993RS FRONT SUSPENSION ...

[Laurence Gibbs]

A few points that might help. First off before putting the old suspension in the nice shiny KW box (that's where my old set is !) it's worth making sure all the basics are covered. Are the tyres good ? i.e. they're less than a year old and if not the sticky R tyres do they have reasonable life left in them ? Quite a bit of difference happens in tyres and pressures alone. Old tyres will screw the handling. The cars are very adjustable and the geo for one track might be less effective on another. Once satisfied that it's not any of that there are a few things to note on suspension changes.
There is quite a choice. You might want to base your choice on what you want most , i.e. good track manners or good road or a compramise. The cup cars use single tube dampers with linear springs (the standard RS are twin tube design at the front) if you use your car mainly on track and those tracks are billiard smooth then that is the route to go. Be mindfull that you will need new top mounts(monoball) as these are unique to the RS Twin tube damper. These will add to your cost.The 993 fronts are well worth a look if your not wanting to refresh the whole suspension. Next up are the dual spring set up's that are made by various companies , these in general will improve the on road experience for reasons already explained in other posts. To the best of my knowledge KW are the only company (though this might have changed by now) to offer a suspension kit that is designed for the RS's Monoball top mounts . The other manufacturers expect you to buy their top mount, which is ok if yours are worn out.
I'm no chassis expert so can only describe my setup as i find it. The dual spring set up definately improves the on road experience, the car feels like it soaks up the bumps better whilst still retaining the stiffness and lack of roll of the original set up. it still retains the RS character if you like. It's also better under braking . The same applies on track . I don't notice that much difference on smooth tracks but on bumpy surfaces and more undulating tracks it's better than the standard set up. The difference is notable braking at paddock hill which has quite a bumpy section in the braking area.
Hope this helps.

 

[PhilRS]

Chris, no, the RSR set up is dual-spring and is specific to the RSR and I believe the 964 3.8 RS. KW and H&R also make dual spring suspensions.

Ian, if I was to use a 964 Cup on the track, I would keep the original suspensions, or change to a proper RSR set up if you have deep pockets. The difference is noticeable. I know that the H&R dual-spring can be made with different spring rates. In my view, the default "nurburgring" rate is too soft for a fast track with fast corners--such as Spa. You might also have problems with ride height. If I remember correctly, you will only be able to lower your CUP to its original height if the "helper" spring is in full compression, defeating the purpose. Hence the "4x4" appearance of some RSs on H&R dual-springs. At least, that's how it was 5 years ago. Things may have changed since then.

 

[Melv]

"GT1 did an exact Melvin Cup Car set up" -actually Des, when I heard this I seriously suggested they didn't and put it back to standard RS set-up. So I don't know what it ended up with......As ppl have pointed out, that's a pure track/slick set up on my car.....and on the road back in 2004, with a less extreme set up, it was a b1tch when it hit a bump mid corner......

However......I drove a pal's 993RS a few years ago and instantly felt at home......much more compliant suspension on bumpy Berkshire roads....I assume the same would occur if it was switched over to a '64 front end?? It was a pretty 'standard' mod over the years....

GT3's I drove also exhibited the same tendencies, on track or road, until you pushed on at XX leptons when the whole car just seemed to come together and grip............but at far too high a speed for road use!!![] I did find that a lot of ppl went for a more track focused set up on the GT3 but were not prepared to push it hard enough to get it to really work.

I suggest that one sticks with a book 964RS set up unless one is tracking the car and even then, learn to drive it standard before messing about with the settings.

From personal experience, I only started to alter the Cups settings once I ran slicks and could gauge from how the tyres were wearing as to where I needed to make alterations......................

Caio
Mel
-still in France....

 

[Tony]

Just to pick up on one of Laurence's points.
The uniball mounts can wear, and if worn will prevent you getting a good consistent setup . But the rebound issue will remain.

It's worth regularly checking for play in the top mounts. Last year mine seemed fine, this year after only a couple of thousand miles one was completely shot - on removal about 3mm vertical movement!

 

[carreraboy]

It was your road set up Melv I discussed with Craig and Peter and I remember when the car went back for another service they put it all to Factory on your suggestion, which they did and it still pitched and lurched the odd time on a B road .... but funnily on track it seemed to behave 100%, but thats because on a smooth surface it works well and that was factory settings.

Agree about the GT3 totally ..... gone but not forgotten....[]

 

[Steve Brookes]

As an outsider my view of the standard RS suspension is that it's near perfect. On the road it has that edge-iness that keeps you on your toes and warns you not to take liberties with it. A very good way of keeping your license on your way to and from the track. At the track it shows you that it is a thoroughbred. Taught, sure of foot yet adjustable in the corners.

