Sometimes, I buy used parts on ebay, just to do measurements, comparisons. There quite few 993 hubs on ebay in $130 price range, maybe worth time waiting ...

993 RS top mounts
 

This note is about 993 RS top mono-ball mounts/camber plates. This topic is well covered by 993 owners (see links below), but they also fit 964 with PSS9/10.

Factory part differ from most aftermarket units:
1. Dust control. Porsche parts are sealed from both top and bottom and also between plates. Dust/sand really hurts open ball joints, using open balljoints on the street or on autocross parking lots wears them off very quick. Most DE tracks are not clean either.

2. Street/track setting - it's not unusual to drive 100miles to and from driving events. Trip will wear inner tire very quick with 2+ degree camber. Factory units can be switched from street to track configuration in 5mins per side - 3 bolts.

3. Factory units cost only $200 more compared to most of aftermarket parts.

4. Here's not good one - you need special top mount nuts described by ToSi (Tom) on rennlist in this thread. Otherwise failure described by Richard on his website in this post will happen. Richard eliminated spacer #18 - turned to be bad idea.


Here are some pics with details.

Parts needed (also described in 993 links above)


part #'s


ToSi nuts (I bought them from him, there was discussion on rennlist to do batch), dimensions see his thread.



Factory street/track settings description:



And illustration:


Top sealing nut (all aftermarket have hole in it to get dirt/sand inside:)



Inter-plate hard rubber seal:


Lower strut seal (rennline started to use similar seal, but most of other aftermarket plates have open ball joint)





Also, strut brace is highly recommended with hard ball joint. Stock rubber mounts have enough rubber to flex and not transfer load to chassis, so I do not see need for strut brace and rubber mounts. There was nice post on miata forums where somebody calculated all loads. Also, I think with autocross tires strut brace is probably enough. Full blown race slicks may stress chassis more and extra welds on chassis is probably good idea - factory did that on RS

Oleg.

Ok, new update here. here we go.

Weights

993 front rotor weight - 8.265kg



964 front rotor weight - 6.920kg



993 front caliper weight - 3.354kg



964 front caliper weight - 2.870




964 upright with bearing, abs gear and big bolt/nut - 7.915kg



993 RS upright with bearing, abs gear and big bolt/nut - 6.555kg




964 front strut upper mount/bearing - 1.215kg



993RS front strut upper mount/bearing - 0.900kg



run out of images per post limit - see next ....

Oleg.

PSS9 front strut (only) - 4.145kg



PSS9 front main and helper springs - 1.320kg



PSS9 assembly + 993RS top mount - 6.75kg




More to come.

Can somebody please weight stock 964 strut/spring assembly?

Thanks!
Oleg.

Here's from my view

SmileWavyThe ultimate 964 enthusiast front suspension setupSmileWavy

Suspension that factory never put in 964 (even factory RS lacks some goodies). Built with mostly factory parts. One may have "faster" race setup, but for enthusiast and semi street car this is pretty good.







964 cross member
993 longitudinals NOT 964 longitudinals - see Jan 12 post
993 control arms
993RS uprights
993RS tie rods
993RS upper mounts/camber plates
993 brake calipers/rotors (or big reds/big rotors are bolt on this stage, too heavy IMHO)
993 wheel hubs, hybrid ABS gear (see posts above).
993 brake booster (... some know this may get replaced with hydraulic booster :p)
993 brake master cylinder
H&R sway bar
993 Bilstein PSS9/10 coilovers

WOW:D

I'll post details of conversion
Oleg.

My likely inaccurate, and not precise, analog home scale puts the front strut/spring assembly w/ OEM top mount between 16-18lbs and the rear shock/spring assembly w/ OEM top mount between 13-14 lbs.

converting 964 to 993 brake master cylinder/booster

Here are few notes on 993 master cylinder/booster fitting.

You need to use 993 mounting bracket, here's difference:





I heard that some people had problems with sway bar clearance. I had no issues with H&R bar - plenty of clearance:



Here's 964 plumbing for MC/booster:



993 MC uses 12mm thread. There are few of ways dealing with it. I tried BMW brake lines and had trouble fitting them - too short.

I ended up getting 12 to 10mm adapters from Autozone. They require flare fitting instead of bubble which is used on Porsche. I bought 2 bubble end lines and one flare end line. Cut bubble end lines to fit and reused flare end nuts ....










here's result:

993 vs 964 ball joints

Now and then it was discussed here and on rennlist of 964 ball joints can be used with 993 uprights (RS or regular). Cone section will fit opening, but cone geometry does not match and also length is different. At end of the day - use 993 ball joints.

