Kolbjorn S

I've replaced the 20 year old original M474 red Boge's on my '87 S4 with brand new ones so I decided to go one step further and change my original brown-coded (2 marks) front springs to new orange-coded CS springs, part 928 343 511 12 504. But what shall I do with the original rear springs - leave them alone? Probably not a good idea since they're 20 years of age (low mile though and do not appear soft or worn), but since the CS seems to come only with stiffer front springs is there a rear upgrade I could do? I failed to find it in the WSM. Should I just replace the rear ones with exactly same spec new ones?

Vilhuer

There aren't any special springs for rear from factory. Move old fronts to rear. This is old trick which many have used. I can't recall if you need old or new style end plates for them but it should be doable with factory parts.

Garth S

If any spring maintains its free height spec, then IMHO, it is as good as new.

IcemanG17

If you increase the stiffness of the front end, but not the rear then you will increase the understeer.....but I'm not sure the difference in spring rates between CS vs sport springs...it might not be much different?

BB928GT

Hi Kolbjørn,

As far as I know the club sport suspension featured bilstein shocks, so I don't know if the CS springs match with the M474 red Boge ones.

Also the information I gathered from some guys who did racing with 928s and which I later cross checked with Porsche, the club sport suspension did definitely not only cover the front springs but also rear springs and at least a stronger front sway bar. The racing people even told me about some brackets to add to the Weissach axel on the rear suspension. (Porsche however could not give me any parts numbers for the brackets nor approve the latter information).

=> Anyway you asked on opinions on the springs:
Since the club sport suspension was developed as a package, I would at least change all four springs and add the matching dampers.
If you stay with the red boge ones, may be it is best to buy standard springs for front and rear, since that is what they are designed to work with.

As for mixing the springs together with the red boge, perhaps someone on this board aready has some experiences with this combination?

Vilhuer

BB928GT, I think Club Sport models didn't have that stiff suspension. 928 race cars are different story. Its interesting to know they did more hardcore racing parts for 928. Weissach brackets must be to pin Weissach joint to allow use of slicks without too much movement from it.

BB928GT

Hello Erkka.

Well, I don't know if the 928 club sport cars were equipped with the above mentioned club sport suspension. But that was only a hand full of cars anyway. But apparently the club sport suspension was not strictly a race suspension either (unlike the cup ones for the 944). More like a full featured sport suspension for road and track use.
One thing that is still confusing me is the fact that the parts number of the front springs which are still availabel does not match the one I was given by the Porsche people. Yet they confirmed that they were talking about the same CS springs that were still available.
Front CS spring part no.: 928.343.511.12
Front CS spring part no. of CS suspension: 928.343.531.70

martin D

The CS package you where told about was a RACE package. The CS/SE road cars only had uprated front springs, rear springs were stock.

martin D

Here you go Erkka
The race CS package front anti roll bar next to a stock one.




The Porsche P/N (its not in PET !)


The race CS springs

BB928GT

Martin thanks a lot for the clarification and the pictures. The values on the springs match the ones Porsche gave me.
So I was wrong and the CS suspension package was a real race package.

Bernd

Vilhuer

Few years ago there was some talk about some GTS having 030 option in option list. Maybe that swaybar and perhaps even springs were available to street cars under that code. In any case normal model PET doesn't know many interesting parts done by Motorsport department, for example 968 Turbo S engine and gearbox etc.