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Front end slides when turning

Discussion in 'Motorsports' started by GRISLOVE, Jan 27, 2014.

  1. racerb

    racerb Well-Known Member

    Having raced FWD cars since the early 80s, we always wonder how the really fast guys made their cars handle so well. We learn many years into our racing that they were all removing their front swaybars, enlarging their rear bars, and running higher rear spring rates. Our previous racecar, a Nissan Pulsar had Koni front struts with 175 ft lb springs no swaybar, Carrera inverted rear shocks, 275 ft lb springs and a 7/8" rear swaybar, car did and still does handle like a go-cart.

    I'm building the Celica around Koni Struts front/rear, 8" coil-over springs in various rates from 600-900 ft lbs depending on the track, and a Whiteline 18mm rear swaybar, but I'm also experimenting with rear bars from the 94-99 Celica GT which is a larger bar. With radial tires, street or DOT race rubber, the car requires some body roll or else it will just plow or slide the front end, in racing this is know as understeer, what you attempt to do is induce oversteer, like RWD.

    Be careful not to make wholesale changes, do one thing at a time and give that a try, if it doesn't fix your problem try something else until it works better, this way you'll know what fixed it....

    racerb :science2
    Last edited: Jan 29, 2014

    GRISLOVE Well-Known Member

    We'll thank you for the info. I will have to try that. I have the koni yellow sports up front. But with the stock weak springs.

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  3. zk0729

    zk0729 Well-Known Member

    I know it's about two years late but with stumbling into this thread on the front page of the Motorsports tab, I figure I'll add a little to it, for future readers.

    What you're referring to is understeer, which is highly common on FWD cars. This is mostly caused by asking the tires to do too much (accelerate, turn, and/or brake, with two at the same time). One of the biggest things to help this are tires. Rubber is one of the most vital selections you can make for your car. Typically, if you're having this issue, you need stickier tires.

    Beyond that, you have to understand that a FWD doesn't act like a RWD when driving. As opposed to a forward push on the front making a four corner effort, most of the strain is put on the front to both steer the car and pull it forward. The reason the rear end slides out when you release the gas is because the front tires are finally able to bite and begin to pull you around (my verbal cue is, "release the gas to swing the ass"). This is actually something you need to remember while driving. In addition to that, a FWD needs greater bite in the front and not in the rear. Keep in mind, a RWD needs traction at all four corners, a fwd doesn't. A larger swaybar in the rear allows the car to stay more flat overall, but removing the front swaybar allows the front to roll and gain extra traction on the outer tire, and gives it more "bite". Keep in mind though, a FWD WILL NOT kick out if you give it gas like in a RWD, it will do the opposite. With some of the professional racers I've seen, I've actually seen them run stickier tires up front with less sticky tires in the rear, which allows the rear to slide more easily (which angles the front), but I personally don't recommend it, I've seen the rear try to slide around when braking at high speed.

    While that manages to be vague and complicated at the same time, I hope it at least somewhat helps.
  4. CelicaSteve

    CelicaSteve Well-Known Member Staff Member Super Moderator Donated!

    Thank you for that reply, it doesn't matter about the timescale. Your contribution on this site is appreciated.

    GRISLOVE Well-Known Member

    Jeez forgot about this post. Lol I'm still running the same setup.
    And yep, there will always be some one out there that can use the extra info.

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  6. lone wolf

    lone wolf Well-Known Member Donated!

    I'm happy with the info. Now running koni's and having the whiteline rear swaybar ready for install I'm allready facing the fact my tires cannot keep up with me anymore as they did before the koni's went in. While exchanging shocks I found out why....the OEM's were totally toast :).

    As I only drive about 1000 km's a year I am going to find me some semi-slicks, I guess that will improve handling even more :).
  7. thesherv

    thesherv Well-Known Member Donated!

    I'm running BC 'BR' series adjustable coilovers on my car,6kg front 4kg rear. Toyo T1-R tyres,205/45/16, damping set softer on the front than the rear alongside a Whiteline rear ARB and droplinks with adjustable camber bolts fitted,and I've improved understeer pretty dramatically,lift off oversteer is still something to consider but its much more predictable,which is why i havent used a stiffer front ARB.Cornering is much improved and I also have a Beams derived S54 gearbox with LSD,which helps keep the power down when i need it.

    GRISLOVE Well-Known Member

    I use to have the problem with the lift oversteer. Than it just kinda, disappeared

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  9. thesherv

    thesherv Well-Known Member Donated!

    I'd only get it if i was to drop the throttle back halfway through a fast tight corner,I'd have to be pretty rough with it and frankly thats not the right way to take a corner anyway LOL

    GRISLOVE Well-Known Member

    Yeah, I got it a lot when I would autocross. Havnt changed the car. So maybe I just got better or something lol idk

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