horst

I can attest to the effectiveness of the 21mm bar. It is without qualification the single most useful change I have made. Your challenge is to find one. The only cars that had em were the 91 (I believe) C-2's. Find a used one and you will need new bushes. The bar doesn't wear out, so as long as the donor car hasn't been in a horrendous wreck, it should be fine.

Adrian

Dear Piers,
I do not see any point in updating the front sway bar unless you are going racing. The rear is important because excessive understeer on the road can cause problems, like head on collisions with tractors. Something I am familiar with. In a 944 by the way.
All USA owners should know that the alignment specs were changed for US versions only in 1994.
Off the top of my head I can only remember that caster was changed. There is a TSB for this. ROW owners please do not use these figures. Stick to the old ones. Caster changes were made earlier to ROW versions. 1992 I think. Horst is correct. 1990 C2s are the only supplier of fixed 21mm rear sway bars. Hard to find but worth it. Do not forget to replace the rubber mounts with new ones. Strut braces are easy to fit. The FVD (Porsche) versions fits nicely under the carpet.
Ciao,
Adrian
911C4

Roygarth

OK thanks everyone for your input, but before I make an expensive mistake, let's confirm what I am going to do!

1) I buy a strut brace from <a href="http://www.powermarques.co.uk" target="_blank">www.powermarques.co.uk</a> having first confirmed with them that it will fit.

2) I buy a 'used/2nd hand' 21mm fixed rear sway bar from a standard (not MO30 optioned) 1990 C2, and buy new rubber mounts. Does anyone know of a source for this? UK based preferably but European OK.

Thanks in advance!

Piers
1990 C4 Coupe

Bill Gregory

[quote]<strong>All USA owners should know that the alignment specs were changed for US versions only in 1994.</strong><hr></blockquote>

The factory manual shows that in MY1992, caster was changed from 4 degree 25' +/- 15' to 4 degree 25' +15' -30' and is applicable to earlier models. In 1994, rear settings were changed for toe-in and camber where the values were changed from toe +15' +/- 5' and camber -20' +/- 10' to toe +10 +/- 5 and camber -40' +/- 10. The factory manual notes that these values are applicable retroactively to all C2/4's from the start of production. Note the factory manual does not specify these changes as US only.

Adrian

No Bill but the Technical Service Bulletin does and there are some differences. Very important if you own a Turbo 3.6. One other important point is the revision status of the manual being used. Many people have the manuals but do not have the revision service. This is why I always refer to the TSB 49311 issued Sep 1993.
Ciao,
Adrian
911C4

PS: There are quite some significant differences between the German language manual and the English language manual as well.

Bill Gregory

Adrian,

I'm convinced that during the early 90's, Porsche used the factory documentation to make inroads on expense reduction. Such differences between the various publications from the same company! And some is just shabby in it's absence of information (thinking the HVAC section of the factory manuals, for example).

Bill Wagner

Maybe this is a dumb question, but WHY is it so difficult to get a 21mm rear swaybar? If I owned a '91 C2 I would think that Porsche would provide a direct replacement for it. Is this now an updated part of lesser diameter???


<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Cheers,

Bill Wagner

Adrian

Dear Bills,
I will answer Bill Gs comments first. Totally agree. The owners manual is another area of difference. The german version is 111 pages the US version 131. Huge amounts of "liability based explanations".
To Bill W. I cannot understand why in the USA it is so hard to obtain a 1990 C2 21mm sway bar. I had no problem here and it came from the factory. I do not understand why you cannot order a part number from a Porsche dealership and they cannot deliver.
This is the part number.
964 333 701 07 21mm 1990 Carrera 2
Ciao,
Adrian
911C4

puma1824

Bringing back a post from the past...

So here's my question, if I were to switch from 205-50-17 to 225-40-17 would the tire rub? Furthermore, looking from the side would the tires look taller, shorter, or the same? I'd prefer it not to look any taller than it already does. Pics anyone?

I have H&R Sport springs, Bilstein shocks, 21mm OEM Porsche rear sway, Schnell front upper strut bar, 17 OEM Cup 1s.

Thanks,
Puma

964rh

Puma

I've fitted 225/45/17 on my 1990 964 C4 at the front and 245/40/17 at the back.

If you were to switch from 50 ratio to 40 ratio the tyres will look shorter (from wheel rim to top of tyre) but this may have an adverse effect on your abs. The closest ratio I could get in the uk was 45's. Bear in mind your looking to increase the contact surface of tyre to road, not the ratio.
My 225's are installed with 5mm spacers and I don't suffer from any wheel rub. Recently on a sprint day (the first day the car was driven in anger with the 225's) it was the best the car has performed ever. Hardly any understeer apart from when the driver (me!!!) was driving way beyond his abilities. Felt like the car had far larger ***** than me and could take whatever.

I have virtually the same set up as you apat from the sway bars. I can mail you some pix at the weekend if I get the car from the shop.

Rob

Pesty

Recently fitted a 21mm rear sway bar and Polyuri whatsit bushes. It does seem to have made turn in more possitive. the rear end also seems more composed.

relitivly cheap mod. worth doing I recon