Jump to content

Massive Understeer At The Track, What To Do?


xr_velocity

Recommended Posts

Guest XR09
  • Guests

The Fg does not go from understeer to oversteer as bad as the BF.

I have also found that the more I chase getting rid of the understeer. The more trouble I am having getting the power to the ground. Also I lose a bit of confidence in it when throwing into very high speed turns.

I'm finding it better to drive around the little bit of understeer I have for the better high speed control, Braking and traction.

Link to comment
Share on other sites

  • 3 months later...
  • Donating Members
  • Member For: 17y 4m 27d
  • Gender: Male
  • Location: Sydney

I took it to Powercruise in Sydney weekend just gone. There was a huge improvement in front end grip to say the least!

While the car is still heavy and more prone to understeer than oversteer, I was able to come into corners a lot faster than before. Corner speed was much higher as well. I found myself completely unacquainted with the car with the huge difference the front bushes and alignment had made. I was throwing it around a lot more and could not feel the weight of the car so much as before. I could confidently ask for more in corners because of the slight tendency to more understeer than oversteer. I could easily hold a tight corner at high speed, get on the gas after the apex and be on full throttle on the way out with the front still gripping and the back in complete control, there were moments of slight oversteer out of corners on power but you get that with full throttle and almost 400kw. But the oversteer was very controlled and completely linear. I was darting in and out of cars, passing on the inside and outside of other cars on corners with no loss of grip or any unnerving unexpected behaviour of the car. I would not stiffen up the rear anymore as a lot of people have with a larger sway bar because it has great balance how it is right now. I can't see that making the rear stiffer and reducing weight transfer to the back under power is going to make it any faster. I have no issues with the rear end at all (again, at my level of ability).

To say I was impressed compared to the last outing is an understatement.

I have not tried taking the rear sway bar off as yet, and not sure if I will try until I get some more track time as I am pretty happy with the balance it has now. A little understeer is always good for a novice like me.

There was a little body roll in the car with the current setup but I think that helped me get out of corners cleanly by moving the weight to the back of the car under power. I think I have a pretty good street/track balance in the current setup.

Setup is:

Lovells Eliminator shock and spring package they sell as a kit form (has one part number)

Poly bushes in centre of diff mount and for control blades.

Poly bushes in front lower control arm front and rear.

Whiteline 27mm sway bar on the front.

Tyres Falken FK452 245 front and 275 rear.

I would also like to add that the Falken FK452 tyres are a ripper for the price they ask for them. Give them a bit of heat and the grip is exceptional under power and brakes. Though you can get them too hot on a track day but they are just a road tyre after all.

Link to comment
Share on other sites

  • Member
  • Member For: 16y 3m 7d
  • Gender: Male
  • Location: Brisbane

Great, intuitive and thorough write up....well done. Just what is required to see how it has improved without actually being there.

Setup (IMO) is now within the "window"....an effective window showing that bucket loads of money don't need to be spent, just spent in the right areas.

Sounds much better and much more pleasurable to drive:

-increased and sustainable mid turn grip, not just transient turn in

-balance

-compliance

-controllable and easy to drive at the limit

-able to be steered to good effect on the throttle

......just how the car should be. And all linked to one another.

The last 2 points are very good indicators that the chassis is now much happier and more balanced.

This is good info that shows monster spring/sway bar rates are overkill and achieve more in "unbalancing" the car than anything else.

Keep an eye on the front inside tyre wear as time goes by. If it starts to happen, replace the upper control arm bushes with poly as well. That will put an end to that issue. Easy to do as the spring/damper assy remains untouched. A press is required though. Make sure to have a good look at the upper ball joint lock bolt. One of mine had a thread issue. I replaced both of them just to be sure. I think the std ones may be a bit soft. A 6 point hex head will fit in it's position ok.

For fine tuning......

When you feel comfortable with it, I would still try it with no rear bar, but having the "baseline" to judge the difference is important. It's effect should be to help lessen the front understeer at the limit (ie help unload it) and improve rear traction also especially on bumpy exits. Having the 275's at the rear will help it greatly with no rear bar.

