Project 987.2 Cayman S, Cup Car Suspension for the Street!

On the KW Clubsports, the compression damping is adjusted by this large easy to adjust knob at the bottom of the strut.  Having knobs that are easy to reach and adjust by feel are a huge advantage when setting up a car at the track.  The knobs on KW’s are perhaps the best in the industry.

The KW Clubsports have remote reservoirs.  With short struts, the reservoirs are needed to assure that there is sufficient gas volume to make room for the fluid displaced by the shock shaft.  The fluid is separated from the gas by a rubber bladder.  This assures that there are no gas bubbles in the system that can cause inconsistent damping.  The pressurized gas also reduces the chance of cavitation as the fluid passes through the shocks valves. This reduces the potential for fluid frothing and inconsistent damping under hard use.

The rear KW Clubsport struts are very similar to the front.  The main difference is the upper mounts are different.

The KW’s have brackets for the brake lines and all the sensors in the correct place that fit the OEM hardware.  Nice and clean, no more zip ties!

Since our friend’s beach apartment has subterranean parking with a fairly steep driveway, we are installing KW’s HLS system.  The HLS system is a hydraulic system that allows the driver to raise the car 1.5″ at the touch of a switch.  This way we can have decent ground clearance but an aggressive track worthy low ride height.  We will be doing a lot of aero work on the car as well and the HLS system will give us clearance to make a decent splitter streetable.  The HLS consists of 4 hydraulic spring perches and a hydraulic pump assembly.

16 comments

  1. Ok, I really like the idea of using the HLS to do rake; will be cool if that works well. Do you know what the roll centers end up like on these things when lowered and strut inclination? I was looking at a bunch of more modern McPherson strut cars and trying to figure out what they’re doing for geometry lately.

    1. I am waiting for the right springs to come in so I can figure stuff out and get it all set up. Next article.

      1. Cool, looking forwards to it. I’m in the middle of some some relatively weird design work for an SCCA car so wanted to sanity check some stuff before I start machining a bunch of NLA parts; I’m basically mulling over changing steering axis inclination on 1st gen RX-7 knuckles.

        Whole project is going to be going relatively slowly because I have a one month old daughter now, but I figure if I’m going to the extent of having shock pistons made for struts and doing cambered floater hubs on a live axle, might as well be thorough.

        1. You can look to off road and circle track parts for camber floating live axle hubs. Some Mustang guys run that stuff on drift cars too. I am in the middle of figuring out how to control scrub on a strut suspension with really wide tires. My first idea got banned by FD before we could even make it.

          1. I’m cribbing design of it from circle track practice certainly, but scaling down – the circle track stuff with the right features all tends to be 5×5″ bolt pattern and all the affordable good 15×7 wheels (yay SCCA rules) are 4x100mm.

            I assume you’ve seen the Revoknuckle, Superstrut, and the dual pivot lower control arm solutions… I’ve been thinking of the same thing and how to get something like that through the rules. Only about 9.5″ of tread width, but on slicks, and I’m not sure power steering is in the weight budget.

          2. What about something like the Chevy Cruze WTCC front strut – they had a big bracket moving the strut around the tire which could let you sink the knuckle deeper into the wheel.

  2. “The anti-corrosive construction is one of the reasons why KW Clubsports have a limited lifetime guarantee.” The KW Clubsports do not carry a warranty as stated by KW’s web site, unlike the other models. Unless you’re referring to another guarantee, thought I’d point that out for those in the market.

  3. Nice program !
    I like the pinch bolts instead of jam nuts to lock the alignement settings ! Far more convenient and precise.
    The Rennline brace doesn’t look that well engineered though, it’s more for show than actual stiffness.

    I’ve had a really good result with tightening the front end with a triangle brace on the front subframe, where there is usually just two stamped steel braces, I have a solid piece that triangulates the whole subframe instead and the difference is quite noticeable ! Should be even more so with full spherical bearings suspensions !

      1. It’s a Ultra Racing brace. I’m sure you can easily fabricate one like it. But it was very cheap.
        It protrudes a bit underneath the car, but no big deal on mine, it never touched anything (and I’m lowered).
        Check out their strut brace too, looks much stronger than the rennline 😉

  4. I’ve been running Tarett parts for 15+ years on my aircooled cars, top notch stuff that is built to last. We recently added the Tarett cockpit adjustable sway bars to our 987.1 Cayman racecar and they are awesome too. It’s so nice to be able to make adjustments on the fly without losing time on track or having to roll around on 100+ degree asphalt between sessions.

  5. Is this project still going on, I’m building up my 2009 Cayman S and looking for ideas.
    So far I have JRZ RS’s front and rear, Tarett lower control arms front and camber plates up top. Rennline tie-downs and rear support. Adjustable Rear toe links and I have a Tarett 22mm rear anti-swaybar and adjustable swaybar links.
    My car is a PDK and I live in Arizona so I just had a BGB transmission cooler installed. Next, I have Sparco EVO race seats and harness bar going in as soon as I get my BBI mounting brackets, any day now.
    It’s an ongoing prosses so I’d like to see how this build is going.

  6. Mike, Two of us own a 987.2 and are about to embark on suspension upgrades. We are both instructors with BMW and PCA and Audi. We have stock suspension, albeit low mileage car. 18″ wheels and 200 R comp type tires. We have experienced understeer, wheel hop and lack of ease to slip angle the car and get on throttle. As we research we are leaning to the Tarett and have watched your video on the suspension work you did on the 987.2. We are wondering if the work you did to lower the tension/thrust arms, etc. (to reduce anti dive and anti squat) actually worked to reduce hop? Stephan and Zafer

    1. Billy Johnson tested the car at Buttonwillow and he did not complain about wheel hop, there is an aero imbalance that we need to fix. that was causing understeer. Billy said the back of the car was very planted. It was turning 1:57 laps which is ok for the type of tires. I think the car has another 2 seconds in it easily with some more suspension and aero tuning. I was not there that day and I could have worked it better working with Billy.

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