Initial Impression-- Koni FSD Dampers On an E91

Ordered them last week, installed them today and just got back from the 10 mile test drive. Of all the things said about the FSDs, the two that come most to mind are “there is a very noticeable improvement in comfort and handling” and “these are the dampers that should have been on this car when it left the factory.”

As many of you already know, Koni FSD dampers are unique in that they claim to be designed to have a two tier damping action. At rapid weight transfer, such as cornering, accelerating or stopping, the car stays level, not swaying or diving as much as OE dampers. At second damping action point, sudden bumps and deformities in the road surface are absorbed and smoothed out. These dampers are sold as a kit, which includes two front struts and two rear shocks. You can use your OE springs on the struts, purchase aftermarket springs, or buy a different kit from Koni that includes matched Eibach springs. I went with the regular FSD kit, i.e., I am using my OE springs with the FSD front struts.

I have been thinking of getting some Koni FSD dampers since I got my E91. Now that it has 50k miles on it I didn't want to put it off any longer. When I got serious about it, I started talking to car people and checking various forums online. Real life people generally spoke highly of FSDs. In the forums, most reviews were positive, but there were some incidences of premature leaking or outright failure.

One name came up in a post in 2007 and then again three or four years later. I paid particular attention to this guy’s posts because he had installed Koni FSD dampers on a touring and he owned them over a period of time. In fact, Highland Pete was the first to fit Koni FSD dampers to an E91 in the UK. Five years and 53 thousand miles later he told me he compares the ride on his touring to that of a Mercedes C-class sport with their version of the mechanical selective damper, i.e., nice and smooth with decent handling. This was a very persuasive endorsement.

Next step was to locate a vendor. There was pretty much just a generic BMW 328i fitment. But I knew that the OE E91 struts have a different part number than the E90 struts (although I don't know why) so I wanted to double check on the fitment. Koni's North American website only lists the 2100-4036 as fitting the E90 and E92, so just to be certain I contacted Koni tech or customer support. Their response: "These should work on your E91."

In the meantime, it seems these particular dampers were on nationwide backorder, no supplies expected until sometime in July. Two bimmerfest board sponsors basically said there were none to be had, give it up. One went so far as to add: "Koni does not list or approve this kit for any wagon models, so this would be a non returnable sale, 'order at your own risk' situation."

Now that is a pretty strong statement from this generally reputable vendor, so I put the question to Koni. Three times. The first two times they addressed other questions, but ignored my concern about their vendor's statement Koni does not approve or warranty FSD dampers for tourings. The final time I asked the question, their reply was "They should work." Apparently they are unable to say, "Yes, they WILL fit your E91, we guarantee it." Highland Pete, on the other hand, had actually been running the same model number on his 320d E91 for five years, with good results. I asked him why he took a chance and he said he contacted Koni support in Western Europe and they assured him it was a fit.

So I found a vendor in Southern California who not only had them in stock (“we have three sets in our warehouse in Michigan right now”), but even with the sales tax they came out significantly less than any of the other vendors would have charged if they had them, which they didn’t. And less than a week later, Federal Express delivered them to my door.

The ride on the touring from the factory is a bit harsh, noticeably more so than the ride on our E93. Up until I got behind the wheel for the first time with the newly installed FSDs, accelerated through the first turn and came to a quick stop I was thinking, “I should have got the kit with the Eibach springs.” My thinking is now I am glad I didn’t. I’ve never ran the touring hard and never will, but if I have to do some quick maneuvering the handling is definitely better than it was with the OE dampers.

The biggest difference I noticed is the ride comfort. Some of it is the new Michelin non runflats I put on about 1,500 miles ago, but most of it is the new FSDs. I’ll test it some more on some twisties and particularly bad roads this weekend, with an open mind. But for now my initial impression is noticeably better handling and significantly more comfort. I’m taking a short cut home in a bit, through Turnbull Canyon, a road I usually avoid because of all the twists and turns. Now, I'm looking forward to the ride home.

Did you lower the body?

Originally Posted by dtc100

Did you lower the body?

Replacing just the shocks will not lower the car. To lower the car you would need to use lowering springs or adjustable coilovers.

