Whiteline RSB + Liftoff Oversteer

[DaveMack]

I've had mine on the stiffest setting for more than six months, tracked it at Morgan Park and had no problems (maybe I didn't lift off enough in the corners ).

One thing I would add is ... there is such a thing as approaching a corner too fast ... and if you are not prepared to admit that (at least to yourself), you WILL come to grief sometime either from snap oversteer or simply understeering right off the corner (and perhaps over a ledge ... voice of experience here ).

Dave

[Blitzen]

I have had mine on the stiffest setting the whole time. The only way to fly!! I really don't know what all the fuss is about...The thing is the dogs bollocks.

[Bubu]

When I spoke to Whiteline about getting my a RSB for my Charade (this is where somebody will say its not relevant because its not a Polo), they said they recommend getting the front one done also or I may experience some rear oversteer. I realise that a RSB helps the front bite harder and turn in but too much of that can cause your FWD car to oversteer.

I dont yet have aftermarket swaybars fitted to the Polo so I cant comment on the Polo. But in theory a really stiff RSB can cause oversteer.

[GoLfMan]

i get bloody induced oversteer in my 97' Polo with no sway bar

its just how you drive it you can induce oversteer in basically anything

[GT3]

Whiteline

Swaybar size. The swaybar size that we, and most aftermarket companies, specify is only the physical size/diameter of the material. This however does not indicate the rate or resistance of the swaybar, as there are other factors that would need to be accounted for to be calculate the rate. These are the width and length of the swaybar, whether the swaybar is made from a solid bar or a hollow tube and the strength properties of the material used. In simple terms, the longer the swaybar the softer it will be, and the shorter the bar the stiffer the swaybar will be.

Swaybar rate/stiffness. Even if the swaybar rate is known, it in itself is still of little relevance to the overall outcome and handling balance of the car. This is because handling balance depends on the swaybar and swaybar link installation and motion ratio, and by applying all these factors it is only then possible to finally end up with swaybar roll resistance.

Once the swaybar roll resistance has been established, and adding spring resistance and suspension mechanical resistance, it is possible to work out the total roll resistance which determines the handling balance.

I think you can see that this is starting to get quite complicated. As you are aware, most vehicles are designed with and understeering balance. This is because it is a safe state, but is not necessarily fast. However, this is easily fixed by fitting a larger rear swaybar.

To sum up, for your car we have designed a rear swaybar only to be used together with the original front. The result is reduced body roll and understeer by balancing the total roll resistance between front and rear of the car, without actually inducing oversteer.

Wojtek Rogulski (Polo GTI RSB developer)

[GT3]

Balancemotorsport.co.uk

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.

Another big plus of the anti-roll bar is they are often easily adjustable. You may have spent a lot of time and effort setting up coilovers to ensure the best weight distribution, you then find for instance the front end is understeering on a tight circuit you've not visited before. It is much easier to adjust an anti-roll bar than change the springs.

[Timbo]

The (current) Polo (GTI) is fundamentally an understeering car, both through its layout as a FWD car with much of its weight over the front axle, and by design, because understeer is regarded by all mfrs as a 'safer' handling characteristic than oversteer.

Despite this, it is still possible to induce an oversteer reaction in the stock GTI...but doing so involves some fairly abnormal driving actions.

If you wish to drive on a track or in any form of handling event, or even a bit faster on the road, most experienced drivers want to reduce the understeer characteristics of the car, and fitting a RSB is the easiest and cheapest way of doing this. Whiteline seem as good as any others I've fitted; it's a good Aus product and I know Whiteline undergo extensive testing (are there others for the Polo GTI available in Aus?)

Having fitted the RSB -- yes, the GTI's natural understeering characteristics are reduced and yes, there is a greater susceptibility to oversteer. Indeed, as above, it is even easier to induce some oversteer reaction...but basically, doing this still involves some "unnatural" driving acts to unbalance the car mid-corner. It's not something anyone should experience in normal -- even 'spirited' -- driving.

So, does fitting a RSB lead to "unintended" snap oversteer on the GTI? I say "NO". But I am not saying that you cannot induce snap oversteer on the GTI, even with no RSB.....just that in doing so one must have acted unnaturally (or failed to act sensibly) to induce the situation.

The RSB and "snap oversteer" issue goes way back to something Lams banged on about on Vortex, relating to a MkIV Golf GTI fitted with a RSB. I recall asking at the time what other factors were present during that situation (ie, was it wet, what were the tyres like, were pressures up to scratch, was the rest of the suspension OK) but I don't recall seeing an answer (he may have...just don't recall seeing it).

Finally, the Golf GTI is quite a different car to the MkIV GTI, as anyone who has searched for suspension parts knows. It has different weight distribution, as is the case with Astinas, Charades etc. So, while it is always useful to draw on those experiences, they are not necessarily precedents.

[DaveMack]

That about covers it, Timbo.

Dave

[shaneth]

Well said timbo. And i couldnt agree more.

[mitch_gti]

I wont go into too much depth, but after the swaybar upgrade the polo was a very different car to drive.

After a couple more changes like springs, slightly higher pressures and front strut brace the polo handles EXTREMELY well.

Its hard to tell just driving around town, but a recent cruise through old pac and berowra opened my eyes to what the modified polo is capable of.
What an incredible little car (after you spend some cash on it)
I could not find its limits and it always felt safe, very neutral and I had zero understeer.
Also, it was great exploring the higher gears which you normally dont get to experience.

Would love to take this car to a track.

[DaveMack]

Would love to take this car to a track.

DO IT! You won't regret it!

Dave

[Blitzen]

.

Dave[/QUOTE]

I didn't know the Polo GTI had a Maclaren F1 seating set up!!

[DaveMack]

.

Dave

I didn't know the Polo GTI had a Maclaren F1 seating set up!!

Hehehe ... mine does (well ... in my mind when I'm on the track).

Dave

[Guy_H]

I think Timbo & Len & ~ 10 years each track experience helps them out a little!

I agree, wrong tyre pressures, unknown roads, approaching corners too fast - certainly most QLD' drivers can probably remember a case of "snap oversteer" that sent a certain Golf over on its roof on a drive day a while ago.

Mind you, on the track it pretty hard, all that lovely consistent surface, lots of room for error - stuff you don't get on a mountain road.

Good place to demonstrate it is on a big skidpan with lots of room & try some high speed "moose" maneuvers - for those who have not experienced it, it will become clear very quickly.

Suggest everyone tries to get out on a skidpan to see what their car can do!

Here is Al walkers quick demonstration of lift off oversteer in an R32:

(and yes, it happens that quick)

http://www.youtube.com/watch?v=lGQHXeBNw7U

[FL00DY]

Yeah I think it has as much to do with driver skill and control as it does the RSB.

Either way I think for such small $$$ the RSB is a must, once you learn the differences and limits of the car.