[Trelos]

Anyone know if these are compatible? From what I've read on Koni's website it's not a great idea to mix FSD's and lowering springs, but considering the Dinan springs drop the car maybe a quarter of an inch I was thinking they may work.
Honestly I just want the car a touch lower and a touch firmer, more like my RWD E90 was.
Do I need the "supplemental ride quality kit" as well if I go this route?

[NiNeTyOne]

The Eibach Pro springs are totally fine. They drop the e91 1.33 in front and 1.25 in the rear. Been running them for thousands of miles. The car at that height is right in the center of the range of the damper. Confirmed with Koni in Europe.

[Trelos]

Originally Posted by NiNeTyOne

The Eibach Pro springs are totally fine. They drop the e91 1.33 in front and 1.25 in the rear. Been running them for thousands of miles. The car at that height is right in the center of the range of the damper. Confirmed with Koni in Europe.

Thanks, not sure I want to drop it that much (yeah I know it's not a lot) it's a daily driver and I want no concern with bottoming out on anything or any issues in snow, also moving to a home with a slightly rutted gravel driveway soon so I don't want that hassle either.

But if the eibach kit is ok for them then I'm guessing the Dinan will work fine too.

[NiNeTyOne]

Originally Posted by Trelos

Thanks, not sure I want to drop it that much (yeah I know it's not a lot) it's a daily driver and I want no concern with bottoming out on anything or any issues in snow, also moving to a home with a slightly rutted gravel driveway soon so I don't want that hassle either.

But if the eibach kit is ok for them then I'm guessing the Dinan will work fine too.

You'll have no issues at all. You'll be about 1/2" below a stock non-Xi car.

I have never bottomed out and drive up to Mt. Baker in deep snow all winter, I've never once had a problem.

This is where you'll end up:

[Trelos]

Originally Posted by NiNeTyOne

You'll have no issues at all. You'll be about 1/2" below a stock non-Xi car.

I have never bottomed out and drive up to Mt. Baker in deep snow all winter, I've never once had a problem.

Hmmm

Not bad, how do you like the the FSD's?

[NiNeTyOne]

I have driven them back to back against the other commonly used dampers, and frankly, I think they do a better job of keeping the tire in contact with the pavement.

The technology is completely different from traditional monotube dampers, so they feel different. They are much more like Ohlins R&T tech, which I believe to be superior to almost everything people are putting on these cars, including the FSD's from Koni.

Remember that FSD came out of a co-development program between Koni and Maclaren's F1 program. As a pure mechanical damper, they are very good tech.

IF I had a non-xDrive car I would be putting Ohlins R&T's on the car without question (unless of course I was going to TTX dampers, but we're talking about a performance level that exceeds the requirements of street applications). Where the Ohlins improve on the Konis is how they deal with ride height (keeping the damper in the optimal range at all heights which is a critical performance feature), and the fact thet the damping is adjustable as well as height. With the FSD's they are what they are. You get no adjust-ability.

Ultimately I think it depends on what you want to achieve.

I prefer linear springs over progressives for a host of personal reasons, but they are a PITA to put onto FSD's or any other non-coilover application. I also prefer a coilover for adjust-ability as I would want to better balance the corners. However, having driven on KW's vIII's, Bilstein, etc. and I'm not impressed with how the standard crop of coilovers perform until you get up to the Ohlins R&T tech (DFV) which are NOT available for the xDrive cars (stay tuned, we're working on that). Stasis (now defunct) used to make Ohlins cored damper kits for Audi RS and S cars that were a step above what we can get in that price range on BMW's, and they were good for the price.

With xDrive, our options are pretty severely limited.

With all that in mind, I chose the FSD's because I feel they do what I want them to do on the street, and I drive fairly aggressively. They pair nicely with the Eibach Pro springs (even though I'd much rather have ERS springs). In the balance I think for most street applications they are a good choice. Having put about 7500 miles on them, I have a good sense of how they are holding up, and I'm pretty happy there as well.

I would even use them on track on rare occasion.

All this said, I am working on figuring out the Ohlins DFV solution for xDrive cars in my copious free time.

[DS3IAM]

Originally Posted by Trelos

Anyone know if these are compatible? From what I've read on Koni's website it's not a great idea to mix FSD's and lowering springs, but considering the Dinan springs drop the car maybe a quarter of an inch I was thinking they may work.
Honestly I just want the car a touch lower and a touch firmer, more like my RWD E90 was.
Do I need the "supplemental ride quality kit" as well if I go this route?

why not just go with the Koni Yellow as listed on the Dinan website? I have the set up and very happy with it .. if you like you are more than welcome to take a spin in the car. let me know


https://www.dinancars.com/products/?...id=1123#page=2

[Trelos]

Originally Posted by DS3IAM

why not just go with the Koni Yellow as listed on the Dinan website? I have the set up and very happy with it .. if you like you are more than welcome to take a spin in the car. let me know


https://www.dinancars.com/products/?...id=1123#page=2

Think I may just take you up on that offer.