Originally Posted by Wihelm G

Ordered them last week, installed them today and just got back from the 10 mile test drive. Of all the things said about the FSDs, the two that come most to mind are “there is a very noticeable improvement in comfort and handling” and “these are the dampers that should have been on this car when it left the factory.”

As many of you already know, Koni FSD dampers are unique in that they claim to be designed to have a two tier damping action. At rapid weight transfer, such as cornering, accelerating or stopping, the car stays level, not swaying or diving as much as OE dampers. At second damping action point, sudden bumps and deformities in the road surface are absorbed and smoothed out. These dampers are sold as a kit, which includes two front struts and two rear shocks. You can use your OE springs on the struts, purchase aftermarket springs, or buy a different kit from Koni that includes matched Eibach springs. I went with the regular FSD kit, i.e., I am using my OE springs with the FSD front struts.

I have been thinking of getting some Koni FSD dampers since I got my E91. Now that it has 50k miles on it I didn't want to put it off any longer. When I got serious about it, I started talking to car people and checking various forums online. Real life people generally spoke highly of FSDs. In the forums, most reviews were positive, but there were some incidences of premature leaking or outright failure.

One name came up in a post in 2007 and then again three or four years later. I paid particular attention to this guy’s posts because he had installed Koni FSD dampers on a touring and he owned them over a period of time. In fact, Highland Pete was the first to fit Koni FSD dampers to an E91 in the UK. Five years and 53 thousand miles later he told me he compares the ride on his touring to that of a Mercedes C-class sport with their version of the mechanical selective damper, i.e., nice and smooth with decent handling. This was a very persuasive endorsement.

Next step was to locate a vendor. There was pretty much just a generic BMW 328i fitment. But I knew that the OE E91 struts have a different part number than the E90 struts (although I don't know why) so I wanted to double check on the fitment. Koni's North American website only lists the 2100-4036 as fitting the E90 and E92, so just to be certain I contacted Koni tech or customer support. Their response: "These should work on your E91."

In the meantime, it seems these particular dampers were on nationwide backorder, no supplies expected until sometime in July. Two bimmerfest board sponsors basically said there were none to be had, give it up. One went so far as to add: "Koni does not list or approve this kit for any wagon models, so this would be a non returnable sale, 'order at your own risk' situation."

Now that is a pretty strong statement from this generally reputable vendor, so I put the question to Koni. Three times. The first two times they addressed other questions, but ignored my concern about their vendor's statement Koni does not approve or warranty FSD dampers for tourings. The final time I asked the question, their reply was "They should work." Apparently they are unable to say, "Yes, they WILL fit your E91, we guarantee it." Highland Pete, on the other hand, had actually been running the same model number on his 320d E91 for five years, with good results. I asked him why he took a chance and he said he contacted Koni support in Western Europe and they assured him it was a fit.

So I found a vendor in Southern California who not only had them in stock (“we have three sets in our warehouse in Michigan right now”), but even with the sales tax they came out significantly less than any of the other vendors would have charged if they had them, which they didn’t. And less than a week later, Federal Express delivered them to my door.

The ride on the touring from the factory is a bit harsh, noticeably more so than the ride on our E93. Up until I got behind the wheel for the first time with the newly installed FSDs, accelerated through the first turn and came to a quick stop I was thinking, “I should have got the kit with the Eibach springs.” My thinking is now I am glad I didn’t. I’ve never ran the touring hard and never will, but if I have to do some quick maneuvering the handling is definitely better than it was with the OE dampers.

The biggest difference I noticed is the ride comfort. Some of it is the new Michelin non runflats I put on about 1,500 miles ago, but most of it is the new FSDs. I’ll test it some more on some twisties and particularly bad roads this weekend, with an open mind. But for now my initial impression is noticeably better handling and significantly more comfort. I’m taking a short cut home in a bit, through Turnbull Canyon, a road I usually avoid because of all the twists and turns. Now, I'm looking forward to the ride home.
Attachment 327539

Thanks for the review. I am patiently awaiting delivery of my FSD's. Last week I was told that there was a 2-3 week backorder of the shocks.

I do have 1 question for you: Did you need to align your car after installation?
Thanks.

Originally Posted by SD 335is

Replacing just the shocks will not lower the car. To lower the car you would need to use lowering springs or adjustable coilovers.

There is always a chance he sawed off the springs but forgot to tell.

