supernova
Nomadio
PeteB is offline   Reply With Quote
Old 12-09-2006, 03:37 AM   #279
Tech Rookie
 
Join Date: Dec 2006
Location: Victoria..Australia
Posts: 7
Default 540 J Run in experiance

Hi everyone and thank you all for the run in tips....
Now, i got a black end 2 slot Johnson 540 ...
And thought, hey why not run it in... so i read all of the cool posts and got all the info and went for it... first , i ran it at 1.5 volts in H20 w/ dishwashing liquid for about 1 hour and the brushes were same as new...so , then i put her in kerosene for 20 hours... and then ran it in water for 1 hour at 1.5 volts, still nothing, so i i got some Autosol ( light metal polish ) and put it between the brushes and in about 30 minutes, my brushes were looking good...cleaned her out with motorspray( not wd40 ) and run in water for short time, then ran her with Brasso(soft metal polish ) for about 20 minutes... the results..hmmm got no dyno , so ran it some more at 3.2 volts ( 1 hour) and then 1.5 hours @ 4.6 volts...all the run in was just a guess with some advice from these posts, finally i ran the 540 with a homemade nylon prop for some resistance for 2 hours, it sounds like it revs quite freely and i think it was worth the effort( i totally enjoy a challenge ) in the whole process i used light gun oil for the bushings, so time will tell when i run it in my yet to be bought Mini, or put it in my Cyclone...i will post the results..
Can someone suggest a final drive ratio or roll out for the 540 /Cyclone...?
All the best and thanks again..

Anthony
1/10 RACER is offline   Reply With Quote
Old 12-09-2006, 03:48 AM   #280
Tech Elite
 
t4m1y4niac's Avatar
 
Join Date: Feb 2006
Posts: 4,309
Default

Quote:
Originally Posted by 1/10 RACER
Hi everyone and thank you all for the run in tips....
Now, i got a black end 2 slot Johnson 540 ...
And thought, hey why not run it in... so i read all of the cool posts and got all the info and went for it... first , i ran it at 1.5 volts in H20 w/ dishwashing liquid for about 1 hour and the brushes were same as new...so , then i put her in kerosene for 20 hours... and then ran it in water for 1 hour at 1.5 volts, still nothing, so i i got some Autosol ( light metal polish ) and put it between the brushes and in about 30 minutes, my brushes were looking good...cleaned her out with motorspray( not wd40 ) and run in water for short time, then ran her with Brasso(soft metal polish ) for about 20 minutes... the results..hmmm got no dyno , so ran it some more at 3.2 volts ( 1 hour) and then 1.5 hours @ 4.6 volts...all the run in was just a guess with some advice from these posts, finally i ran the 540 with a homemade nylon prop for some resistance for 2 hours, it sounds like it revs quite freely and i think it was worth the effort( i totally enjoy a challenge ) in the whole process i used light gun oil for the bushings, so time will tell when i run it in my yet to be bought Mini, or put it in my Cyclone...i will post the results..
Can someone suggest a final drive ratio or roll out for the 540 /Cyclone...?
All the best and thanks again..

Anthony

you can try from 4.00 final drive ratio..
__________________
SABRE S4 by TOP RACING....
t4m1y4niac is offline   Reply With Quote
Old 12-09-2006, 03:52 AM   #281
Tech Rookie
 
Join Date: Dec 2006
Location: Victoria..Australia
Posts: 7
Default

Thanks Mr Tamiyaniac..good to see someone else is up late
1/10 RACER is offline   Reply With Quote
Old 12-09-2006, 03:58 AM   #282
Tech Elite
 
t4m1y4niac's Avatar
 
Join Date: Feb 2006
Posts: 4,309
Default

Quote:
Originally Posted by 1/10 RACER
Thanks Mr Tamiyaniac..good to see someone else is up late
mo problem bro
__________________
SABRE S4 by TOP RACING....
t4m1y4niac is offline   Reply With Quote
Old 12-15-2006, 09:46 AM   #283
Tech Addict
 
Steven Key's Avatar
 
Join Date: Mar 2005
Location: Wisconsin
Posts: 643
Trader Rating: 7 (100%+)
Default

I scored a number of never used original Mabuchi silver can motors. After the first dyno test they all seemed kind of weak; 1.3 to 1.5 amps and 11,400 to 11,800 rpm at 5 volts. I took the weakest one of the bunch to see what a break in would do. I ran it in water backwards for about 2 minutes, the water turned black right away. When I looked at the brushes I could see that they were fully seated and about 1/3 of the brush was already gone. When I redyno-ed the motor the amps were 2.2 and the rpm went to 13,400 RUNNING BACKWARD. When I tested the motor forward it was only 1.4 amps and 11,400 rpm. So I had an awsome motor when I ran it in reverse. You could hear the difference running it backwards verses forward. I was afraid to run it in the water anymore because of the brush wear. I eventually completely wore the brushes out on this motor and was never able to get it up to even 12,000 rpm running forward.

So the brushes in the original Mabuchi motors are much softer. I could have run a Johnson motor in water for hours and not had the same about of brush wear.

Any suggestions on how to break in the remaining motors so I get the awsome numbers running FORWARD
Steven Key is offline   Reply With Quote
Old 12-15-2006, 09:54 AM   #284
Tech Regular
 
Join Date: Jul 2004
Location: Winchester, VA
Posts: 490
Trader Rating: 14 (100%+)
Send a message via MSN to BigJim14226
Default

I run my silver cans at 1amp with fan backwards for 12 to 14 hours. make sure the bushings are oiled.

I have been told by someone only to use the water method to clean the motor between races.

I used my MM MotorMaster to check RPM's, and found that if I use comm drops I can get about 1000 RPM's more.

Good Luck....
BigJim14226 is offline   Reply With Quote
Old 12-15-2006, 12:09 PM   #285
B3x
Tech Adept
 
Join Date: Feb 2003
Posts: 120
Default

What do you mean by "fan backward" ?
B3x is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
X-ray T2, Tips and Tricks trailranger Electric On-Road 4 05-17-2008 02:44 PM
Silver Can (Mabuchi) Motor Tricks miller1990 Electric On-Road 1 03-06-2007 10:06 PM
Co27 motor tuning tips, hints, or tricks schmidt452 Electric Off-Road 16 11-08-2006 11:04 PM
tips and tricks XXX-NT streetstock Electric Off-Road 2 05-13-2005 10:50 AM
Tips And Tricks rctc3 Electric On-Road 36 03-10-2002 10:54 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 04:23 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net