Koni FSD Shocks

[guitaraholic]

Ok, I know when something out of the ordinary is asked, the flaming begins, but I will ask anyways.

Koni has a new technology called FSD, (frequency select dampening?), The only prob is they only make them for BMW, Mini, Audi and a few other makes and models. Now here comes the big question.

Would it be possible to adapt a shock from maybe a 3 series BMW. Would it make it more likely if you converted to say a coilover suspension, by using coilover sleeves.

[SoSideways]

If they sell inserts of the FSD shocks, which I don't think they do, then you can do whatever to put them on your car.

For the money though, yellows will do you just fine.

[guitaraholic]

I'll have to check, the reason I'm interested in the FSD's are they are almost the perfect compromise between good handling and comfortable ride. They act like a soft shock on rough roads, moving a lot and absorbing the shock of the bumps. On hard cornering, acceleration and braking they resist movement and keep the car level.

In fact, they did a test Koni Yellows, 8080?s (whatever the track version is) and FSD's and for the most part the FSD's scored higher than both, and had faster lap times. Yes, I do believe you can fine tune the adjustables to work better for a certain track, and if the track is really smooth, you can go stiff has hell, but in real world situations and in normal spirited driving, the ability of the shock to help keep the wheels planted on the ground through bumps and imperfections in the road would ultimately win over the adjustables.... But that is just my 2 cents

btw, I've heard that not that much more expensive than the Yellows, if not the same price. I'll call Koni tomorrow and find out.

[SoSideways]

I honestly don't believe that Koni would sell something that was meant to be a compromised setup (for comfort and supposedly handling) that would cost about the same as Yellows, that would out handle something like their Race shocks.

Unless the Yellows and the Race shocks weren't touched and left at like the softest setting or something.

Either way, the FSD shocks have either a very digressive valving, or they use some type of electromagnet type fluid in their shocks, like those found in the Corvette with the Z51 package IIRC, and some of the newer Ferraris... which suggests to me that those shocks cannot cost the same as Yellows if it indeed has that technology in it.

So yes, please call Koni and find out what the deal is with the FSD.

[aznpoopy]

Koni: FSD (http://www.koni.com/58.html)

How does it work?

In standard shock absorbers the main damping characteristic is defined by the oil flow going through the piston assembly. (1)

Combining it with the FSD feature, KONI added a special valve (2), which controls an oil flow parallel to the one going through the piston rod. (3)

This parallel oil flow is closed by the FSD feature, giving a rise in damping force almost linear to the time that the piston is moving in one direction.

Put simply: the FSD feature is a hydraulic amplifier that delays the build up of pressure. One could say that an extra tuning option has been created in order to get the best possible combination of handling and comfort.

Since it is an integrated part of the hydraulic valve system inside the damper, no additional cables, sensors or any other electronic devices are needed to operate an FSD damper.

FSD is the simplest and most economic way to significantly improve the ride and driving characteristics of every car. Certainly in comparison with costly systems which work on the basis of computer technology, complex electronics and sensors.

edit: found the patent
http://www.freepatentsonline.com/7395907.html

[SoSideways]

OK, so basically it's just a digressive valving.

[racepar1]

OK, so basically it's just a digressive valving.


I believe that the pretty much all koni's have digressive valving. As far as I can tell these are supposed to kind of auto adjust dampening as you drive. They would be good for a street car, but if you really wanna track your car you want to be able to adjust the shock yourself.

[aznpoopy]

explained simply, the system comprises an extra flow passage (besides the normal one) and some kind of valve/diaphragm that controls the passage.

when you hit a hard bump, the fast compression of the shock makes the liquid inside move fast. the diaphragm responds to fast flow slowly, so the extra flow passage stays open. that makes the shock softer.

when you brake/corner/etc., the slow compression of the shock causes the liquid inside to move slowly. the slow movement of liquid causes the diaphragm to respond rapidly, closing off the extra passage. this makes the shock harder.

what does this mean in real terms?

OK, so basically it's just a digressive valving.

not at all. imagine your typical adjustable shock with a hard setting and a soft setting. if you can picture it on a dyno that means there will be two lines represented, one for hard and one for soft.

if it were merely a digressive shock you'd simply have two digressive paths traced out, but no way to alternate from one to another on the fly (minus something like an EDFC), and no way to utilize the settings in between those two lines.

As far as I can tell these are supposed to kind of auto adjust dampening as you drive.

i believe this is correct.

now take a FSD shock... it can have the same range of damping as the old style 2 click shock described above. but it has the ability to utilize the entire range between the old hard and soft settings depending on how fast the shock is moving. that's analogous to a traditional shock with an infinite number of clicks within the set damping range, with the shock automatically setting itself to the appropriate click for the situation based on frequency of oscillation.

you can see this at the end of the application (and in FIG. 5 of the drawings).

[SoSideways]

Hmm... ok, but I still don't see how they can incorporate something like that into a shock for the price of a Yellow.

In any case, I think the FSD type shock would be better for someone who drives the car on the street a lot, but want to hit the track here and there, and that the Koni Race series dampers are still going to be better for the track, once you've tuned the dampers to suit that particular track's layout.

[guitaraholic]

Hmm... ok, but I still don't see how they can incorporate something like that into a shock for the price of a Yellow.

In any case, I think the FSD type shock would be better for someone who drives the car on the street a lot, but want to hit the track here and there, and that the Koni Race series dampers are still going to be better for the track, once you've tuned the dampers to suit that particular track's layout.


You pretty much nailed it right on the head. I plan on spending a little bit of time on the track, but most of the time will be DD. So the FSDs are the perfect compromise.

[Def]

Sounds like a typically high speed blow-off valve(yes, that's what they're called) in a shock.

These aren't uncommon in nice dampers(Penske, Motons etc.). I guess Koni is just trying to bring this feature downmarket and market it more heavily.

[aznpoopy]

i doubt it, as they received a patent on it. its must either be a new feature or a totally new way of doing it. if it wasn't, it would have never made it through USPTO examination.

edit: i did a quick read on high speed blow off.
http://www.patentstorm.us/patents/5113980.html

it's very different. high speed blow off valve is normally closed, and opens upon meeting a certain amount of preset amount of pressure, basically like a bov for a turbo.

the FSD bypass is totally different. the bypass valve is normally open, and closes during movement of the shock. how fast it closes depends on how fast the fluid is moving. the faster the fluid is moving, the slower it closes, and vice versa.