the flyin' scotsman

The title is the question.............what was the stock suspension set up?

Was it the same as the S4 unless customer specified sport suspension?

The car has the blue/grey shocks which are assumed to be Boge.

Marine Blue

Standard shocks are Boge, Sport Bilsteins were optional.

Rob Edwards

If they're gray and original and there's no '474' on the options decal, then they're the stock suspension for that car.

See https://rennlist.com/forums/928-foru...unt-on-it.html

the flyin' scotsman

There's no decal and they're not red..............so even though its a GT the 'sports' suspension was still optional?

Marine Blue

yup

My GT also has the standard Boge shocks.

worf928

Weren't the GT springs different though?

Hmmm... PET only shows 2 springs. One is M637 (Clubsport)

the flyin' scotsman

I was going to ask the same question Dave. Option 474 is shocks only?

Rob Edwards

Dunno whether there was a 'special' spring for the 474 optioned GT, but the 3 brown marks were the highest spring rate in the three tolerance groups. Lots of info on spring tolerance groups on WSM 40-46 to -48.


My 90 GT with the 474 option originally had 3 brown marks on the front springs, Boge Reds, and 1 blue mark on the rears. I replaced the fronts with CS springs (2 orange marks)

the flyin' scotsman

Thx Rod.............my '88 S4 had 3 'brown' marks and I now recall discussion years ago of 'orange' marked springs.

So................a full sport suspension as offered as options by Porsche are the red Boges 474 and the 'orange' springs?

I did read the WSM........the suspension sections are as confusing as the motor mounts

Ragnar Joensen

No !

S4 and GT (M639) have grey Boge dampers and brown-marked springs in the front and blue marked springs rear.

M474 (both S4 and GT(M639)) have either Bilsteins or red Boge shocks, but the same springs.

Club Sport (M637) normally has the M474 and always M637 springs (orange-marked) in the front. Standard springs (blue-marked) rear.

As pointed out earlier there may be several paint marks on the springs, to identify tolerance as per WSM.

As a curiousity the Club Sport has the same brakes and the same suspension, except front springs as a M474 S4.


Ragnar

Vilhuer

'89 GT might have had M474 as standard for some markets (not in US) but '90-91 definitelly did not. No other model except maybe UK only SE (S4 Sport) should have M637 springs from factory. IIRR M474 shocks were changed from Bilstein to red Boge in '89 MY.

the flyin' scotsman

Excellent clarification............thanks. I wonder if the M637 spring was optional.

No matter, its all 20YO and with Marks super sale on Eibachs I know where I'll be headed

Bill Ball

Option 474 is just sport shocks and could be S4 or GT. I haven't seen any 637 Clubsport springs.

Ragnar Joensen

M637 springs are NLA. I did get one of the last pairs last year for my 1989 GT (with Club Sport rims). They are shown in the PET and have been sold as a replacement part, and I believe that a few GT's have them fitted. However they are not as firm as the Eibachs, the Weltmeisters or the Hypercoils. Not even close, as they are only about 8% stiffer than stock springs.


Ragnar

RyanPerrella

the GT in 1990 was a 5 speed G28/55 equipped chassis with an M28/47 engine..... that was a standard GT.

Anything else would have been an option, which could likely be ordered on an S4 as well.

I think the above is concise yet complete.... am i really missing anything?