Motor lag problem

[dusty sweep]

Setup: xr10. / Duel tekin fxr. / futaba 4pl.

I have a problem where at very low throttle input the front engages first then as I apply more throttle the rear then engages.

I was running my setup on 2s lipo and did not encounter this problem.

I then changed to a 3s lipo and now at very low throttle the rear motor dose not start turning until I give it some more throttle.

I have recalibrated both esc. I have checked all the profile setting on the esc and the futaba 4pl and they are the same for both.

Seems this problem started only when using a 3 cell lipo as apposed to a 2 cell that I was running before.

Any help would be appreciated.

I have checked everything twice and still now go.

The only change on my settings that I made when I went from a 2 cell to a 3 cell was change the lipo cut off on the fxr from 2 cell to 3 cell. (cant see how this would create the problem I now have

[EeePee]

What happens if you put the 2S lipo back in?

What's the chance you smashed the rear motor on a rock hard enough to move the gear mesh more tight?

[dusty sweep]

Originally Posted by EeePee

What happens if you put the 2S lipo back in?

What's the chance you smashed the rear motor on a rock hard enough to move the gear mesh more tight?

Don't have a 2s to check at the moment will try that.

I think the motor/mesh thing is out of the equation as it started from the moment I went to 3s.

I am sure the mesh is fine as I crawled for about an hour without any mesh problems.

Its the motor that is not engaging straight away as the front does

[killswitch]

Maybe a dirty/bent brush hood on the rear motor causing a hung brush issue?

[EeePee]

You can advance the timing of one of the motors a little and see what happens.

You can swap the motors front to back and see what happens. That will help determine if it's a motor thing, or an axle thing.

[dusty sweep]

Originally Posted by EeePee

You can advance the timing of one of the motors a little and see what happens.

You can swap the motors front to back and see what happens. That will help determine if it's a motor thing, or an axle thing.

Looks like I got some work to do.

Seems to me that the general consensus is that it is not electronically related but more mechanical.

I would have thought it would be electronic as everything seems smooth etc.

Remember its at very slow throttle. just apply more throttle and it is smooth and operates as it should.

[EeePee]

Yep, right at start up, right? Front motor spins first?

What motors are they anyways? And how old are they?

[SMR 510RR]

Just to eliminate the radio I would swap the two plugs in the receiver to see if now the front lags. If the rear is still doing it then it isnt the radio.

I had a similar issue and it turned out to be the calibration. Make sure that you are at neutral bias before calibration otherwise your calibration will be off (ask me how i know). I also like to do the calibration on both speed controllers at the same time to avoid any small difference that may cause issues like you are having. It is a little tricky and you will need another person to either hold the buttons down or plug the battery in but it solved my issues.

If you do both those things and it is still off check your motor timing and make sure that isnt it. You could swap motors front to rear and see what happens, if it still is the same (but in reverse now) then you know it has to be in the axle.

[dusty sweep]

Originally Posted by EeePee

Yep, right at start up, right? Front motor spins first?


What motors are they anyways? And how old are they?

Yes. front motor spins first.

Brood matched pair 45 t . Only about 10 packs old (3s 1300mah from Mike at cheapbatterypacks. so I doubt its the motors or battery.)

Just went out today after recalibrating radio and checking settings etc and it was even worse.

when ever I went into reverser the front would lock up.

I reckon its electric. Going to start again. reset fxr's and radios etc.

Thanks for the advice guys. Will keep you posted.

[dusty sweep]

Update.

First I re calibrated both fxr's back to factory spec.

Ran motors and the problem was still there.

Then I swapped channel 2 and 4 around and the front was then lagging.

So I guess this rules out the motors / axles / mesh etc being the problem.

I think we need to look at the electrics side.

Remember that I have not changed any of my settings on the 4pl.

I then did the neutral / forward / reverse throttle position calibration again and there problem was still there.

On the 4pl in the dual esc mode I run the "rate" at 70. (running 13 t pinion front and rear) This settings seems the best for getting both front and rear to turn at the same rate. I then use dt2 to change the rate in 10 increments, either up or down.

I have noticed that when I bump the rate up to 120 the rear does not have as much lag time to engage as compared to when I run it at 70.

The problem with running it at 120 is the rears obviously turn much faster then the front.

So for now I am stumped.

[SMR 510RR]

Originally Posted by dusty sweep

Update.

