Confused about suspension...

[sawood12]

A plea for help from all you M030 runners!
I've always assumed my car is not kitted out with M030 because there is no 030 code on the sticker in my boot and my front brake calipers are the same as my rears (in their design at least - can't tell if they are a different size though) and not the 928 S4 calipers. However several other people have commented that they think my car is running a bit low and also i've recently compared an M030 front anti-roll bar i've bought (2nd hand off a Silver Rose) and it looks like its the same diameter as the one already fitted - well as far as I can tell with rudimentary measuring equipment in the absence of any micrometers or calipers. There is nothing in my cars comprehensive service and repair history to say the anti roll bars have been changed separately or M030 has been installed retrospectively. So i'm confused now. Did M030 always include the 928 S4 brakes or was that an added extra to the uprated suspension (i.e. M030 suspension upgrade and M030 brake upgrade)? Also does the 030 code appear on the boot sticker or is it another code that corresponds to 030 suspension (I believe it was M753 or something on the Silver Rose which was the same a M030)? I thought 968's had M030 as standard and all the 968's I've seen have the same front brake calipers as mine.
Cheers.

 

[944Turbo]

MO30 suspension could be purchased without the big brakes. The dampers will be yellow and have an adjustable spring mount in the front. If its not on the sticker it could have been added later - probably secondhand.
Most 968's do not have MO30 even the CS's
Tony

 

[Fen]

Further than that on the 944 M030 was always independent of brakes. Any 944 Turbo had brakes to suit the model year it was made and there were no options. 944 M030 was only ever shocks, struts and front springs I think - maybe there were ARB differences too but I don't think so. 968 M030 was all of the above plus brakes (but only to the same as the standard 250bhp Turbo ones) with drilled disks and ARBs.

 

[944Turbo]

I think rubber stiffness also changed (M030 castor mounts etc.) and ARB's might of got thicker depending on which version you had already.
IIRC very late model S2 M031 had turbo brakes and turbo boge suspension whether any were sold with that configuration I don't know!
Tony

 

[Fen]

Yes! Castor bushes. I should have known that as have a set of 944 M030 castor bushes with very little wear in my box of spare bits. I had to buy brand new 968 ones and then press the bush out of the frame to fit Powerflex ones so i also have brand new rubber centres for 968 ones if anyone wants any.

 

[944Turbo]

And I only have them after your tip off on the cheap ones. []
Tony

 

[sawood12]

So that appears to explains why my ex-Silver Rose ARB's are the same dia as my std Turbo ARB's - because 944 Turbo M030 didn't include uprated ARB's (not at least the early ones).
Also by the explanations above M030 doesn't include uprated torsion bars on the rear suspension(?) Strange. I thought stiffening up the front end relative to the back end would be detrimental to the handling - induce oversteer earlier? cause more body flex? Oh well what do I know - I bought a pair of ARB's I don't need! So if anyone out there want's a pair of 944 Turbo ARB's give me a shout - A nice upgrade for a 944 Lux I bet!

 

[Fen]

I don't think the springs are any different rate on the front either. The difference was (front) height adjustability and rebound all round. You can only stiffen it by increasing rebound.

 

[sawood12]

Just done some digging. It appears the Silver Rose cars did have the full M030 suspension and brakes although it was called M758 on those cars. The differences are noted below - M030 in brackets:-

Front ARB dia 25.5mm (26.8mm)
Rear ARB dia 18mm but changed to 16mm from May '89. No M030 rear ARB.
Rear Torsion bar dia 23.5mm (25.5mm)
Front disk dia 298mm (304mm)
Rear disk dia 299mm (299mm)
Front disk thickness 26.6mm (30.6mm)
Rear disk thickness 26.6mm (26.6mm)
M030 included the 928 S4 front brake calipers and modified front hub/spindles to accommodate the thicker brake disks to maintian offset.

So it appears the rear ARB is not included in the M030 option and they actually reduced the ARB dia by 2mm on the later 944's for some reason.

My confusion is fading but at least there is no need for me to replace my rear ARB, just my front.

 

[TTM]

Here are some datas about various suspension set ups :

http://mapage.noos.fr/tjmm/Suspension

Unless I'm wrong some late turbo 220 featured a 20 mm rear sway bar.
I guess they switched from 18 to 16 mm on the late turbo 250 to reduce oversteer - we all know how the back end can behave out of wet roundabouts []

 

[Fen]

ORIGINAL: sawood12

Just done some digging. It appears the Silver Rose cars did have the full M030 suspension and brakes although it was called M758 on those cars. The differences are noted below - M030 in brackets:-

Front ARB dia 25.5mm (26.8mm)
Rear ARB dia 18mm but changed to 16mm from May '89. No M030 rear ARB.
Rear Torsion bar dia 23.5mm (25.5mm)
Front disk dia 298mm (304mm)
Rear disk dia 299mm (299mm)
Front disk thickness 26.6mm (30.6mm)
Rear disk thickness 26.6mm (26.6mm)
M030 included the 928 S4 front brake calipers and modified front hub/spindles to accommodate the thicker brake disks to maintian offset.

So it appears the rear ARB is not included in the M030 option and they actually reduced the ARB dia by 2mm on the later 944's for some reason.

My confusion is fading but at least there is no need for me to replace my rear ARB, just my front.

While I'm not disagreeing that the Silver Rose had M030 and those specifications the point is that all of the above was identical on a non-M030 '90-on Turbo. Actually I think the rear ARB data is wrong as I'm sure mine was thicker and I have a feeling they were 23mm. I'm not going out to the garage now but I'll try to remember to measure it in the morning.

 

[TTM]

Non-M030 '90-on turbos have 25.5 mm torsion bars and 28 N/mm stiff front springs, just like previous 88' and '89 turbo 250 (with M030, then).

Fen, please let us know if you have a 23 mm rear ARB - I thought Porsche would not have made something bigger than the 21 mm of the Cup car spec.

 

[Fen]

Thom, my bad memory - it's not 23mm. I eyeballed it at 19mm with a tape measure but it could be 18mm. No way is it 16mm though and as my car is a '90 I don't believe they dropped to 16mm from May '89.

 

[TTM]

Well, I know a '91 turbo with M030 (German spec) that has a 16 mm rear ARB.
I would not find surprising they specified something different for the UK market.
That said I know an '89 S2 cab (French spec) with a 25.5 mm front ARB while other S2 cabs (French & German specs) I looked at have the usual 26.8 mm one.

The truth must be out there, Scully []

 

[944Turbo]

from the manual,



However i am fairly certain my rear bar was 18.5mm ish as i had to measure it to buy bushes. I would measure it now but don't have it any more. Maybe it was thinner for the US market.

Tony

 

[sawood12]

I got the infor from a combination of the proper Porsche 944 workscope manual and querying my local OPC. Not sure how old my workshop manual is (i.e. if there were any revisions relaeased after the one i've got) but it is for UK cars. Just for clarification it does say that the M030 equipment is standard on the later 944 turbo's and is not an option - but the equipment is the same as the M030 option.

 

[Fen]

ORIGINAL: sawood12
Just for clarification it does say that the M030 equipment is standard on the later 944 turbo's and is not an option - but the equipment is the same as the M030 option.

Even that's weird - Slim's '91 car for example has adjustable Konis and (I assume) lists M030 as an option code whereas my '90 car had Boge and no M030 option code. My brakes were the same as Slims' though as they were standard from '89 - I wonder if he remembers what size ARB's he took off the car?