Suspension

[Guest]

Hi there, I posted a question about two weeks ago, in regards to a rumbling wheel noise when turning right,

I was after further advice, and recomendations,

I replaced all the bearings, and both rear CV joints and the noise is still there, I have been told by my garage that there is a lot of play in the shocks and that basically because of there age they are knackered, so I am going to replace them hoping that it is road noise that I am hearing and that the bushes are also gone, however I am a little confused.

I understand that Spax, do direct replacements, and that also you can get Blistein shocks as well whic are more expensive, is it worth the extra outlay, what benefits would I see, I have also been told that with the new shocks I can also get harder and lower springs which will lower the car by 35mm, (I have standard tele dials and not looking at replacing them for bigger wheels) I am tempted to get the shorter shocks however is this a bad idea? should I just settle for standard, what would be the benefit or draw backs of considering this, my car is and will remain standard, in all other forms!

 

[sawood12]

I think you need to consider your damping rate in comparison to your spring rate. If the Spax and Blistein dampers are a higher rate than standard and you compress your springs by 35mm (i.e. effectively stiffening the spring rate) then you might end up with rediculously hard suspension. If you want to lower your car and maintain a good balance between comfort and handling the best thing to do is to buy new springs as well. Maybe a lowering spring/shock absorber set is the best way to go.

Having said that if your current dampers are old and knackered simply replacing with good new standard dampers will probably transform the handling compared to what it is now.

 

[sawood12]

Sorry, just re-read your post, you were already talking about a new spring/shock kit. I thought you were on about compressing your current springs by using shorter dampers. However my comment about replacing with good standard shocks still stands. It depends what you want out of the car. I personally don't mind a hard ride (ooer) so would be very tempted with the harder/lower set up. I'm not sure how it will affect the handling of the car though if the front end is stiffened up in comparison the the back end - maybe someone with a bit of racing experience could comment.

 

[mik_ok]

If you are only changing the fronts, I wouldn't do anything extreme with springs.I believe Fen tried -35mm springs and reckoned them too low (?) You may want to go for stiffer dampers, but you'd ideally do this as a front-rear combo.

You can get std front shocks very cheap from Design911 - if your existing ones are knackered you'll notice a big difference. I just replaced all 4 shocks on my 80K mile S2 for std units and the improvements in ride and body control are superb.

New OEM rear shocks will cost you less than £85 delivered to your door via Eurocarparts (using Stu in the sticky link atop this section).

 

[Fen]

I did try -35mm springs and ended up taking out the sump on some road debris. That said I'm probably running more like -45mm now.

 

[Guest]

It's a very tricky question to answer. For the track, it's fairly simple to spec some new springs and dampers, because you've got a very good idea of what you're going to want them to do. You are out for maximum performance, and comfort is relatively unimportant (and if you're not doing endurance racing, it's completely unimportant).

When it comes to the road, it's a completely different matter. The manufacturers usually come up with a reasonable compromise of ride quality and handling. Performance cars like ours often have an optional suspension pack that will stiffen things up a bit for better handling (usually at the sacrifice of a bit of comfort and a lot of cash). Some of the more extreme examples of this are really quite uncomfortable on the road, and generally aimed at track focussed use.

If you are looking at a 3rd party offering, you're in a complete minefield of personal choice. Some people will want their suspension rock hard (even though they never use the car anywhere near the smooth track where it might actually have any benefit) because it makes them feel like thay are race drivers. These people are often referred to as "Chavs"[] Other people want to improve the visual impact of their cars by lowering them a bit to get a bit of a more racey look. This can look nice, or if overdone it can look quite comical, especially when "enhanced" by some ground hugging front splitter (I still laugh when I remember the low slung BMW I used to walk past every morning in London which gradually acquired more and more gaffer tape holding the front together as he hit more speed bumps).

The big problem that you get is that, what I might find comfortable and stylish, might rattle your fillings loose. The questions to ask yourself are:

Am I doing this to improve the handling of the car?
If so, what is wrong with the handling (a lot of people don't actually know what they don't like about the handling, they think that just by changing it, somehow the car will be "better").
If so, am I looking for road or track handling?
How much track use will I get out of the car?
Will I want to take my wife/mum/kids/dog to the shops in the car, and will it matter if they get shaken to death on the way?

If not for handling, is it just for visual effect?
If it's just for visual effect, what am I trying to improve about the looks?
How high are the speed bumps that I meet regularly. People don't realise just how important this is until they discover that they can't actually drive up their own road (I did meet somebody who had to park their car round the corner from their house because of this).

If the answer is that you are going to turn this car into a track monster, the thing to do is to go along to a few races and speak to people who run 944s in various series (remember that some series mandate that you can't change the suspension at all, so you may have to ask around a fair bit).

