Suspension update news - kind of.

So I am still considering what is best to do with my suspension that is set too low - now confirmed as 15mm below Euro RS !

I have Chris Franklin at Center Gravity researching his Eibach catalogue to come up with the correct ERS Spring combo. Whilst with Chris we diagnosed badly worn wishbone and top mount rubbers, so they will be replaced at the same time as we figure out the springs. Chris doesn't like going to more than RS +5mm as it induces too much bump steer, but I have a set of correct RS / Turbo uprights to fit at the same time, as well as RS wishbones so all I need are the RS tie rods :-)

I had in the meantime located a set of RS suspension (not the top monoballs though) on Pelican (TasRacer) and we were working on a deal to have him ship them to the UK - good person to deal with and I still have that option open.

However, I got wind of another RS Suspension setup for sale here in the UK, and despite reservations (the top strut damper thread looked too short) I went for it, only to find that it arrived today and is in fact original 1992 Euro Cup suspension - correct part numbers verified over on the PCGB 964RS Register - but with reddish brown H&R 120 and blue H&R 100 springs.

So, does anyone know what the H&R springs might be, and anyone have any thoughts on using the Cup setup on the Road ?

If not, then I will thoroughly clean it and assemble the dampers in to the strut bodies and sell it to fund correct RS setup.

In the meantime I am still enjoying using the car regularly, having done 6K miles in 6 months despite being 15mm below RS height on the not so smooth UK roads.

Ian

 

Hi Ian, have you not considered something more modern? KW Clubsport?

I know Chris sells this setup so wonder what is views are as a comparison.

I run them and find them perfect for road use with the added bonus of adustability for bump and rebound.

Not sure where you are but if you want to check them out let me know.

Also running rennline monoballs.

Cheers

Lee

 

There are better set ups than the RS springs and dampers, especially if they are second hand.So don't pay "RS money" for these parts.

The RS wishbones are the same as the stock 964 expect for a notch stiffer rubber bushings but it doesn't matter after 20 years so I hope you didn't pay more money for a "RS part". Replace the bushings with nylon bushings from Powerfelx i.e instead. Better and cheaper.

The uprights are also the same except that the mounting holes for the calipers are made to fit the bigger calipers but you can solve this with an adapter if you´re planning for RS/Big red calipers. The uprights won't do anything for bump steer.

The tie rods are the same to and doesn't either do anything for bumpsteer. C4 and RS uses the same tie rod with a little stiffer rubber than the C2 part. It's a good upgrade but not a big thing. The cup car also have rubber in the tie rod joint, but again, a little stiffer.

Running Cup or RS suspension on the street works and the difference isn't big, but the cup damper and springs are better tuned and gives a better ride.

just my thoughts....

best/Thomas

 

I agree with Lee and Thomas. Only go for original RS suspension if you want to make an RS replica. KW or Bilstein PSS9 suspension will do the job you want just as well (and probably better for road use).

 

Here's a Bilstein set up fine tuned by the master:

http://www.albertweb.de/fahrzeugkata...bstimmung.html

http://www.albertweb.de/modules/prod...ailimages.html

I am sure google can give a good emough translation for those whose German vocabulary begins and ends with Porsche;-)

 

Agree with everyone above. I would only go for original RS/Cup suspension if you're trying to preserve originality for an RS/Cup car. Even for a rep I'd go aftermarket.

 

Many thanks for the responses.

Lee :-
I am in Stratford-upon-Avon and would very much welcome an opportunity to see how your car is setup - followed the thread and it looks great (is it still for sale though ?).

Thomas :-
I bought a package of parts that were at a good price so no I didn't pay RS prices. I got a complete set of wishbones that were cleaned and fitted with 'hard' urethane (?) bushes to emulate the RS stiffness. These came with the chassis attachment piece, ball joint, RS upright and hub as an assembly. I also got a set of 964RS calipers and 993 rears - all in one big box.

The uprights were good value as these alone a sought after by RS / Turbo owners, but I realise caliper adapters would do the same thing.

I am very interested in your opinion of the Cup setup being better tuned and giving a better ride than the RS - I thought Cup would be way too hard for the road ?

I came across the Cup setup by chance and so bought it - not expensive and it is genuine 964 Cup front and rear struts and dampers but (none original ?) H&R springs. These were off a low mileage car and are marked as 'CUP OK 12 6 93' implying someone inspected them - but I will take them to Bilstein and have them test them for me.

I also know that to really cure bump steer you need the 993RS /EVO uprights and tie rods (Porsche or ERP).

Steve :-
Look forward to a passenger lap at Donington to see how your setup performs.

Talat :-
I appreciate that newer technology is probably the way to go but at £2K is on the steep side for me at the moment, given I have already have Bilsteiin B6 Sports with Eibach ERS spring system that just needs longer top springs to raise it up from its current 15mm below RS height !

I will formulate a plan as I am inclined towards the RS Lightweight Replica but I wouldn't start with an immaculate right hand drive car with sunroof though !

Evoderby :-
Thanks for link and will look at later.

Ian

 

Hi Ian,

Its not currently for sale but it will be later this year.

I am going to miss it so much. Im sure I will regret it but I am going to race in the Boxster series. I will run a standard 993c2 for every day and try not to modify it

Let me know if you are in the Surrey area and we can meet up. Im at Silverstone next month in it and Bedford in July.

Cheers

Lee

 

Lee

Do you still have that spare set of Rennline Mounts ?

Ian

 

I sold them to a friend, not sure if he is going to use them as his car is in bits.

I will check for you.

 

The springs are a little to stiff for the dampers which may work just fine on a smooth race track.But on the road it feels a bit skittish and harsh. this makes the car feel stiffer than it actually is. The cup dampers/springs are a little harder but they are better tuned together which makes it less harsh and gives the car a more planted feel compared to the RS. the cup is more pleasant to drive IMHO.

The difference in hardness isn't that big so if you can drive a RS on the street you can also drive a Cup on the street.

also congrats to your "party box" of RS-parts, sounds like a good find!

Thomas

 

Thomas

Can you shed any light on the H&R springs that ame with the Cup setup I acquired - marked 100 and 120 in red/brown and blue colouring ?

Do you know if you can still buy Cup Springs, or would you have to bye the modern equivalent from Eibach - and if so, what specification spring would it be ?

Ian

 

Thomas

Here is a picture of my box of 'RS' bits as they came assembled :-



Wishbones with new solid (urethan ?) bushings :-



RS Uprights :-



And finally the RS brakes fronts and 993 rears :-



All to be repainted and checked over before fitting - or I may go big reds on those EVO Uprights :-)

Ian

 

I think H&R list their springs in N/mm rather than lbs./inch,

100 N/mm = 570 lbs.
120 N/mm = 684 lbs.

From the chart included the rears appear to be what is known as H&R 964 Supercup springs:

https://rennlist.com/forums/5983707-post1.html

Although the chart looks nice it has some flaws, Porsche never gave data on 964 RS springs (they do for a 993RS BTW). If I'm not mistaken the data mentioned for the 964 RS stems from this forum and is nothing more than a guess made by a contributor.

 

Nice set of bits Ian

Take the opportunity to have the spring plates in the calipers removed, the corrosion cleaned out and the plates refitted, to cure any 'plate lift' that is no doubt developing after all this time.