Did you do the full setup? Springs dampers and "ride quality kit"?

[AtlasM]

I have FSDs with B&G springs which lower the car a lot more than the Dinan springs. For the most part they work fine but I'm probably lower in the front than is ideal for the crappy roads here in Wisconsin. The xDrive front suspension has less travel than rwd and I had to get creative with Speedthane polyurethane bump stops to make up for the reduced travel.

The FSDs do a solid job of controlling the car's body motions. People complain about "pothole explosion" problems with them, but I believe that most of the people having that problem are experiencing it because they have paired the FSDs with E36 M3 front bump stops, which are way too soft, especially on xDrive cars.

The E36 M3 front bump stops are the common choice for lowering an E9x because they're an OE BMW bump stop that's shorter than the stock E9x bump stop. But the E36 M3 is a much lighter car and its bump stops are much softer. With the FSDs, when you have a sharp impact, they go soft to absorb the impact. With a soft bump stop it's not enough to work with the shock going soft. When I first installed the FSD/B&G combo, I did it with the E36 M3 bump stops, and yeah, they did the pothole explosion thing. Once I ditched the E36 M3 bump stops for the poly ones, that fixed the problem.

So basically don't use E36 M3 bump stops with FSDs. For a mild lowering like Dinan springs, better to keep your stock bump stops.

[Trelos]

That's what i'm worried about, going too low and causing an issue. Too often people don't realize how complex the geometry is in the suspensions of these cars. It's designed to be a certain height with (X) bump stop and (y) damper spring combo. Not to mention the control arms etc.

Also I noticed the Koni yellow's are no longer on Dinan's website for the front (AWD model) they have rear's but no front strut listed. So at this point I'm not sure what to do.

[Dan Bilzerian]

Originally Posted by Trelos

That's what i'm worried about, going too low and causing an issue. Too often people don't realize how complex the geometry is in the suspensions of these cars. It's designed to be a certain height with (X) bump stop and (y) damper spring combo. Not to mention the control arms etc.

Also I noticed the Koni yellow's are no longer on Dinan's website for the front (AWD model) they have rear's but no front strut listed. So at this point I'm not sure what to do.

My dude, get the FSD's with the Eibachs pros!

[335xs2dinan]

Originally Posted by Trelos

That's what i'm worried about, going too low and causing an issue. Too often people don't realize how complex the geometry is in the suspensions of these cars. It's designed to be a certain height with (X) bump stop and (y) damper spring combo. Not to mention the control arms etc.

Also I noticed the Koni yellow's are no longer on Dinan's website for the front (AWD model) they have rear's but no front strut listed. So at this point I'm not sure what to do.

I dont think they ever were on Dinan s site, but Koni does make Koni Yellow front struts for x drive models. you can get them from various e90post vendors. i have them and they match nicely with dinan springs - very pleased.

[DS3IAM]

Originally Posted by Trelos

Think I may just take you up on that offer.

Did you do the full setup? Springs dampers and "ride quality kit"?

the original owner did the set up .. everything Dinan expect the front struts .. he kept the sport struts but lowered it with Dinan springs. the rear he went with the koni yellow with Dinan springs. im not sure if he got the kit .. i have to check the receipts.

[NiNeTyOne]

Originally Posted by Trelos

That's what i'm worried about, going too low and causing an issue. Too often people don't realize how complex the geometry is in the suspensions of these cars. It's designed to be a certain height with (X) bump stop and (y) damper spring combo. Not to mention the control arms etc.

Also I noticed the Koni yellow's are no longer on Dinan's website for the front (AWD model) they have rear's but no front strut listed. So at this point I'm not sure what to do.

I have had no issues whatsoever, and I've been on them for nearly a year. I have never once bottomed on anything, including speed bumps, and my driveway is wicked steep.

Eibach sells the FSD/Eibach Pro kit in Europe, and it works great, ask Dan, he's driven my xi Wagon in anger.

[AtlasM]

Originally Posted by Trelos

That's what i'm worried about, going too low and causing an issue. Too often people don't realize how complex the geometry is in the suspensions of these cars. It's designed to be a certain height with (X) bump stop and (y) damper spring combo. Not to mention the control arms etc.

Also I noticed the Koni yellow's are no longer on Dinan's website for the front (AWD model) they have rear's but no front strut listed. So at this point I'm not sure what to do.

Generally the springs designed for awd keep the front end relatively higher in order to maintain a decent enough amount of suspension travel.

