Torque Vectoring in the Rain

Discussion in 'Fiesta ST Road Racing' started by MLKN, Nov 25, 2014.

  1. MLKN

    MLKN Active Member

    Dear all. I mentioned this in my Sonoma post but thought it deserved its own topic.

    I had some scary experiences thanks to the TV in wet conditions. Specifically turn 11 which is a tight hairpin.

    With breaking in a straight line the car is more predictable, but with trail breaking on accelerating out of the corner, TV kicks in and induces oversteer.

    In dry conditions, the back wheel remains fixed and acts as a pivot point. In wet conditions, it behaves like an e-brake turn. A warning to any road racers out there.
     
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  3. razorlab

    razorlab Active Member

    Was this with the system fully on? Half off? Fully off? Need more context.
     
  4. RodMoe

    RodMoe Well-Known Member

    TV is always FULL ON can't shut it off as I know of
     
  5. razorlab

    razorlab Active Member

    I meant the TC system as a whole. On, sport or fully off
     
  6. MLKN

    MLKN Active Member

    It was on given that it was raining. I usually have it in sport mode for HPDE in dry conditions.
     
  7. razorlab

    razorlab Active Member

    Did you try it with it fully off?
     
  8. MLKN

    MLKN Active Member

    No, but I attributed it to TV, not ABS.
     
  9. RDgolfer

    RDgolfer Active Member

    ESC does not equal TVC...TVC is constant...ESC can be turned off
     
  10. MLKN

    MLKN Active Member

    I think we are all saying the same thing.

    TV was on, regardless of ESC status. And it was TV that caused the car to act unpredictably in a low speed but sharp turn in wet conditions. I was just seeing if anyone else has had that experience and offering a warning as it could have spun the car if I didn't correct.
     
  11. RodMoe

    RodMoe Well-Known Member

    Not in the rain but my car sometimes will wiggle a little bit under hard corning while trail breaking for me it was a learning curve and I tryed to avoid it after the first big wiggle or squirm and just braked straight and harder then off and into the corner with throttle.. weird feeling to say the least. wish McRib would get back and try out the Brake Module from Ford racing..
     
  12. razorlab

    razorlab Active Member

    How do you know for certain if you didn't try it with ESC fully off?
     
  13. razorlab

    razorlab Active Member

    As I have stated before, my FiST does not exhibit any of those characteristics under trail braking, it's totally solid, no wiggles unless I do something to upset the chassis (like any normal car). However it might be because of my upgraded brakes and alignment settings.

    That is basically what I am getting at here. Cars do different things depending on alignment settings. That's why alignments are a HUGE part of the chassis tuning process. Even brake compounds front to rear have a lot to do with how the chassis reacts to trail braking.

    OP, what are your alignment settings?
     
    Dyn085 likes this.
  14. MLKN

    MLKN Active Member

    Factory alignment and Porterfield r4-s pads up front only. I ordered the rear pads because the last track day finished the stock ones off with 8000 miles on them. That may effect the front rear braking balance.

    Interestingly, the right rear brake pad wore out before the left, because my home track, Sears Point, runs clockwise.
     
  15. MLKN

    MLKN Active Member

    I don't know for sure... but why else would the rear tire "lock up"? ESC shouldn't do that, should it? Maybe I just don't understand the subtleties of the ESC.
     
  16. Dyn085

    Dyn085 Active Member

    Torque-vectoring is just an electronic lsd and, from my understanding, only works with the brakes of the drive wheels.
     
  17. MLKN

    MLKN Active Member

    I think you are talking about the EDiff in the Fiesta. TV acts on the inside rear wheel.
     
  18. Dyn085

    Dyn085 Active Member

    Torque Vectoring acts on the inside front wheel.
     
  19. razorlab

    razorlab Active Member

    It would be interesting to see what your alignment is. Mine was all wack from the factory. Crazy toe, which does crazy things at the limit. ;)

    btw, you should look into some camber bolts for the front and dial in some more negative camber, makes a world of difference, especially if you keep tracking the car.
     
  20. FORZDA 2

    FORZDA 2 Member

    Uhhmmm..., you're not correct here. The Torque Vectoring affects the FRONT (drive) wheels only. There is no "EDiff". The TV functions by applying "some" brake force to the spinning wheel which transfers "some" of the torque to the other side. Quite simple and effective for the most part. The Torque Vectoring function can NOT be disabled. The Electronic Stability Control (includes traction control and slip angle control) however, is the system that may apply a front AND/OR rear brake to correct accelerometer-sensed slip angle, and/or modulate the throttle to eliminate front wheel-spin in relation to the rear (traction control). The ESC has 3 user-selectable modes; "On", "Sport", and "OFF". The Sport mode allows more wheel-spin before it modulates the throttle and the OFF mode, well the entire system is simply OFF.

    I have tried out the ESC modes in autocross competition (class winning, not also-ran) and I can tell you that the ESC should be completely OFF for best results, regardless of surface conditions. With the ESC in Sport mode, the car "feels" more stable and wheel-spin is reduced, but the car is much slower when measured with the unblinking timing clocks. The clocks don't lie, so turn the ESC fully OFF and drive the car.

    Oh yeah, my measured wheel alignment was spot-on from the factory. -1.2 front camber, -0.7 rear camber with 3/32 toe-in front and rear.
     
    landwombl likes this.
  21. razorlab

    razorlab Active Member

    Exactly why I was asking if he tried it with the system fully off. :)
     

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