Koni FSD Review (very lengthy)

I had a set of these put on my 2001 330i about a year ago, and my car drove a little better than it did with stock shocks, but I had to replace all 4 wheels because they were all badly bent and now I am in the process of replacing the Koni FSD shocks with a new set of stock shocks. So if you live someplace with less than perfect roads like I do here in NYC, I would recomend sticking with stock BMW shocks.

Originally Posted by Dunlin

I had a set of these put on my 2001 330i about a year ago, and my car drove a little better than it did with stock shocks, but I had to replace all 4 wheels because they were all badly bent and now I am in the process of replacing the Koni FSD shocks with a new set of stock shocks. So if you live someplace with less than perfect roads like I do here in NYC, I would recomend sticking with stock BMW shocks.

Hmmm the OP said that these shocks were great because of the poor roads in Boston and you're saying they're not good on your car because of the poor roads in NYC?

You seem to have a different opinion than the OP. Could you explain why the shocks were responsible for your bent wheels and why stock shocks wouldn't have bent your wheels?

Originally Posted by Watchdog

Could you explain why the shocks were responsible for your bent wheels and why stock shocks wouldn't have bent your wheels?

Here's my guess...he didn't feel the bumps as much because of the FSDs so he just pounded over the potholes too fast, bending the wheels.

Sorry it took so long to respond, You definately feel the bumps and potholes alot more with the fsd vs stock shocks. I drove the same way with both stock shocks and Koni fsd's.
4+ years on stock shocks no bent rims, 1+ yrs on koni fsd's 8 bent rims my summer and winter rims!

This has not been my experience at all. I've had the FSD's for 2 years now, and I stand by what I said in the OP - there was a noticeable positive difference in ride quality compared to the OEM shocks, and a smaller improvement in handling.

The car does feel slightly stiffer on smooth pavement and small bumps (which is a good thing), but it just soaks up the large ones. Dunlin, maybe there's something wrong with yours?

Thank you for this review. My 01 330i with 85K is due from front and rear end suspension overhaul. I believe this is what I need and price wise sounds very reasonable.

Regards

Okay - I've been debating for almost two years and now I have to decide. I almost pulled the trigger then I took the easy route - I only needed new Fronts and got the bilstein for the front. I hated it at first, but grew to like them but the ride is a little harser than stock.

I need rears now. I can either get bilstein for the rear and be done with it or I was thinking about the FSD's again.

I need honest feedback from everyone who has lived with them for a few years....the OP stands by his review. I live in outside of NY in Queens and would love a car that handles great while I can also drive over pot holes....

One other negative I've heard is that the car feels "floaty" at higher speeds (the post defined higher speed 100 MPH), anyone experience it at highway speeds (60 - 80 MPH)

Thoughts?

You really should match what you have up front for best handling. The valving will be compatible and you won't have a difference in dampening by mixing brands/models of shocks.

I'm a big fan of doing all corners at once for best results, but YMMV.

I'm either replacing the rear with the matching bilstein or all 4 with the Koni FSD.

Originally I thought the bilstein were close to the factory sport ride so I could get away with replacing the fronts now and rear when I needed too....but its a stiffer ride. I can live with it, but I wouldn't mind the best of both worlds if I could really have it.

Originally Posted by gtvr6

I'm either replacing the rear with the matching bilstein or all 4 with the Koni FSD.

Originally I thought the bilstein were close to the factory sport ride so I could get away with replacing the fronts now and rear when I needed too....but its a stiffer ride. I can live with it, but I wouldn't mind the best of both worlds if I could really have it.

You can if you get adjustable shocks, which Koni makes as well. I have them (single adjustable) on my car and I like them a lot. I have it a little softer for street driving and stiffen them up for track time.

Bilstein also makes adjustables, but I think you need to get the whole coilover setup for them, and that's mo' money.

Koni FSD are the shocks in a Lamborghini Gallardo and Mr Ceccarani Technical Ditrector said they took the ride/handling to a new level. That will do my BMW thanks.

Originally Posted by 330ximd

Thanks for the feedback Avalys, excellent review as well, I'll look into it more, thanks again!

Let me know what you find out, and I'll do the same.

I've been pretty happy with my FSD/Eibach setup. It mostly rides better than stock, absorbing expansion strips and potholes better than stock. On rough undulating roads (e.g. concrete overpasses and bridges), it is firmer that stock, so you feel more vibration transmitted to the chassis -- kind of like driving on cobblestones.

Handling is slightly better than stock, but not dramatically so. Non-progressive springs and sways would do more for handling. I have not experienced any floatiness at high speed.

Also note that installing the FSDs alone will give you a slight drop for some reason. My car is pretty slammed on the pro-kits, which surprised me. That's the only real downside for me, as I did not want such a low drop. I have to be super careful on driveway ramps and parking garages, otherwise I will scrape (or bang the undercarriage!).

Also, regarding potholes, I feel the FSD will actually help prevent rim bends, as they are able to absorb large impacts much better than stock. I could be wrong, though.

Originally Posted by Dunlin

Sorry it took so long to respond, You definately feel the bumps and potholes alot more with the fsd vs stock shocks. I drove the same way with both stock shocks and Koni fsd's.

