Straight from Koni:
DO NOT USE LOWERING SPRINGS WITH FSDs under an circumstance. Due to the fact that the MINI has very limited suspension travel going lower than stock causes the frequency sensing valve in the FSD shocks to be bypassed which puts all the rebound damping on the intertia valve, a job it was not designed to do.

As AntiqueCarNut said, lots of people are running FSD's with lowered springs but the shocks are not working as Koni has intended them to - even if people think the setup is terrific. Read the reviews, yada, yada. I did that and it was a bad move. Ya' spends yer money and ya' take yer chances.

 

I posted that exact same thing last summer. I had a discussion with a product development guy at Koni and he implored me not to run anything but stock springs with FSD's.

 

Thanks for the heads up!!! What would be a recommend alternative with lowered springs?

 

then are we to understand that the FSDs that Koni itself is packaging with Eibach lowering springs are valved completely differently? If they aren't, then this doesn't make any sense.

 

Koni offers that package for other cars, not for MINI.

 

Koni offers Eibach/FSD kits for some vehicles, *but* the MINI is not one of them. Vehicles with more suspension travel than the MINI *may* be candidates for FSD's with lowering springs. If Koni offers an Eibach/FSD kit for a particular vehicle, it's likely that they have thoroughly tested that configuration and will accept the liability of an issue due to either component.

The way I understand it, is that on cars with more suspension travel, the frequency sensing valve operates over a wider range than it does on the MINI, before the intertia sensing valve is actuated, so lowering the car a moderate amount is OK - on other cars - but the MINI.

 

From the Koni website: "FSD kit must be used with stock height suspension."

http://www.koni-na.com/display.cfm?m...ubmit=Continue

 

IMHO? Bilstein SP's... Personally, I've had it with Koni.

If you're a Koni fan, Koni Yellows would be what you want.

 

Leda because they are fully customizable and can be used with 2 1/4" springs which becomes very nice if you want more than 2 degrees of negative camber.

 

Great ! !

I have a set of FSD in my garage waiting to be installed tomorrow with the TSW springs.......

Please tell me I am not going to regret this suggested system !

 

I think I am starting to understanding things a bit more as to how the FSD's work, and why Koni does not approve of lowered springs for the MINI. I'm referring to Koni's website and also trying to make sense of the Koni patent for the FSD's, I am going to relate this the best as I understand it, but would appreciate anyone who can analyze this better than me, to chime-in. It's interesting to note that this patent, issued in 1995, also covers an electro-magnetic version of the FSD design, as well as the mechanical version, which is what we're all familiar with. Koni makes a similar design shock for use on trains.

The FSD design is really two, seperate, dampers inside one housing; a frequency damper and a parallel-acting intertia damper. The frequency sensing valve, piston and chamber referred to as an 'amplifier' in the patent, operates first and restricts the action of the intertia valve - to a point. This amplifier operates at high frequencies (in chassis terms), of about 10Hz, and is made specifically to match the unsprung mass of the wheel, hub, brake assembly, control arm, etc. This mass is referred to as the 'wheel guide' in the patent. If the shock is compressed - past where it would normally be when the weight is on the car with stock springs, this amplifer valve is open all the time, and unable to adapt to the high frequency of bumps and undulations in the road. With huge bumps and while cornering, the effective frequency of the wheel guide changes, to approx. 1Hz, and the intertia acting valve rapidly takes over the damping function. I can see where this interita valve is not designed to operate at high frequencies for an extended duration - that's the frequency sensing valve's job. So, it makes sense, that the rapid operation of the inertia valve could possibly contribute its early demise.

Now, here's a thought -- What if the FSD's piston rod was shortened, by the length of the drop on a set of lowered springs and then re-threaded to allow proper mounting to the upper shock mount, if this would help the shock to function as intended? I don't know if this is an option - and I'm certainly not going to be the one to try it! The FSD's piston rod is hollow - and who's to know how much of the rod is hollow .

 

