thehelix112 Posted November 12, 2008 Share Posted November 12, 2008 From the link that Jon (Mortensen) posted the other day (http://farnorthracing.com/autocross_secrets6.html) I found this little gem: Crack open a Bilstien street shock, and inside are the same parts as inside their NASCAR shocks. That means that there is a simple conversion process (involving welding a boss onto the shock body to fit a Shraeder valve into the gas chamber) to turn an off-the-shelf street Bilstein into a full-race, user-servicable, user-revalveable NASCAR Bilstein. Which sounds great to me, unfortunately is beyond my level of understanding of damper internals. I have seen however that the P30-0032 Bilsteins are an inverted design, and that it is possible to unscrew the bottom off the shock and pull it apart to.. err.. do stuff. But I'm assuming there is some nitrogen in there, coz that seems common, and I almost even understand its purpose. So my questions are these: 1. Is the Shraeder valve modification simply there to support an external canister? 2. If you pull it apart, and the gas escapes, how do you get it back in? even with an external canister? 3. Assuming you have some way of pulling the damper apart, and putting it back together and having it continue to work, what exactly are you changing when you pull it apart? How do you things? I assume you need an array of parts to tweak settings? 4. Anyone done any of this before? 5. Anyone have a shock dyno handy? Many thanks, Dave Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted November 12, 2008 Author Share Posted November 12, 2008 Oh while I'm more or less at it, I've heard a rumour that P30-0032 (and other) Bilsteins have internal bump stops, so you don't need to run one. Anyone know if thats true? Dave Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 12, 2008 Share Posted November 12, 2008 Our struts use smaller 30mm pistons. The "good" Bilsteins are the 36 and 46mm pistons, which don't fit in our strut housings. If they could fit into adapters like AZC sells that would really really really be worth doing, as they are much more digressive in nature. The 30 mm pistons are pretty linear, and although they can supposedly be valved to be a bit digressive. Nitrogen charge is there to prevent the shock oil from foaming. It is possible to pull the strut apart and tap it for a schraeder valve. I had discussed doing that with the Shock Shop and ended up just having Bilstein revalve my struts instead, as it was cheaper to send them back to Bilstein to have them revalved (if they needed it later on) than it would have been to have the schraeder installed and revalve them at the Shock Shop. For what it's worth, I'm not entirely impressed with the Shock Shop. I would suggest that if you know what valving you want, just order them from shox.com or Bilstein if you can. Cary and I were working on this kind of in tandem. I paid the Shock Shop to do a valving analysis with the spring rates I want to run and he came back with a recommendation, then I ordered the shocks and they were revalved by Bilstein. I haven't used mine yet. Cary was doing the same thing on Dave Kipperman's car. They ran the struts as per the Shock Shop's recommendations and found the car to be really bouncy. I asked the Shock Shop to dyno all of my struts, but they only dynoed one of them. Since ours are inserts he had to make a fixture to hook them up to the dyno. http://www.shox.com can dyno shocks for you as well, as can a bunch of other places. We had a guy with screen name wiisass post a couple times here who has pulled these things apart and seems fairly knowledgeable. I tracked him down at his forum (which gets NO traffic) and posted and there was a bit of discussion what the terms mean, etc. The second link shows him pulling apart a strut, the internal bumpstop, etc. http://www.theoryinpracticeengineering.com/forum/viewtopic.php?t=84 http://www.theoryinpracticeengineering.com/forum/viewtopic.php?t=85 Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted November 12, 2008 Author Share Posted November 12, 2008 Legend. Much obliged. Dave Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 13, 2008 Share Posted November 13, 2008 No problem. If you get really into it, trying to figure out what the valving should be, maybe even trying to revalve a set yourself or anything like that I'd love to follow along on your progress. After Cary's report back on the valving analysis I had done I think it is a pretty safe bet that I will be redoing mine at some point. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted November 13, 2008 Author Share Posted November 13, 2008 Will do. As soon as I've got the damn things on the car. Progress on getting them on: http://forums.hybridz.org/showpost.php?p=953034&postcount=2 Quote Link to comment Share on other sites More sharing options...
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