random notes on 964/993 suspension

[perelet]

Originally Posted by Captain Ahab Jr

...... If anyone has either one out on a bench and wouldn't mind taking a few measurements for me please PM me and I'll send you a picture showing what to measure

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 ...

[perelet]

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.

[perelet]

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.

[perelet]

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.

[perelet]

Here's from my view

The ultimate 964 enthusiast front suspension setup

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 )
993 brake master cylinder
H&R sway bar
993 Bilstein PSS9/10 coilovers

WOW

I'll post details of conversion
Oleg.

[Vandit]

Originally Posted by perelet

Can somebody please weight stock 964 strut/spring assembly?

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.

[perelet]

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:

[perelet]

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.

[perelet]

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 .

[perelet]

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

Originally Posted by Captain Ahab Jr

just revisiting this informative thread and thought I'd share some pictures and ask some more questions

I've found some photos of the 964 and 993 front suspension side members and can spot a few differences

.....

Note the thicker webs and extra web at the forward front wishbone mounting point, also the wishbone mounting axis looks like it is positioned a little further outboard than the 964, does this easily give extra camber??

There is another 993 side member used on the RS and C4/TT but I have not found any photos so am assumming it is stiffer or has extra mounting holes for the front diff than the 993 C2 version

....

and this:

Originally Posted by Bill Verburg

the main difference between 993C2 and RS/C4 longitudinals is the mounts for the differing brake boosters

993C2 and C2S both have vacuum boosters mounted to the longitudinals as seend here
....

RS and C4 have electro-hydraulic units mounted in the trunk, that area is clear on those cars

....

If possible can you measure the A-arm(wishbone) o/s difference?

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.

[metalracer]

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

Thanks,
Marc

[perelet]

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.

[Bill Verburg]

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

[perelet]

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.

Originally Posted by Bill Verburg

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

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)

Oleg.

[perelet]

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

[Bill Verburg]

Originally Posted by perelet

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

[perelet]

Originally Posted by Bill Verburg

I'm not following you here
... and given that the difference between 964 and 993 longitudinals is 5mm/side

Where 5mm come from? Differece is 12.5mm.

Oleg.

[Bill Verburg]

Originally Posted by perelet

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

[perelet]

Originally Posted by Bill Verburg

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

[Bill Verburg]

Originally Posted by perelet

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.

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.