beanbag

I want to send my 8211's in to get revalved, so may as well take a look inside anyway, right? What tools would I need to work on them besides a pin wrench?

unrealwrc

no 1 will know better then u once you go to take it apart

MAKE SURE YOU TAKE PICTURES FOR US

solo-x

I would advise against that. Ask Lee Grimes if he can send you some pics of the insides if you're really that curious. I've seen the insides of Moton's, and I'll tell you right now, it's really not impressive to see the individual bits. Like see the skeletal structure of a hot chick vs. seeing her curves. The curves are what matters!

essex

I love your topics! Do it!

MAV3RiCK478

there is a shop at infineon that is koni certified if you want to bring it to them. i'm sure they can take pics or let you come up when they open them.

turboteener

OH, NO, he might expose the secret ninja technology. Men from Koni will be knocking on your door shortly, to remove you, your camera, your shocks and tools. Don't do it.

Not sure but I am pretty sure Konis are gas charged so you will have to release the pressure before you start work.

beanbag

Ok, here we go:

Upon popping off the top cap and seal, this is what you get


I think these holes and shims allow directional flow between the inner and outer tubes


Piston out. I'm reasonably happy with the rebound valving, so no need to mess with it.


Inner tube. The hole is for the compression valving.


**** and compression valving. Remember a few weeks back when I mentioned that an o-ring was leaking, and people recommended I send the shocks back for a full rebuild? Yeah, well I changed that o-ring. It's not that hard.


Another image of the foot valve. Note the tiny hole. Well, I think this may be the crux of my problem, i.e. too much low speed damping.


So I emailed Koni, and one of the guys there suggested I could drill this hole bigger. I was disinclined to modify an original part, but neither Koni nor any of it's rebuilders will sell me another foot valve.


However, I did at least find out a bit about the oil that these shocks use. I've had two sources tell me that Mobil Velocite 10 (an oil for machines, not even suspension oil) is what they sometimes use. I was also told that suspension fork oil for motorcycles would work as well.

So here's the deal. I don't know that much about how to change the compression valving, which I want to get to look like the 8041-1153 I posted in my "DIY shock dyno" thread. Here's some options I see so far:

1) Make another foot valve, but drill a bigger bleed hole this time. This should reduce the low speed compression.

2) Somehow buy another foot valve for another shock that may have a different bleed hole, as well as another shim stack if I felt like tweaking the curve some more.
Maybe it will be from a motorcycle store, or maybe some other shock where the manufacturer is willing to sell the parts.

3)???

Looking for other suggestion. Thanks

BTW, there shocks are not pressurized. Also, I'd feel kind of stupid paying somebody $360 to rebuild both shocks just to change this little compression stack.


Modified by beanbag at 11:52 PM 7/14/2008

turboteener

NIce post. I always wondered why Koni was the way they were. Bilstein is great about helping with revalving. Plus they are 65 bucks a shock. At least they dyno the shocks and tell you what the curves look like.

slammed_93_hatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteener &raquo;</TD></TR><TR><TD CLASS="quote">. At least they dyno the shocks and tell you what the curves look like. </TD></TR></TABLE>

I dunno about you but i got dynos with my 3011s...

turboteener

Sorry, meant to clarify that. Bilstein and Koni both Dyno their shocks when they revalve and rebuild them.

577HondaPrelude

Thanks for sharing the pictures!

3) drill a 2nd small bleed hole in the foot valve. This way you can always plug it up to get back to the OEM valving.

beanbag

and how does one plug up the hole?

essex

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beanbag &raquo;</TD></TR><TR><TD CLASS="quote">and how does one plug up the hole?</TD></TR></TABLE>
looks aluminum? why not tig it

beanbag

It's not aluminum, and I don't weld.

Vitt1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteener &raquo;</TD></TR><TR><TD CLASS="quote">NIce post. I always wondered why Koni was the way they were. Bilstein is great about helping with revalving. Plus they are 65 bucks a shock. At least they dyno the shocks and tell you what the curves look like. </TD></TR></TABLE>

Bilstein cost $65 per shock for the non-adjustables. For shocks from their PSS9 adjustable coilovers the cost was $125 per unit last time I checked.

beanbag

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">

I dunno about you but i got dynos with my 3011s...</TD></TR></TABLE>

For a $550 shock, a $20 dyno is a courtesy service

slammed_93_hatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beanbag &raquo;</TD></TR><TR><TD CLASS="quote">

For a $550 shock, a $20 dyno is a courtesy service</TD></TR></TABLE>

damn thats a whole lot more then i paid for mine, i guess prices have gone up a lot

turboteener

For the non adjustable shocks you can revalve them at the track. It takes about 15 minutes per shock. Yeah, I know it isn't as nice as the whiz bang 27 way adjustable JDM stuff.

Drill the hole out and test it. If it isn't what you like, you can solder the hole shut and re-drill it. Treat it like carb jets. Drill and solder until you get what you want.

beanbag

In the process of putting the shocks back together, I messed up and shredded that black rubber gasket shown in the very first picture. That gasket serves a dual purpose. One is to keep air at the top of the outer tube from getting into the inner tube. I put a regular o-ring in it's place and hopefully that is good enough. The other purpose is to keep oil from seeping past the threads on that top cap. I guess I will have to seal that with some kind of liquid gasket or something. In retrospect, I didn't have to take all the insides of the shock out because I only intended to work on the compression stack

Anyway, I drilled another small hole in the foot valve. I made it barely smaller than the original hole (#79 drill) so that should decrease the low speed compression damping by about 1/2. I filled up the shocks with Mobil Velocite 10. Why the Koni Service centers chose to use this instead of some specific suspension oil is beyond me. Anyway, the dyno showed that the viscosity was about the same as original.

