strange handling

[SUSIT]

What you all make of this, My S2 has three times tried to bite me when overtaking, on each occasion starting from about 50 mph in third floor the throttle as I pull out and the back tries to overtake the front requiring a fair amount of opposite lock to hold it.

First time was as I drove it home from buying it, it was very wet and I put it down to the tyres being very old and the rubber having gone hard. Happend next in damp conditions same tyres then lastly at the weekend again very slighty damp and cold but on quality winter tyres.

checked the tyre pressures all good, tyre wear even, the car handles well giving me no cause for concern in the bends.

What would you check next? I dont believe it has a LSD.

 

[david924s]

Are you sure its an S2 not a Turbo! Never experienced this before in my S2, had the odd interesting oversteer on bends when pushing on too hard but really only in the damp or wet and never on a straight road overtaking. What size wheels is it running has someone fitted the wrong wheels or indeed swopped from to back. Like you I would have suspected old or worn out tyres.

 

[Cater_Racer]

1. Tyres
2. Rear Shocks
3. The rest of rear suspension
4. Front shocks/suspension.

 

[Riverside]

ORIGINAL: Cater_Racer

1. Tyres
2. Rear Shocks
3. The rest of rear suspension
4. Front shocks/suspension.

I agree with this. Also worth bearing in mind that a car will only react violently to violent inputs.

 

[peanut]

I've never experienced it either ?

The only thing I can think of is that you have a rubber do-nut type clutch which is knackered and is 'winding up' on immediate hard acceleration then unwinding as the drive load eases off a bit .

How much backlash is there in the transmission of you drive along in second say and put your foot on the throttle then off again a few times ?

 

[SUSIT]

ORIGINAL: david924s

Are you sure its an S2 not a Turbo! Never experienced this before in my S2, had the odd interesting oversteer on bends when pushing on too hard but really only in the damp or wet and never on a straight road overtaking. What size wheels is it running has someone fitted the wrong wheels or indeed swopped from to back. Like you I would have suspected old or worn out tyres.

must look under the bonnet for a turbo, nope defo an S2, its strange but this one does feel much quicker than my other one, despite my white one having had a fully reconed head (EMC) and brand new cams. Wheels are standard cup ones 16 inch 8 rears 7 fronts I run 215 on rear with the winter tyre as they dont do 225.

Doesnt feel under damped and i would expect shot dampers to show up in tyre wear.

 

[SUSIT]

ORIGINAL: peanut

I've never experienced it either ?

The only thing I can think of is that you have a rubber do-nut type clutch which is knackered and is 'winding up' on immediate hard acceleration then unwinding as the drive load eases off a bit .

How much backlash is there in the transmission of you drive along in second say and put your foot on the throttle then off again a few times ?

That an interesting thought, must give that a go but cant say i have noticed any clunks in the transmission

 

[peanut]

ORIGINAL: SUSIT





That an interesting thought, must give that a go but cant say i have noticed any clunks in the transmission

thats the thing.. you won't notice any clunks until its practically disintegrating which is why the rubber do-nut was a standard fitment on most cars. It insulates the transmission from the engine and cushions the backlash and takeup on hard acceleration and de-acceleration.

'Wind up' is often noticed on some front wheel drive cars , quite scary when you suddenly get a turbo-boost you are not expecting

 

[zcacogp]

It's a commonly know fact that S2's are quicker than turbos, but they develop they power in a more progressive manner so are less likely to bite as hard as your experience. []

I'd go with Gerry's list (below), but would also suggest a good look 'round to make sure that there is nothing broken. I had some very strange handling on my S2 when one of the front ARB mounts snapped, so do a good search for things not being attached as firmly as they should be. Have a look for badly perished bushes, and think about a full geo as well.


Oli.

ORIGINAL: Cater_Racer

1. Tyres
2. Rear Shocks
3. The rest of rear suspension
4. Front shocks/suspension.

 

[944 man]

My first thought was rear bushings and mountings, so number three on the list.

 

[SUSIT]

ORIGINAL: peanut

ORIGINAL: SUSIT





That an interesting thought, must give that a go but cant say i have noticed any clunks in the transmission

thats the thing.. you won't notice any clunks until its practically disintegrating which is why the rubber do-nut was a standard fitment on most cars. It insulates the transmission from the engine and cushions the backlash and takeup on hard acceleration and de-acceleration.

