[Ennoch]

So I've been looking at Eibach springs alongside damper options (more on that later). Now I've seen there are two options that are obvious; E10-20-031-05-22 and 06-22 which are referred to for F31 335d's on here, with the 05 being lower at the front. However, most sites seem to list E10-20-031-16-22 for this car. Are they superseded parts? Simply higher ride height options? I might be failing at my googling but I can't seem to find any obvious explanation for the different part numbers (I know Eibach have multiple options for different engine/body combos) given every post I've seen on here says it's either the 05 or 06 options for the 335d wagon.

[danb1979]

Originally Posted by Ennoch

So I've been looking at Eibach springs alongside damper options (more on that later). Now I've seen there are two options that are obvious; E10-20-031-05-22 and 06-22 which are referred to for F31 335d's on here, with the 05 being lower at the front. However, most sites seem to list E10-20-031-16-22 for this car. Are they superseded parts? Simply higher ride height options? I might be failing at my googling but I can't seem to find any obvious explanation for the different part numbers (I know Eibach have multiple options for different engine/body combos) given every post I've seen on here says it's either the 05 or 06 options for the 335d wagon.

Pro-kit ending 22 is what you need squire:

https://www.eibachshop.co.uk/product...ll-wheel-drive

c30mm front and c15mm rear; you'll get the rear drop about 15mm as they say; for the front, more than likely 10-20mm max in my experience; but they'll remove that BMW rake look and you should have an even wheel.arch gap all round

The POTN website, the link above; is what I tend to use and never had an issue re springs and part numbers etc

[Ennoch]

Indeed, so it is - I think the posts I was looking at yesterday were for the F30 and RWD F31 with the 05/06 part numbers vs the 16/17 for the F31 XD. I'm also considering the damper situation now the warranty is done; probably between B6 and EDC delete, B6 DT's and the Koni Sports. The B6 option would probably push me towards getting the 16 Eibach's to account for the increased ride height the B6 charge pressure adds. I would like to keep EDC but the cost is quite stark, and I haven't found anyone comparing the damping rates between B6 DT and passive B6. Koni are great on the Impreza but they're also usually underdamped in compression IMO which is where some of the instability seems to come from on the F30, albeit not as much as the wildly underdamped on rebound rear pre-LCI dampers.

[danb1979]

Originally Posted by Ennoch

Indeed, so it is - I think the posts I was looking at yesterday were for the F30 and RWD F31 with the 05/06 part numbers vs the 16/17 for the F31 XD. I'm also considering the damper situation now the warranty is done; probably between B6 and EDC delete, B6 DT's and the Koni Sports. The B6 option would probably push me towards getting the 16 Eibach's to account for the increased ride height the B6 charge pressure adds. I would like to keep EDC but the cost is quite stark, and I haven't found anyone comparing the damping rates between B6 DT and passive B6. Koni are great on the Impreza but they're also usually underdamped in compression IMO which is where some of the instability seems to come from on the F30, albeit not as much as the wildly underdamped on rebound rear pre-LCI dampers.

See what Evolve offer re their partnership with Bilstein - Can't remember off the top of my head

But having a decent damper IMO is better than a standard damper and then EDC adjustability

And personally I'd go for the B8s over the B6s if you're going to run Eibach pro-kit springs; they pair much better

However, for every day driving, I cannot fault the Bilstein B4S (correct ones for M Sport) at all - they've been superb on our F31 with the Eibach pro-kit springs

[Ennoch]

I had a look just now at their site and their single '335XD' listing says it doesn't work on XD. Now I suspect that's an error, but at £600, you then add on £300 for EDC delete modules, and you're at £900. Sure, that is £500 shy of some Bilstein EDC B6's but I do like the contrast between comfort and sport - I'd happily have a setup where comfort is softer than OEM and sport is harder. The main issue is the general lack of control over repeated rollers and crashiness over broken surfaces. My mate's old car had Schnitzer spec KW adjustable coilovers which felt superb but just didn't have the wheel travel for a lot of the roads I enjoy pushing on. Smoother roads like the A822 from Dunkeld down towards Crieff you never noticed it but the A832 in places is a very different proposition. In the interests of preserving negative travel I'd be inclined to stick with B6's over B8's if they don't leave the springs rattling around. I wish manufacturers would post their damper rates more openly, it would make life a lot easier.

