Go Back  R/C Tech Forums > General Forums > Electric Off-Road
How to make it rotate under braking? brake bias adjustable? >

How to make it rotate under braking? brake bias adjustable?

How to make it rotate under braking? brake bias adjustable?

Old 07-30-2012, 12:03 PM
  #1  
Tech Initiate
Thread Starter
iTrader: (2)
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 23
Trader Rating: 2 (100%+)
Default How to make it rotate under braking? brake bias adjustable?

I have a MMP/1415 in a Losi 810, and I can't get the buggy to rotate under braking like I could when it was nitro. Rather than tightening the turn radius, it decreases it (it understeers under braking). On the nitro I could just adjust the bias rearward to make it rotate, but now my braking is all coming from the central point (motor). Is there a way to get an electric to have rear brake bias?

Thanks in advance.
porschefile is offline  
Old 07-30-2012, 12:33 PM
  #2  
Tech Elite
iTrader: (21)
 
Join Date: Dec 2011
Location: Texas
Posts: 3,768
Trader Rating: 21 (100%+)
Default

Originally Posted by porschefile View Post
I have a MMP/1415 in a Losi 810, and I can't get the buggy to rotate under braking like I could when it was nitro. Rather than tightening the turn radius, it decreases it (it understeers under braking). On the nitro I could just adjust the bias rearward to make it rotate, but now my braking is all coming from the central point (motor). Is there a way to get an electric to have rear brake bias?

Thanks in advance.
You would have to put mechanical brakes on it to make that happen. Many of Tekno's nitro-brushless conversions have that as an option but I don't know if they make anything specifically for the 810 or not.

Last edited by MX304; 07-30-2012 at 02:49 PM.
MX304 is offline  
Old 07-30-2012, 12:39 PM
  #3  
Tech Prophet
 
tc5 man's Avatar
 
Join Date: Oct 2007
Location: levittown pa
Posts: 16,997
Default

I would try out the ABS setting on your radio and see what happens i may try it out. Even though you cant use brake bias inless you run a extra servo i dont bother with that though.

But at least you can limit the skiding when braking.
tc5 man is offline  
Old 07-30-2012, 12:45 PM
  #4  
Tech Initiate
Thread Starter
iTrader: (2)
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 23
Trader Rating: 2 (100%+)
Default

Thanks for the replies. I will try playing with the ABS setting. Bummer that I can't change the bias, I am used to being able to rotate the rear under braking and now I have to blip the throttle to get it to rotate as desired.
porschefile is offline  
Old 07-30-2012, 12:55 PM
  #5  
Tech Prophet
 
tc5 man's Avatar
 
Join Date: Oct 2007
Location: levittown pa
Posts: 16,997
Default

Originally Posted by porschefile View Post
Thanks for the replies. I will try playing with the ABS setting. Bummer that I can't change the bias, I am used to being able to rotate the rear under braking and now I have to blip the throttle to get it to rotate as desired.

No dont blip the throttle on electric especially high power motors you will just heat the electrics up and have wheelspin. Thats whats diffrent with electric compared to nitro driving wise. If the Abs doesnt work for you than set the brake setting on your radio where the wheels do not skid a lot.
tc5 man is offline  
Old 07-30-2012, 12:55 PM
  #6  
Tech Elite
iTrader: (53)
 
Join Date: Feb 2008
Location: Belleville, MI
Posts: 4,513
Trader Rating: 53 (100%+)
Default

Believe it or not, you can make a electric powered car turn just a tight as a nitro with bias. The main problem is 95% of the people learning how to drive 4wd electric cars over brake on corner entry which causes the tires to loose traction (push/under steer). Most nitro guys converting over to electric carry a bad habit of using rear only brake bias to "slide/drift" the car around the corner which is slower.


With your E-buggy practice only applying 10-25% brakes(from natural) while the car is going straight before the corner, as soon as you start to steer release brakes in sync with your turn in the car should follow a smooth continuous arc without pushing or loosing traction/corner speed.
nv529 is offline  
Old 07-30-2012, 12:55 PM
  #7  
Tech Master
iTrader: (2)
 
scwrod's Avatar
 
Join Date: Apr 2008
Posts: 1,420
Trader Rating: 2 (100%+)
Default

turn early and hit the throttle You will get use to direct drive.
scwrod is offline  
Old 07-30-2012, 01:31 PM
  #8  
Tech Initiate
Thread Starter
iTrader: (2)
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 23
Trader Rating: 2 (100%+)
Default

Interesting, I'll try that. I am just so used to being able to tighten the line with a little rear wheel drift that so far I've been punching the throttle to try to achieve the same slip angle.

What brake force settings or brake curves do you guys run? I've tried 75% and 90% and neither works for rotating. But I guess as you all have said, I shouldn't trail brake so much with electric. The motor doesn't get too hot, I have the castle fan on it and it stays 140-150 running 3s 16/40.

Aside from the braking issues I like the electric better, it is stupid fast. It can wheelie vertical on pavement on standard buggy tires running 5/5/3 diff fluids. I don't do that often, I just did it a couple of times to see how hard it could pull on a high grip surface.

Any suggestions for throttle curves? I tried linear and with a dampened middle end, and have used the linear lately so I can spin the tires easier to get it set up in slow sections.

EDIT: Would running 7/5/3 fluids instead of 5/5/3 help power out of corners? I always ran 5/5/3 nitro and still run that.