I, being obsessed with getting rid of the unsightly wheel gap, went with the B&G springs to get the ride height where I wanted it. I used shorter, very stiff (but progressive) polyurethane bump stops in order to make up for the decreased travel.

With the FSDs and the trick bump stops, my car's body control is excellent and generally it handles bumps fine for a lowered car. I happened to test drive a Fiat 124 Abarth recently and over all the little tar strips and generally crappy roads around me, that 124, stock, was stiffer over the bumps than my car, and I'm running 19" wheels and a bunch of hardened bushings.

The only ill effects are on very sharp bumps like potholes the front of the car gets upset a bit, or when turning across sharp transitions in road grade I need to be a little careful to not take that turn too fast or the front end will bounce off the bump stops.

But again, these compromises are because I picked the springs that basically give you the most possible lowering on the front of an xi. If you use Dinan, Eibach or H&R springs you will have more front suspension travel than me.

The main thing to avoid doing is the E36 M3 front bump stops. They're way too soft for the front of a lowered xi.

[NiNeTyOne]

Originally Posted by AtlasM

Generally the springs designed for awd keep the front end relatively higher in order to maintain a decent enough amount of suspension travel.

I'm not sure that's exactly true. Springs are designed with a specific target rate, linear or progressive, and then someone who knows how to build a proper suspension setup then matches a damper to the correct rate spring for a given application, insuring that the travel is within operational range of the damper.

It all has to work together, and you can't just throw x-brand springs onto y-brand dampers and expect it to work properly.

That's one of the reasons the Ohlins DFV's are so good, they solved the damper range issue when lowering with that design, and it makes a huge difference. You just can't fit them on X-drive.

In Europe, Koni and Eibach sell a pre-assembled kit for our cars, but not in North America (apparently Eibach in CA didn't have cars to test so they never assembled kits). They are matched and work very well together. This kit pairs the FSD damper with the E10-20-014-10-22 spring kit. This is what's in my car.

[AtlasM]

Originally Posted by NiNeTyOne

I'm not sure that's exactly true. Springs are designed with a specific target rate, linear or progressive, and then someone who knows how to build a proper suspension setup then matches a damper to the correct rate spring for a given application, insuring that the travel is within operational range of the damper.

I'm generalizing.

If you look at most off-the-shelf lowering springs like Eibach, H&R, Dinan, etc., they're not sold as a kit with shocks, and most commonly used either with stock and/or off-the-shelf aftermarket performance shocks.

Since they're marketed as lowering springs, in addition to the things you mentioned, the spring manufacturer is also taking the ride height into account. Since the E9x xi front suspension has less travel at a given ride height than the E9x rwd, and its stock ride height is accordingly set higher than E9x rwd, it would stand to reason that the spring companies don't lower the front of the E9x xi so much because they're trying to not reduce the travel so much.

No, I'm not the engineers at those companies, but it makes sense. Generally speaking.

[NiNeTyOne]

Originally Posted by AtlasM

I'm generalizing.

If you look at most off-the-shelf lowering springs like Eibach, H&R, Dinan, etc., they're not sold as a kit with shocks, and most commonly used either with stock and/or off-the-shelf aftermarket performance shocks.

Since they're marketed as lowering springs, in addition to the things you mentioned, the spring manufacturer is also taking the ride height into account. Since the E9x xi front suspension has less travel at a given ride height than the E9x rwd, and its stock ride height is accordingly set higher than E9x rwd, it would stand to reason that the spring companies don't lower the front of the E9x xi so much because they're trying to not reduce the travel so much.

No, I'm not the engineers at those companies, but it makes sense. Generally speaking.

There are a small handful of kits out there making use of the Eibach Pro springs, of which there are many, many different heights and rates.

Having spoken to the folks at Koni in Europe directly, I was told those kits were carefully matched for specific applications by both parties.

[AtlasM]

Ok, I think this is getting a little too...specific.

Eibach has many different Pro-Kit springs depending on E9x body style, engine, and drive. Yes, there's kits in Europe that combine the FSDs with the Eibach springs.

But that doesn't mean you need to run those springs with the FSDs or they won't work. Even within the different FSD/Eibach kits they all have the same shocks. That's Koni part # 2100-4123 which is the same for all E9x xi cars.

My point was simply that if someone wants to run FSDs on an xi, they'll work fine as long as the springs that don't lower the front of the car too much, and don't run the E36 M3 bump stops.

Sometimes a general answer is a good enough answer.

[NiNeTyOne]

Yup, and for those looking to get a good spring/damper rate match, these kits do a good job of providing you a good measure of what the spring/damper manufacturers consider work together.

Personally, if I had my preference, I would up the rate on the Pro kit by 50# front and back with the FSD's. I'm pretty sure they can handle it without any issue and still be really good on the street. On track a really good driver is going to want a bit more rate if they haven't over bar'd the car.