Rear suspension

[sawood12]

I'm getting my hands on an M030 upgrade kit that includes the front struts, hub assembly, front brakes, rear shocks and ARB's. The only thing it seems to exclude is the rear torsion bars. Instead of fitting M030 torsion bars what do people make of these coil-over assemblies? They seem to be reasonably priced and can work in conjunction with the existing torsion bars but more importantly are a doddle to fit.

 

[Fen]

You would still need to re-index the torsions if you fit coil-overs. Good result though getting hubs and callipers and all.

 

[sawood12]

I've not got them yet!! The guy i'm getting it off works at the local Porsche breakers and he's refurbing the kit in his spare time. It's one of those where he's had them for months and I've got first refusal but he's taking his time to get it all prepared. I just hope after all this waiting he asks a reasonable price for it all!

 

[Diver944]

I may be wrong, but I thought the torsion bars were the same thickness for all Turbos regardless of wether they are M030 or not. It's only the shocks that are different at the rear.

My PET is bust so I can't confirm just now though, and I can't get the online one at www.porsche.com to work

 

[Fen]

But the 220 and 250 Turbos were different diameters and only 250 Turbos had the M030 option, but Scott's is a 220, so he has thinner bars than the M030 was supposed to have.

 

[sawood12]

Fen's right although my rear ARB is the same dia as an M030, which is why the coil-over option is very tempting. I can increase rear spring and damper stiffness without having to go to all the trouble of replacing torsion bars. According to the spec on the Koni kit you only need to re-index if you go for spring rates greater than 80lbs so i'll have to work out what the equivalent M030 stiffness is and I might be able to get away without having to re-index as i'm not wanting to lower the ride height at the rear - it's low enough already!

Also my car has a history of one side dropping requiring re-indexing of the torsion bar. It's only happened once and not to me but hopefully the coil-over kit will assist the torsion bar and prevent this from happening again.

 

[Guest]

mail jason at paragon if you want to be sure. I've had a few conversations with him in the past, and he's a very amiable guy!

As far as I understand it, the coil spring effectively just raises the rate of the torsion bar, so unless you are adverse to spending cash, then it seems an easy way of increasing the rear rate.....

 

[berg944]

What are the actual sizes of a 220 and 250 turbo rear torsion bar?

Where do I measure?

Mike[:'(]

 

[Guest]

ORIGINAL: berg944

What are the actual sizes of a 220 and 250 turbo rear torsion bar?

Where do I measure?

Mike[:'(]

well, you take the torsion bar out........

(at this point you should be put off sufficiently, and trust the websites with that info on it!) []

 

[Fen]

From memory, something like 23.5mm and 25mm. I'm sure it was posted on here once. That's the diameter and to measure you'd need to be able to see the bar, which means removing the arm.

 

[Fen]

Found it: http://www.porscheclubgbforum.com/tm.asp?m=132328&mpage=1&key=torsion&#132442 post #9. I was 0.5mm out on the 250 size...

 

[berg944]

OK I am convinced.............won't be measuring that bit until it falls off.

Probably will now[]

Mike[:'(]

 

[Andy Duncan]

Chaps,
I have a table somewhere which gives the effective spring rates of torsion bars(ARB's also) including diameters and it gives the bars data for the various 944 models and 968, take a look at www.paragon-products.com in the US I think this is where I got the info, meantime I'll have a hunt for the stuff and let you know.
andy

 

[Andy Duncan]

This is only part of the info as I can't post the Word file in the desired format;

Rear Spring Rates vs. Effective Rates
An effective spring rate is the value when taking into consideration the placement, construction, and type of the sprung materials. Torsion bar diameter is expressed as the effective diameter. Hollow bars will always be advertised with their effective rate which may not be the actual O.D. If using coil-over springs and T-bars, simply add the effective rates together to find the overall effective rate. ..................................................

924/944/968 Rear Coil Over
Coil Spring Rate (mm) Effective Rate (lbs/in)
200 112
225 127
250 141
275 155
300 169
325 183
350 197
375 211
400 225
425 239
450 253
475 267
500 281
525 295

Torsion bar Size (mm) Year/Model Notes
23.5mm 924S, 944, 944S includes M474
23.5mm 951 86-88 includes M474 24 944S2 includes M474
24.5mm 924S, 944, 944S (all thru '86) with M030 or M637
25.5mm 924S, 944, 944S, 944S2 (all from '87) with M030
or M031
25.5mm 951S 88, 951 89, 968

I've cut this short so I'll EMail the document to interested parties, let me know via email.
.
andy

 

[wardtimothy]

I would check the suspension struts, they may be adjustables like spaxs. If so you can make the suspension lighter or harder with a screwdriver. You will just have to count how many clicks you have maved and make sure both sides are set the same. I had Spax on my Capri and there were 22 settings, I would turn them both fully one way and then keep adjusting by 2-4 clicks andf then stop when it gets to a position that your comfortable with.

Tim

 

[Suffolk944]

Doesn't sound entirely right - They should be firm of course but not rock hard. Do you know if your car has aftermarket shocks fitted ? Has it been lowered ?

 

[Diver944]

In reality it all depends what you are comparing it with. Personally I think the S2 has a very comfortable and compliant suspension (some would say soft). However if you are used to a modern car with an emphasis on comfort as opposed to an '80s sports coupe then you might think the S2 was hard.

Does your service history show if the shocks have been changed in the last 10 years or so. If not they could be well past their best and not really damping the bumps at all. New rears are around £100 each last time I looked

 

[lookingfora944]

Hello thank you for the help.

The ride can definitely not be described as soft, I think it's likely that the shocks have gone.
As far as I know the car has had no modifications and the service history I have does not have any record of the shocks being replaced. I am taking it into Jaz at Wembley next week for a service so I guess I can ask them to have a look at it.
I will see if there is anything I can adjust on them tomorrow in the meantime.

Cheers

 

[BlackMagic]

They are firm and can crash a bit through potholes. You will get very good at looking well ahead to spot holes before you fall into them!

Also, look at the tyres (both type and pressure). 20 years ago they had quite soft side walls and the factory recommended 44psi(!). Newer (and possibly cheaper) designs of tyre can have much stifffer sidewalls and combined with high pressures can make for a very rough ride. General consensus is drpping the pressures to 34-36 psi all round.

Bear with getting it sorted out and then enjoy it.

William

 

[lookingfora944]

Funny you should say that about the tire pressure. I put 42 psi all round last week as that's what was recommended.
Will reduce them to about 34 tomorrow and see if that helps