Friday 12th November 2010

Porsche 993 Buying Guide - Rolling Chassis

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Underneath the sleeker skin of the 993, the rear suspension employs an LSA (Light-Stable-Agile) multi-link system with hydraulic coil-over-shock absorbers and an anti-roll bar. Looking much like a double wishbone set-up, this arrangement finally put paid to the hoary stories of 911 lift-off oversteer. Porsche designed the rear suspension to be part of a sub-assembly, including the engine and gearbox, that could be more easily and quickly installed and removed.

Up front, MacPherson struts are used with gas pressure shock absorbers and anti-roll bar. A power-assisted rack and pinion steering set-up is used on all 993 models to give an 11.8m turning circle. A sport suspension option was available for Carrera models that offered firmer springs and dampers, and also came with a 10mm lower front ride height and sat 20mm lower at the back. The RS models have a front ride height 30mm lower than a standard Carrera’s and 40mm lower at the rear. Other than wear and tear, the 993’s suspension is tough and straightforward to service, though make sure there are signs of this being carried out in the logbook.

Search for Porsche 993 911s here

Although they shared the same suspension design, the standard Carrera and other 993 models had different brake sizes. All use a twin circuit system with Bosch ABS anti-lock brakes. The Carrera has 304mm front discs and 299 cross-drilled and vented rear discs, and both front and rear discs have a four calliper piston. For the Turbo, RS and GT2 models, the discs increased to 322mm and were cross-drilled. The Carrera 4S also shared the Turbo’s brake set up, easily spotted by the red-painted callipers in place of the usual black coloured callipers.

The brakes on a 993 are very powerful but need a longer push than some may be used to. The discs also need careful inspection as they can pit and score on the hidden rear surface, which means a new set of discs.

Cup Design 93 five-spoke alloy wheels were the standard fitment for the Carrera 2 at its launch with 205/55 front and 245/55 rear tyres. These 7x16 front and 9x16 rear wheels were more usually upgraded by their first owners when ordering the car to the optional 17in Cup style of wheel. Only the RS came with 18in alloys in the early days of the 993, while the Targa was the first to be offered with 17in wheels as standard.

The Turbo also came with 18in alloys as standard in 8in front and 10in rear sizes, though these wheels were only and option for the Carrera 4S.

Buying Guide Index:

Porsche 993 - Introduction
Porsche 993 - Powertrain
Porsche 993 - Rolling Chassis (viewing now)
Porsche 993 - Body
Porsche 993 - Interior
Porsche 993 - General Experiences
Porsche 993 - Insurance (Sponsored link)

Search for Porsche 993 911s here

[RRG]

My experience is limited to the RS but agree that the whole system is extremely tough and there aren't even really any bushes to wear on an RS either - the whole suspension is rose-jointed. I've found dampers extremely hard wearing, while ride quality is much better than you might imagine - certainly a way better compromise than the rock-hard 964RS. This car is enjoyable on the road and hugely competent on the track.

The RS is probably one of the best braked road cars ever made. It uses the brakes designed for the Turbo but weighs 250kg less and has 100 fewer bhp. The net result is brakes that are near impossible to fade, even on a track, and pads/discs that last surprisingly well. A car that has had frequent disc/pad changes has been driven EXTREMELY hard. I disagree with the above comment that the brakes need a bit of a shove. Braking feel and response is as good as anything I've driven.

If you like the 911 weight distribution and handling characteristics, then the car is hard to fault from a chassis perspective.

My only gripe relates to the RS wheels. Made by Speedline, the outer rim is polished and lacquered from new but corrodes rapidly around the bolt heads. Keeping these wheels looking cosmetically sharp is difficult. I tried having them just polished (no lacquer) and quickly got bored using the Autosol to get them shiny. Next I tried getting them anodised. They looked good but the finish quickly went milky - probably due to some aggressive cleaning fluid used in error. Now I'm trying getting them powder coated and lacquered. Apparently this is the ultimate solution! We'll see...

[Orangecurry]

AFAIK the standard calipers are black on the C2 but silver on the C4.

You've got a typo on the rear tyres - 245/45/16

The rear suspension was lifted from the 989.

Edited by Orangecurry on Friday 12th November 21:39

[bergmeister]

you are no doubt a great fan of the 993rs,as am i.
The rs is not rose jointed through out,only the top mounts of the dampers,the joints do wear and perish.The brakes also fade,and front discs warp when pushed hard.Saying that the brakes are good and very well balanced for the car.
The rear suspension works well,but lost a bit of feel compared to the 964, the diff set up correctly had more effect on controlling lift off steering etc.
The suspension was unique at the time for the rs and Gt2,and very different to a standard 993 or other models.
Enjoy the car.

