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  • Users: GEspo
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  1. GEspo

    Slip and Axle Stiffness

    enter “more predictable”: when the rear starts to slide on the rear engine youll notice it and still be able to control the car I suppose id like to test all this since so many variables, tires etc.. ie when youre making huge slip angles there lots of factors to whether a mid is less...
  2. GEspo

    Slip and Axle Stiffness

    im going to take a stab at this: the reason theres NOT alot of mid engine drift cars, when the rear brakes loose on the rear engine theres still some traction on the fronts so the car can be controlled a bit.. when traction breaks on the mid engine the more evenly distributed grip is lost both...
  3. GEspo

    Slip and Axle Stiffness

    Theres no question the rear will loose traction first on the rear engine, question is what car will be able to “swing back” the other direction to right itself.. Im wondering what motivates people to say “mid is better in turn but when you loose it you cant get the car back”.. ie what math...
  4. GEspo

    Slip and Axle Stiffness

    On the 911 architecture there have been tests comparing 911 to cayman.. on accel weight at rear wheels 911 74% vs 67% cayman.. stopping 58/42 for 911 vs 63/37 cayman.. so if stop and go goto the 911.. and correcting a skid to rear engine, 911 wins? im a fan.. who ironically has the exact...
  5. GEspo

    Slip and Axle Stiffness

    interconnected suspension
  6. GEspo

    Slip and Axle Stiffness

    citreon is HIS.. 2008 911 GT3 RS is 2nd, supposedly newer 911 strays from the original.. its said 997 is the last true 911.. just cant afford it, 2006/2007 gt3 engine alone is $45k, add another $20k for the gearbox, they pretty much giving the body away..
  7. GEspo

    Slip and Axle Stiffness

    Something makes sense that a mid engine is harder to get to break traction than a rear engine but harder to get corrected when it does, possibly because the higher moi rear is quick to break traction back the other direction? ie pendulum.. The math must be there to back this up because ive heard...
  8. GEspo

    Slip and Axle Stiffness

    (car/trailer system differs from car.. makes sense) Why is a mid engine harder to control once traction breaks vs rear engine?
  9. GEspo

    Slip and Axle Stiffness

    Does a similar principal apply here: a higher moi is more resistant to change in direction but can correct more easily than a lower moi, ie mid vs rear engine loosing it.. Wouldnt the toy car on the treadmill more easily correct with the higher moi? (it needs a tiny driver)
  10. GEspo

    Slip and Axle Stiffness

    Google turns up a quick description of shredded street tires at track temps.. looks expensive and dangerous. Not sure if this is a good case of the exception vs the rule, but the saying “bring a knife to a gun fight” may apply...
  11. GEspo

    Slip and Axle Stiffness

    Im a bit limited for tires for the sti as far as R-comp, not sure a non track tire would last out there. I’ll probably end up trying all the track rated stuff before too long.. I went through a practically new set of stock front pads in 2 20 min sessions, completely gone.. needles to say im hard...
  12. GEspo

    Slip and Axle Stiffness

    Interesting.. curious how do the R888R compare? what metrics are you using? Why not an R-comp tire? car mainly sees track use.. thx
  13. GEspo

    Slip and Axle Stiffness

    Great info on the sti. I have little to compare the car since I haven't had a "sports" car in about 15 years. Tires are 215/45/17 Toyo R888R and seem to be holding up ok. After last session I notice the fronts outer edge got burned up a bit as I was perfecting my slide through turn method. The...
  14. GEspo

    Slip and Axle Stiffness

    I like this approach, so we're skid pad testing.. yes can compute no prob. Interesting thing about the sti is im having a hard time driving it off the track, ie oversteer. Since I've done lots to lighten the car, keeping the original suspension actually makes for stiffer rear rate so the...
  15. GEspo

    Slip and Axle Stiffness

    Gotta love it.. a tad of understeer it is. Now to find a way to test that (in my stripped down 07 sti) Thanks!
  16. GEspo

    Slip and Axle Stiffness

    Gotcha.. My initial question has been answered so thank you.. however its created more questions.. so a question to "sensing response" and understeer: If my main objective is to get a car around a (asphalt)track the fastest, lets say this track 2.5 mi should I be setting up for under...
  17. GEspo

    Slip and Axle Stiffness

    Thanks for the twisting tube analogy, I will consider... So as far as "likely very poor dynamics (transient response) because the system collapses down to slow first order behavior", how else can I understand this? an explanation would be helpful.. thx
  18. GEspo

    Slip and Axle Stiffness

    So best case is: having both outside tires with identical load on them, ie Fz_out_front = Fz_out_rear -> neutral steer and maximizes grip ** assuming same tire F & R (if the rear were a larger tire you may want more Fz there relative to achieve neutral steer) Lastly, why does the stiffer axle...
  19. GEspo

    Slip and Axle Stiffness

    So increasing axle stiffness increases the weight transfer to that axle relative to the other.. and with more vertical force(on that outside tire) it develops more slip, ok?
  20. GEspo

    Slip and Axle Stiffness

    Hello Eng-tips experts. Is there a short answer to why increasing axle stiffness at one axle will create more slip at that axle relative to the other axle? This question is related to how to get more oversteer/understeer ie suspension tuning/roll bar tuning.. Thanks!

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