DG-FNR

It's good to see somebody else going down this road. It's really not all that hard and you get amazing results.

Some tips:

1. Cleanliness is indeed next to godliness when it comes to working on shocks. Any **** that gets inside the shock will chew up seals and score the inside of the tube, and that's just bad.

2. It is important to get as much air as possible out of the shock, and you'd be amazed at how much air is dissolved into the oil. To do this, I made a plexiglass plate with a rubber pad under it and tapped a hose nipple into it. When the shock was filled with oil, the plate goes on top of the shock body and the air pumped out of the shock using a Mitivac attached to the hose nipple. Once I got all the air out (you can see the bubbles through the plexiglass) the piston and rod goes in, and then you pump it up and down until the bubbles stop coming out.

That could take a long time... but it made the shocks much more consistent.

3. I stopped using the lower snap ring on the upper seal assembly. It doesn't do anything and Bilstein themselves stopped using them a while ago - and it makes disassembly WAY easier as you just tap the seal down a little (once the shock is depressurized) to get at the upper snap ring. I could get one of my Bilsteins apart in less than 30 seconds.

4. Bilstein makes a little cup that fits over the top of the shock that provides a pry surface so you don't mar the top of the shock tube when popping out the seal.

5. Most of the interesting stuff happens sub 3 in/sec, and it's rare to see anything faster than 11 in/sec or so - and when you do, it's a transient spike. Shock manufacturers like to provide data at fast speeds (when they provide data at all) because the high speed runs primarily exercise the shim stacks, not the bleed and the bleed/shim crossover, so the high speed runs hide tons of misbehavior. A shock that dynos fine at 15 in/sec peak speed might be junk at 3 in/sec peak speed. See the data example at http://farnorthracing.com/autocross_secrets6.html - I have some velocity plots there of suspension position sensor data at actual events.

6. Your feeding of non-sinusoidal motion into the shock is very interesting and an area that I didn't explore, given that I had a SPA dyno and the cool Rhorig electro-mechanical, feed-any-waveform-you-want dyno was WAY above my price range. You're breaking good ground there.

Keep it up!

DG

beanbag

Congrats on surviving your tour?

I haven't been running the lower circlip either, BUT for somebody who likes to run large amounts of compression damping (and not enough gas pressure), a big hit could cavitate the upper half of the oil space and suck the top cap inwards.

redzcstandardhatch

subscribed just so i can read this again...awesome

DG-FNR

BTW, massive update to Autocross To Win...

http://farnorthracing.com/autocross_secrets.html

DG

modernbeat

I use motorcycle chain cleaner and lube to keep my spherical bearings lubed. It's easy to use, so it encourages regular cleaning and lubing.

beanbag

What I ended up doing was replacing the bearings with Teflon-lined ones, and haven't had any problems since. The Bilsteins used a metric size, 26mm by something, so what I did was take a normal COM-8T (1" OD) and first put it on the lathe to trim away a tiny bit of the outer race to reduce the width to whatever the Bilstein metric size was. Then I used .01 sheet metal to shim the OD 25.4mm to 26.

Geez, that was a long time ago...

macr88

Have you had to buy anything for your bilsteins yet? If so where did you get your parts from?
I ordered mine from Voigt Racing and I'm looking for someone that's a bit closer.

BTW thanks again, it's actually surprisingly easy to valve them as far as labor and tools is concerned. Getting them right is a different story though.

beanbag

I got my parts from Bilstein in Poway, but in the future I would get them from Bilstein North Carolina since it's been getting more and more troublesome to get them from Poway.

macr88

They won't sell directly to me, I had to go through an authorized dealer. Pat in North Carolina had me get the parts through Voigt Racing.
I guess I'll keep using Voigt, he's easy to talk to and get a hold of.

Thanks

hispanic panic

Bump for some awesome goodness.

Low speed compression damping with a solid knee and super digressive high speed behavior is what sets the joe shmoe (koni) apart from the high end motorsports stuff (AST/JRZ/Moton/MCS).

I have MCS 2 way coilovers on my Evo X and at 800 in/lb spring rates, they're more compliant and comfortable than my KWv3's that had HALF the spring rate. Why is that? Because of the digressive behavior in the high speed compression. This is exactly why you liked your 8 series better.

OP, please PM me. I have lots i want to talk to you about.

Dilbones

Subd

Vee Moose

[QUOTE=beanbag;36099931]The first goal of this project is to get the Bilstein to look like a Koni Sport. So here's a dyno plot of the shocks next to each other:



What I need to do on the Bilstein:
Bigger main rebound shim
Maybe back the preload down a notch to take into account this bigger plate
Slightly smaller compression bleed plate

After:


OK, so I missed a little on the compression stroke. Shrug. One thing that kind of surprised me was how little low speed rebound the koni has relative to the compression damping. The ratio is nearly 1:1, so why did I even both whipping out the COB piston for this? Anyway, unless I accidentally turned the rebound ****, the Koni shock was set for 300# springs, which I think is about 1 turn or so.

I am very interested in the valve stack configuration that you used to get this plot. I have my shocks apart and am trying to get the dip in the low ips. I would greatly appreciate any help you can give me on this.

boost ben

You have actually got me so into this that I started to build my own dyno. My dyno is going to be pneumatic but gather data using a load cell and a linear pot. I hope to finish it up and get it running in the new year. I have all the parts in now and have the program written to run it, just need to build a frame to hold the ram.

I'm going to try and find a set of the Bilstine Civic sport shocks for 99 civic then go from there.