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I've been chasing my tail trying to order the 993RS versions from KW.
Originally Posted by boomboomthump
Thinking about moving to the RS-specific kit from KW (shorter bodies + longer threaded shaft) since my build now has full RS geometry (RS uprights, etc) and ride height.
Are there any other differences between shorter bodies + longer threaded shaft?
Also, can you share the KW part numbers for the RS-specific kit please ? DIdn't realise it existed, unless you are referring to what they call the 'KWv3 Clubsport'? It's interesting they make a "RS-specific" solution given the RS pre-dates their v3, and that the RS is a limited production model.
Are there any other differences between shorter bodies + longer threaded shaft?
Also, can you share the KW part numbers for the RS-specific kit please ? DIdn't realise it existed, unless you are referring to what they call the 'KWv3 Clubsport'? It's interesting they make a "RS-specific" solution given the RS pre-dates their v3, and that the RS is a limited production model.
Not Clubsports, they are RS-specific V3's. It is PN: 35271020 on their Euro site. [Link] [also link to instructions]
1) Both front/rear struts are different part numbers as they have shorter bodies to contend with the lower ride height. If you're running standard V3 coilovers at RS height, you're too close to bottoming out/riding on the bump stops, so the shorter body compensates for that.
2) The shouldered/threaded portion at the top of the shaft is longer, which allows for the thread to sufficiently pass through the spherical bearings in the RS top mounts (and aftermarket camber plates which use RS style top mounts + spherical bearings). There are aftermarket nuts available which provide more thread engagement via a stepped shoulder that fits inside the center of the bearing but there is no way to hold the shaft and torque the nut to spec. Common practice to just zap it "good & tight" with an impact gun.
3) The spring rates are the same as standard C2/C2S kit but no clue about dampening characteristics. I'd imagine there are some internal differences in the valving/oil to deal with the shorter bodies but given the adjustability of compression/rebound, this is likely irrelevant.
4) I'd imagine (not confirmed) that since they are designed for an RS specifically, that the mounting tab for the rear sway bar link is in the correct location and doesn't require fabricating an extension when using RS sway bars/links.
In my case, since I'm running RS uprights, RS ride height and everything else RS when it comes to suspension, it doesn't make sense to run coilovers designed for a non-RS.
Last edited by boomboomthump; 04-15-2024 at 12:30 PM.
BBi started mounting them on the top, it's the 993 equivalent of raising the spindle on a 911, don't think it's necessary w/ the RS or BBi wheel carriers.
This came up recently in another thread where apparently some 964 folks have done this. Scratching my head though...
How would it raise the spindle? The wheel carrier/hub are fixed to the wheel. The centerline through the hub is a constant measurement to the ground. The ball joint is attached to the carrier, so the ball joint to ground measurement is also constant, no?
The only thing I believe that would accomplish is changing the angle of the control arm (putting it more in harms way relative to road obstacles) and make the ball joint angle more severe.
A quick simplified drawing. Perhaps I need more coffee. Or perhaps I'm still too aggravated with my tax bill due to the IRS today to give this more thought.
Not Clubsports, they are RS-specific V3's. It is PN: 35271020 on their Euro site. [[url=https://www.kwsuspensions.net/catalog/product/view/id/21908/category/2/?c_make=92&c_model=160&c_car=16034&ag=&pgs=160]Link] [also [url=https://docs.kwsuspension.de/ea-KWGFwEA-h68671020.pdf]link to instructions]
1) Both front/rear struts are different part numbers as they have shorter bodies to contend with the lower ride height. If you're running standard V3 coilovers at RS height, you're too close to bottoming out/riding on the bump stops, so the shorter body compensates for that.
2) The shouldered/threaded portion at the top of the shaft is longer, which allows for the thread to sufficiently pass through the spherical bearings in the RS top mounts (and aftermarket camber plates which use RS style top mounts + spherical bearings). There are aftermarket nuts available which provide more thread engagement via a stepped shoulder that fits inside the center of the bearing but there is no way to hold the shaft and torque the nut to spec. Common practice to just zap it "good & tight" with an impact gun.
