apw964

Folks,

I posted a question recently on the best options available to me for lowering my car (primarily for aesthetic reasons).

Adrian you mentioned in your response that options were limited on that year of car. I meant to follow up ? Could you eleborate on that statement please ? Is there really anything significantly different between a 1990 car and 1991 ?

Thanks everyone - Andy

Bill Gregory

Andy,

Around that time (between 1990 and 1991), Porsche changed the geometry of the rear suspension. So now you're talking a much smaller potential market for 1990 and earlier suspension upgrades. I can send you a scan from the factory manual showing the differences just in the rear strut, if you want. It would be interesting, though to see what they did for the 1990 Carrera Cup cars. Maybe there are some parts you could steal from them?

SonnyV

Without doing a lot of research, I see a lot of lowering springs offer in catalog such as: Performance Products, Tweeks.

There are at least the H&R, and Eibach springs to just lower the car for looks and possibly some improve handling.

Is there something I am missing here.

Sonny Vo

Jack667

I have a 1990 C4 and I'm very happy with my H&R Coil-Overs ($1850). I just upgraded to adjustable sway-bars and I'm very pleased with my ability to dial in/out oversteer on my C4. Many have stated that the excessive understeer in this model feels like a FWD car, and mine used to be in that group. Not anymore!
Jack http://people.ne.mediaone.net/jbalthasar

Adrian

There are significant differences between a 1990 C4 and a post Oct 1990 build date C4.
I am not going to list them all here for many reasons. The entire rear suspension was changed from size, mounting angles and mounting methods. Not all of this is clear from the parts catalogue either.
There were less significant changes on the front but there were some. Steering stops and the like.
You HAVE to be VERY careful when reading the catalogues. I have managed to save a few people from wasting money but not all. If you purchase any kit or any part, be 100% sure that it will suit your model year. The sales people will tell you, it fits ALL. This is not TRUE.
The catalogues here in Europe clearly identify the kits and parts for pre Nov 1990 and Post Oct 1990 model years. This is very serious from a financial perspective. I know of one person who installed a full Koni kit advertised in the catalogues. He found that he could not install the rear shocks at all. Tried the springs and found his 964s rear end sitting 1.5 inches higher than before.
You cannot install the Porsche option kit M030 on the pre Nov 1990 964s either.
To the best of my knowledge there were no 1990 model Carrera Cups manufactured. 1991 was the first model year for the Cup and I know 100% that these had the same suspension set up as the post Oct 1990 standard models,
Ciao,
Adrian
911C4

Anatol

Hello Adrian,
I remembered vaguely and have now checked:

I have a track test of a 964 Cup in Sport Auto April 1990! The car had 265 hp, some 1130 kg and cost DM 123.000 (incl. second set of wheels). So there seem to be model year 1990 Cup cars around, too!

The car gave some interesting performance:

0-100 km/h in 4.8 sec and 280 km/h top speed. Around Hockenheim in under 1' 14"!

Hope this helps!

Anatol
1991 C2

Adrian

Dear Anatol,
There were no VINs allocated to Carrera Cups in the 1990 model year (that I am aware of).
I have one of the first road tests of the C4 from September 1988. The first C4s were not produced until Jan/Feb 1989. I have similar reports for Turbo 3.6 and 968CS long before they were aloocated VINs and released for public sale. I have every VIN range issued for the 964 series and no Carrera Cups in 1990 model year. Calendar year is different,
Ciao,
Adrian
911C4

phil@tech9

Adrian,

Here is a chassis number for your records, it is the earliest 964 C4 that I have seen.

WPOZZZ96ZKS400089

I know that Porsche only allocate the production numbers 00061 to 05000 for the '89 model year, so I would think that this is one of the first.

Adrian

Dear Phil,
Yep that is an early one. They built just over 3000 ROW and USA versions of the 1989 C4. I have 1786. They made some changes from the really early ones as well, around March 89 but exactly what they were I have not been able to find out. All I know was that they were quite substantial. The majority of 89 C4 owners in the rennlist system seem to own later build models.
Ciao,
Adrian
911C4

phil@tech9

Adrian,

I am racking my brains to try and remember what the differences were. The last time we had the car in was January 01, we gave it a full engine rebuild, as she was a little tired.

The car is due back next month, so when it's in, I'll run through the major differences

Adrian

I look forward to seeing the list of differences. I can then run them by my shadow who can confirm all for me. I know the DME was one change. I think there was an PDAS/ABS control unit upgrade as well.
Ciao and thanks,
Adrian
911C4

GeoffD

I have an 89 C4, number WPOABO96XKS450459. I'm not sure if it is an early (number 459) or late (number 50459) but it was built in March 89. It has suspension upgrades, yellow adjustable Koni's and Eibachs all around. It is significantly lower than stock but not unreasonably so and works very well on the track while not being too stiff for the street. It is an everyday driver. I could try to find part numbers on the springs and shocks if it would help you. I've never checked the anti-roll bars so I don't know if they are stock or not.

Judging from the way the car is set up, it appears that the previous owner who did the mods was following the recommendations of the "Wringing Out the C4" series of articles from Excellence magazine.

Adrian

Dear Geoff,
456 is an early one. In the first 25% or so built. I would be interested to know the DME part number you have installed.
I have the similar suspension set up. I suspect you will be at RS or submariner ride height rather than the standard astronaut ride heights. Mine is set up to 964 RS specs,
Ciao,
Adrian
911C4