If you want to use it on the occasional track day, I would suggest that you just replace the current suspension with the standard 944 suspension (I wouldn't even bother about going for an M030 upgrade unless you can find a set at a reasonable price). Track days aren't about "winning", they're about having fun, so there's no point in fixing something that essentially isn't broken just for the sake of it. If you're using your car mostly on the road and just doing the odd one, remember that you have to live with that rock hard suspension for the 99% of the time where you're driving to work or the shops.

If you're just doing it for cosmetic reasons, try to keep as much as possible standard. This will mean that a) you spend less money. b) you'll be less likely to make the car uncomfortable. c) it's easier to revert to the standard ride height when you find yourself ripping the bottom off your car on all the speed humps the council have just decided to put in near your house.

I hope that this has been of use to you. It's all down to personal opinion at the end of the day.

James

 

[mik_ok]

Nice post James [8D]

 

[Guest]

James thank you for your time a most impressive post, well there is a lot to think about, my car will probably never see the track, well maybe a couple of times but believe it or not, it is my full time car that I use for work, and generally I cover around 20k a year in her, I do find the suspension soft and there is a lot of body roll, however according to the history the shocks and springs I do not think have ever been changed and she has covered to date, 123k In regards to comfort, I could handle being rattled around a little, but saying that I have never experienced the ride quality of hard shocks and springs! I am looking at keeping the wheels standard, so I am hoping that with the large tyre wall it will help absorb a little of the road bumps.

However the thing that does worry me is the speed bump factor, I love the profile of the car, but do sometimes wish that she was ever so slightly lower; however I do not want to lose my sump, and I do not intend to put any kind of skirt on the front!

Crikey I am a little confused now!
Do I want lower ride and crappy ride quality, and better handling, it seems that you are not gaining a great deal from going with the harder route, I mean how "much" better would the handling be over new stock springs and damperners, (I am ovbiously looking at replacing both front and back)
So one thing that maybe you can clear up is the old and very difficult road noise problem, I am presuming that worn shocks bushes can cause road noise the trnmit through the car?

 

[Guest]

If you're looking for road use, I'd just replace with the standard setup. Perhaps look at lowering slightly with springs for the cosmetic effect that you are after, but keep a similar rate, maybe slightly stiffer on the springs.

Could I ask why you want to "improve" the handling on your car, if you only use it on the road? I use the word improve advisedly, as most kits that you get will actually just make it different, not better. There is no way that you should ever be driving on the road in a manner that would ever reach the limits of the standard setup.

Just my opinion of course.

 

[John Sims]

I used to race a Westfield that was also road registered. Despite, in the first instance, considering that it could be both a good track/race car and a road car it soon became apparent that it had to be one or the other. Obviously I went the race route.

The problem is that the condition of UK roads is generally very bad. They are rough and uneven. As James has said, the best suspension on a nice smooth track is hard and low (more of low later). On the road this can border on the dangerous and, indeed, the 964RS was considered such for this very reason - though suggestions that driving over a pebble could throw you into a ditch were perhaps a bit of an exaggeration.. The trouble with stiff low suspension is that the suspension can't react far and fast enough to accommodate the changing surface and so wheels will skip. Obviously while a wheel is skipping it isn't providing any form of traction at all - not good if you hit a bump mid corner.

The Westfield demonstrated all of the traits as above and used to dance down the road as I corrected one direction change after another all caused by no more than an uneven road surface. My Westfield was 1/3 of the weight of a 944 (but the same power as a Lux [8D]) so these effects were that much more extreme. but the principal remains. The plus side was, on a dry track, levels of grip that exceeded all expectations to the point where grip was often so far beyond my comfort factor that I would have to push the car into bends trusting that it would stick when all logic and self preservation instincts said it wouldn't. There is little to beat the first time you hoist your spherical danglies and take Craner Curves flat.

Also, when considering road use, you need to appreciate that race/track cars run different setting for wet and dry weather. Wet weather is much softer and more compliant so as to allow less aggressive changes in weight distribution and resulting sudden loss of grip. You don't want to have to get under your car to adjust ARBs and dampers every time it rains so, in effect, road cars are always on a wet setting - except the M3 coupe CS whatever it is which is sold with a warning not to drive it in the wet.

Ride height - As suspension compresses and extends the geometry changes, generally increasing or decreasing camber - think back to pictures of racing Triumph Dolomites and Imps who's rear camber would change alarmingly. Car manufacturers set up the suspension to provide the optimum at a set ride hight allowing the camber to change within tolerance as the car dips and rises. If you reduce the ride height (without changing the position of the mounting points) there is every possibility that the car will ride just within or even outside of the ideal camber envelope. This will get worse as the car dips or the suspension compresses under cornering.

In summary - suspension is difficult. Best not mess about with it unless you know what to expect when you do.

 

[Fen]

Chris,

Might I suggest what you look at is new standard suspension with the Anti-Roll Bars of a late Turbo? That way you retain the standard ride height and compliance (which will be stiffer than the 123k suspension on the car) but lose a lot of the roly-poly cornering attitude. It also will not cost much as replacement struts and shocks are not dear and I sold my Turbo ARBs for only £80.