[bennysbimmers]

I used to have EDC and got rid of it and had it coded out. Getting rid of EDC was the best thing I ever done, the car is much more predictable with passive dampers!

I fitted Eibach springs and Bilstein B4s at first but it was too soft for me, hitting bumps at speed would unsettle the car. I’ve just upgraded to Bilstein B8s and they are a million miles better!

You can definitely feel the bumps more, but it’s worth it for the superior handling! I wish my front arch gap was smaller though

[Ennoch]

Originally Posted by bennysbimmers

I used to have EDC and got rid of it and had it coded out. Getting rid of EDC was the best thing I ever done, the car is much more predictable with passive dampers!

I fitted Eibach springs and Bilstein B4s at first but it was too soft for me, hitting bumps at speed would unsettle the car. I’ve just upgraded to Bilstein B8s and they are a million miles better!

You can definitely feel the bumps more, but it’s worth it for the superior handling! I wish my front arch gap was smaller though

So EDC in itself isn't making the car unpredictable, that's the dampers not having enough damping to control the mass of the car and the wheels as they ride bumps and compressions and is down to the internal valving that BMW chose. Given the miles I do on the A9 I'm keen to keep the split; driving for three hours after a 16hr day in the hills I want comfort, not a sports car, but on the way there I want to have some fun on the B road bits. And I've got the Impreza if I want to have real fun which is running Prodrive/Eibach springs and Koni Sport damper inserts although they're a bit lacking in compression compared to the rebound only adjustment available. On the BMW my goal is to gain better control of the car's motion on B roads which doesn't need to come from running it super stiff. It's why I'm not totally sold on the idea of the coilovers, my mate's ACS ones were awesome but I never drove that car on the roughest of roads I use and that's where greater droop travel comes in.

The problem is that I know what I want to achieve, but the lack of info on everything makes it hard to make the right choice, especially given different people online describe different things in different ways and drive different roads. One person's 'too soft' is another's 'too crashy'. What I do know is that the current springs are too linear which means they're too stiff at low speed and too soft at high speed, and the rebound is definitely a little lacking, particularly at the rear which leads to the car pitching around a lot when hitting multiple rollers in close succession. Cheers for the input on the B4 vs B8 though, I appreciate it.

[danb1979]

I deffo think speaking to Evolve and seeing what they have / or what they may have coming from Bilstein is worth it Ennoch

Their shocks in unison with Bilstein are getting really good reviews; Sreten of M539 fame has them fitted to a few cars now; and he's said that they're softer than M Sport when set and then firmer when set that way etc

Have you considered the likes of KW StreetKomfort coilovers at all?

I know what you're saying re the roads around you and the A9 - when we were up in Dunkeld in my E39 this Feb; the Bilstein B14s were absolutely superb. Took the rougher parts of the road really well; were super-smooth and quiet on the newly refreshed parts of the A9, and when we went over to Braemar via Glenshee etc - they took that roads brilliantly

Yes; a touch firmer, but not stupidly so. Even my wife commented on how well the car drove (albeit on the 17" Goodyear all seasons)

When I went onto the 18" Style 65s with the Hankook tyres it drove fantastically then as well; she borrowed it to go up to East Lancs with her pals for an afternoon and there were no complaints at all

Whereas when they did the same trip but in my previous E81 130i LE with the B14s fitted; they said it was too firm and not a comfy ride (it wasn't meant to be)

[Ennoch]

I did speak to Evolve today but wasn't particularly impressed with the guy I spoke to who clearly wasn't the suspension expert. Not that that in itself is a problem but they said their dampers are basically OEM replacements (not necessarily what I've seen them describe elsewhere) and that they don't have any EDC plans for the F series of cars, albeit I see they do offer them for the E90 M3, for all the good that does me. He said they were essentially just a slightly tweaked B4.

I did look at KW's but all the coilovers options are just a bit lacking in travel for me. The car already doesn't like the wheels becoming airborne over crests and such and these will only exacerbate that. KW are probably the only one I'd consider though in the absence of the ACS one being available but overall I'd still just prefer to stick with struts although the damping adjustability would certainly be a nice to have. The glenshee road is great fun, I've melted a lot of brakes on the section between Blair and the Spittal, although compared to a lot of roads around here it's all pretty smooth! And on that note I'm also keen to keep the 403M wheels rather than dropping down to 18" for summers despite the trade offs that I know that gives which again changes how I'd view spring rates. Basically I want OEM style suspension that actually works, I'm not fussed about dropping it or having it stupidly stiff etc, it's more a controlled suspension setup that's comfortable when it needs to be but not wallowy. Taught and controlled might be the best description of that?