My own C2's performance has been transformed by fitting KWs (V3 in my case) but when I get out of the passenger seat of an RS into my own driver's seat it feels soft in comparison. KWs are a real upgrade for a C2 but for an RS....I think not. []

 

[h_____]

ORIGINAL: ianmcg

This seems like a timely thread for me too...

I had the Clubsport at Brands with Sean Edwards a few weeks back and the executive summary was that even he was struggling with the front end. Coming out of clearways and turning into to paddock was a real problem. We concluded that the dampers are knackered or there is a problem with the spings especially left front - it's definitely not right compared to others he's driven and the geometry has been done so it's not that.

I'm sure I can get the standard suspension on there rebuilt etc but having put KW Clubsports on the GT3 I am seriously thinking about them for the CS. I know it's going to compromise the originality so vic will be cross with me, so I promise to box up in the originals in tissue paper so it's reversiable, but they aren't visible from outside and technology really has moved on. On the GT3 they are fantastic - for example braking from 150+ it was rock solid compared to scrabbling being all over the place before - even after a proper setup.

I see there are a few KW users around here but any reason I shouldn't or any better plan??? I use Jaz who were not that familiar with KW as he uses JRZ on the race stuff but I need to do something - I might be able to get a deal on the JRZ stuff but KW's will do the job.

Comments much appreciated...



Ian

Ian, I know you mention the geo is done, but has the car had ride height adjustment and been corner weighted. That is required for a fully "set-up" This can make an amazing difference, even if the geo is good.Personally I think it would be worth getting that done, prior to spending cash on replacing suspension (unless you know the suspension is worn). My N/GT was awful at Brands, and would understeer horribly out of clearways, but when put on the scales was a good 30kg out on cross wieghts. Also the front was on the lowest adjustment both sides, which looked cool, but didnt help the handling. Sorting all that out, has made the car much more neutral, and was cheap compared to fitting new parts.

 

[Laurence Gibbs]

Steve
Don't confuse the V3's made for the C2 to the ones made for the RS. The RS's character is made up from a lot more than the springs and dampers. A lot of work went into getting rid of the slack and stiffening the shell. The Monoball top mounts along with the harder bushes in the front control arms and the seam welding go a long way to giving the RS the feel it has.
Porsche themselves went to dual springs for the 3.8 RS, most testers of the time thought the car was better for it !

 

[Hacki]

ORIGINAL: h_____

Ian, I know you mention the geo is done, but has the car had ride height adjustment and been corner weighted?  That is required for a fully "set-up"  This can make an amazing difference, even if the geo is good.

Good point! Absolutely correct, it´s an essential part of the set up. The ride hight and the angle of the car to the road (is it called rake angle in Islandspeak?) is important.

Hacki

 

[carreraboy]

ORIGINAL: Laurence Gibbs

Steve
Don't confuse the V3's made for the C2 to the ones made for the RS. The RS's character is made up from a lot more than the springs and dampers. A lot of work went into getting rid of the slack and stiffening the shell. The Monoball top mounts along with the harder bushes in the front control arms and the seam welding go a long way to giving the RS the feel it has.
Porsche themselves went to dual springs for the 3.8 RS, most testers of the time thought the car was better for it !

Excellent reply L ... yes there is a lot more to the RS than cosmetics, indeed shell stiffness is a huge factor ... even more obvious in a Cup/NGT or indeed a full cage car .....

 

[Steve Brookes]

ORIGINAL: Laurence Gibbs

Steve
Don't confuse the V3's made for the C2 to the ones made for the RS. The RS's character is made up from a lot more than the springs and dampers. A lot of work went into getting rid of the slack and stiffening the shell. The Monoball top mounts along with the harder bushes in the front control arms and the seam welding go a long way to giving the RS the feel it has.
Porsche themselves went to dual springs for the 3.8 RS, most testers of the time thought the car was better for it !

Thanks Laurence. Indeed I'm not confusing V3s on my C2 (standard top mounts at the front, rear KW mounts as the KW coilovers won't fit the standard MY90 C2 mounts, hydraulic engine mounts rather than the RS's solid ones, standard ARBs, no shell strengthening, no roll cage, etc) with the RS set up. It clearly doesn't compare. Just saying that an RS in standard configuration is in my experience a hugely more capable machine on track. I just can't see that fitting KW to an RS (even if they are clubsport rather than V3) could make it perform any better. On bumpy roads maybe....but they aren't really made for that are they []

p.s. in case I didn't make it clear, I am a big fan of KW. Mine is a world of difference to a C2 on standard suspension and is easily the best upgrade I have done. I have no aims to make it an RSalike, just to make it as good as a C2 can be []

 

[h_____]

ORIGINAL: Hacki

ORIGINAL: h_____

Ian, I know you mention the geo is done, but has the car had ride height adjustment and been corner weighted? That is required for a fully "set-up" This can make an amazing difference, even if the geo is good.