I wanted to order FSDs for my E93 in 2007 and was told that they were not available for the E93. I called Koni and asked why I could not use the part number for the E92 and was told that I could not. In 2010 FSDs were finally available for the E93. When I checked I found that the part number was the same as the part number for the E92,

CA

Originally Posted by dtc100

Did you lower the body?

Nope. The car feels a little higher, if anything, but that is just a perception. The FSD kit with the Eibach springs lowers the car 1 to 1.5".

Originally Posted by jhorowitz128

Did you need to align your car after installation?
Thanks.

Yes, I did need to.

Some people say if you're careful enough in your install, you won't need to align. Others say at least check the alignment after the install, which is similar to those who say always align.

I had mine checked. It needed an alignment. If you're interested, I suppose I can scan the alignment report, which shows exactly how much realignment was needed after the install.

Originally Posted by captainaudio

I wanted to order FSDs for my E93 in 2007 and was told that they were not available for the E93. I called Koni and asked why I could not use the part number for the E92 and was told that I could not. In 2010 FSDs were finally available for the E93. When I checked I found that the part number was the same as the part number for the E92,

CA

I don't get it. It seems that many of the E9x models use a different damper in the Koni models other than the FSDs. Yet all four of the E9x RWD models use 2100-4036. The AWD models use the 2100-4123 kit. I think the Eibach springs FSD kit is 2150-4036 for all E9x RWD models. Good luck getting anyone to confirm that.

Originally Posted by Wihelm G

Nope. The car feels a little higher, if anything, but that is just a perception. The FSD kit with the Eibach springs lowers the car 1 to 1.5".



Yes, I did need to.

Some people say if you're careful enough in your install, you won't need to align. Others say at least check the alignment after the install, which is similar to those who say always align.

I had mine checked. It needed an alignment. If you're interested, I suppose I can scan the alignment report, which shows exactly how much realignment was needed after the install.

Thanks for the offer, Wihelm, but I'm sure that our starting points and ending points for alignment will be different. I'll check the alignment after the install. Glad you're happy with the shocks.

Does anyone know why the FSDs are not installable on 335xi? I would like to get these - but Koni says they have no application. Why won't the RWD FSDs for an E92 work?

Agree with the much improved ride with FSDs. I had mine installed about a month ago. 3 of the 4 wheels were out of alignment specs after they were installed. With other cars I haven't found that new struts changed the alignment. But I always have the alignment checked.

Originally Posted by Princeton

Does anyone know why the FSDs are not installable on 335xi? I would like to get these - but Koni says they have no application. Why won't the RWD FSDs for an E92 work?

This is an example of what I'm talking about. There are FSDs that are installable on a 335xi. They apparently are just not available in the United States. As for why the RWD FSDs wont work, comparing the two front suspensions on realoem.com might give some insight.

The struts on the 2008 E90 AWD and the E92 AWD are different. But Koni's "Worldwide" catalog lists the identical FSD part number, i.e., 2100-4123. So clearly there exists an application for the E90/92 AWDs.

The U.S. market catalog does not list FSDs for either the E90 or E92 AWD (the Sport dampers are the same for both E90 and E92 AWD models, to further confuse things). The 2100-4123 does not appear to be carried by any of the U.S. distributors I did a quick check on. I know they are available in Europe and my guess is that they are only available in Europe. I would further guess the reason they are not available in the U.S. is that Koni makes so few of them, coupled by a low demand.

My conclusion based on all this information and conjecture is there is an application for a 335xi E90 and E92, but you will have to get them from Europe. Or maybe check Canada. I wonder if someone could have had them fitted in Germany while they had their car for European Delivery.

Originally Posted by ramblinman

Agree with the much improved ride with FSDs.

All-season grand touring tires plus Koni FSD dampers seems to be a winning combination for my uses on a RWD dog hauler. I'm curious about opinions on other combinations of tire types (runflat, non runflat, summer performance, all season performance, etc.). What kind of tires do you have?

Originally Posted by Wihelm G

snip...

My conclusion based on all this information and conjecture is there is an application for a 335xi E90 and E92, but you will have to get them from Europe. Or maybe check Canada. I wonder if someone could have had them fitted in Germany while they had their car for European Delivery.

That could be an option as I doubt BMW does a detailed up-on-the-rack inspection of ED cars when they are dropped off for shipment to the U.S. Of course, the owner would be in a bit of a pickle if they needed a warranty replacement....