3) The spring rates are the same as standard C2/C2S kit but no clue about dampening characteristics. I'd imagine there are some internal differences in the valving/oil to deal with the shorter bodies but given the adjustability of compression/rebound, this is likely irrelevant.
4) I'd imagine (not confirmed) that since they are designed for an RS specifically, that the mounting tab for the rear sway bar link is in the correct location and doesn't require fabricating an extension when using RS sway bars/links.
In my case, since I'm running RS uprights, RS ride height and everything else RS when it comes to suspension, it doesn't make sense to run coilovers designed for a non-RS.
Thanks for the comprehensive reply - all great info! They'll compliment your RS setup brilliantly.
That said, considering the quality and extensiveness of your project, I'd have bet on you going for (or at least considering) the likes of MCS or EXE-TC (what Tuthill may have preferred?) or TracTive (what Tuthill may now prefer?) for your suspension rebuild.
Originally Posted by Coleman
ERP is making a set as well, and considering ERP's reputation, and BBI's reputation, I would definitely be buying the ERP.. Or the factory, GT2's ..
We don't hear such gossip in the UK - what does each reputation entail? Or, what's been reported re: the BBi items?
This came up recently in another thread where apparently some 964 folks have done this. Scratching my head though...
How would it raise the spindle? The wheel carrier/hub are fixed to the wheel. The centerline through the hub is a constant measurement to the ground. The ball joint is attached to the carrier, so the ball joint to ground measurement is also constant, no?
The only thing I believe that would accomplish is changing the angle of the control arm (putting it more in harms way relative to road obstacles) and make the ball joint angle more severe.
A quick simplified drawing. Perhaps I need more coffee. Or perhaps I'm still too aggravated with my tax bill due to the IRS today to give this more thought.
It pushes the outer end of the A-arm do
wn, this lowers the instant centers which raises the roll center, that's a good thing
OK, will take your word on that. I thought we meant physically raising the spindle, which of course isn't possible (unless the tires are hovering off the ground).
OK, will take your word on that. I thought we meant physically raising the spindle, which of course isn't possible (unless the tires are hovering off the ground).
Thanks for clarifying.
should have said , raise the spindle relative to the outer end of the a-arm
Thats what he RS and BBi wheel carriers do
the goal is to keep the roll center near the CoM, this reduce roll forces and keeps the wheels planted.
It pushes the outer end of the A-arm do
wn, this lowers the instant centers which raises the roll center, that's a good thing
doesn't do anything. you'll notice the lines in he diagram pass through the center of the articulating elements, ball joints on the outboard and pivot bushings on inboard sides respectively.
The uninformed owner could add several inches of spacers between the ball joints and lower arm and it still wouldn't do a thing for kinematics.
doesn't do anything. you'll notice the lines in he diagram pass through the center of the articulating elements, ball joints on the outboard and pivot bushings on inboard sides respectively.
The uninformed owner could add several inches of spacers between the ball joints and lower arm and it still wouldn't do a thing for kinematics.
True the uninformed don't understand the geometry here
The basic principle was introduced back in the '70s on Porsche sedan derived race cars.
These are Bilstein struts that have had the spindles raised 30mm.
The reason to do this is to restore the front-end geometry on a lowered car. When lowered to angle of the Arm goes from down to straight to up
normal
lowered some
lowered too much
what happens as the car is lowered is the instant center which is determined by the A-arm is lowered, this in turn caused the roll center to go down which increases the moment arm causing roll , here you can see that A1 < A2
This is exactly what RS or BBi wheel carriers do.
BBi raised the spindle than the RS version
RS
Here you can see the raised spindle on an RS compared to a stock 993-wheel carrier.
placing the ball joint on top of the A-arm does the same thing, I don't know that it's a good idea but BBi seems to think it is.
04-15-2024, 10:53 AM
It is PN: 35271020 on their Euro site. [Link] [also link to instructions]
- all great info! They'll compliment your RS setup brilliantly.
