Koni woes

Keith Quistorff · **Posted:** Tue Jan 18, 2011 3:00 pm

To solve the mystery -
the rear Koni SAs I included along with the ZHP Donnie purchased had top mounts from BimmerWorld (that no longer appear on their website) which use the same stamped steel mount design as OEM with a 100% rubber center bushing, as opposed to steel center bushing inside rubber webbing. The bushings are virtually indestructible, and I verified their condition myself when I sold the car to Donnie - so I'm sure the noise was not due to deterioration of the mount/bushing, but more likely the bushing flexing enough to allow the sandwiching washers to tap the surrounding metal portion of the mount during sudden shock loading. I recall hearing a very rare/occasional knock when I ran that set-up myself, but keeping in mind that I kept the shocks set on full soft at all times (due to open diff), I'd venture to guess the increase in noise since Donnie had them reinstalled is a result of setting the damping somewhat stiffer.

Anyway, glad to hear it's resolved with some better mounts.

Keith Quistorff · **Posted:** Tue Jan 18, 2011 3:04 pm

JamesShort wrote:

Yeah, normal e36/e46 Koni's are adjustable only by compressing the damper shaft all the way and then spinning it......given how easy it is to install on the rear of bimmer suspension, I don't think this is terrible. But externally adjustables sure are nice

.

No, believe me, it's terrible. I had a set on my E36 M3, adjusting them really sucked. No problem unbolting the bottom of the shock and compressing them, the real problem was removing the black rubber Koni bumpstop that resides inside the top of the long steel tube that covers the shock shaft. Koni provides two small holes to push a punch through in order to dislodge the bumpstop from the groove that firmly holds it in place. It's a real bitch, virtually impossible to do on the car.

Keith Quistorff · **Posted:** Tue Jan 18, 2011 3:11 pm

DickRasmussen wrote:

Questions for my engineering education since I'm hoping these "issues" are mostly due to engineering tradeoffs and packaging constraints:

2) BWM shock mount failure: What is so special about these parts that they have limited life "before noise" when used with stiff shocks? Are these "rubber" failures or "metal" failures, or something else?

They are rubber failures. BMW suspends a metal bushing in rubber webbing, and the rubber webbing fails very quickly, even with OEM shocks, but especially with aftermarket/stiffer shocks. The reason there's a metal bushing in the center of the rubber webbing is because the material the shock shaft passes through needs to be incompressible so when you tighten the top nut you make positive metal-to-metal contact as you torque the assembly.

JamesShort · **Posted:** Tue Jan 18, 2011 3:16 pm

Ahh crap, I forgot the bumpstop has to be removed.

If I understand you correctly, Matt McGrain's Civic is very similar to get the dust cover and bumpstop off. There is a sleeve with a dimple that needs to be removed to get the dust cover and bumpstop off.

So yes, I take back what I said

.

Karl Shultz · **Posted:** Tue Jan 18, 2011 5:27 pm

JamesShort wrote:

Maybe the name dropping of Karl helped me out. But now I have Lee's personal cell number in my phone due to all the calls I had with him

.

That's the first time that's ever been said.

Donnie Barnes wrote:

First, Koni-NA is ALWAYS backed up like that. Never expect anything different. And I know of no other shop I'd trust with those shocks. Sucks.

Yeah, it's been that way as long as I can remember. :cry:

Lee hates it too. Among the issues I've been told, is that, for someone to become an authorized rebuilder, that someone needs to keep parts in stock for some unimaginable number of cars, and it's a huge ask, and people don't want to do it. So you end up stuck with the same old group of vendors who have been doing it - often wrongly - for years.

I know Performance Shock out in CA has become known for being excellent, but I've never used them personally. I will if and when I ever send the S2000's shocks out for service. I believe they built the shocks Keith ran on his S2000, they did excellent work, were competitively priced, and were pretty fast about it. Lee himself endorses the place.

(Totally OT item that probably only Donnie will get: I typed that whole thing with two spaces. I can't break the habit to save my life.)

DickRasmussen · **Posted:** Tue Jan 18, 2011 8:17 pm

Karl Shultz wrote:

Yeah, it's been that way as long as I can remember. :cry:

Lee hates it too. Among the issues I've been told, is that, for someone to become an authorized rebuilder, that someone needs to keep parts in stock for some unimaginable number of cars, and it's a huge ask, and people don't want to do it.

That sounds like an "excuse" that someone is using. With the internet and overnight shipping a tech could diagnose the problem today and have the part from Koni USA tomorrow or from Europe in a couple of days. At Koni prices and "racer" time schedules the shipping of individual parts would be relatively small expense. Most customers would be happy to wait a week or two for the part if they didn't have to deal with the multi-month waiting list for Koni to even start the job. Plus who knows how many of the parts Koni USA even has in stock at all times. :lol:

DickRasmussen · **Posted:** Tue Jan 18, 2011 8:25 pm

Keith Quistorff wrote:

They are rubber failures. BMW suspends a metal bushing in rubber webbing, and the rubber webbing fails very quickly, even with OEM shocks, but especially with aftermarket/stiffer shocks.