Originally Posted by Wihelm G

All-season grand touring tires plus Koni FSD dampers seems to be a winning combination for my uses on a RWD dog hauler. I'm curious about opinions on other combinations of tire types (runflat, non runflat, summer performance, all season performance, etc.). What kind of tires do you have?

Thanks. I went to the European Koni site - and here's what I found:

Soirry - my jpg will not upload. At any rate - they recommend 2100-4123.

Originally Posted by jhorowitz128

I do have 1 question for you: Did you need to align your car after installation?

One ALWAYS aligns after suspension part install, front and/or rear.

Toe & Camber min, simple adjustments. BMW has a sophisticated setup for that, or you can do it w/toe plates, measure, iPhone, & 19" o'extruded aluminum stock.

In a pinch, string & ruler sub for plates. Precision? Reasonable. Shop w/tri-laser tools better. BMW best.

Originally Posted by Wihelm G

This is an example of what I'm talking about. There are FSDs that are installable on a 335xi. They apparently are just not available in the United States. As for why the RWD FSDs wont work, comparing the two front suspensions on realoem.com might give some insight.

The struts on the 2008 E90 AWD and the E92 AWD are different. But Koni's "Worldwide" catalog lists the identical FSD part number, i.e., 2100-4123. So clearly there exists an application for the E90/92 AWDs.

The U.S. market catalog does not list FSDs for either the E90 or E92 AWD (the Sport dampers are the same for both E90 and E92 AWD models, to further confuse things). The 2100-4123 does not appear to be carried by any of the U.S. distributors I did a quick check on. I know they are available in Europe and my guess is that they are only available in Europe. I would further guess the reason they are not available in the U.S. is that Koni makes so few of them, coupled by a low demand.

My conclusion based on all this information and conjecture is there is an application for a 335xi E90 and E92, but you will have to get them from Europe. Or maybe check Canada. I wonder if someone could have had them fitted in Germany while they had their car for European Delivery.

If you Google search on "Koni 2100-4123" you will also get hits for UK distributors (English language websites), that show this pn for the 328 xi application.

Angie

Originally Posted by zeeway

If you Google search on "Koni 2100-4123" you will also get hits for UK distributors (English language websites), that show this pn for the 328 xi application.

Angie

Yup. Apparently for all E9x AWD models except the cabrio. Which makes no sense to me.

Hey wilhem,
I saw that you posted this on the 1st of this year.
I was looking to purchase some fsds for my e36 but no one had them in stock that I could find.

Which distributor did you buy yours from? And how much were they charging for them?

Month**

Originally Posted by Wickles

Hey wilhem,
I saw that you posted this on the 1st of this year.
I was looking to purchase some fsds for my e36 but no one had them in stock that I could find.

Which distributor did you buy yours from? And how much were they charging for them?

The company I got mine from, on Mira Mesa in San Diego, doesn't seem to carry the FSD 2100-4095. Call them, maybe they'll order it. Or try one of the bimmerfest board sponsors, like modbargains, esctuning or tirerack.

Thank you, yeah I don't think anyone has them in the US.
Guess I'll wait for them to ship from holland.
I can't wait to put them on!!!!

Did you install them yourself? This is one of my nexts mods.

Originally Posted by 07335i_sport

Did you install them yourself? This is one of my nexts mods.

Didn't install them myself, just watched carefully. And showed the installer that trick of putting the male end of a 1/4" drive extension through the 3/8" opening of a spark plug socket, popping on a hex socket at the end of the extension, slipping a box wrench over the top of the spark plug socket before attaching a 1/4" ratchet to end of the extension, placing the whole thing over the nut and hex-holed shaft at the top end of the strut, and then keeping the shaft from turning while tightening the nut with a box wrench slipped over the top of the spark plug socket. He said, without much enthusiasm, what a great idea that was, so I had to ask him how he would do it I hadn't been watching and he showed me a way I thought was rather crude, but apparently effective.

Other than that, and accidentally locking my keys in the compartment under the floor of the cargo area (whoever says it's not possible to lock your keys in your car if you have CA just isn't dumb enough to figure out how to do it) , the job seemed real straight forward. You will need a set of spring compressors, but other than that no unusual tools.