ARB/sway bar question

[Pat D]

Just been confirmed, no charge for extra holes to make it adjustable.

I might give them the rear bar as well, might as well do both in one hit. Adjustable rear 26mm and adjustable front 28mm is what I'll go for.

[Rusty]

FYI the RS2 used stock S2 springs from the air conditioning cars

26 is too large at the back for the OE design. I'd say 22mm is as high as yous want to go. The references to 25/26mm are front bars that have more leverage. Still use front cups with 22mm bushes.

To compare ARB stiffnesses, use diameter to the power 4 and divide by the relative length of the lever, compared to the basic design.

[Pat D]

Right, so I've decided to give them the rear bar initially and see how that goes when its done. I opted for 22mm with extra holes front and rear of the original holes for adjustment, similar to the whitleline bar. The price will be a little cheaper than a 28mm since its a narrower bar. Should hopefully get it back in a few weeks.

[Tonks4x4]

I have opted for fitting a standard front ARB on the rear and kept the standard upfront.

With coilovers all round 300lbs front and 325lbs rear.

The car is very stiff but I prefer the way it wants to step the rear end out instead of wanting to go straight on if I enter a corner too quickly.

I run 17" wheels with a normal profile to keep the ride a little comfy.

I will be using this setup all summer with summer tyres to make sure I am happy with the way it handles with grippyer tyres. As winter tyres tend to slide earlier.

It is a trial and error process as everyone has a different driving style and a different perception of how a car should handle. And retaining as much comfort to handling balance as possible.

[malncol]

what setup would you recomend for a gravel rally SWB car?? I will be in the market for some bars if i can work out whats needed
mal

[Kliminati456]

Can someone explain why put a larger FARB on these cars. They already suffer from bad under steer, will this not make the problem worse? I left the 25mm FARB on and added a beefy 26mm RARB (4kq FARB), and love how the car handles. That being said I did not try the 22mm (4k FWD) bar first. I have never encounter a time in spirited street driving where I thought it was too much. Have yet to bring the car on any full speed track laps though.

[Pat D]

Still use front cups with 22mm bushes

Any idea where to get 22mm bushes that fit the same cups?

I found RS4 bushes 8E0 511 327A that are 22mm but they use a different part number for the cups

[Error404]

Pat there was a 22mm front bar option on the Type85 cars, hopefully the rubber bush for them are still in production.
If I don't get home from work too late I will have a look this evening and try and find a part number for you

[Error404]

Can someone explain why put a larger FARB on these cars. They already suffer from bad under steer, will this not make the problem worse? I left the 25mm FARB on and added a beefy 26mm RARB (4kq FARB), and love how the car handles. That being said I did not try the 22mm (4k FWD) bar first. I have never encounter a time in spirited street driving where I thought it was too much. Have yet to bring the car on any full speed track laps though.

On its own yes a stiffer front bar will introduce more understeer.
People tend to use a stiffer front bar in conjunction with a stiffer rear bar to maintain similar handling balance. i.e. on a coupe RS2 front bar with a Whiteline rear bar is similar to stock, with a bit stiffer rear axle to reduce understeer somewhat.
As you probably know its the change in relative stiffness between the front and rear axle that will change the rate of weight transfer and alter handling characteristics.

I would think you will find that your 26mm short armed front bar whilst nice on the road will be a bit too unstable once you get towards the limits of grip on track
Don't forget also that stiffer bars reduce the body roll so the car feels nicer to drive, regardless of the amount of grip or actual cornering speed, so people often report how good it is based on that, rather than any scientific basis.
Of course the feel is what matters 95% of time - simply having fun and enjoying your car (IMHO)

[4WheelDrifter]

Pat there was a 22mm front bar option on the Type85 cars, hopefully the rubber bush for them are still in production.
If I don't get home from work too late I will have a look this evening and try and find a part number for you

The bushes are no problem.

I did away with my stock RS2 bushes in favour for some Superflex ones. I just had to make a back-plate for the universal bush bracket, then hunt on ETKA for some slightly longer bolts.