This is the exact opposite of everything else I've read.

I recently put FSD's on my car (last month), and really like them. The roads here are brutal, and I did not want something that rides harsh. I think the FSD's hit bumps very well, in fact, better than the stock setup I had with 70k on them. I like the handling as well, very stable in hard turns.

Originally Posted by gtvr6

I'm either replacing the rear with the matching bilstein or all 4 with the Koni FSD.

Originally I thought the bilstein were close to the factory sport ride so I could get away with replacing the fronts now and rear when I needed too....but its a stiffer ride. I can live with it, but I wouldn't mind the best of both worlds if I could really have it.

Hi gtvr6, which Bilsteins did you get, the Heavy Duty or the Sport?
IMO the Sport were FAR too stiff on my e36 sedan, but were wonderful on my e30 318is.

Can anyone else comment between Bilstein HD vs Koni FSD on a e46 with stock 'sport' suspension?
Like the OP, I feel the ride is a little rough on my 330i, but I love the handling.
With 106k miles, I'm due for an suspension overhaul, probably including bushings due to bad inside rear tire wear, and am torn between the Konis and Bilsteins.

Koni FSD and Bilstein both have 'Digressive' pistons, so it's probably mostly a question of valving.

Thanks,
Bob

Originally Posted by bobbozzo

Hi gtvr6, which Bilsteins did you get, the Heavy Duty or the Sport?
IMO the Sport were FAR too stiff on my e36 sedan, but were wonderful on my e30 318is.

Can anyone else comment between Bilstein HD vs Koni FSD on a e46 with stock 'sport' suspension?
Like the OP, I feel the ride is a little rough on my 330i, but I love the handling.
With 106k miles, I'm due for an suspension overhaul, probably including bushings due to bad inside rear tire wear, and am torn between the Konis and Bilsteins.

Koni FSD and Bilstein both have 'Digressive' pistons, so it's probably mostly a question of valving.

Thanks,
Bob

The Bilstein HD and the Bilstein Sport have the same valving, one is just shorter than the other. My FSDs were about the same stiffness as my stock ZHP shocks in the twisties, but they were much better over bumps.

Bilsteins have a rep of riding harsher than stock, so if you want a smoother ride, just go with the FSDs.

Originally Posted by bobbozzo

Hi gtvr6, which Bilsteins did you get, the Heavy Duty or the Sport?
IMO the Sport were FAR too stiff on my e36 sedan, but were wonderful on my e30 318is.

Can anyone else comment between Bilstein HD vs Koni FSD on a e46 with stock 'sport' suspension?
Like the OP, I feel the ride is a little rough on my 330i, but I love the handling.
With 106k miles, I'm due for an suspension overhaul, probably including bushings due to bad inside rear tire wear, and am torn between the Konis and Bilsteins.

Koni FSD and Bilstein both have 'Digressive' pistons, so it's probably mostly a question of valving.

Thanks,
Bob

Thanks... I'm gonna go with the FSDs.

Originally Posted by KrisL

The Bilstein HD and the Bilstein Sport have the same valving, one is just shorter than the other. My FSDs were about the same stiffness as my stock ZHP shocks in the twisties, but they were much better over bumps.

KrisL: did you keep your stock ZHP springs, or go with Eibach's? I've got a leaking shock at 55k and will change out all of them while I'm at it. However, I'm thinking that the Koni/Eibach kit will be batter matched than Koni/BMW ZHP. What are your thoughts?

Hi all, i'm driving an e46 330d limo with m-tech package and i want to replace all suspension kit. i want to put FSD shoks, but i'm not decided what springs to use...either Eibach Pro 30/20 or H&R Sport 35/20 ... any advice?

Originally Posted by sp_w

Hi all, i'm driving an e46 330d limo with m-tech package and i want to replace all suspension kit. i want to put FSD shoks, but i'm not decided what springs to use...either Eibach Pro 30/20 or H&R Sport 35/20 ... any advice?

According to Koni, you can use Eibach with FSD shocks: "Pair with Eibach springs for 1"-1.5" lowering" http://www.koni-na.com/fsd.cfm
If you don't get the info you want here, try contacting Koni directly.

Search this forum for more on FSDs: http://www.bimmerfest.com/forums/forumdisplay.php?f=49

See: http://www.tirerack.com/suspension/tests/koni_fsd.jsp

Very nice write up. Suspension really depends on the type of driver and what your looking for overall in my opinion. I could careless about how soft and good it feels. The stiffer and sportier to me the better.

Eibach Pro Kit/FSD fitted. For crap roads to freeways it's a revelation. This should have been the the OEM suspension, not the crap it came with!

FSD + Eibach do not ride better than stock. I think people go from bad stock shocks to brand new ones, and make the comparison that way.

If you have poly-urethane bushings, lowered car and aftermarket shocks, be prepared to ride uncomfortably.

This should have been the the OEM suspension, not the crap it came with!

I don't know what model you own, but you can't compare the suspension of a 325i to that of an M3. For what they are meant to do, OE suspension is fantastic.