Last edited by porschefile; 07-30-2012 at 01:47 PM.
porschefile is offline  
Old 07-30-2012, 02:19 PM
  #9  
Tech Elite
iTrader: (53)
 
Join Date: Feb 2008
Location: Belleville, MI
Posts: 4,513
Trader Rating: 53 (100%+)
Default

Originally Posted by porschefile View Post
Interesting, I'll try that. I am just so used to being able to tighten the line with a little rear wheel drift that so far I've been punching the throttle to try to achieve the same slip angle.
Have you ever seen a full scale drift car set track records? NOPE! And I'll bet $100 you'll never see one because you need traction to go fast. Imagine yourself driving around in a real car, do you slam full brakes before turning a corner? Nope, chances are you will "lightly" press the brake to "set the nose down" before turning. The concept is the same with any RC car the key is to use minimal brakes without sliding/drifting(over steer) or pushing (under steer)

The key to getting around any 90 or 180 degree turn is to use the following steps

1) brake ( do not slide!)
2) release brake
3) steer into corner
4) simultaneously steer out and accelerate slightly after corner apex


Originally Posted by porschefile View Post
What brake force settings or brake curves do you guys run? I've tried 75% and 90% and neither works for rotating. But I guess as you all have said, I shouldn't trail brake so much with electric. The motor doesn't get too hot, I have the castle fan on it and it stays 140-150 running 3s 16/40.


Any suggestions for throttle curves? I tried linear and with a dampened middle end, and have used the linear lately so I can spin the tires easier to get it set up in slow sections.

I run everything linear Travel/EPA set to 100% throttle/ 80% brake, no EXPO and use the ATL function (futaba radio) to control overall brake power "on the fly" depending on how "hooked up" the track is.
nv529 is offline  
Old 07-30-2012, 02:21 PM
  #10  
Tech Champion
 
Zerodefect's Avatar
 
Join Date: Apr 2008
Location: Columbus, OH
Posts: 5,194
Default

7/5/3 in the diffs. Also try 5/7/3 and 7/10/5.
7/5/3 will give you a ton of exit steering, if you brake early you can use throttle to rotate hard. But you still have to get the car turned a bit first.

More rear droop
2 degrees toe out in the front.
Stiffer rear springs/swaybar
Better tires up front
Lighter damping all around.


With proper setup an electric car can enter turns as loose as a nitro. Neither needs trail braking to rotate hard, just more time with a proper setup.

Some tight turns are best navigated by braking early, turning in early and sliding into the turn backwards, IE: pointed into your exit direction completely at the apex of the turn. Driving like an onraod carpet pancar is not allways the fastest way around the track at all.

Rally drivers do it all the time. Perfect for certain spots on a fluffy dust track.
Zerodefect is offline  
Old 07-30-2012, 02:53 PM
  #11  
Tech Initiate
Thread Starter
iTrader: (2)
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 23
Trader Rating: 2 (100%+)
Default

Thanks for all of the input. I will try 7/5/3 and try to adjust my driving style. Regarding the loose not being fast, I dunno. I used to race 1:1 cars on road courses, and most of the time it is faster to slide slightly (i.e. ~5-8 degree slip angle). But even on asphalt, it is fastest in really tight corners to kick the rear out and power out (at least on 1:1). FWIW I nearly always use the brakes to set the chassis into a oversteer situation, not the throttle.

That being said, I don't know nearly as much about r/c racing as you guys do so I will try to take that into consideration. The reason I thought sliding through the 180 degree stuff is fastest is 1:1 rally cars. I know a lot about 1:1 racing and very little about R/C racing, just what I've absorbed as a lurker here (this board in invaluable though, thanks to all).

Current setup is 2 degrees toe out in front, stiffer rear springs (hard rear; medium front), no front bar and stock rear bar, 27.5 wt Losi oil with M2c pistons (zero or near-zero rebound), Proline Snipers M2 or Recoil XTR.
porschefile is offline  
Old 07-30-2012, 04:36 PM
  #12  
dtr
Tech Master
 
dtr's Avatar
 
Join Date: May 2011
Location: budapest, hungary
Posts: 1,662
Default

Try to move weight forward, that will help the rear rotate, though you lose some acceleration.
dtr is offline  
Old 07-30-2012, 04:44 PM
  #13  
Tech Addict
iTrader: (13)
 
SolderGlob's Avatar
 
Join Date: Nov 2011
Location: Wilm.Il.
Posts: 588
Trader Rating: 13 (100%+)
Default

I'm running the same vehicle as you and I have the opposite issue. On power i have a lot of under-steer and off power I have too much over-steer.

This is the set-up I'm running at the moment. It's for the Ten-T but it works very well on the 810 as well.
SolderGlob is offline  
Old 07-30-2012, 04:46 PM
  #14  
Tech Initiate
Thread Starter
iTrader: (2)
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 23
Trader Rating: 2 (100%+)
Default

Originally Posted by SolderGlob View Post
I'm running the same vehicle as you and I have the opposite issue. On power i have a lot of under-steer and off power I have too much over-steer.

This is the set-up I'm running at the moment. It's for the Ten-T but it works very well on the 810 as well.
Thanks! I can't move weight forward without adding unnecessary weight, since I don't currently run any ballast.
porschefile is offline  

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.