993 ABS sensors and strut mounts




Also when converting to 993 uprights ABS sensors from early 993 (p/n 993-606-404-00) should be used - they have different orientation from 964.




Also bolts #3 & #5 parts from 993 need to be used. 964 parts will not fit.
#3 (p/n 999-072-006-01) M14 on 993 and M10 on 965
#5 (p/n 999-067-039-09) M12 on both but pitch is different .

Alignment

Well after I put that all together. I started to align. I run 12' per side - stock toe. Toe barely aligned - to get to stock toe I had to remove steering stops and even after that - this is how much thread was left:



Also my camber maxed out at 1deg negative - no good.

Now returning back to this discussion back from Feb 2013

and this:

I remeasured 993 and 964 A arms and geometry is pretty much same.

Ordered and got 993 longitudinals. WOW - that is the most 993 unique piece of 993 front suspension! Looks like porsche engineering did some serious work here ...




So 993 longitudinals push control arms out about 10mm per side - that explains official difference in front track between 2 cars!

Here's pic of another side:


Weights




After installation of new longitudinals I had to move stops on swaybar - again about 10mm outside:




After this change - plenty of thread for alignment and steering stops in place:



at stock toe:


I got about 2.5 camber at 964 RS height with plates maxed out. Still not huge. One thing that makes me think - on 964 upper mounts are close to each other - this gives extra room for camber. Camber plates were designed for widebody 993 which made me think that installing RS camber plates on narrow body 993 is probably not best solution ....

So on 964 993 longitudinals is way to go. Also on 964, because upper mounts are "narrower" you get extra camber.

Oleg.

Hi Oleg - Thanks for sharing so much good info! What bushes are you running?

Thanks,
Marc

Marc, I use Chris Warlod poly bushes:

964 / 993 Control Arm Bushings - Rennlist Discussion Forums

993 people are happy with them, Jeff from Rothsport suggested them also.

Probably ideal will be to have rubber (stock or Elefant) in back - rubber does absorb vibration, saves stress from chasis and steering rack. As for fronts - poly should be much better than rubber, see my other post on front rubber flex that causes toe out under braking.

PS I also ordered poly bushes for steering rack, but did not used them - fit was not good and I do not want to put extra stress on fragile looking steering rack mounting brackets. i did used 993 steering rack brace - it is on pics.
Oleg.

so w/ the 993 longitudinals did you find any more tire interference at the lips?

as to the bushings
in front you have 3 options, in order track oriented to street oriented
uni-balls hopefully w/ seals -no play and on stiction and no maintenance but they will wear out quicker than most others

p/u w/ no give and must be kept lubricated at all times or wear and noise will be accelerated

sport(stiffer) rubber in the leading and trailing positions, this is a wonderful compromise

sport rubber in the trailing regular in the leading, this is what was used on RS

regular rubber in both leading and trailing position, this is what all the regular cars have

Had few hours after work. With 993 longitudinals camber maxes out at 3deg at RS+5mm height. That's more than enough even for full blown race setup. So, one can have 1deg in "street" single hole setting and adjustable 2.30-50 in slotted holes for weekend events.


I have Fuchs 17j7 et55 front whels and kuhmo ecsta xs 215x45x17 tires. Lots of clearance at RS height.

After all, according to official specs track increased 25mm or 12.5mm per side. Think about it as having 1/2in wheel spacers (very expensive:D)

Oleg.

One more note on narrow vs wide body front suspension:

distance between longitudinals mounting points on cross member is 30mm:



this is wider than 12.5mm by using 993 longitudinals in inner holes. Available front configurations:

964 longitudinals in inner holes - 0mm (stock track width)
993 longitudinals in inner holes - +12.5 mm (on each side)
964 longitudinals in outer holes - +30mm (on each side)
993 longitudinals in outer holes - +42.5 mm (on each side), that must be sick wide, RWB should use that:)

I'm not following you here
the alternate holes in the chassis are 30mm outboard on each side and given that the difference between 964 and 993 longitudinals is 5mm/side
964 longitudinals in inner holes - 0mm (stock track width)
993 longitudinals in inner holes - +5mm mm (on each side)
964 longitudinals in outer holes - +30mm (on each side)
993 longitudinals in outer holes - +35 mm (on each side)

as I noted earlier in this thread some 993Cups used the 964 long. in the outer mounts on a n/b w/ the same wheels as w/ 993 long. in the inner mounts

the cars that used the outer mounts were the 964 3.8RS, 993RSR and 993GT2 evo
all of these used 9 to 11" front wheels

Where 5mm come from? Differece is 12.5mm.

