Front end traction

[noone]

I've been playing with my suspension (again).

Today I increased the height of the front suspension a tad (need the clearance)and changed the front swaybar to the harder setting (whiteline sways).

I went for a drive and the front end traction is lovely. Powering out of a corner holds plenty of traction.

I decided to corner hard at about 60kms to see how it managed. The steering seemed to hesitate and my tyres felt like they were being asked for too much.

With some suspension and chassis upgrades (rear control arm bushes, front and rear sways, front brace, coilovers) I'm wondering if the power steering is not upto the challenge I gave it. I need to check my tyre pressure, have a gauge on order as I don't trust the readings at petrol stations.

I have never experienced this before as there should not really be a need to suddenly throw the car into a turn at speed. If my tyre pressure is low (for me below 35ish) then this would help explain the hesetation, interested in any feedback.

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On the topic (but also off topic) is there a reason to change the bushes on the rear suspension? As its torsion beam, I don't really understand how they would help.

[Desmo]

What do you mean by hesitation?

Also increasing front roll resistance increases understeer if nothing else is changed

[RoSonic]

If by "hesitation" you mean understeer, then I think you shoud set the front swaybar to "soft" and the rear one to "hard" to reduce understeer.

Uprated anti-roll bars are one of the most effective ways of improving not only the handling of a car but also outright grip levels. The majority of cars produced today have some form of anti-roll bar. The biggest advantage of the anti-roll bar is that you can limit roll in corners whilst still retaining suspension travel and a good ride. Uprating the anti-roll bar for a larger one increases the roll stiffness at that end of the car (Eibach kits contain front and rear bars). If the roll stiffness is increased so is the weight transfer.

Uprating the bar at one end only means that pair of tyres must carry a higher load. Depending on the handling balance of front to rear this will either increase or decrease outright grip. For example on a Mk4 Golf if you uprate the front bar only the car will reduce it's outright grip level as it already has too much front roll stiffness and not enough rear. To make the Golf Mk4 handle you need a stiffer rear bar only.

This is the case for most front wheel drive cars - uprate the rear bar - which makes the rear of the car work more and prevents understeer. If you bought front and rear you would tend to run the front soft and the back hard. In a rear wheel drive car you'd tend to uprate the front bar more than the back as you can steer with the throttle. Four wheel drive vary between these two depending on a number of factors including torque split. For example Audi Quattros need rear bar only in most cases. Another factor to consider is feel - body roll can be nauseating so adding anti-roll bars makes the drive more pleasant, again without ruining ride.

Go too far on the bar which is connected to the driven wheels and you will run into traction problems. This is why you tend to uprate rear bar on FWD and front bar on RWD. However do bear in mind that increased grip can come not only by optimising the tyre loads front to rear but also by better geometry underload. Excessive body roll on most macpherson strut cars causes unfavourable geometry change - eg loss of camber and caster. A stiff anti-roll bar combination will keep the wheel closer to it's optimum angles.

[noone]

I guess hesitation I would put down to a load in the steering. There is a small amount of under steer incurred which i expected, but the steering felt reluctant to pull the way I wanted to.

I'm not flagging an issue, just commenting on something I noticed

[Desmo]

Mate thanks for the comments, quality discussions on here are sometimes lacking.

The hesitation or reluctance to steer is a good description of understeer, the steering loads up as you turn the wheel but car continues straight.

I think I remember you saying you were running the rear sway in the soft position, be worth trying medium. I would only change one end at a time and in single increments, then retest. He front height increase should have helped reduce the understeer a little, but the bar change would mask this somewhat.

Also as you stiffen the suspension overall, it means that when it lets go be it under or oversteer, it will be less benign, I keep mine rather rather tight especialy at the rear but mine is a weekend/track car.

By the way thanks for the H&R's had them on at Oran Park on 25/1 for the last event ever there.

[Plautos]

I've been playing with my suspension (again).

Today I increased the height of the front suspension a tad (need the clearance)and changed the front swaybar to the harder setting (whiteline sways).

I went for a drive and the front end traction is lovely. Powering out of a corner holds plenty of traction.

I decided to corner hard at about 60kms to see how it managed. The steering seemed to hesitate and my tyres felt like they were being asked for too much.

With some suspension and chassis upgrades (rear control arm bushes, front and rear sways, front brace, coilovers) I'm wondering if the power steering is not upto the challenge I gave it. I need to check my tyre pressure, have a gauge on order as I don't trust the readings at petrol stations.

I have never experienced this before as there should not really be a need to suddenly throw the car into a turn at speed. If my tyre pressure is low (for me below 35ish) then this would help explain the hesetation, interested in any feedback.

------

On the topic (but also off topic) is there a reason to change the bushes on the rear suspension? As its torsion beam, I don't really understand how they would help.

So, what is your conclusion? With the softer setting the handling is better?

[Plautos]

I've been playing with my suspension (again).


On the topic (but also off topic) is there a reason to change the bushes on the rear suspension? As its torsion beam, I don't really understand how they would help.

Yes! The rear bushes have the same problem as the control arm bushes. They change the geometry of the rear suspension.
Solid bushes, like the control arm bushes, will help the car to be more precise… and it is a big difference.
Do you have the WL rear toe kit? This is other big upgrade for the car’s handling.

[noone]

So, what is your conclusion? With the softer setting the handling is better?

No conclusion. I believe that the power steering was not able to keep up with the added strain of the stiffer front end. As a result the steering became briefly heavier and with a little understeer added I was unsure exactly what I was feeling.

I prefer the added turn in grip and traction under power with the FSB on hard, but combined with the other mods, there is a considerable strain on the power steering compared to stock. I've never had an issue, just noted that I cant throw the front end around and expect it to bite.