'Wind up' is often noticed on some front wheel drive cars , quite scary when you suddenly get a turbo-boost you are not expecting

just been out in car and dont think there is any clutch issue, it has had a new clutch about 40k ago

nothing obvious hanging off, will need to wait until i can get it on mates ramp to fully check it out and will take it for alignment once I change the castor bushes over for the 968 ones fitted to my white car that is now being broken for spares


thanks for all the suggestions

 

[pauljmcnulty]

First time was as I drove it home from buying it, it was very wet and I put it down to the tyres being very old and the rubber having gone hard. Happend next in damp conditions same tyres then lastly at the weekend again very slighty damp and cold but on quality winter tyres.

Might it be as simple as the tyres? If the old ones were that bad it would be "lively", and the winter tyres on our Legacy have noticeably less grip when it's not really cold, say on a sunny winter day. They are masses better in bad conditions, when you're going slower anyway, but I certainly can't push it as hard on them when the weather allows. For some reason it does tend towards more oversteer on winters, where on normal tyres it's understeer all the time. [8|]

 

[ChasR]

On my old S2 (it had a nasty habit of following the road when it wanted to with the back end being a little lively) I put it down to poor geometry. Whilst changing the tyres helped it drove nothing like my Turbo (which is a much easier car to handle (it drives straight etc.)). The Turbo has a geometry check. FWIW, my S2 had new front arms, and 968 castor mounts, but it was on Boxster wheels.

The back of that S2 seemed to have a mind of its own at times.

An old thread I started seemed to support this as well, but it was mentioned last time that a geometry check alone may not sort it, since the tyres will wear to the geometry of the car.

 

[George Elliott]

Steve, as mentioned above just tyres makes a huge difference, I once had Avon zzr rear tyres which made my car drive like it had 600bhp, replaced with conti sports, problem solved.

If you had a diff it would be less hairy and more balanced side to side, an open diff always behaves differently on the crown-wheel driven side to the opposite side and can cause the unbalanced behaviour you refer to.

BTW, what did you drive before, excl the Stratos [] just thinking if you are used to an A4 Quattro or similar the s2 will be a bit analogue.

George
944t

 

[Duffman502]

Another point with tyres is that both rears should be the same brand/ model etc i saw some comparisons of an rx8 with different brand of tyres on the rear axle having the same symptoms under acceleration.

 

[Copperman05]

I think this is mainly down to low temps, wet roads and summer tyres, even winter tyres perform poor in wet cold conditions (a recent evo winter tyre test showed that summer tyres actually perform better than winters in wet cold and dry cold conditions, winters only really come into their own when there is snow). You really have to drive to the conditions, cold wet tyres perform pretty poorly in contrast to when the roads are dry. Being rear wheel drive and torquey the 944 S2 can step out in greasy conditions quite easily, if suspension is firm, tyres pressure low it can exacerbate the issue.


Edd

 

[peanut]

I was starting to think you guys are right about the tyres being the culprets but re-reading Susit's first post the problem only seems to occur under aggressive straight line acceleration and never in bends, even in wet conditions .??!

My S2 is Promax chipped but I've never experienced this in my car over 6x years of daily use. I'm beginning to wonder if something else isn't involved here like maybe the suspension ?

 

[david924s]

Same view as Peanut, my S2 is fitted with a Promax chip K&N filter etc and even when it had Kumho Ecstas on the rear and Pirelli P4000 on the front with the Kumhos being well worn it never behaved like described, it had a tendancy to understeer due to the front tyres being hard and old but the rears always seemed under control. Same when the Toyo T1Rs were worn out on the back, still felt stable when accelerating hard in an overtake, obviously wet roads and bends were treat carefully.

It would suggest either mismatched or poor tyres, 215 is narrow for 8" wheels, (minimum width) so maybe when its put on full size tyres for Summer use it may behave better.

 

[pauljmcnulty]

I was starting to think you guys are right about the tyres being the culprets but re-reading Susit's first post the problem only seems to occur under aggressive straight line acceleration and never in bends, even in wet conditions

But, in winter conditions and on winter tyres you probably wouldn't be booting it in wet bends? Unless you wanted to throw the back out, and it certainly would be sideways if you floor it at 50 in third on a slippery bend!

I wonder if it's as simple as standing on the accelerator to overtake, then pulling out, and it just breaks away. Reading the OP it's not happening in a straight line?

 

[tref]

I try and always run matched tyres front to rear as well as just one side to another. I had a base model on which I changed the rears, and went through all sorts of things on the car trying to determine what was wrong with the suspension, cured by changing the front tyres to match. I have never come across a car so sensitive in that respect. That said, I have got away with different tyres front to rear, so it is only certain combinations - I found such a combination again recently - Pirrelli's on the back, and Continental Winters on the front - nigh on undrivable... I guess that is no surprise though.

The other one mentioned that isn't so easy to spot as you might think is a carcked ARB hanger... well, ok, it may be that I am not observant!