did early turbos have thinner torsion bars
08-08-2006, 05:39 AM
#1
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did early turbos have thinner torsion bars
Hi,
I am sure I read it somewhere but know cant find it.
Does my 1987 turbo have thinner, i.e. 23.5 mm torsion bars.
And does later 1988+ have the thicker 25.5 mm torsion bars.
If so I could swap them for slighlty upgraded suspension.
I am sure I read it somewhere but know cant find it.
Does my 1987 turbo have thinner, i.e. 23.5 mm torsion bars.
And does later 1988+ have the thicker 25.5 mm torsion bars.
If so I could swap them for slighlty upgraded suspension.
08-08-2006, 09:59 AM
#4
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86-88 Turbos have 23.5mm bars. 88-89 TS cars have the 25.5 bars.
Effective spring rate at the wheel is approx 125 lb/in for the 23.5 and approx 175 lbs/in for the 25.5.
The general consensus is that if you go to the trouble of swapping torsion bars, most guys will go with much stiffer aftermarket bars to make the upgrade more noticeable/worthwhile (28-30mm). But if you are upgrading the front suspension to M030 spring rates (or equivalent), the 25.5 bars will match that balance-wise.
Effective spring rate at the wheel is approx 125 lb/in for the 23.5 and approx 175 lbs/in for the 25.5.
The general consensus is that if you go to the trouble of swapping torsion bars, most guys will go with much stiffer aftermarket bars to make the upgrade more noticeable/worthwhile (28-30mm). But if you are upgrading the front suspension to M030 spring rates (or equivalent), the 25.5 bars will match that balance-wise.
08-08-2006, 10:21 AM
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Balance with a Capital "B" is the key guys. Running the risk of bringing down friendly fire flames on this useful thread, you can make a 944 handle with springs rates that vary from the ridiculous (stock 125#) to the mongo sublime (600#) as long as the nose and tail are balanced.
If you took a stock 951 and stuck 400# springs and a 30 mm bar on the front and did nothing else, you would be lucky if it turned in the same circle as your tow vehicle
When 50/50 weight distribution is augmented by a balanced stiffening on the effective spring rates nose to tail, the resulting handling can be remarkable even at the low end of the scale for springs and bars. If your camber and toe are well tweaked, even in that slewing "on the gunwhales" attitude we see in stock Turbo trim, you can get around the track quite quickly.
If you took a stock 951 and stuck 400# springs and a 30 mm bar on the front and did nothing else, you would be lucky if it turned in the same circle as your tow vehicle
When 50/50 weight distribution is augmented by a balanced stiffening on the effective spring rates nose to tail, the resulting handling can be remarkable even at the low end of the scale for springs and bars. If your camber and toe are well tweaked, even in that slewing "on the gunwhales" attitude we see in stock Turbo trim, you can get around the track quite quickly.
Last edited by TheRealLefty; 08-08-2006 at 11:58 AM.
08-08-2006, 12:12 PM
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I will be keeping it balance, as I am using the same settings as a 968 CS.
I already have the front springs, just need the torsion bar, as that also uses a 25.5mm bar so i can use a late turbo one.
Did you get a 968 Club Sport in the USA?
I already have the front springs, just need the torsion bar, as that also uses a 25.5mm bar so i can use a late turbo one.
Did you get a 968 Club Sport in the USA?
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08-08-2006, 04:56 PM
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I take it you mean using stock porsche items?
If so, then you can take your pick from any setup porsche used.
1988+ turbos, had stiffer front and rear springs.
968 club sprort (non M030) has the same stiffness suspension as later turbos, except the on the non M030 models they used shorted front springs to ower the car instead.
I suppose the best setup from stock items would be the 968 CS with M030.
Anything more custom, I will have to let someone with more experience chime in.
If so, then you can take your pick from any setup porsche used.
1988+ turbos, had stiffer front and rear springs.
968 club sprort (non M030) has the same stiffness suspension as later turbos, except the on the non M030 models they used shorted front springs to ower the car instead.
I suppose the best setup from stock items would be the 968 CS with M030.
Anything more custom, I will have to let someone with more experience chime in.
Last edited by ross255; 08-08-2006 at 04:58 PM. Reason: cos i cant spell
08-08-2006, 05:15 PM
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My Turbo S has a complete 968 M030 retrofit...30mm/19mm bars, 968 front control arms with upgraded caster blocks and front brake air diverters, 968 M030 adjustable perch struts and springs and dealer sourced rear coil over Koni's with 80 lb helpers. Stayed with OE rear 25.5 torsion bars.
With rear bar on short setting, front shocks on soft, Cambermeister front strut brace and bit of extra negative camber it is a tick toward understeer from neutral...which, based on my meager driving skills, is a good thing
With rear bar on short setting, front shocks on soft, Cambermeister front strut brace and bit of extra negative camber it is a tick toward understeer from neutral...which, based on my meager driving skills, is a good thing
08-08-2006, 05:18 PM
#11
Race Director
It is hard to say what the best sway bar is without knowing what tires, wheels, springs, schock absorbers (and valving) that are used - and of course how the driver wants the car to be setup.
09-12-2006, 04:31 AM
#12
Burning Brakes
if upgrading an early 951 to the 25.5 turbo s torsion bars, what is the ideal spring rate for the fronts? i want to get the paragon coil overs and am curious what spring rate would go with that rear set up.
09-12-2006, 10:29 AM
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If you look in the porsche workshop manual, it shows spring rates were increased from about 21nm to 28 nm (dont quote me on the figures) when they went to 25.5 torsion bars.
Dont ask me what nm (newton Metres) is in lb as I havent a clue.
It all depends what you want it to handle like, as to stiff coilovers in comparison to the back and you will understeer
Dont ask me what nm (newton Metres) is in lb as I havent a clue.
It all depends what you want it to handle like, as to stiff coilovers in comparison to the back and you will understeer
09-13-2006, 06:53 AM
#15
Burning Brakes
Originally Posted by ross255
If you look in the porsche workshop manual, it shows spring rates were increased from about 21nm to 28 nm (dont quote me on the figures) when they went to 25.5 torsion bars.
Dont ask me what nm (newton Metres) is in lb as I havent a clue.
It all depends what you want it to handle like, as to stiff coilovers in comparison to the back and you will understeer
Dont ask me what nm (newton Metres) is in lb as I havent a clue.
It all depends what you want it to handle like, as to stiff coilovers in comparison to the back and you will understeer