Standard replacement S2 Shocks Fitted!!

[evoboy69]

Taking advantage of the good weather today I managed to get to my S2 and take it for a drive to see how much of an improvement the new shocks have made. Now I am aware that the Geometry needs sorting before I can properly judge but my first impressions are generally very positive. The biggest difference is in the way the car no longer drives under braking or squats down at the back so much under acceleration.

The only slight disappointment seemed to be that there seemed to be a little more body roll than I remember before they were fitted. Do I need to wait for it to settle?

(New Sachs front struts fitted with matching new rear dampers)

 

[ChasR]

Excellent news. It may be worth renewing the ARB bushes up front if you are handy with a spanner, but they are not too tricky to change.

Furthermore, how is the ride? Is it better over the bumps etc?

 

[mik_ok]

New shocks won't increase roll resistance.

I put new OEM shocks on ours and the improvement over the 16yr old originals was (unsuprisingly) marked. Response to mid-corner bumps was the most noticable improvement - I hadn't appreciated quite how much it wriggled beforehand.

 

[Neil Haughey]

This all depends on the car. On the S2 I found OEM replacement shocks dramatically improved the ride but didn't improve the handling much, if anything the car rolled more. On the 968 it was the other way round, very little improvement in ride but much better handling dynamics, in fact really surprising improvement in handling. Basically S2 suspension is very soft and tuned more for a smooth compliant ride.

 

[ChasR]

It could be that the S2 in question had M758 or M474 suspension fitted to it, over the stock Sachs items.

 

[zcacogp]

I wouldn't judge anything until you have had it fully geo'd. Without this, any improvement from new suspension will be completely negated by the fact that the alignment settings are all over the place.


Oli.

 

[evoboy69]

ORIGINAL: zcacogp

I wouldn't judge anything until you have had it fully geo'd. Without this, any improvement from new suspension will be completely negated by the fact that the alignment settings are all over the place.


Oli.

Thanks for all the replies guys. I think the point about the alignment is a very valid one!

I am thinking of replacing the anti-roll bar bushes and upgrading to 968 Caster Mounts before getting the Alignment set.

Would Poly Anti-Roll bar bushes help take out some out the body roll?

 

[zcacogp]

ORIGINAL: evoboy69
I am thinking of replacing the anti-roll bar bushes and upgrading to 968 Caster Mounts before getting the Alignment set.

Would Poly Anti-Roll bar bushes help take out some out the body roll?

Definitely replace the caster mounts and ARB bushes before the alignment.

New ARB bushes reducing body roll? Perhaps, but only a little. As I understand it, stiffer ARB bushes allow the ARB to work earlier (as in, there is less flex in them so the bar starts working earlier), but it doesn't stiffen the bar itself so it won't radically reduce the roll for a given cornering force.


Oli.

 

[wolfie308]

James - had all these done last year when I had the KW's fitted.... Powerflex bushes x 8 about £90, 968 castor mounts £60 each plus decided to go the whole hog and have 968 MO30 front and rear anti roll bars at £220. Prices do not include VAT or labour

 

[zcacogp]

Scotty,

No. Chassis dynamics fascinates me, and is something I'd love to learn more about. My limited understanding is thus:

SPRINGS hold the car off the road. Can be hard or soft. Harder means they more firmly resist both instant (such as is exerted at turn-in) and continuous (such as is exerted once settled into a corner) force. Clearly, firmer springs therefore mean less body roll in corners, but also mean firmer ride.

SHOCK ABSORBERS damp the action of the springs, and prevent repeated bouncing of the car. Again, can be hard or soft, but are measured (and sometimes can be adjusted) both in bounce and rebound (i.e. whether they are hard to compress, or hard to extend.) The amount of firmness needs to be 'matched' to the stiffness of the springs for ideal ride and handling, otherwise weirdness results. Harder (or firmer) means they more firmly resist instant (such as at turn-in) force, but DOESN'T mean that they more firmly resist continuous force. Therefore fitting firmer dampers DOESN'T affect body roll, or vehicle attitude once it has settled into a corner; by the same token they don't affect ride height either. (Hence, to the OP, new dampers won't be affecting your bodyroll at all.)

ANTI ROLL BARS ('Sway Bars' if you live on the wrong side of the Atlantic) or ARB's link the two sides of the car together, preventing one side of the suspension from compressing without the other side from compressing similarly. This will therefore stop the car from leaning in corners (where one side compresses and the other side extends.) The heavier (thicker) the anti roll car the more effect it has, and the less body roll there will be. Thinner ARB's mean that the connection between the two sides is weaker than that with thicker ARB's.

BUSHES are the things that connect all the various bits together. Soft bushes mean that things can move around a lot before they exert any much force on anything else - leading to a comfortable but less-responsive set-up. ARB's are mounted in bushes, and hence when the car leans, the ARB's will exert force via their bushes. Soft bushes therefore will compress more before exerting as much force on the car, lessening the effect of the ARB's.

(Castor Mounts are a type of bush with a special name. They mount the back of the front wishbones to the car. As before, the stiffer the caster mounts, the less the wishbones can move around under the car, and hence the more firmly the wheels - attached to the wishbones - will be controlled. This makes the steering sharper and much more precise-feeling.)

