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Leave rear bump rubbers out of Konis?
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TOPIC: Leave rear bump rubbers out of Konis?

Leave rear bump rubbers out of Konis? 14 years, 9 months ago #7077

It occurred to me, that changing rear shock settings on our cars is only a PIA because we have to take the shock entirely out to remove the bump rubber, and get the adjustor to engage,then reverse the process.

With the rear bump rubber out, we could just unbolt the lower mount, adjust away, and then replace that bolt. Makes a 25" process a 5" one.

If I ran the car low, there would be some risk to bottoming, and damaging the adjuster, I suppose, though with enough foce, the bmp rubber could be compressed that far anyway (msybe).

Thoughts?
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re:Leave rear bump rubbers out of Konis? 14 years, 9 months ago #7089

  • cbuzzetti
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Excellant question. It looks to me like my car is so low already that the shock is already compressing the foam insert. I will have to make a mark on the shock body at rest and then remove shock from car and check that out. My guess is that the foam insert adds to the compression damping of these shocks.
Since these shocks only adjust for rebound it really only controls the spring as it is extending after compression. And they are not really up to that job anyway.
Give it a try and let us know what happens, try it on an old one if you have one.
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Re:Leave rear bump rubbers out of Konis? 14 years, 9 months ago #7092

I'm not sure the foam would do much to damp the spring, but it would increase the effective spring rate in a non-linear fashion. That would chew up the foam insert after a while.
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re:Leave rear bump rubbers out of Konis? 14 years, 9 months ago #7093

  • JRichard
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Yup, the snubber is exactly that, they are designed to be the last progressive rate in the system. You can buy them in different rates like springs (you can even bump up your effective spring rate in the rear by adding longer/stiffer snubber to balance out stiffer front springs with the limited TBars in the rear, but I don't know if that makes for a spec legal setup). My old TBar 911s used to go through a set a year. I don't know if you'd be ok or not, it would be nice not to have to deal with it but you may find it affects the handling at the limit...

Re:Leave rear bump rubbers out of Konis? 14 years, 9 months ago #7094

Here's some interesting reading on bump stops:
www.wrxtuners.com/forums/f53/microcellul...talking-about-17337/

Re:Leave rear bump rubbers out of Konis? 14 years, 9 months ago #7095

I have always cut my koni snubbers in 1/2. Front and rear. The front use the "competition" bump stops and I cut off the back end and used the tapered end. IN the rear since it uniform I just cut it in 1/2. This seems to be enough to create a usefull bump stop in case of off track excursions and still provide decient on track performance.


Maybe I am foolling myself, but I don't feel I have ever hit the bump stops on track ever. I am sure I have hit them going off track. I also have never "blow out a shock". I did have leaker years ago that I replaced, but no leakers since.
Joe Paluch
944 Spec #94 Gina Marie Paper Designs
Arizona Regional 944 Spec Director, National Rules Coordinator
2006 Az Champion - 944 Spec Racer Since 2002
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