[danb1979]

Originally Posted by Ennoch

I did speak to Evolve today but wasn't particularly impressed with the guy I spoke to who clearly wasn't the suspension expert. Not that that in itself is a problem but they said their dampers are basically OEM replacements (not necessarily what I've seen them describe elsewhere) and that they don't have any EDC plans for the F series of cars, albeit I see they do offer them for the E90 M3, for all the good that does me. He said they were essentially just a slightly tweaked B4.

I did look at KW's but all the coilovers options are just a bit lacking in travel for me. The car already doesn't like the wheels becoming airborne over crests and such and these will only exacerbate that. KW are probably the only one I'd consider though in the absence of the ACS one being available but overall I'd still just prefer to stick with struts although the damping adjustability would certainly be a nice to have. The glenshee road is great fun, I've melted a lot of brakes on the section between Blair and the Spittal, although compared to a lot of roads around here it's all pretty smooth! And on that note I'm also keen to keep the 403M wheels rather than dropping down to 18" for summers despite the trade offs that I know that gives which again changes how I'd view spring rates. Basically I want OEM style suspension that actually works, I'm not fussed about dropping it or having it stupidly stiff etc, it's more a controlled suspension setup that's comfortable when it needs to be but not wallowy. Taught and controlled might be the best description of that?

Not being snarky or sarcastic pal; but do you think you might be asking too much of an F3x car?

All I can think of are coilovers or custom coilovers (goodness knows at what cost - GAZ, Nitron etc)

Going through shocks and springs will cost a fortune...

I will say that when I've done the run through to Braemar in the F31 on the B4S shocks / Eibach pro-kit springs, the F31 took the road superbly; but it is on 18s and I wouldn't go bigger personally.

I do think dropping to 18s for you would be a good decision; that extra bit of rubber can make a lot of difference on the ride & handling

[johnung]

Always check European manufacturers European catalogs because they are most complete. Other regional catalogs are notoriously incomplete such as US catalogs. They often only show the sunset of a manufacturer’s products that are distributed in that area. That doesn’t mean that you can’t get any part that’s made if you find the part number in the European catalog and have it shipped.

Note: It’s obvious that sources who were advising Eibach -05/-06 part numbers were looking at F30 335i XDrive, instead of F31 335d XDrive. Those -05/-06 part numbers are incorrect for your car.

For your F31 335d XDrive, the Eibach.de catalog clearly shows two pro-kit spring options- please see below. Both claim a rear 1,300kg axle weight and drops of Front 30mm, Rear 15mm (assuming the specified axle weights).

Looking at the individual front & rear spring specs, both kits use identical rear springs. Their front springs use identical 13.2mm thick wire and 4.5 coils. They only vary in a 15mm front spring height difference. So if these two spring kits were installed on the same car, the front of the -16 kit would be about -15mm (-0.6”) lower than the front of the -17 kit.

The -17 kit is intended for cars that are heavier in front by 20kg. They compensate with a +15mm spring height with the intention of matching the same -30mm front drop.

E10-20-031-16-22 for front axle 1,075kg
Spring height= 235mm

E10-20-031-17-22 for front axle, 1,095kg
Spring height= 250mm

https://www.eibach.de/iam/fahrzeugidentifikation

So you should use the E10-20-031-16-22 Eibach Spring kit. The -17 kit would be 15mm higher in front than the -16 kit.

DAMPER OPTIONS
For at least a year now there has been a high quality Adaptive replacement that is a lot less expensive than Bilstein B4-Damptronic. MonroeEDC are made at their factory in Spain. People in the US are having the MonroeEDC shipped from Europe and they are still much more reasonably priced than B4-D’s. See attached photo.

Tip: When I’m unsure about an aftermarket part number catalog description, I use the realoem website with the last 7-digits of a car’s VIN to look up the BMW 11-digit part numbers. Most catalogs list compatibility with the car makers part numbers.