Oleg.

according to this the suspension difference is 5mm, No? The difference on the backside is irrelevant to the suspension

Oh, boy, I was not clear enough. Bill, if you look at red curved arrows and also at crossmember (steering rack side) mount you'll see whole longnitudal is pushed out and brake booster mounts are extended inwards. A arm mounts are extended about 5mm, but total is 12.5mm. You can easily derive 12.5 from track width difference between 964 and 993 also:).

Here's repost of reverse side

Ah ok now I see, thanks for the correction

I was going to ask for the measurement from the chassis mounting hole axis to the suspension mounting hole axis but it appears that you did that and that is where the 12.5mm # comes from.

Thanks for taking the time to do this, it's something that has bothered me for years.

Just for completeness sake I checked the factory specs for front track w/ the same 7ET55 & 205/50 x17 setup
964 1374mm
993 1405 mm

difference 15.5mm per side, all of which appears to be in the longitudinals

and the mounting holes are 30mm apart

That's about what I got (counting difficulties to measure from mounting hole to center of a-arm hole) .

Also 993 rotors space wheel a bit wider. I found out that Fuchs wheels can not clear 993 caliper without rotor mounted (scared the @#$%^ out of me when I tried wheels on the bare hub before I realized:)

Next time I get around I'll measure outer rotor wall thickness for 993 and 964 rotors.
Oleg.

that I know if you use 964 or 928 rotors you use 964t or 964RS wheel carriers or 964 wheel carriers w/ their correct o/s build into the caliper adapters

W/ 993 rotors you use 993 wheel carriers or w/ 964 wheel carriers a caliper adapter w/ their o/s

here's the difference between a 964 322 and a 993 322

Got around to look at rotors. Wall thickness is same, 993 hat is about 10mm shorter.






So looks like longitudinals are major contributor to track change. I may measure uprights...

Also, I can not find 964 RS track width spec anywhere, Bill do you have any reference for it?

Thanks!
Oleg.

That looks to ba a 964 28x298 rotor on the right, What rotor is on the left?


When comparing 964RS/t 322x32 to 993 322x32 I think that the height difference was ~5mm

964RS came w/ 7.5x17ET55 & 9x17ET55 wheels 205/50 & 255/40 tires, factory spec for track is 1379/1380mm

964 base wheels were 6ET52 & 7ET55 wheels 205/55 & 225/50 x16 tires, factory spec track is 1380/1374mm

964 option was 7ET55 & 9ET55 wheels, 205/50 & 255/40 x17 tires, factory spec track is 1374/1374mm

993 base 7ET55 & 9ET70 wheels 205/55 & 245/45 x16 tires, factory spec track is 1405/1444mm

993 option was 7ET55 & 9ET70 wheels, 205/50 & 255/40 x17 tires, factory spec track is 1405/1474mm, rear also used 9x17ET55, I believe that the 9ET70 used a spacer but I've never seen those wheels so don't know for sure the spec is for the 9ET55 wheel

993RS was 8ET52 & 10ET65 wheels 225/40 & 265/35 x18 tires, 1413/1452mm

It's 993 stock rotot, I labeled pics.

One thing that I want to understand - why factory rolled fenders on RS? It did used 964 turbo wheel carriers and unique upper strut mounts but other suspension pieces were practically 964 parts mounted in NB configuration.

Before switching to this new suspension, I had my car with stock 964 parts & 7.5et55 front wheels at much lower than RS setting and never had problems with lips ... I had bump steer and tire rubbing inner fender issues, but no lips issues.

PS. After move to CA all my books and old reference mags/docs are still boxed up..

Ops I missed the labels

My guess is that they were prepping the cars to almost Cup specs, as they also flattened the oil line. These are both steps that allow the use of 8 & 9.5" wheels on the Cups

Great thread! Thanks for all the info.

Does anyone know the difference between the regular (99334101700) wishbones and the Carrera RS wishbones(99334101780) ?
Tks P

I just noticed Bill has the optional Cup I's for the 964 narrow body as 7 & 9's. All the info I have shows the RSA wheels as the option wheels which would be 7 ET 55 & 8's ET 52. The 7 & 9's were standard on the turbo.

If anyone has info on the track of the 3.8RS 964 I would be interested.