Edited by Smoke them tyres
Link to comment
Share on other sites

  • Donating Members
  • Member For: 17y 4m 27d
  • Gender: Male
  • Location: Sydney

I think for someonhe like me who enjoys a little track time but is definitely a novice the setup I have is ideal. I have only spent approx $1500 to get it where it is today on springs, shocks, sway bar and bushes. Now it's time to enjoy it and learn more about the feel of the car. I'll take off the rear sway bar later on in the year when I've had some more time with it the way it is.

The only noticeable downsides to my setup is in the front end over sharp edged bumps while turning (eg a sharp edged exapnsion joint on a bridge) the front wheels seem to unload from the ground for a split second as they are bounced up from the jolt causing the steering to lighten for a very short time. This started once the poly bushes went in the lower control arm, I guess the lack of give in the bushes no longer absorbs the shock. The other being that when getting the car drifting it can kick back the other way quite fast if you take your foot off the gas too quick or the rev limiter kicks in mid burnout. But on the gas it lays some nice fish tails, very controllable.

Link to comment
Share on other sites

  • Member
  • Member For: 16y 3m 7d
  • Gender: Male
  • Location: Brisbane

Sliding and taking the foot of the loud pedal :)

The nice slides show that there is no available wind up in the driveline ie no tramp from the blade links. Exactly how it should be. The design engineer's reason for putting them there in the first place.

The momentary lightness in the wheel is probably a moment of tyre slip as well. The old soft bushes would have just deformed to absorb it. Not the lightest cars. A small price to pay for the gains made.....

Link to comment
Share on other sites

  • 1 month later...
  • Donating Members
  • Member For: 17y 4m 27d
  • Gender: Male
  • Location: Sydney

I had her out to at Eastern Creek again today.

As suspected from my drive at Powercruise a month or so earlier, the car behaved much better on the track. The balance between the front and rear end was great.

It is still lacking camber in the front, to get more I need to get some adjustable mounts put in. I am only getting about 1.7 degrees of negative camber at the moment, which is a lot morfe than factory, but nowhere near enough for the track in a barge arse of a car.

The car would still understeer, as any car would when pushed, but the front end grip was far better than before I gave it more camber and changed the bushes in the front to Superpros.

The car was only slightly more inclined to understeer, meaning I when getting on the throttle mid corner it was more likely to push the front out than the rear, but with just a little more throttle I was able to steer with rear getting the front to grip andf point me to where I want to go with just a slight amount of oversteer out of the corner. I must say the C&V tune in the car is excellent, more than I could ever have asked for. THe power delivery is so linear it makes it so easy to drive, there is no sudden spike in power to catch me unawares, just complete predictability.

Having said that, I outdid my ability a couple of times coming out of the hair pin. I was trying to get the back to come out to get the front end to grip in a bit more, gave it a bit too much and ended up pretty sideways. But I just backed off the throttle, the back end gripped and came straight back into line. No kicking back the other way, nothing nasty at all.

With near on 400kw, this car is actually pretty easy to drive...as long as you stay focused that is.

The front definitely needs more negative camber, the rear end feels great....though it did feel a tiny bit drifty at times, nothing major. It could be more to do with using road tyres that are a little hot than the setup of the car as the front was certainly sliding as well.

Having softer suspension than a lot of other XRs around really makes this car very forgiving. I am able to comfortably hit the sweeping left hander after the main straight at approx 150 to 160...it's a little bumpy through some of that turn and the car just soaks it up never going the line I pointed it in. Under brakes there is no squirming or nervousness, just a straight line stop.

I think the next step will be to get some adjustable mounts for the upper control arms to get a bit more camber out of her. Might try 2.2 or so and see how the tyre wear goes. I'll be taking the rear sway bar off next time out to see if that helps with front end grip at all.

My day was cut short due to an exhaust leak somewhere around the turbo. Got to check it out this weekend. I have had dramas with the turbine housing making a high pitch whistle....probably due to cracks, I am thinking it will be that....

Anyone wanting a good street/track compromise....I think I am on the right track :)

Update to come in one month hopefully :)

Edited by xr_velocity
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
  • Create New...
'