koni posted this at, uh on the Internet
Hello, my name is Lee and I am the guy from KONI who has been mentioned and quoted in several recent suspension threads. I joined *** to learn a bit more about my recently acquired '08.5 MS3 GT and also hopefully clarify some misunderstandings and misinformation. With the Admin and Mods approval hopefully (as a newb my PM doesn't work yet to contact them) that this is more for clarification and explanation and not just about selling product, I'd like to provide some explanation and information.
Sometime probably in 2007, we at KONI America were asked if the new parts that were developed by KONI in Europe for the regular Mazda3 would also fit the MS3. We borrowed an '07 MS3 from an eager autocrosser and tried both the existing KONI Sport (yelow paint and adjustable for rebound valving) and FSD (gold paint, non-adjustable)dampers on the car with some road testing and found it to be fine as they were. Unfortunately the limited production volumes of the MS3 were such that it would not justify doing specific part development for the MS3 by itself. Sometimes the low production exclusivity of a performance model car can work against it in needed potential sales market size to offset engineering and manufacturing costs (see also Integra Type R, etc.). So we knew that we would need to give a "thumbs up" or "thumbs down" to the MS3 listing. Luckily the car was pretty good with both the Sport (better handling and responsiveness plus adjustability) and the FSD (better handling and greatly reduced ride harshness on bumpy roads). So we gave them both the "thumbs up" and listed them in our catalogs, to dealers, etc.
Fast forward to about December 2009 and I got a few emails at work asking about the MS3 application, valving, and bump stops. It was the first MS3 discussion comments that I had heard since we listed it. By this time I was already looking to buy one for myself. Also that summer I had been doing some research on a Volvo C30 application and learned from my associates in Europe that the Volvo C30, S40 and V50 shared the same platform as the Mazda3, MS3, Mazda5, and the European Ford Focus and Focus C-max MPV. Thanks to modern shared platforms, these cars had many very similar parts and KONI had applications for all of them in Europe. So I started reviewing the many valving, dimensional, and mounting specifications to see if there were any more aggressive options for the MS3. It turns out that one Volvo and the Mazda5 were dimensionally correct and actually at an advantage on minimum length but also had an increase in rebound damping by roughly 20% which would help with the higher weight, stiffer springs, etc. of the MS3.
So in recent weeks we have tested a set of the FSDs on my car and found that the Volvo had the wrong lower rear mounting bushing but the Mazda5 was dead-on correct. The testing went well, the car as nicely improved and we have approved the application. This Monday morning I got three emails asking me MS3 questions so I explained that we would soon be listing a different part number for the MS3 as we thought this would be a better option for the car. This thread got posted within a few hours and we still have not yet had the time to change our on-line or notify our dealers of the change. We will probably also list these parts as a more aggressive option for the normal Mazda3. In the next few days we'll be announcing the application for the second gen Mazda3 and MS3 as the rear shock mounting changed from the first gen. That is where we started and how we got here.
Bump rubbers or bump stops- This basic piece has seemed to have grown into a major topic and likely pretty far out of proportion I think. The stock MS3 bump stops are relatively long and at stock ride height sit very close to the factory struts and shocks. Simple foam units that are neither that good or that bad. Although bump rubber contact many years ago was essentially taboo and often a last ditch safety from bottoming, modern bump rubber materials are often much softer and more progressively designed than the hockey puck-like hard bump rubbers of many years ago. Car designers often now use bump rubbers as a working suspension part as a progressive booster to the spring. This is the case on many cars like VW Jettas, many SUVs that want to live mostly on a smooth riding softer sprigns but be backed up my more strength when loading the vehicle, towing, etc. This is also the case on the MS3 as the car sits very close to the bump stop at stock ride height, especially at the rear and will make contact relatively often if the suspension compresses very much. Again, bump rubber contact is not always bad if it is well designed to work with the system.
So when I did the recent FSD installation on my car, I read the multiple threads on *** with many measurements, photos, thoughts, and impressions and did a lot of measurement on my car. My rear stock bump rubbers were full length and in good condition so we took many measurements and installed them as-is. Although with FSD we are always very concerned about side effects of bump rubber impacts and how the FSD feature will damp it, we found that there was no negative side effect with quite a bit of street mileage, on track, etc.. We tried loads ranging from just me in the car alone, to my rear hatch area stuffed with 6 x 18 inch wheels and race tires, and also two 300+ lb guys riding in the back seat specifically going over bumps and evaluating the ride quality and function. They did just fine at stock length with stock MS3 springs and no negative effects so I currently intend to leave them there. If someone wants to trim their stock bump stops or replace them, that is entirely their option (or their problem if it gets messed up) but our testing showed that they were just fine as-is with no mandatory changes.
My front bumpstops were not in as-new condition like the rears but like many photos on *** have shown, the very thin, soft bottom ring had been broken off from wear. This shortened the effective length of the bump stop by about 14mm but the end missing was so soft that probably would not really mean much if present. We installed the now slightly shorter front bump stops and there is quite a bit more free stoke travel, especially since the KONI Sport and FSD front strut and rear shock bodies are slightly shorter than the OE MS3 dampers giving a little extra free compression travel before contact.
So that is the status of my test car as it sits on the newer FSD struts with the higher rebound valving and nearly stock bump rubbers. I am very happy with it and I assure you that after 14 years and lots of testing and development work at KONI, I am very picky about suspension motion, control and ride quality. We won't approve something if we don't think that it is truly "good to go". We have tested several FSD applications on US spec cars and decided not to approve that listing in the US and Canada.
Many people are asking "Should I get KONI Sports or FSDs?". That question should be followed by "Do you ever plan to lower the car?". If you plan to lower the car, your choice should be the KONI Sport as lowering would put the car even more into potentially non-stop usage of the bump rubbers which likely would not get the best preformance from the FSDs. It won't hurt the shocks, the car might just feel underdamped in harsh bump rubber impacts. If you have no intention to lower your MS3 (as I do not since I have other lowered cars), then either Sports or FSD will be fine. FSD was designed to greatly smooth out rough road impact like ridges, seams, patches, etc and making the car more refined while making it handle better and more responsively. It is especially good and taking away some of the choppy ride issues passed along by the 18 inch wheels and low compliance, low profile tire sidewalls. The Sport is the adjustable option for someone who would rather trade a somewhat bumpier ride for slightly more crisp or sporty handling and sharper turn-in response and the ability to tune the dampers for car balance, other car mods, personal handling preferences, possible track or autocross use, etc. It is up to you to decide how you use your car and which set of questions best fits your desires for your car.
Sorry for the long write-up but hopefully this sheds some light on some current confusion.