Any idea what the ride/handling gain is from the "webbing" approach versus doing the same thing with shock valving, etc.? Is this another example of German engineering which avoids doing things the easy/durable way when there is a complex/fragile way? :wink:

steve remchak · **Posted:** Tue Jan 18, 2011 11:43 pm

DickRasmussen wrote:

Karl Shultz wrote:

Yeah, it's been that way as long as I can remember. :cry:

Lee hates it too. Among the issues I've been told, is that, for someone to become an authorized rebuilder, that someone needs to keep parts in stock for some unimaginable number of cars, and it's a huge ask, and people don't want to do it.

That sounds like an "excuse" that someone is using. With the internet and overnight shipping a tech could diagnose the problem today and have the part from Koni USA tomorrow or from Europe in a couple of days. At Koni prices and "racer" time schedules the shipping of individual parts would be relatively small expense. Most customers would be happy to wait a week or two for the part if they didn't have to deal with the multi-month waiting list for Koni to even start the job. Plus who knows how many of the parts Koni USA even has in stock at all times. :lol:

rather than excuse i think it is their marketing strategy Dick. when i bought my "re-built" DA TC Kline set-up i was told it would be many months before new versions of the product would be available. the re-builts were flying off the shelves as i understood at the time.

Karl Shultz · **Posted:** Wed Jan 19, 2011 12:44 am

DickRasmussen wrote:

That sounds like an "excuse" that someone is using. With the internet and overnight shipping a tech could diagnose the problem today and have the part from Koni USA tomorrow or from Europe in a couple of days. At Koni prices and "racer" time schedules the shipping of individual parts would be relatively small expense. Most customers would be happy to wait a week or two for the part if they didn't have to deal with the multi-month waiting list for Koni to even start the job. Plus who knows how many of the parts Koni USA even has in stock at all times. :lol:

:shrug: I'm just telling you what I was told.

Donnie Barnes · **Posted:** Wed Jan 19, 2011 12:59 am

Given how they often just "run out" of products and take MONTHS to get stuff back in stock at all, I personally believe this is just another example of how they are a poorly run business. Lee is great, but he's not "in charge" at a level that can fix this from what I can tell.

I vote with my wallet by not buying from them when I can help it, generally. Even though Lee is great.

--Donnie

Keith Quistorff · **Posted:** Wed Jan 19, 2011 9:31 am

DickRasmussen wrote:

Any idea what the ride/handling gain is from the "webbing" approach versus doing the same thing with shock valving, etc.? Is this another example of German engineering which avoids doing things the easy/durable way when there is a complex/fragile way? :wink:

The rubber webbing serves to absorb torsional flex as the shock shaft changes angle relative to the shock tower during shock compression/rebound. Aftermarket solutions involve replacing that (rubber) portion of the mount with polyurethane or a spherical bearing for durability.

Chuck Branscomb · **Posted:** Wed Jan 19, 2011 9:41 am

I agree with Donnie -- appears to be an upper level management problem (either incompetence or a lackadaisical attitude about the market).

I realized this morning I left an important part of the story out, and once I thought of it, I realized I'm basically 100% sure it is the shocks. Tia (my wife) and I went to a movie for the first time in months (thanks Netflix), and as we were coming out to the car in the cold, she said this would be a good time for them to make a lot more noise, right? I'm like, um, well, yeah I suppose since it has cold soaked for a couple of hours in 30F temps, the viscosity will be high, so I guess (not *really* thinking it would make much of a difference). We had set them on 2 full turns off full soft on the way to the theater just to see if that affected the noise which it didn't really.

Well, for the first 2-3 miles they were knocking much louder than on the way over there, and after 4-5 miles it was not nearly as loud...back to the "normal" knock more or less which we supposed was due to them warming up, oil viscosity decreasing some, etc.

What are the options besides Konis? Unadjustable Bilsteins? The new Moton sport shocks at >$2k? Perhaps the answer to that question precisely answers why these shocks have the problem they have, and why said design or manufacturing problem isn't being addressed, and also why the rebuild/repair "problem" isn't being addressed.

Aaron Buckley · **Posted:** Wed Jan 19, 2011 10:24 am

Chuck Branscomb wrote:

What are the options besides Konis? Unadjustable Bilsteins? The new Moton sport shocks at >$2k? Perhaps the answer to that question precisely answers why these shocks have the problem they have, and why said design or manufacturing problem isn't being addressed, and also why the rebuild/repair "problem" isn't being addressed.

AST, Moton and Penske to name a few. I think if I were running at the local level, I would never spend this kind of $$ for shocks. OTS Konis, even if they fail in a year or two, are WAY cheaper to replace multiple times. - AB

MarcusMcRae · **Posted:** Wed Jan 19, 2011 10:40 am

This is an interesting read about this vs that. http://farnorthracing.com/autocross_secrets18.html

JamesMilko · **Posted:** Wed Jan 19, 2011 10:43 am

I know there are quite a few people who revalve Bilsteins for Miatas and can make them SA/DA while they do it. Is it the same for BMWs? Also I have the bonus of running SP so I don't have to worry about the spring perch location.

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