EVERYONE WHO IS USING FSD'S WITH LOWERING SPRINGS RAISE YOUR HANDS!!! Mine have been on my car for 28000 plus miles now-see my other threads about it-H-sports, M7,H&R springs used, H&Rs currently on the car for over 5k now. WERE THEY DESIGNED FOR THIS? who cares-DO THEY WORK BETTER THAN STOCK SHOCKS FOR A REASONABLE AMOUNT OF MONEY-DARN RIGHT THEY DO!! Do they improve ride and handling accross the board, regardless of sprng used? DARN RIGHT THEY DO! do they fail prematurely dueto lowering spring? MINE HAVE NOT AND THEY ARE ONE OF THE EARLIEST SETS RELEASED!! If anyone has more than 28k on a set of FSDs chime in-mine have NEVER been used with a stock length spring. FOR THE RECORD, DON IS CORRECT-KONI DOES NOT WANT THESE USED WITH A SHORTER THAN STOCK SPRING-AND the government would like us all to drive 55 and BMW would like us all to return our cars to stock configuration asap because none of this aftermarket stuff is any good, in thier eyes. As car tuners/modifiers/owners/drivers/enthusiasts we are always pushing the limits and the only way you find out if something works or not is to try it. I put my money where it counts and have been doing so with every product on my car. I DO NOT endorse any product that did not perform as advertised on my car. I beleve I hav emore experience with this product than anyone else out there on these cars, and I am only aware of 6? failed fsd shocks period, lowering springs or not. If there are more, no one is talking about it publicly. Might they work better with a stock length spring? could be, but my car is lowered and I like it that way. so do the 24 other people who have had me do this installation for them, as well as the other 12 who have purchased these shocks through me and done thier own installations. FOR THE RECORD, I HAVE ONLY INSTALLED ONE SET OF FSD SHOCKS ON A CAR WITH STOCK SPRINGS, SO ALL MY EXPERIENCE IS WITH LOWERED SPRING CARS.

 

"WERE THEY DESIGNED FOR THIS? who cares"

Brilliant argument.

 

Beyond reproach…
I have no dog in this hunt. The only reason I posted was to inform those with FSDs or those who are considering purchasing FSD that Koni does not endorse their use with lowing springs. I called the tech line and they explained the reasons to me. I just took that information and posted it.

From your post it is quite clear that you do not understand the reason why it is ill-advised. And you have now demonstrated to all that you either chose to ignore Koni's warning or that you did not read the instructions, the box, or the web site and are now trying to rationalize your error. But ignorance is not really a good excuse.

Your illogical attempt to tie this in with aftermarket parts and me is absolutely staggering. And in the end you conclude with “could be.” Shame on you.

 

IS SOMEONE TAKES WHAT YOU SAY OUT OF CONTEXT TO POKE FUN AT WHAT YOU HAVE SAID
THE SENTENCE READS:
" WERE THEY DESIGNED FOR THIS? who cares-DO THEY WORK BETTER THAN STOCK SHOCKS FOR A REASONABLE AMOUNT OF MONEY-DARN RIGHT THEY DO!! Do they improve ride and handling accross the board, regardless of sprng used? DARN RIGHT THEY DO!"

WAS NOT INTENDED TO BE AN "ARGUMENT"-WAS STATING THE FACTS I AM AWARE OF.

I have been away from the computer for a few days and had not read up on the most recent experiences posted-and now that I have, apparently there are somewhere in the area of 6? failed struts out there we are now publicly aware of. I don't expect KONI to make a big splash advertising thier failures any more than any other manufacturer does-HOWEVER- I represent 36 sets of FSDs, totalling 144 shocks out there in the real world, and AS FAR AS I KNOW, NONE OF THESE HAS FAILED. It is unfortunate acn has a failure on his hands, and texas speedwerks is doing any and everything they can to help-they are good guys and I stock and sell thier products. Koni may or may not have some quality issues at the moment, if they do it has not appeared in my customer base, but that doesn't make it impossible. My point is, in my daily driving on crappy concrete socal freeways, some hard canyon running and some auto x my early, 28000 mile set of FSDs continues to perform well with lowering springs. as do the others I have sold and installed.
I would also point out, every manufacturer who makes ANYTHING sold in this country today, attatches product disclosures to make them less liable in the event the product is not used as they intended. lots ofpeople have made bmw buy thier MINI R53 and R50 products back under lemon laws. That has not stopped the rest of us from buying and enjoying these cars-the amount of cars that actually are lemons is relatively small compared to the amount of cars built and sold, and so far it would appear the KONI FSD failure rate is also small compared to the amount sold and used.

 

Don didn't post anything that Koni or the shock designer didn't advocate. The fact that there is existance proof that one CAN use them in a way that isn't reccomended by the manufacturer doesn't change the fact that the designer thinks it's a bad idea.It does raise interesting points about the trade offs in using this part, as there are in using many parts, outside of the intended design envelope.

For those that have been working on Mini front suspensions, there are a few things to keep in mind when working on them. Most of these issues are caused by the fact that there isn't much room for a long spring given the suspension travel that's needed for the car. While going to thinner springs like Hypercoils and the like do let you get more camber, they do it at the price of a higher block length, effectily limiting travel. If you lower as well, this is a double hit.

As many have found, the design of most aftermarket struts for the Mini are somewhat travel compramized. Lowering on the Mini takes risks not only from compramized geometries (mostely in the front) and further increasing the mis-match in camber gain, but in severly limiting suspension travel such that firm springs and damping settings are needed to prevent constant bottoming.