I'll check the tyres shortly, likely a higher PSI will help. I'm also running Kuhmo KU31's at $110 a corner, so I don't expect miracles.

[noone]

Mate thanks for the comments, quality discussions on here are sometimes lacking.

By the way thanks for the H&R's had them on at Oran Park on 25/1 for the last event ever there.

Yeah the Polo section has been getting pretty slow, guess the novelty is wearing off and many of the originals have either finished the work or moved on. I really enjoy this site, but probably swamp every thread which puts people off. Sorry...

Glad to hear the springs are getting good use! How did the setup compare?

Interested in the front sway-bar? I'm loving mine, but would be a pain to fit on its own.

[Desmo]

Setup is good, it reduced my rear ride height over the previous springs. I only put the rears in but they worked well. I am about to order the WL front sway, and drop links, and will put the front springs in then. Also looking at some other bits for the rear to tighten it up.

I have to post a vid of the Oran Park day, apart from being 40 deg it was great.

Plautos, the rear toe kit is an alignment product, as there is a lot of difference in rear alignment in some cars ex factory, mine included. I have this installed, I did not find it made a great difference compared to springs shocks or swaybars.

Yeah the Polo section has been getting pretty slow, guess the novelty is wearing off and many of the originals have either finished the work or moved on. I really enjoy this site, but probably swamp every thread which puts people off. Sorry...

Glad to hear the springs are getting good use! How did the setup compare?

Interested in the front sway-bar? I'm loving mine, but would be a pain to fit on its own.

[Stuwey]

Mate, you need to learn about how suspension works before just willy nilly adjusting stuff.

http://farnorthracing.com/autocross_secrets.html Read this. Then read it again and again until it makes sense.

What makes a car fast? The driver. Smooth is fast.

First up, tyres are the number one biggest performing modification you can make. Whats the point of exxy suspension mods if you're gonna throw cheap tyres on it?

Suspension is a black art which takes many years to learn. It is also a complete "package" which must be carefully considered. Any one modification will drastically affect others.

Dampers must be valved to the mechanical frequency of the spring. This is paramount. It affects the weight transfer onto your outside tyre, thus controlling over/understeer through differing stages of a corner.

Camber, castor, toe all must be considered.

More castor (pulling the front wheels forwards) will give more turn in, at the expense of heavier steering at parking speeds; which you won't notice with any car with power steering.

Negative camber is the lean-in of the tyre. Top of the tyre inwards is what you want. But not too much, or your inside tyre will struggle for any contact patch to power out of a corner with, resulting in slow, boring wheelspin. Not fast, not cool.

Toe should be almost neutral, if anything 2mm out (at the front of the tyre) on the front wheels, and whilst factory 3mm+ toe in on the rear is very stable and safe, coming back to 1 or 2mm toe in is much nicer to drive. Toe out should NOT be done unless you're chasing the 11th degree on the racetrack, with ESP off.

A stiff swaybar should only be considered after all of these have been tuned to work with each other. Stiff rear bars work well with lots of front camber AND a limited slip diff. As the inside rear wheel lifts, it puts extra load on the outside front wheel. This also lifts load off the inside wheel, so you'll need a LSD to make it work.

Stiffer is NOT faster. Nor is it fun or comfortable on the street.

I've been playing with fast FWD street and race cars for a while now and its taken 6 years to learn it. I still am.

[noone]

Mate, you need to learn about how suspension works before just willy nilly adjusting stuff.

What makes a car fast? The driver. Smooth is fast.

Um, thanks? I'm not talking about tracking a car or apex speed, if you read my post I mentioned doing something I don't do in normal driving... I was trying to engage people in a discussion. I don't think that changing my swaybar from one setting to the other and adjusting the ride height by 1cm can be classed as willy nilly...

Thanks for the link, but for me to learn about suspension, I need to make changes and feel the differences. I don't have years of experience.

I'm enjoying modding my car and would love the cash to make the changes 1 at a time to really understand the differences. My last works included brakes, sway, coilovers and control arm bushes. they make the car handle very differently and I have mentioned before (eg in the AP Coilover review thread) that I cant say exactly what changes had what effect as it was all done at once.

[Stuwey]

My last works included brakes, sway, coilovers and control arm bushes. they make the car handle very differently and I have mentioned before (eg in the AP Coilover review thread) that I cant say exactly what changes had what effect as it was all done at once.

Which is why you have no clue so as to what to change more or less of to make it faster.

Cars need to be modified in steps. Thus you know what worked or didn't, and by doing so, you'll learn more.

The Mini at home now has (With an LSD i'll add)

Front:
3.5 degrees negative
6 degrees castor
2mm toe out
Koni re-valved dampers
(no sway)

Rear:
2 degrees negative
1mm toe in
Koni re-valved dampers
(no sway)

And this thing skips around Mallala all day very fast, and is still nice enough to drive on the street.

The issue with adjusting sway bars is that the rear one will make the front bite more, and the front sway bar makes the rear bite more. You've added an anomoly into the system by adding a rear sway bar in any case.

Every adjustment works on the opposite corner to which you adjust.

Go find a nice quiet backroad. Drive it again and again and again. Change something. Drive it again. See what you think - You'll learn quick enough.

But any monkey can still ruin a fast car - YOU have to be the fast bit.

Read and learn. That website i linked above is the best one i've seen. I suggest you learn it.

[BRU51N]

^ do your tyres last any long with the front settings the way they are?

sounds like its set up right for the track!

[noone]

Thanks for the lecture Stuwey.

I'm sure the tyres won't last as long Bru5in, I'm keen to get it back to the track shortly, really need some cheap wheels and decent tyres for tracking...