In terms of clearance though I now ride lower than even and have yet to hit anything, even with a splitter on the front of the car. The debris that took out my sump nearly 4 years ago was or the order of half a breeze-block, not just a stone on the road.

 

[Diver944]

Chris, my S2 is a totally different setup to you but I changed all four shocks for standard replacements at 150k miles and it totally transformed the car for the better. It leaned less when cornering, braking and accelerating yet was actually more comfortable when soaking up the bumps. So in effect - stiffer and softer at the same time []

I think for your use you should do the same. Standard shocks from someone like Bert Gear will not set you back more than a couple of hundred but they really will return your car to how it was when it left the factory.

Budget for a full four wheel suspension alignment when you've finished as all the settings will be out after replacement (£100 - £200 depending where you go and how seized your adjusters are)

 

[carlmthompson]

I've recently replaced my Dampers on my BM with 125K on. I considered putting something more sporty on ,but decided to go with the standard set up. Im glad I did, as similar to Paul above the car is much taughter, and much more responsive to direction change.
I think if I'd gone for a bit stiffer, then I would have sacrificed the ride quality to the worse, and the car would have been a pain to drive - it's unbelievable how much stiffer newer dampers are than the same-but-old ones your replace.

 

[944Turbo]

I replaced the 130K set on my lux with new standard fronts and (KYB rears - they came with the car) It was much improved, so fitting new standard ones is probably the best option for road use. IIRC the spax are for square dash cars only anyway.

On my turbo I also replaced with standard ones around 100k this was an improvement but not as marked - also fitted front lowering springs from TechArt which I was impressed with the ride comfort didn't get much worse but the lower front looked nice [] and imprved the turn in. I have since changed to leda (without coil over rears) and these can be a little harsh for the road but are better on the track.

Tony

 

[Guest]

Well I wanted to say thank you, for all responses, I am going to go with the standard option, To be honest I have always found the handling really good anyway, and certainly I think that because my shocks are pretty old I am sure that new standard ones would be far firmer anyway.

I really do not think that I will ever be taking my car to the limit in regards to handling for road driving and therefore thinking about it, any firmer shocks or springs would be purely be a waste of money, I mean we drive cars that are renowned for their sublime handling anyway, even in regards to modern standards! I think that the money saved will simply go to the new sills and respray, or possibly a new clutch or torque tube bearings!

Thankyou for all responses, however thinking about it, I think that I was too taken in by the "oh sproty srings and shocks" option when in fact we already drive a car whose handling has been designed with sprot in mind!

Kindest regards
Chris

 

[ChasR]

KW V3s really are that good I am afraid. A country road which can be bumpy in a 944 is surprisigngly settled in a KW car. But at £2k as you say it's not cheap. Damn you MarkK!

If it were me, it would be between the Bilsteins (But AFAIK, they do not fit an S2 (or at least the fronts don't)), Sachs (but they will make you consider KWs with each leg being £240 each after VAT (Rears are £70ish each)), and with Konis last (although they did work well on the last car I had but they seem to get mixed reports here, with some saying they are a little firmer than stock and others saying they are too firm for the road.

Either way, even the Sachs items will be a big improvement over what you have if they have never been changed.

 

[944 man]

Id retain OEM spec dampers but Id up the anti-roll bar diameters: probably opting for 968 M030 parts. Not expensive but theyll certainly control body roll. Fitting 968 castor mounts wont cost a deal either, but the difference will be very noticable. Whilst youre at it Id replace the standard bushes also. Strut top mounts can be more costly, so Id seek experienced counsel as to whether theyre going to be needed.

If youre looking to improve the original spec dampers then Id consider GAZ. They have a large range from a cheap but impressive sporty upgrade to full-on remote resevoir race dampers...


Simon

 

[ocallen]

And there is also Spax, available from DemonTweeks, and highly rated in Germany.

 

[andy watson]

Hi James

See my thread "Replacement Shocks" for prices of replacements.

I have been quoted £964.00inc VAT to supply and from my Indie

Design 911 have quoted £607.66inc VAT to supply and fit Fichter & Sachs

Regards
Andy

 

[zcacogp]

Sc0tty,

I have an S2 with Koni dampers and standard ARB's. Dampers are about 35k miles old now. There is lots of discussion on the forum about the pros and minusses of all the options; I'd say you will never get a true, objective opinion of the merits of any one option over another as no one person will have tried every option. You will also never find two otherwise identical cars to drive back-to-back, on the same road (there will always be differences in geometry, ARB, age of shocks and whatnot else.)

If you want to reduce body roll then new shocks won't made any difference. As Simon said, thicker ARB's are the route you need. BUT new shocks will help with other aspects of the handlng; stability in a straight line, huge increase in stability when braking, better turn-in, more comfortable ride etc etc etc ...

Having said that, if you are ever want a run in an S2 with the Koni option then drop me a line. You'd be most welcome.


Oli.