924Board.org

[Shurick]

Just considered not to mess with torsion bars, just to put some coilovers. And the question is how to select appropriate springs? I have 24,5 t-bars and don't want to go crazy with stiffness and lowering. What springs (stiffness and length) should I use to match, say, #260-280 coils in front struts?
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WBR, Shurick
'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
https://www.instagram.com/ru_pacecar/

[jason c]

The 24.5mm bars are about 213lb so if you like the handling as is, go with the same ratio f&r. Some prefer the front stiffer, some prefer the rear stiffer so it depends on your preference. Size & length will depend on the type of coilover.

[fiat22turbo]

I prefer to do the torsion bars to avoid altering the center of gravity, but if you look around online, the stock T-bar spring rates are available and you can simply add the desired coil spring rates on top of that.

Check out the stickied Cheap Shock option thread in this area for more info on shocks, springs and struts, etc.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[jason c]

I have t-bars and coilovers on my racecar, but the combined rate is 1100#.
The problem with having both in this situation is he wants 260-280 in front. If the t-bars are over 200#, keeping the rear close in weight will require very soft coils.

[Shurick]

Thanks for your replies.
From the clarks garage 24,5 mm t-bars are 149 lbs/in and I was thinking that it's a right figure (http://www.clarks-garage.com/shop-manual/susp-15.htm).

The problem is that my rear suspension feels a bit overdamped with yellow koni sport shocks and those t-bars. It's nervous over the bumps.
Also I'm not shure that putting 100 lb spring over the to the rear will result 249 lb in total. I have 924S arms and 23.3 offset fuchs in the rear. It makes about 200 mm of lever between the wheel center and the shock attachment point.
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WBR, Shurick
'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
https://www.instagram.com/ru_pacecar/

[Rasta Monsta]

[fiat22turbo]

You might also look around for a shop with a shock dyno to get an idea of what the different settings actually mean.

Many Koni's (and other shocks) can also be re-valved to suit the corner weights and spring rates found on your car.

You just need to provide the relavent data to the shop to start working on a ball park valving.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[Shurick]

They are at the middle position now and I really can adjust them softer. But I definitely need to add some stiffness to suspension, just not 400 lbs. This car spends much time of the time on public roads. But sees some track too.

Found this: http://www.paragon-products.com/kb_results.asp?ID=58
If you know the rate you are trying to achieve by adding coil-overs (such as the Koni 3012) to an existing T-bar , you can calculate the necessary spring needed.
....
"<desired effective rate> less <effective T-bar rate> divided by 56% equals linear coil-over spring rate"


They also list 24,5 mm t-bar as 149 lbs. But according to their equation I need to add #200 spring to archive desired 260 effective rate. That scares me.
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WBR, Shurick
'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
https://www.instagram.com/ru_pacecar/

[Rasta Monsta]

Replacing t-bars while refreshing the bushings in the rear end makes so much more sense.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Shurick]

[morghen]

Maybe start by looking at the 968 CS, it had some sort of coilovers on the rears. Some helper springs.
Maybe you can find the specs of those springs.

What rear coilovers are you using?
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Supercharger and EFI kits
https://www.the924.com

[Shurick]

[morghen]

I heard that you could put some sort of segments on a cutout groove on the body of the shocks and they will hold.
Its an interesting aproach...but i wonder how much abuse they can take.

[fiat22turbo]

[Shurick]