Here's a compression sweep dyno:


The foot valve works in kind of a funny way. There is a small hole in the foot valve, but that is covered up with some shims. So at very low speeds, the flow is actually constricted by some shims.The whole assembly is held down by Belleville washers, so at high enough pressures, the entire assembly lifts off the hole in the inner tube, and thus acts as a high speed blow off. When you turn the compression adjust ****, you are actually adjusting the blow off point.

Here's a zoom in of the dyno plot at low speeds. Normally, a "bleed" hole will give a progressive characteristic at low speeds, but since the constriction is shims, it's digressive. Not sure yet if this is good or bad.


Here's a comparison dyno between the original shocks, after revalve, and the goal, which is a Koni 8041-1153. Never mind the rebound side.


Overall, I think it matches the Koni Yellow reasonably well, except at very low speeds. I still may want to work on these things:

1. I need to look at some of my shock velocity datalogs to see if this very low speed damping has any effect on "small bump compliance", and if so, maybe I will need to put in a "real" bleed hole.

2. I think I would like to have the **** actually adjust low speed compression, and not just blow off. The only way I can think of right now is to have a wave washer press down on the shims.

I really don't know what I am doing in terms of valving and shims and crap. Any help is appreciated.


Modified by beanbag at 6:04 AM 7/20/2008


Modified by beanbag at 6:05 AM 7/20/2008


Modified by beanbag at 6:06 AM 7/20/2008

solo-x

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beanbag &raquo;</TD></TR><TR><TD CLASS="quote">
I really don't know what I am doing in terms of valving and shims and crap. Any help is appreciated.</TD></TR></TABLE>

Which is what that $75 + parts rebuild from Koni gets you. I don't know where you got that $360 price, unless that included both shocks, shipping, and replacing every part inside them. IIRC, I got my 8041's shortened and revalved for that price. That's ALL 4 shocks. :giles: Anyway, sometimes the price you pay for a service isn't JUST for the service. Its for the expertise that the service is delivered with. THAT is why I buy Konis. Anyway, glad to see you're enjoying playing with your shocks. I like driving on mine.

beanbag

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteener &raquo;</TD></TR><TR><TD CLASS="quote">For the non adjustable shocks you can revalve them at the track. It takes about 15 minutes per shock. </TD></TR></TABLE>

It turns out that the Bilsteins that you can buy normally (e.g. Sports) are not user serviceable because you can't pressurize or depressurize the nitrogen of the floating piston. The guy there said that I could always drill a hole and put in a Schraeder valve, but that would obviously void the warranty.

beanbag

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">

Which is what that $75 + parts rebuild from Koni gets you. I don't know where you got that $360 price, unless that included both shocks, shipping, and replacing every part inside them. IIRC, I got my 8041's shortened and revalved for that price. That's ALL 4 shocks. :giles: Anyway, sometimes the price you pay for a service isn't JUST for the service. Its for the expertise that the service is delivered with. THAT is why I buy Konis. Anyway, glad to see you're enjoying playing with your shocks. I like driving on mine. </TD></TR></TABLE>

Is that $75 cost in pre-inflation adjusted 1989 dollars? Because it costs $115 per shock now, according to PSI. That's for 8041's. 8211's cost $150 EACH, NOT INCLUDING PARTS. Maybe the cost of rebuild scales with the price of crude or something.

beanbag

I found out from Koni that even if I sent the shock back to them for a revalve, they cannot put in a compression adjuster that adjusts the slope of the compression curve, only the blow off point. I don't think that's very useful, but what do I know. I'm currently trying to come up with a design that uses the current **** to make a low speed compression adjuster, but if that doesn't work, I'll just throw these shocks back on as is.

Oh, one thing I did do was put in a very thin washer under the two shims to try to take off some of the preload. Hopefully, this will offset the blue curve above to match the black curve.

uniseriate

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beanbag &raquo;</TD></TR><TR><TD CLASS="quote">

It turns out that the Bilsteins that you can buy normally (e.g. Sports) are not user serviceable because you can't pressurize or depressurize the nitrogen of the floating piston. The guy there said that I could always drill a hole and put in a Schraeder valve, but that would obviously void the warranty.</TD></TR></TABLE>

Dennis Grant has some great information on his website regarding the conversion of Bilstein shocks to take-aparts: http://farnorthracing.com/shocks_2.html . With relatively inexpensive user serviceable parts, I do not see much for the case of preserving the warranty.

Dennis also has some information on adding a compression adjuster to Bilsteins on this page: http://farnorthracing.com/autocross_secrets6.html

beanbag

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by uniseriate &raquo;</TD></TR><TR><TD CLASS="quote">

Dennis Grant has some great information on his website regarding the conversion of Bilstein shocks to take-aparts: http://farnorthracing.com/shocks_2.html . With relatively inexpensive user serviceable parts, I do not see much for the case of preserving the warranty.

Dennis also has some information on adding a compression adjuster to Bilsteins on this page: http://farnorthracing.com/autocross_secrets6.html</TD></TR></TABLE>
Some day I want to do something awesome like that to my Bilsteins (if I ever end up getting them).