In answer to your question, to reduce roll in corners the options are to fit stiffer springs or heftier ARBs. Some reduction in roll can be achieved by fitting firmer ARB bushes, but the effect of this will be limited.

How much? There was discussion on here about the 968 castor mounts. Think they are about £80-100 a pair. Bushes - I don't know. About £30 for a full set when I did them a while back. Don't know now.


Oli.

 

[craig2105]

Scotty - keep an eye open on ebay and here as M030 ARB's do come up from time to time. Also, I think it's the case that standard 968 ARB's are built to 944 M030 spec so are a good source too. Someone will be along to put that right if I'm mistaken...

 

[edh]

.....and 968 M030 ARB's are the thickest - 30mm F and 19mm R. They are still available new AFAIK

 

[zcacogp]

ORIGINAL: sc0tty

Nice one Oli, thanks for the response oh wise one. []

There are two Oli's on here.

I'm assuming you are addressing the other one! []


Oli.

 

[mik_ok]

As per some of the other posts.

New dampers won't make any difference to roll, or squat/dive. You can squeeze them full travel easily in your hand, so 1300kg of car in a dynamic state has no problem settling to the same end position.

Your mind in playing tricks on you. [] You're probably cornering faster because the car isn't fighting you, so notice the roll more.

Only way to reduce roll is thicker anti-roll bars or stiffer springs.

 

[Neil Haughey]

Lots of disinformtation on this thread.

Why do you guys think ppl adjust damper settings on race cars? As someone mentioned above increasing damper stiffness slows down the damper either compressing or rebounding, it won't stop the body of car rolling, eventually. The word eventually is the key as handling is practically never static, the car is nearly always in some form of transitory state. Damper settings effect these transitions directly and can be tuned to create an effect like increasing oversteer or understeer without touching spring rates, roll centres, arb's or ride heights.

The fact you can slowly compress a stock damper in your hands misses the point, anyone thinking to hard about this factoid is misunderstanding how dampers work. Try the same again by banging a damper hard into the floor with your full body weight behind it, some may find the result shocking, pardon the pun (Hint: if the shock is good it will barely compress at all).

 

[zcacogp]

Neil,

Where's the disinformation? I'm curious.

I think the point about compressing a damper with your hands was made to illustrate that a damper has little effect upon constant forces being applied, but the fact that it moves slowly shows that it has an effect upon transitory forces. The longer-acting the force, the less effect the damper has.

You re-iterate what others have said; stiffer dampers have no effect upon bodyroll.

I think we may be in danger of violent agreement here ...


Oli.

 

[DivineE]

Not sure whether its safe to add here before the explosion but fitting fatter ARB's to my Audi S3 (significantly fatter than standard and recommended by other owners - so the effects were exaggerated) MASSIVELY reduced the body roll on turn in to the extent that the car felt spooky like it was defying physics. It began to lean a little during the corner when force was sustained, it just didn't have the dip and turn effect you expect from a car as you entered corners. Not sure what the downside was though? There must be one or all cars would have very fat anti roll bars.

p.s. ARB's were the only things changed. everything else was standard at the time.

 

[mik_ok]

ORIGINAL: Neil Haughey

Lots of disinformtation on this thread.

Why do you guys think ppl adjust damper settings on race cars?

I like the intentional misspeeling of disinformation. []

I believe most people adjust damper settings on race cars to adjust the damping. If they want to alter the roll they're far more likely to adjust their adjustable ARBs, ride height, or spring rates.

I don't disagree that damping has some effect as the car is rarely in a perfectly balanced state mid-corner, but steady state mid-corner roll is a fairly simple function of weight transfer and stiffness ~ be it vertical or roll stiffness.You could also argue that tyres will have an effect here as each has different grip levels, and even if you don't reach those levels, they have different sidewall stiffness and damping rates. I wouldn't argue with that either, but neither would I recommend changing tyres as a solution to someone seeking greater roll resistance.

 

[zcacogp]

ORIGINAL: DivineE
... fitting fatter ARB's to my Audi S3 (significantly fatter than standard and recommended by other owners - so the effects were exaggerated) MASSIVELY reduced the body roll on turn in to the extent that the car felt spooky like it was defying physics. It began to lean a little during the corner when force was sustained, it just didn't have the dip and turn effect you expect from a car as you entered corners. Not sure what the downside was though? There must be one or all cars would have very fat anti roll bars.

That's a very good question, one I have wondered about on a number of occasions.

I *think* that the downside is that the handling becomes unpredictable: or, more accurately, it becomes prone to sudden break-away. The roll is minimised, it's flatter than a flat thing just after pancake day and all is fine, until it very suddenly lets go and spits you into the nearest ditch.

Whether this is a bad thing or not I don't know. I don't see why having a sharp limit is a bad thing if you know where it is. Keeping a car flat on cornering is very desirable as it keeps the tyre contact patches as large as possible, therefore the grip as high as possible, so the net effect of fitting thicker ARB's has to be beneficial as it allows you to work the tyres harder.


Oli.

 

[mik_ok]

The downside is that you are comprimising the independance of the independant suspension.

When you tie together each side with an ARB, any wheel cannot respond in isolation to bumps etc.... which is what you ideally want it to do.