Good point! Absolutely correct, it´s an essential part of the set up. The ride hight and the angle of the car to the road (is it called rake angle in Islandspeak?) is important.

Hacki

Indeed it is called Rake (angle front to back).

Wedge (diagonal cross weight) will also have inpact on handling, and again is easy to get way out with an adjustable car like the RS. Something else that was out on Minty.

 

[Ben Savill]

Rake is very important as has already been stated. On my 964 track car, we ended up raising the rear ride height and putting stiffer rear springs as it just had too much rear end grip. This was after running out of adjustment on the ARB's.

Admittedly the car had new struts and springs - Bilstein PSS10 - so after two hard days at Spa everything had settled / bedded in but increasing the "angle of attack" has certainly reduced the mid-corner to exit "push" that was being felt.

Having driven my 993 RS to Classic Le Mans a few weeks ago down country roads at speed, I find it difficult to imagine doing the same in a '64 RS and not having to be more aware of the road surface conditions, road space and vision available - I am strictly talking public roads here. I personally would be hard pressed to travel faster without taking more liberties but that shouldn't be the name of the game.

Maybe with the various changes in suspension design on both front and rear between the 64 and 93, it just isn't possible to achieve the same compliance and happy medium that exists on the 93 RS with a 64 RS. In my mind, there is no question that the 93 is more refined and so it should be.

Regardless of all this, everybody's driving style is different, so you just need to have the time and money to find a set up that works for you.

Interesting thread this Des ![]

ORIGINAL: h_____

ORIGINAL: Hacki

ORIGINAL: h_____

Ian, I know you mention the geo is done, but has the car had ride height adjustment and been corner weighted?  That is required for a fully "set-up"  This can make an amazing difference, even if the geo is good.

Good point! Absolutely correct, it´s an essential part of the set up. The ride hight and the angle of the car to the road (is it called rake angle in Islandspeak?) is important.

Hacki

Indeed it is called Rake (angle front to back).

Wedge (diagonal cross weight) will also have inpact on handling, and again is easy to get way out with an adjustable car like the RS.  Something else that was out on Minty.

 

[carreraboy]

Are you driving your Blue one Des or is this something new?


Yes something new, bought a M002 track focussed RS with some very nice mods and weighing 1150 kgs with a full Heigo. Has been well tracked but still very low kilometres which seem to match service book etc ...

Had a full Tech 9, engine, gearbox , LSD rebuild and suspension upgrades. Recent full respray, looks good, shut lines good with some "minor" accident repairs but not major according to Jim Wilkinson P3 so no Virgin! underneath very staright and no leaks .... some minor detailing inside still needed, going to be a carpet out and painted interior, can't do carpet anymore!

Just put it through my local Garage Porsche Specialist for a full mechanical shakedown and £500.00 squids later has the ABS fully working and a few little gremlins sorted.

Not tracked it yet, but as per this thread feels right on the button and does it go with the 993MAF ... bring it ON!

 

[RSGulp]

ORIGINAL: h_____

ORIGINAL: Hacki

ORIGINAL: h_____

Ian, I know you mention the geo is done, but has the car had ride height adjustment and been corner weighted?  That is required for a fully "set-up"  This can make an amazing difference, even if the geo is good.

Good point! Absolutely correct, it´s an essential part of the set up. The ride hight and the angle of the car to the road (is it called rake angle in Islandspeak?) is important.

Hacki

Indeed it is called Rake (angle front to back).

Wedge (diagonal cross weight) will also have inpact on handling, and again is easy to get way out with an adjustable car like the RS.  Something else that was out on Minty.

Who set Minty up for you, was it Centre Gravity?

 

[h_____]

yes, CoG. Chris is a real perfectonist - did a really good job. I had full ride height, corner weight and Geo. To be honest, as said above with a fully adjustable car like an RS, I dont see much point in getting a geo done in isolation (except is saves tyre wear I guess). The other aspects can make so much difference you need to know they are right.

CoG took about 10 hours to do the car, and was happy for me to be there for the duration. Took a few days, and a track session to really appreciate the difference.

 

[Hacki]

ORIGINAL: h_____

CoG took about 10 hours to do the car

That´s how long it takes to do a correct set up. Otherwise it´s not a complete job.

Then on a track day you can have more adjustments done - a little more or less ARB (front or rear), a little change of rake, if necessary. Go out and try, come in and change, finally it´s done!

Then the car will be as you like it, for your purpose. It´s worth the time and the money - way better invested than for installing extra parts. (Which would cause a full set up also!)

Rgds,

Hacki