So you could replace your stock Adaptive dampers with MonroeEDC along with Eibach -16 springs. It’s also a good idea to refresh ride comfort by replacing top hats that have a bearing that wears out, and lower rubber spring perches that loose resiliency. Consider upgrading stock bump stops to F80 bump stops that are shorter to help with reduced damper travel, and have denser foam that increases bump stop spring rates.

They are not inexpensive but KW DDC coilovers maintain the EDC technology. People who have them, like them.

Bilstein B6-Damptonics get complaints about being more stiff/harsh than original Adaptives. Also B6 &B8’s actually raise chassis height and increase tire/fender gap. See video link.

I’m a fan of Adaptive/EDC, but if you decide to scrap your investment, for separate components I would recommend the Eibach -16 springs with Koni Sport Yellow which are adjustable for comfort (rebound).

For standard coilovers, ST & KW are excellent. The ST XA and KW V2 are roughly the equivalent of the Koni Sport/Eibach Springs configuration with adjustability for comfort/rebound, along with much more vertical adjustment flexibility. Remember with XDrive to limit front drop to -1.6” (40mm) to avoid risk of breaking front axles.

Hope this helps!

[Ennoch]

Appreciate the input johnung but as I previously said, coilovers are mostly below sticking with the existing dampers for a multitude of reasons. First of all, not enough travel. Secondly, usually too harsh. Thirdly, unless they're the high end Ohlins or KW, they seize solid after a Scottish winter. And as I do a lot of winter driving, that instantly rules them out. Even the not absolute bottom rung BC ER I had on the Impreza struggled on that front. Mostly they're designed for track and smooth European roads, and I can assure you that is not what I drive on a regular basis. In fact one of my old L322's was still the quickest I've still ever hit a section of road because I could clip both sides of the dirt edging the single track road due to how much travel it had. Travel, as far as I'm concerned, is king. And on a road car, struts are infinitely preferable to a coilovers from a longevity perspective despite any potential advantages of easy ride height adjustment. I just wish an OEM style strut was available with external damping adjustment as there is for the Impreza from STI and KYB.

As to springs I have looked at both the 16-22 and 17-22 and in the interests of trying to generate a better roll centre and reducing understeer I'd be inclined to look at the former, despite lowering not being the priority. My mate set up his car after many laps of the Milbrook alpine circuit when using the ACS coilovers and came to the conclusion that a proper positive rake angle works wonders. I found the same thing with the Impreza when setting that up and used spacers under the rear top mounts to generate the angle I wanted. I hate understeer, especially in an AWD car where you've already got front drive to deal with any oversteer issues.

Bump stops are already on the agenda although I'm inclined to go the opposite of what most people do and rather than go shorter and harder, go longer and softer. This means that they are more progressive when on bigger compressions mid corner (I'd stick with longer and harder on smoother roads and track).

Monroe dampers aren't on the radar; they will have the same issues as the OEM cars where they are simply underdamped. Nobody has said anything to the contrary on this. For the same reason I'm not particularly interested in B4's. The 'issue' of raising the car with the B6 is simply not an issue for me due to the aforementioned point of travel being king. I'm a lot more bothered about handling than looks, mostly, and extra height means more clearance when driving up dirt tracks.

The biggest question I have is where non-EDC B6's sit against Koni Sport, and the EDC spec B6. Currently the favoured option is the EDC B6 despite the cost and then potentially getting a mate to revalve them if they prove to be too stiff, albeit that would be more money.

[danb1979]

FFS - 'johnung' spouting the usual drivel he copies and pastes every time suspension thread crop up on here

[Ennoch]

Originally Posted by danb1979

Not being snarky or sarcastic pal; but do you think you might be asking too much of an F3x car?

All I can think of are coilovers or custom coilovers (goodness knows at what cost - GAZ, Nitron etc)

Going through shocks and springs will cost a fortune...

I will say that when I've done the run through to Braemar in the F31 on the B4S shocks / Eibach pro-kit springs, the F31 took the road superbly; but it is on 18s and I wouldn't go bigger personally.

I do think dropping to 18s for you would be a good decision; that extra bit of rubber can make a lot of difference on the ride & handling

Absolutely not taken as such, and you may well be right. I'm definitely not asking for perfection, the chassis is a bit limited for that, although the F80 seems to go okay so there should be some scope for improvement over the current setup even with the leccy steering. I have no interest in trying damper after damper, I'm looking for a one and done, hence all the research I've been doing recently! Too many other things to be spending money on for that nonsense...