Thinking about disconnecting traction control

Discussion in 'Gen 2 Prius Accessories & Modifications' started by syncmaster, Nov 22, 2005.

  1. syncmaster

    syncmaster New Member

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    How many times has this happened to you?
    You are waiting to pull out of a shopping center into fast traffic. You see a chance to pull out and floor it. The prius starts to take off and then the traction contorl kicks in because the wheel slipped a little and the the car hesitates a half second before it again tries to accelerate .
    I heard from a prius owner that he had a steep gravel driveway and he had trouble going up with the prius because the wheels would spin a little in the gravel and the traction control would keep cutting in.
    I am thinking about adding a switch so I can shut off the traction control.
    I think if you open the wires going to the sensors in the rear wheels that would disable the traction control but would the also disable the stability control?

    Has anyone tried it ?

    I would like to hear from others on this subject.

    Thanks for you input!
     
  2. jayman

    jayman Senior Member

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    Well, that has happened to me too, especially on icy intersections. I don't think trying to disable the Trac is a good idea, you could destroy the power split device.

    I do wish Toyota had considered the climates the car would be operated in, and offered a "cancel" button that would desensitise the Trac algorithm. Otherwise you really do need good sticky studless or studded winter tires in winter.
     
  3. ceric

    ceric New Member

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    I agree with jayman,
    what you really need is better tires at four corners. If traction is lost, w/o TC, the tire just spins. That won't help what you would like to achieve. Sticky tires for summer and snow tires for winters are the ways to go.
     
  4. Tempus

    Tempus Senior Member

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    I agree with the previous opinions.

    Disabling Traction Control because your wheels are slipping is compounding the problem, not making it better.

    Yes, your approach might also affect Stability Control, and even possibly ABS.

    If you do decide to go ahead, be sure to cut the wires to the air-bags and disable your seat belt warnings just to be complete :)
     
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    I think it's cheaper to get a set of better tyres than replace the electric motors and/or PSD.
     
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  6. Mojo40

    Mojo40 New Member

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    The physics behind traction control are that sliding friction is less than static friction. In other words, a spinning tire get you less grip on the road than a non spinning tire.

    Now, this next part is not fact, but my interpretation (can anybody verify?) Traction control as implemented in the Prius does two things, 1) applies the brake to a wheel that is spinning, thus driving the torque to the other wheel that has a better grip, and 2) backs off the engine power until the wheels can grip.

    Here's the key point. Although the engine backs off on power to maintain tire grip, the Prius is probably giving you better acceleration than if the engine was racing and the tires were spinning. Again, this is theory, and I don't have data to back this up.

    I did read an article a few years back about this technology being applied on a two wheel drive Saab. It provided winter driving performance equivalent to an all wheel drive.

    As far as cutting wires - you have to be completely nuts to try and reengineer a sophisticated, highly integrated system like this. Just leave it alone. Go get an old VW beetle and reengineer that.
     
  7. Tideland Prius

    Tideland Prius Moderator of the North
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    Mojo, what you described is traction control on normal cars. I think the Prius does it differently. Something with the electric motors rather than the brakes being applied.

    Also, unlike other TCS's, if you keep your foot there, you won't go anywhere. I've tried letting go and pressing again and the whole car seemed to have "stalled". In other TCS, if you kept your foot on the accelerator, all you'd hear is the tyre spin, stop, spin, stop and so on until you regain traction. With the Prius, I got nothing. Zip zero nada. I had to go into reverse to get any power to the wheels.
     
  8. oly_57mpg

    oly_57mpg New Member

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    Has anyone seen the post from Club Lexus about disabling vdis?
    http://clublexus.com/forums/showthread.php?t=187987

    start the car with the parking prake on ....then foot brake twice....(keep the foot brake down)....then parking brake twice (keep it down )and repeat till skid light is on the dash
     
  9. syncmaster

    syncmaster New Member

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    here is a link to someone having problems getting up their driveway because of Trac control.

    http://priuschat.com/Slippery-hills-vs-TRAC-t12883.html

    I copied this section from the posted link above, USE AT YOU'RE OWN RISK.

    to disable traction control on the prius:
    1) Turn the car to ignition by pressing START twice without pressing the brake.
    2) Floor the gas pedal two times (two full top to bottom pressings)
    3) Make sure the Emergency brake is on now and put the car into NEUTRAL
    4) Again press the gas pedal two times
    5) Push PARK and press the gas pedal two more times
    6) Now put your foot on the BRAKE and press START one time while holding the brake down.

    The prius will reset traction control to normal the next time you start it.
     
  10. Alainc

    Alainc New Member

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    How can you (step 3), put the car in NEUTRAL since the Hybrid is not READY. You are only in the ignition mode from step 1).

