Do you hear a clunk or thunk from the front suspension when using H&R Street Performance coilovers on your Porsche Cayman, Porsche 997 911 - or another application? You might be hearing the front H&R spring slapping into the H&R aluminum…
Do you hear a clunk or thunk from the front suspension when using H&R Street Performance coilovers on your Porsche Cayman, Porsche 997 911 - or another application? You might be hearing the front H&R spring slapping into the H&R aluminum upper spring perch. The tolerances could be tighter...
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During a fun initial test drive a few days, my customer pointed out (and I also heard) noise from the front suspension when we went over sharp / large bumps. I had a feeling either something in the front strut / sway bar mounting was loose, or there might be a larger-than-ideal clearance between spring and coilover adapter. He was sure he'd tightened everything up well so we needed to diagnose the noise examining clearance on the H&R Street Performance coilovers.
I went down to his house where he had his Cayman jacked up for easy suspension access. I also wanted to test the front bump travel so he initially removed the spring so we could put the car into full bump. This video shows the front Cayman suspension in that position.
My estimate for the bump stop stack was pretty good!! I had used 2 soft-density Bilstein segments (~40mm) and the medium-density progressive 'cone' from the original H&R bump stop (~20mm). This gave a nice two-stage behavior to the suspension and we could verify there wasn't any contact between the tire and the fender liner. This custom bump stop arrangement definitely gave more useful and safe suspension travel than the Ohlins DFV had as well as the OE Cayman suspension. The factory always is more conservative in their travel estimates which I can understand when using softer OE springs vs. the higher rates we're now using.
The short video on my custom bump stops for this '07 Porsche Cayman project is here:
https://www.youtube.com/edit?o=U&video_id=01AVpU0YxAs
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Regarding the noise, we found about 2mm total clearance (1mm per side) between the H&R 60mm spring OD and the ID of the aluminum upper spring adapter they provide. Not good. I kne..
