Massive Understeer At The Track, What To Do?

[nelsonian101]

At this stage seing it was your first time at a track, I would just keep it simple and not touch the rear camber. Stock is fine. More negative front will be more beneficial for the track.

What you need in my opinion:

1. Better tyres (see my recommendations above), and set them to mid 30's hot.

2. A track wheel alignment at Wholesale Suspension with more negative camber.

3. A rear adjustable sway bar (set to max) seeing you already have the front sorted.

[seduced]

Different tyres wont improve it. The Falkens are more than capable of a good flogging if the car is set up right. Too many people blame their tyres when its actually a poorly set up suspension. Some stiffer springs, sway bars and lower shocks doesn't automatically mean better handling. Unless they are all tuned and chosen for a specific feel, its all for looks and brag factor.

A rear sway bar will help alot, and so will negative camber in the front. It sounds like your spring rates in the front maybe too stiff though.

[senna_T]

If he has Lovells, I would be very surprised if the spring rates were too high, generally they are very soft in Falcons

[xr_velocity]

The spring rates are not too high, seat of the pants is a little firmer than stock.

Tyre wear on the rear looked very even, tyre wear on the front was all on the outer edge, chunks falling off!

I will try the sway bar with a more aggressive alignment then.

[nelsonian101]

Different tyres wont improve it. The Falkens are more than capable of a good flogging if the car is set up right. Too many people blame their tyres when its actually a poorly set up suspension. Some stiffer springs, sway bars and lower shocks doesn't automatically mean better handling. Unless they are all tuned and chosen for a specific feel, its all for looks and brag factor.

A rear sway bar will help alot, and so will negative camber in the front. It sounds like your spring rates in the front maybe too stiff though.

I disagree that better tyres will not improve the understeer. Sticky R rated tyres can often mask poor handling characteristics like understeer up to a certain level. However, I do agree that this is not addressing the cause of the problem. Just a bandaid cure, but one that will improve everything from braking to acceleration on a track day, so therefore first on my list of mod suggestions.

[Smoke them tyres]

Chunks off the front and understeer......I'm not surprised. On the front of the tread blocks no doubt? Pics?

A good read here would help our understanding of chassis dynamics.....http://home.scarlet.be/~be067749/58//index.htm

Different tyres will only change the overall characteristics (understeer) if the grippier ones are fitted to the front only.

The stiffer rear bar will restore the balance, but at a lower grip level than can be possible....re slower. This stiffer bar will cause less weight transfer to the rear outer in cornering. Therefore, it will induce more slide and more heating of the tyre over a run of laps.(That is why the Top Gear one lap dash is unrealistic. It should be done over 3-5 laps to accurately check how fast the car ACTUALLY is and then the average used).

Removing the rear bar (more weight transfer) will compress the rear suspension more, allowing shorter upper arm to do it's job of counteracting body roll. This will keep the tyre squarer to the road with no additional camber dialled in. The std rear spring is what I am running and I have no reason to change it.....std is spot on in this case IMO.

The max negative camber I could get out of my BF on each side on the front was 1 degree (minimal/nil shims), but trimmed equal on both sides. I now have 2.5 neg on each side on the front and response is much better again, although a few tricks have been employed to get this at the std ride height.

The Fulcrum upper arm mounts are exactly the same as std. All you need to buy is their slide in shims if the wheel aligner doesn't have them. The 1.5mm shim pack is the one to get if running minimal shims.

I would think that if the Lovells are only slightly stiffer as Pat has said, that they are right on the money. I wouldn't be changing those.

I think everyone should try it without the rear bar on....it's no cost anyway. I have done the same to a friends BA XR8 and he was surprised at how much better it was. I don't see the point in restoring the "balance" by detuning it and making it slower than it could otherwise be. It also adds no additional weight to these heavy cars once the heavier front is fitted.

Edited 02/09/10 11:19 AM by Smoke them tyres

[Smoke them tyres]

The front understeer is not helped by a gripped up rear pushing it.

Using the stiffer bar on the rear end of the car will reduce the understeer and push of the car. But why do that to ungrip the rear when the real problem is still at the front? Traction over bumpy surfaces will be an unintended consequence of this stiffer bar. This does not help our cars, which are already somewhat under tyred.

[Guest XR09]

I have a 27mmm rear bar. And I took it off. And put the std one back on.

I am really not sure if it made it faster or slower on the track. It felt faster but it really got nervous at the limit. It did not drift it just went out very quickly at the rear.

It did stop the front pushing under throttle though. Turning in was always turn in grab some oppisit till the nose pointed where u wanted and then turn in again

I am running teins as well. It might be better with softer shocks though ?? or a fatter front bar. But its already 32mm or something like that on the FG

Edited 02/09/10 11:38 AM by XR09

[nelsonian101]

I have a 27mmm rear bar. And I took it off. And put the std one back on.

I am really not sure if it made it faster or slower on the track. It felt faster but it really got nervous at the limit. It did not drift it just went out very quickly at the rear.

It did stop the front pushing under throttle though. Turning in was always turn in grab some oppisit till the nose pointed where u wanted and then turn in again

I am running teins as well. It might be better with softer shocks though ?? or a fatter front bar. But its already 32mm or something like that on the FG

There are a lot of factors when it comes to making these cars handle and there are really only a handful of people with real experience that have had success with trial and error over the years. Often the best theory does not work in practice. Wholesale suspension are good for street track applications, so are East Coast Suspenion in Sydney.

I went through this process last year and could not find any off the shelf products that suited my requirements. Ford engineers fitted the larger (from BF) 32mm front bar to the FG for a reason, but it is still hollow. I took it one step further and had a "solid" front 32mm front sway bar to my FG, fitted from Selby/East Coast Suspenion. I think Wholesale have a bigger one for FG now too.

Another, and I believe the most important factor to getting handling correct is matching your damping and spring rates. I went with a rebuildable Koni shock with custom made internals to suit the spring rate of my lowered springs. Costs a little bit more but worth it long term as a perfect street/track compromise.

[xr_velocity]

I am certainly going to do some more reading on this as I really only have a limited understanding.

So moving to the stiffer front sway bar has also brought more understeer at the same alignment settings, so why not go back to the stock bar with the stiffer springs and shocks that are on the car now? Is this also an option? I know the car feels a lot flatter now though through corners with the fatter front bar. Less body roll is supposed to be better yes?

I am far more inclined to remove the rear bar now and see how that affects the front. Though I will do that after an alignment at Pedders to gauge how each change feels. Do it all at once and I won't understand what has done what.

A stiffer rear bar is going to move more weight to the front when shifting weight in a corner? Hence taking weight off the rear? So in theory going to the stock front bar would have similar effect?

Edited 03/09/10 01:43 AM by xr_velocity