[5cylinderman]

I may be querying a basic theory here but I still don't understand it.
The S2 is a nose heavy vehicle, and suffers from inherent understeer as we all know.
Why use a stronger rear ARB to help counteract understeer, which sacrifices rear grip to the benefit of the front end, when at the end of the day you are robbing Peter to pay Paul in terms of overall balance and bottom line GRIP on the road.
If a vehicle understeers why not try to reduce it at the front end.
I Rally Sprinted a Talbot Sunbeam and a Mk1 Escort in a previous life and to reduce understeer I removed the front ARB's altogether. This gave huge benefits with turn in, and with the different attitude of the car it increased feedback from the rear end.
I understand that the S2 is a totally different setup and vehicle, but my thoughts remain the same. Why unsettle the grippy end of your chassis to mask the deficiencies of the front end?
Why not go for more aggressive castor and a bit more of negative camber and deal with the problem end of the vehicle and leave the other end alone?

[Pat D]

Pat there was a 22mm front bar option on the Type85 cars, hopefully the rubber bush for them are still in production.
If I don't get home from work too late I will have a look this evening and try and find a part number for you

Cheers Alex,

I will prob go with the superflex universal bushes and clamps. Sounds easy enough

[4WheelDrifter]

It my be easier for you to get Superpro bushes where you are, Pat. There are no inserts involved, so there's probably not much sense in getting Aussie bushes from the UK.

[Error404]

Superflex are made by Superpro anyway - they are the same

[Error404]

I may be querying a basic theory here but I still don't understand it.
The S2 is a nose heavy vehicle, and suffers from inherent understeer as we all know.
Why use a stronger rear ARB to help counteract understeer, which sacrifices rear grip to the benefit of the front end, when at the end of the day you are robbing Peter to pay Paul in terms of overall balance and bottom line GRIP on the road.
If a vehicle understeers why not try to reduce it at the front end.
I Rally Sprinted a Talbot Sunbeam and a Mk1 Escort in a previous life and to reduce understeer I removed the front ARB's altogether. This gave huge benefits with turn in, and with the different attitude of the car it increased feedback from the rear end.
I understand that the S2 is a totally different setup and vehicle, but my thoughts remain the same. Why unsettle the grippy end of your chassis to mask the deficiencies of the front end?
Why not go for more aggressive castor and a bit more of negative camber and deal with the problem end of the vehicle and leave the other end alone?

Its all about weight transfer.

http://www.s2forum.com/forum/showpos...7&postcount=99

When you corner in the car, you get weight transfer from the inside to the outside tyres. Generally, the more weight transfer the less grip because the outside tyres get overloaded until they loose grip. Weight transfer is controlled with the cars roll stiffness but it is not affected by the total roll stiffness but the relative stiffness of the front and rear axles. The roll stiffness is made up from the ARB and the springs.

All other parameters being equal, increasing the front and rear axle roll stiffness by the same amount doesn't affect weight transfer - the total weight transfer remains constant so whilst the body roll is reduced and it feels nicer there is no actual performance change.
It is the relationship between front and rear roll stiffnesses that affects weight transfer. Centre of Gravity is the important factor where weight is concerned, not specific axle weight. It is the track width and centre of gravity that affect the total weight transfer. for example if you could get your CoG to be at ground level you would have zero weight transfer. The amount of body roll is affect by the distance between the roll centre axis and the CoG.

So you would think that more axle roll stiffness would decrease lateral weight transfer but actually it increases it. So for in this instance if you just stiffen the rear axle you increase the weight transfer on that axle, but because the total weight transfer remains constant the net result is reducing the front weight transfer also. So the grip balance shifts forwards and understeer is reduced.

More simply as Aaron has shown above stiffer rear springs also help with traction under acceleration as the front wheels can get more traction with less squat from rear weight transfer - as you want to go WOT as early as possible when exiting the corner less squat helps you with tractive grip.