    I tried these steps and .... the drive selector isn't doing a thing so .... you can't get to NEUTRAL. In fact if you push the selector to NEUTRAL, the car beeps at you after keeping it there for 2 sec or so.

    Alain

     
  11. hobbit

    hobbit Senior Member

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    In IG-ON, you can shift into neutral or park, but not D or R or B.
    You have to press the brake to get to N, which is what you were
    missing and why it was beeping at you. The idea is that you can
    power up the car enough to unlock the parking pawl and push around,
    but not engage any of the drive system.
    .
    _H*
     
  12. hdrygas

    hdrygas New Member

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    I hope Efusco and Dantheman show up in this discussion. I think that disabling the traction control is a bad idea. It is there to protect the PSD and the motors from over riving. The “ Dance “ as Dan calls it is to temporarily disable traction control for testing under controlled conditions. I would be very very careful. Get better tires.
     
  13. ez2bgreen

    ez2bgreen New Member

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    I agree with Ceric regarding good treads. I recently upgraded to all-weather tires, and I have yet to engage traction control or ASC, despite driving under slick road conditions. I have experienced your problem when pulling out of driveways, and I agree it can be both annoying and dangerous.
     
  14. syncmaster

    syncmaster New Member

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    It's nice to know that a tire upgrade can solve this problem, would you like to share the name of the all-weather tire?
     
  15. jojov

    jojov New Member

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    I can testify that tires are not the cure-all for this problem. I have BRAND NEW Goodyear Ice tires on mine. After a good snow and ice storm, my Prius comes to a complete halt half way up the drive despite being plowed. It's a very slight incline and studded tires are illegal in Ohio.

    My previous cars with TC had a "Trac Off" button that permitted me to CAREFULLY and strategically gun the car to maintain momentum. Thus my search for a TC defeat on this site today.

    Knowing the drive train could be seriously damaged by defeating TC deters me from trying that option. I have to agree with Jayman. For a car that is so smartly engineered, it IS surprising they didn't add a safe method of overriding TC.
     
  16. syncmaster

    syncmaster New Member

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    I found this post on prius-2G (yahoo forum)
    It might help you with your problem:

    In most slippery driving situations I agree with you, Gary, but one
    of the quirks of the Prius is that its traction control can
    effectively bring you to a stop when trying to climb a slick hill as
    first one wheel and then the other stops trying to turn. In a
    vehicle without traction control flooring it in such a scenario is a
    sure way to lose total traction and control and find yourself
    sliding back down the hill with no way to steer. But in the Prius,
    counterintuitive as it may seem, flooring it does not result in
    spinning tires, but on a slick grade seems to send the message to
    the computer to try just a little harder and you end up creeping up
    the hill.

    I learned this through trial and error on a short stretch of gravel
    road near my home that has now been eliminated by a new bridge
    opened in the last couple of weeks. We used to cross an old iron
    bridge, make a ninety degree turn left up a short steep stretch that
    gets no winter sun and never got plowed due to the low weight limit
    on the bridge, then another right angle turn to the right as it
    leveled out. It was impossible to get up much speed before
    attempting the grade and often there would be days at a time when
    the traction was quite limited. Some days I just couldn't get the
    prius up the hill and had to drive my 4x4 Tacoma all the way to work
    just because of 100 feet of non-navigatible road. Then I tried
    flooring it as soon as I started up and the prius responded by
    providing slightly more aggressive traction control, with the dash
    light flashing on and off regularly as it switched from one wheel to
    the other as I slowly but surely climbed the grade.

    I've also used this technique effectively when climbing out a
    friend's sloped gravel driveway.
     
  17. Tideland Prius

    Tideland Prius Moderator of the North
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    So you're saying, when the TRAC cuts power, just floor it and hold it there and it'll eventually get the message?
     
  18. Ghoti

    Ghoti Member

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    That seems to be the gist of it. I remember vaguely reading that thread, and seem to recall the author confirming that flooring it will, albiet slowly, get you up those slick hills.

    Another option, if you have the room, is to reverse up the hill- as more weight is on your front tires in that situation, you will have more traction.
     
  19. Tideland Prius

    Tideland Prius Moderator of the North
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    True but the problem is, the engine isn't directly connected to the wheels (well, in the sense that it's not like a normal car). You don't get the same power reversing.
     
  20. michalopoulosgk

    michalopoulosgk New Member

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    To all of you who responded to this topic, please check yesterday's topic "Going up the driveway on ice and Traction Control" which I started, relating the problems I had going up my driveway and the car stopping due to Traction Control. It is sort of a messy situation wich Toyota should correct.
     
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