First I re calibrated both fxr's back to factory spec.

Ran motors and the problem was still there.

Then I swapped channel 2 and 4 around and the front was then lagging.

So I guess this rules out the motors / axles / mesh etc being the problem.

I think we need to look at the electrics side.

Remember that I have not changed any of my settings on the 4pl.

I then did the neutral / forward / reverse throttle position calibration again and there problem was still there.

On the 4pl in the dual esc mode I run the "rate" at 70. (running 13 t pinion front and rear) This settings seems the best for getting both front and rear to turn at the same rate. I then use dt2 to change the rate in 10 increments, either up or down.

I have noticed that when I bump the rate up to 120 the rear does not have as much lag time to engage as compared to when I run it at 70.

The problem with running it at 120 is the rears obviously turn much faster then the front.

So for now I am stumped.

I dont have a 4pl but I would assume that you should run the "rate" (im guessing this is percentage) at 100 to make the two even. Of course any time that you change settings in the radio you have to recalibrate the esc because if the signal the rear esc was getting was only 70% and then you change it to 120% then you will get to full throttle much quicker on the rear esc.

Change it to 100 and recalibrate and let us know how that goes.

Also are both FXR's running the newest firmware? They tweaked the startup to be smoother in the newest firmware, if you had it on one running one version and the other running another version that would screw you up.

[SuperRoo]

When all else fails start all over with a new unused model memory in the radio. It can be a pain but at least you'll no that simple things like sub trims are set to 0 or rates are the same for the front and rear motor.

It might also be worth posting this problem in the 4PL thread.

Do you no what firmware your running in the radio, I think there was a firmware issue with the dual motor side of the software in the 4PL's in the early run of the radios but this has since been fix. Again you can find this info out in the 4PL thread.

[Harley]

Originally Posted by dusty sweep

On the 4pl in the dual esc mode I run the "rate" at 70. (running 13 t pinion front and rear) This settings seems the best for getting both front and rear to turn at the same rate. I then use dt2 to change the rate in 10 increments, either up or down.

I have noticed that when I bump the rate up to 120 the rear does not have as much lag time to engage as compared to when I run it at 70.

The problem with running it at 120 is the rears obviously turn much faster then the front.

So for now I am stumped.

That's your problem. You need to have the rate at 100. That means 100% of the front esc value is being used at the rear. You should always calibrate with the radio at 100. Only adjust the rate when you want to under drive or over drive the rear.

[Harley]

Originally Posted by SuperRoo

It might also be worth posting this problem in the 4PL thread.

Do you no what firmware your running in the radio, I think there was a firmware issue with the dual motor side of the software in the 4PL's in the early run of the radios but this has since been fix. Again you can find this info out in the 4PL thread.

There was no issue. We just got them to allow us to control the dig function on a different button, no other changes. Don't spread bad info

[dusty sweep]

Originally Posted by Harley

That's your problem. You need to have the rate at 100. That means 100% of the front esc value is being used at the rear. You should always calibrate with the radio at 100. Only adjust the rate when you want to under drive or over drive the rear.

Ok. I will give it a go.

The weird thing s that it worked fine at 70 with the first few 2s packs through it then the minute I change to 3s packs I started having the problem.

[Harley]

Originally Posted by dusty sweep

Ok. I will give it a go.

The weird thing s that it worked fine at 70 with the first few 2s packs through it then the minute I change to 3s packs I started having the problem.

Are you sure you didn't have it at 100 and adjusted it on the radio after with one of the DT buttons? You do have a DT button programmed to adjust that on the fly correct? Why were you leaving it at 70?

[dusty sweep]

Harley

I re calibrated the fxr with the 40pl rate at 100. This has fixed the problem somewhat. (no more lag at low throttle)

With the rate at 100 my rears are turning faster than my fronts. If I drop the rate back to 90 using using dt2 then i am back to the same problem of the rear engaging after the front at low speed.

Another question but unrelated. What is the MXMD (in the dual esc screen) button for? Should it be "on" or "off"

What does the "TRIM" (in the dual esc screen) do? Should it be "on" or "off"

[benoj]

what pinions are you running to have the rear run faster?

[dusty sweep]

front and rear are both 13t

motors are a pair of matched brood 45t

[benoj]

it could be a radio setting but i dont know squat about the 4pl. did you mess with the motor timing? cause if the rear is advanced more that would cause it