It sucks, but there just isn't a lot of room in there for significant changes that don't really require severe compramises.

Matt

ps, what if I had posted that I came across the FSD patent, read it, talked to Koni, and posted all the warnings that Don had? Would the same level of reply happened? Hmmmmm....

 

Don, I humbly apoligize and have edited my posts above to reflect that-I use this product on my car and have good results with it and all the others I have installed in spite of the manufacturers recomendations. and for the record, I am an MTH user as well.

 

Apology accepted.

I own a shop that services MINIs and I even drive one.

I try to use the NAM forum for information sharing. The trouble seems to be some folks just do not want to hear the messages I bring. It is like they are blinded by brand loyalty and the placebo effect. For all but those seeking an extraordinarily high level of performance the Mini was well engineered by BMW. With complete certainty I say that it is far easier to go down the ladder of performance than up it.

 

So

 

So I imagine KONI has weight limitations on the ACTUAL DRIVERS who use FSDs in there MINIs. Scenario #1: A MINI with stock springs and FSDs, one skinny driver. Scenario #2: Same MINI, same spring/shock setup, but now you have a family of three who are all overweight. In scenario #1 the KONIs would work fine because that skinny person won't compress the springs much, if at all. BUT, and we're talking BIG BUTTs now, wouldn't the MINI ride lower in scenario #2, hence causing the KONI FSDs not to work well, because the amplifier valve is open all the time.

Also it sounds like if you change the unsprung mass or "wheel guide", which the KONI FSDs are tuned for then they won't work right either. So it logically follows that you can't have aftermarket wheels, tires, brakes, control arms etc. or the FSDs won't work properly.

All you guys with aftermarket wheels you better think twice about putting FSDs on your MINI. You have a lighter unsprung mass, and the amplifier valve won't work right. Right? I doubt it but that's the conclusion I reach based on the explanation from KONI on how thier product works.

Let's face it. KONI sells stuff, that's how they stay in business. They tell you not to match FSDs with lowering springs to cover their ***. And why shouldn't they. The FSDs are relatively new, and they probably haven't done the testing to determine if it will cause them to prematurely fail. They don't want to have to take a CHANCE to replace FSDs. Its a risk they don't want to take.

But when its all said and done I respect KONI for at least trying to be up front with people on thier product. As well as the other people who are trying to get the message out. Most of the aftermarket products out there are "buyer beware." And your SOL if you buy a product and it doesn't work for you the way it was advertised.

 

If a lowering spring lowers the car 2", how much added weight would it take for the stock springs to compress 2". My guess is it's a hell of a lot.

 

Your guess is right. If we just assume that each corner has ~200 lbs/in springs, to lower the car 2" it would take 400lbs - per corner - for a total of 1600 lbs in the car.

This is, of course, a rough estimation subject to the typical picking-apart, but should be easily accurate to order of magnitude.

 

you're pretty much splitting hairs here... how often in the life of a mini's suspension are the shocks supporting the cars maximum carrying capacity...

in addition... worrying about the sprung weight of wheel changes is not worth bringing up in the discussion such as this imo... it's just doens't change enough of the equation.

Frankly... i've sounded like a dmh fanboi latley... but I haven't even given him a single dollar of my money... although i gotta go with him again on this one. There are very few of us on this board that know as much about suspension as koni... whether you like their company or not... they do have some good people in design and engineering.

That being the case... just because it "works" on a street car, even if you push said street car hard, doesn't mean it's good to go.

Many times with suspension you have problems going on that you won't know about until it is far too late to recover from. Or problems that don't surface very often and only show up under a certain set of parameters. On that note... are you willing to go against manufacterers warning on a part that is vital to you keeping your car on the road/track?

My thing with suspension is similar to my opinion on engine parts. There are alot of people that fancy themselves are car enthusiests... but remember engineers are engineers and hobbiests are just that... The people that get involved with r&d and product development with suspension, brakes and engine parts are very well trained... very well paid and are trusted to make decisions that will affect many thousands of motorists traveling on the highways and byways traveling safley through variable conditions or traveling at maximum speed as safe as possible on the track...

either way... i trust them more then i trust any fly by night... or even local mechanic/aftermarket parts installer...

in short... it's all about the research.

 

Ignorance is bliss...but those of us who hammer our cars on the track and expect a high level of commitment from our components at speeds that kill quickly, tend to follow directions.

 

One front corner example; Take a corner weight ~850lbs and divided by the spring rate. That number is the number of inches the spring will compress when the weight (850lbs) car sits on that spring. Just keep adding weight to see how far the spring will compress...but each spring rate has a given rate of travel, they are not all the same