Turbo Joe

iTrader: (41)

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.

tc4

iTrader: (5)

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?

PeteB

iTrader: (-1)

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

PeteB

iTrader: (-1)

its metal polish, a brown milky liquid. about $8 in any supermarket

did you figure out your rollout yet?

tc4

iTrader: (5)

Forgot to mention 4.1 is my Final Drive Ratio.

It says my rollout is 45mm.

PeteB

iTrader: (-1)

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...

tc4

iTrader: (5)

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.

PeteB

iTrader: (-1)

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...

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

t4m1y4niac

you can try from 4.00 final drive ratio..

1/10 RACER

Thanks Mr Tamiyaniac..good to see someone else is up late

t4m1y4niac

mo problem bro

Steven Key

iTrader: (7)

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

BigJim14226

iTrader: (14)

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....

B3x

What do you mean by "fan backward" ?