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Old 01-16-2006, 03:48 PM   #1
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Default Motor tuning questions

Hi all,
If some one could tell me the effects the following has on a stock motor

Harder springs
Softer springs

harder on the pos
Softer on the neg

Softer on the pos
Harder on the neg

and generally running a monster horse power stock on a tight and twisty track which spring combo should i use?

Cheers all
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Old 01-16-2006, 03:51 PM   #2
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Softer Spring will produce more torque

Stiffer Spring will produce more RPM.....

Using a stiffer spring on the positive is just a fine tuning option to achieve optimal power, while controlling brush bounce....

You should never use a stiffer negative spring than the positive on anything other than an oval motor......the oval guys get it to work, but in touring, offroad, etc.....doesn't work very well....


Later EddieO
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Old 01-16-2006, 03:55 PM   #3
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thanks a lot for the fast reply,

Which springs does every one recomend for a monster on a small twisty track and why would they choose that combination?

Thanks again
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Old 01-16-2006, 03:58 PM   #4
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Also, does anyone have a brush list with the stiffness?
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Old 01-16-2006, 04:17 PM   #5
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Quote:
Originally Posted by EddieO
Softer Spring will produce more torque

Stiffer Spring will produce more RPM.....

Using a stiffer spring on the positive is just a fine tuning option to achieve optimal power, while controlling brush bounce....

You should never use a stiffer negative spring than the positive on anything other than an oval motor......the oval guys get it to work, but in touring, offroad, etc.....doesn't work very well....


Later EddieO
I've always been under the impression that the springs were the other way around (softer more RPM, stiffer more torque).

You know more than I do though. I always learn something when I read these forums. Thanks!
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Old 01-16-2006, 04:43 PM   #6
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Eddie's correct

seems when you run a lighter spring setup you need to add a tooth or so to get the same straightaway speed over an stiffer spring setup

i prefer red/red springs or purple/red depending on what brushes i use
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Old 01-16-2006, 05:29 PM   #7
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Quote:
Originally Posted by EddieO
Softer Spring will produce more torque

Stiffer Spring will produce more RPM.....

Using a stiffer spring on the positive is just a fine tuning option to achieve optimal power, while controlling brush bounce....



Later EddieO
you know i still can`t get my head round that you know

you`ve explained it
but nope !! right over my head (and no! i`m still not convinced ) even
R/C Anonymous has told me different

And we messed around at a indoor carpet track when go harder guy`s come back & say `lost a bit top speed, but more punch in the corners )

doing my head in
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Old 01-16-2006, 06:14 PM   #8
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Im the same Colin, If I run purple purple at any track then change to red red or green green I gain so much rpm but loose my torque.

Ricky Copsey
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Old 01-17-2006, 02:12 AM   #9
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Well, I can guarantee you thats how it is....

Do the test on a turbodyno.....you will get the same results....

Later EddieO
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Old 01-17-2006, 02:22 AM   #10
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Yeah i know Even EA backs you up aswell & proberly ) the other tuners

still can`t get round it
us Brits are very different to the rest of the world you know

any way can`t afford a turbo thingy machine
live & learn live & learn
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Old 01-17-2006, 02:53 AM   #11
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My mate bought a dyno and we've pretty much given up with it.

I can make an awesome motor, messing with timing, springs, and brushes. When I go racing it's never very good, o.k. but not very good.
Then I use harder springs and go faster but on the dyno the motor would look rubbish

Black art methinks, so I'm trying a brood this week, hopefully EddieO is better at it than I am
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Old 01-17-2006, 05:29 AM   #12
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Dyno figures are just that : figures. The ultimate test is the track and sometimes a motor that looks awesome on dyno will not perform well on the track because it's been tuned for a specific load, which is different than the real load.

For example it's no use to have a motor that gives awesome power at high RPM if it means giving up all low RPM power, because by the time you reach the high power band of your motor, you'll have to lift for next corner.

I think that when tuning your motor you should try to look for a wide power band even if it means sacrificing a bit of max power.
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Old 01-17-2006, 06:25 AM   #13
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Thanks for the info --

Why do 1/12 scale guys talk about running green/green and sedan purple/red? Wouldn't you need more torque with the sedans?
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Old 01-17-2006, 06:47 AM   #14
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hehhehe.... the way i look at it is.

the harder the spring the less revs, more torque on the track
the softer the spring the more revs, less torque on the track.

now im a brit, and i agree with mr jolly and prodriver....

Im not saying eddieo or eam are talking rubbish, because there motors are really good.

Perhaps its a track thing.....perhaps its the reason why us Europeans are at the top of tree atm.... dunno.

I mean we could start the whole Brush/spring thing here... i think its all down to personal gearing and feel of the car....

my 2p worth
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Old 01-17-2006, 07:00 AM   #15
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Quote:
Originally Posted by EddieO
Softer Spring will produce more torque

Stiffer Spring will produce more RPM.....

Using a stiffer spring on the positive is just a fine tuning option to achieve optimal power, while controlling brush bounce....

You should never use a stiffer negative spring than the positive on anything other than an oval motor......the oval guys get it to work, but in touring, offroad, etc.....doesn't work very well....


Later EddieO
Me to I'm not convinced that is what is appening on the track... I have a CE Turbo Dyno and yes it's true that it is what you saw on the TD if you look at the same Amp step. But with lighter spring I don't think the motor will draw the same current on the track, so we should not compare the RPM and torq at the same amp load.

Just an example: Let say a stock motor at 5.0v on a TD give you at 20 amp: 17000 rpm and 5 torq and at 22 amp: 16000 rpm and 6 torq.
If you put lighter spring on this motor you could now have something like that on the TD, At 20 amp: 16500 rppm with 5.5 torq and at 22 amp: 15500 rpm and 6.5 torq.
If you look simply at the 22 amp data it look like with lighter spring you lost 500 rpm and gain .5 torq.... But what I think, is that on the track the motor with lighter spring would draw less amp, could be draw only 20 amp now and if you look the 20 amp data, you could just have gain 500 rpm on the track but loose .5 torq.

I don't think we could presume that the motor will draw the same amount of current when we change the spring hardness.
But that is just the way I saw it and I'm just a newbie in motor tuning and dyno stuff, it could be totally wrong but it's my theorie and I will like to know what you think about it...

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