[BrewsterBear]

Regarding the dampers on 993s they are Monroe items as standard. Unfortunately they are well past their best after 40,000 miles. Many people replace with Bilstein units, but there are a plethora of others available depending on what you want the car to do and your budget. It's something to bear in mind and budget for if you're considering a 993, even a low mileage one.

[jackal]

RRG said:

My experience is limited to the RS but agree that the whole system is extremely tough and there aren't even really any bushes to wear on an RS either - the whole suspension is rose-jointed. I've found dampers extremely hard wearing, while ride quality is much better than you might imagine - certainly a way better compromise than the rock-hard 964RS. This car is enjoyable on the road and hugely competent on the track.

The RS is probably one of the best braked road cars ever made. It uses the brakes designed for the Turbo but weighs 250kg less and has 100 fewer bhp. The net result is brakes that are near impossible to fade, even on a track, and pads/discs that last surprisingly well. A car that has had frequent disc/pad changes has been driven EXTREMELY hard. I disagree with the above comment that the brakes need a bit of a shove. Braking feel and response is as good as anything I've driven.

If you like the 911 weight distribution and handling characteristics, then the car is hard to fault from a chassis perspective.

My only gripe relates to the RS wheels. Made by Speedline, the outer rim is polished and lacquered from new but corrodes rapidly around the bolt heads. Keeping these wheels looking cosmetically sharp is difficult. I tried having them just polished (no lacquer) and quickly got bored using the Autosol to get them shiny. Next I tried getting them anodised. They looked good but the finish quickly went milky - probably due to some aggressive cleaning fluid used in error. Now I'm trying getting them powder coated and lacquered. Apparently this is the ultimate solution! We'll see...

RRG, all the bushes seem to wear in my experience .... RS or anything else. Particularly the forward A arms and the top mounts although I appreciate that the RS runs monoballs.

Have yuo consdidered getting stainless outers for your speedlines ? That's the way some RS owners have gone with significant success ?

[jackal]

bergmeister said:

The rear suspension works well,but lost a bit of feel compared to the 964,

Harder rear side section bushes help with this ... (although I have not done it yet).

Going from 964 to 993 Porsche added in a load of comfort NVH measures. One of these was to dangle the whole rear suspension cage on 4 marshmellows.

[RRG]

Jackal
"I know nothing" (as Manuel would say) about the stainless rims for Speedlines - please tell me more: who makes them, what they cost etc
thanks
RRG

[jackal]

RRG said:

Jackal
"I know nothing" (as Manuel would say) about the stainless rims for Speedlines - please tell me more: who makes them, what they cost etc
thanks
RRG

RRG, speak to Steve Kings (mail me for his email address). The stainless rims come from Germany and then you have to have the wheel rebuilt using the stainless rim. Adrian Rowlands in manchester will be able to do that for you.

[silver7]

There are various solutions to the outer rims, anodising is one which gives a slightly more dull finish (bright anodising)but is maintenance free. Another is stainless outers which can be sourced from titanium touch in Germany. I sourced these for myself and Steve and they are very good, as they are slightly thinner they do sit a little lower on the face (2mm) so you do see the casting mark. This is only just visible though. They are shiny though which is not OE look.

Adrian is very good for wheel refurbs, recommended! Hope this helps.

Edited by silver7 on Friday 19th November 09:08

[swissblue]

refurbished speedlines with stainless steel rims

[jackal]

any ideas on total cost of 4 stainless rims + postage from germany and then Adrian to fit onto the centres and etch on the logos ?

[silver7]

Jackal, the outers are approx 650 euros for 4 plus german vat. You can also have 6 point stainless bolts in stainless. As far as adrians costs go you will have to ask him, his etching is very good. You could fit them yourself though, they are quite easy, I have done a few myself.

[jackal]

thanks, i have a few years to go before mine will need doing but worth knowing for when that time comes

[swissblue]

December 2009 prices were 146.30 euro each, transport costs 39.00 euro, you can avoid paying the german 19% vat by supplying a uk company vat number, the M7 x 35 6 point bolts are 0.99 euro each, you can re use your original nuts, Adrian did all the dismantling & spraying & etching etc, his cell phone is 07831 572087, he does a first class job, email [e-mail]

[jackal]

thanks, my rims came from adrian so I have all his details