You are correct the normal 964 C2 wheel was the 6ET52.3 x16 w/ 205/55 tire and 8ET52.3or ET52 w/225/50 x16 tire
option was the Cup 1 7ET55 x17 w/ 205/50 tires and 8ET52 x17 w/ 255/40 tire, this was used w/ M1(steering stop) and M2(bumper edge) mods

RSA used the same 17s as above

964 RS used 7.5ET55 w/205/55 x17 tires and 9ET55 w/255/40 x17 tires

964Cup used 8ET52 w/ 235/40 x17 tiresa and 9.5ET47 w/ 275/40 x17 tires

for '93 this was changed to 18 w/ the same ET not sure what tires

3.8RS street used 9ET48 and 11 ET5 wheels, I'd need to dig some to find the tire specs

Nice suspension setup in this thread!!!!very informative.

Few updates to this thread.

Here’s list of some Porsche wheel studs, diameter 14.70mm

40mm 901 341 671 01 Standard 964
45mm 904 341 671 00 Standard 994 < 94
45mm 993 331 671 01
50mm 928 341 671 01 Standard 928, Standard 993 > 94
50mm 928 341 671 02 Standard 928, Standard 964 Turbo
52mm 901 331 671 00
65mm 911 331 671 00
72mm 901 331 671 01 For S rear with 21mm spacer


Here are common Porsche wheel studs. I have (new) Fuchs wheels and use 12mm spacers at rear. Standard 964 or 993 studs have not enough thread:




I ended up ordering set of 65mm 911 331 671 00 studs that have best fit:





To remove studs, do not use hammer, press them out. To press in 65mm studs hand brakes needs to be partially disassembled:





Car with spacers (needs wash:)

My rubber rear spring booths been cracked:



They are reasonably easy to remove:













At this moment one can install Elephant racing bushings.

I ordered 935 style plates. They look like they may provide independent toe and camber alignment (I was wrong - see later)



They also turned to be thinner than stock, so Weissach effect is probably a bit increased, but also they have welded in bolt section which should make them a bit less flexible.

I'm not sure if they decrease or increase Weissach effect (no matter what advertisements say)





Need also rubber rod ends, otherwise ball joint won't last long:


Need also rubber rod ends, otherwise ball bearing won't last long. Putting them on is ROYAL PITA :o, REALLY:



Now, there's widely discussed topic on what side to put slotted hole. 1st time I put it down. I had hard time getting rear toe to 0, it was always way in. After I flipped them and put slotted hole on top I was able to get toe right and had up to about 3.5 deg freedom in camber.

Note. Adjusting toe screw WILL change your camber, so alignment takes about as long as regular 964 plates.


Putting rear suspension in the car without engine is real pleasure!

Yes, with the slotted hole at the bottom I maxed out at -1.2 rear camber. When I put the slotted hole at the top I could get up to -3.0 rear camber. I set it at -2.0 when aligned.

Regarding Weissach effect, I believe that comes from the rubber in the OE spring plate bushing. The 935-style with the monoball and no rubber will not deflect under braking because no rubber components, so Weissach effect is eliminated.

The rear axle feels much more stable and predictable, especially when over the limit and over the limit in transitions, than with the old OE spring plates. It's a great upgrade.

I think Weissach effect is combination of flexible spring plate and "sliding" bushing. Here's page from Paul Frere book



On RS they used special spring plates (somebody can measure them please?) and modified bushing, here's page from RS broshure:





I yet to sort this car out one more time:)

Wow....! I hadn't run across this thread before, the compilation of info is amazing. Cheers

Is the metal of the spring plate really designed to flex?

The Weissach-effect is suppose to add toe-in under braking.

Let's assume the spring plate member is supposed to flex. Any flexing of the metal of the spring plate wouldn't add toe-in because that member is never longer than when it is perfectly straight. And flexing would shorten the length of the member and reduce toe-in.


The RS-spec bushing is the outer bushing in the cast trailing arm. This RS arm (Porsche never sold the bushing by itself) is NLA and that's why Ninemeister worked with Powerflex to engineer their poly bushing kit for the rear trailing arm to mimic the stiffness of the RS piece.

Yes, they are called spring plates for reason :) Took me awhile to understand that until I installed rear arm and bolted spring plates very loose. You can push arm on front or side and see toe in.

Here's description from same book:



and here's enlarged piece of previous page with comments



I think as time went by that design turned to be less liked by enthusiasts. But I think 964 fans are lucky to be spared from 993 rear which has it's own problems that are not easy to deal with.

I agree, full solution will be to redo bushings, there are few models available. Well - leave me topics to cover here in this thread:)