[adrian_j]

Is it possible to retrofit the electronic damping suspension to 335i? After driving a family members model s Tesla with the Electronic suspension, I thought it was the best thing ever, I’m wondering anything like this is possible on 335i

[bennyball]

Several companies make electronically adjustable damping suspension, Bilstein come to mind

[Torgus]

You can retrofit just about anything with a large enough wallet.

My guess is this is going to go no where unless you are extremely handy and can fabricate.

There is no way the bang for the buck will make sense.

[rbryantaz]

Originally Posted by Torgus

You can retrofit just about anything with a large enough wallet.

My guess is this is going to go no where unless you are extremely handy and can fabricate.

There is no way the bang for the buck will make sense.

I did see a retrofit thread for them using 1M parts IIRC and that seemed like a huge task so I went a different route...


I am just about to fire up my custom controller... It isn't a retrofit but instead a way to use the EDC shocks with a manual controller.


This was inspired by (copied from) @marconi118 who I believe was the first to install a PWM controller for M3 EDC shocks on his 335i.



I have one of these boxes running in the front and one in the rear.

It was modified by replacing one of the original resistors and swapping it with a potentiometer to allow an adjustable maximum duty cycle of ~60% when the main adjustment knobs are fully turned on. This allows up to 2amps of current (full soft limit described by BMW in their EDC documentation) with the turn of potentiometers.

The unit is capable of much more (up to 20amps) but it was an easier unit to modify than the 5-10 amp designs that had a different design or used surface mount devices.
The design is a well known PWM controller running a simple DIP 555 timer with a PMW modulation @ 25kHz - 30kHz so it is not in the audible range and they are cheap and readily available.

I also added a current limiting device (the board on the right) which will shut down the circuit should something go wrong. It is currently set to auto reset after 1-2 seconds.

The unit is stiff by default so it is only likely to go into over current mode when set on a soft setting and given that I also modified the box to limit the PMW duty cycle to avoid it going to 100% (which would hit up to 3 amps) the current limiter is really overkill and for peace of mind so it has one extra level of protection for the shocks.

I further modified these to add a motorcycle volt and amp meter to the box but I don't have a picture on hand.

After considering a lot of mounting points I put them below the climate controls:


I think this location makes them mostly hidden but also accessible and it is also a cheap interior piece to change should I want to remove them or put them in another location in the future.

Blue controls the fronts and red controls the rears independently. These are also switched knobs so the system can be turned off and set to full stiff if desired.

I wired the system through an ignition switched relay so that if it is left on in full soft it won't draw 2amps all night and draw the battery dead.

-Rich

[whyzee125]

Easiest way by far would be to run something like Tein EDFC, it's aftermarket but the only way something like this would make sense IMO.

[marconi118]

Happy to se you did it really professional rbryantaz ! Congrats
Mine is more raw... but still works fine after nearly 10 years service

I have put the pots near the light knob. Indeed good location below aircon

[rbryantaz]

Originally Posted by marconi118

Happy to se you did it really professional rbryantaz ! Congrats
Mine is more raw... but still works fine after nearly 10 years service

I have put the pots near the light knob. Indeed good location below aircon

They are all up and fully working now. I added a cheap motorcycle volt/amp gauge so I can see how they are working. Readings are pretty accurate so it works well as a sanity check.

The front pair of shocks and rear each have a controller. Shocks are wired in series to increase the resistance which limits the current.

I set them to a max current of 1.75amps with a potentiometer in my custom controller. The max current specified by BMW for the EDC shocks is 2amps. The PWM frequency is limited to 60-65% max and runs at ~26kHz which is above the audible range making it silent and stable.

I decided to go only 7/8 to leave some margin on the max current. I also integrated a current governor in m controller as a second board so it will also limit the shocks if the current spikes over 1.9 amps and then will reset after a few seconds. This was added just incase my front adjustment adjustment potentiometer shorts out or fails in some way.

I can vary the stiffness from full stiff (off) to 7/8 soft set via the center console.

Each controllers power is supplied via a dedicated 30 amp relay that is triggered by the lighter socket circuit so that it turns off with the ignition.


Here is the front one in the glovebox (car not running but it shows the placment):



Here is the rear with the controller active running at 1 amp. The car was not running so the voltage is 12v instead of 14v and the voltage is taken after the current limit board so it has a slight voltage drop from the battery (yes this fits behind the side panel so it is completely hidden with the panel installed).


Here is the car sitting on the M3 front and rear competition package suspension with X7 front and X5 rear springs (no height adjustments have been made yet).



-Rich

[GnomeChild]

Going to resurect this old(er) thread

rbryantaz
Did you use completely stock M3 components in the front suspension? Did the M3 struts mount to the 335i Knuckle? Also I don't think I will be going the custom controller mount or even the M3 center console trim (don't think M3s ever came with Walnut). I'm thinking of possibly just having the system activated with M Mode on the steering wheel and being adjusted directly in M Drive menu on the iDrive. I think this is possible but will require some custom coding (clearly) and possibly an emulator (to trick the EDC system into thinking it is installed in an M3). However I just need someone to confirm their front fitment (rears I have experienced bolt right in)

What was your final drop like? I have stock M-Sport suspension and honestly an extra .5-1" drop would be perfect. It's hard to tell in the front with your picture as the wheel is turned

[rbryantaz]

Originally Posted by GnomeChild

Going to resurect this old(er) thread

rbryantaz
Did you use completely stock M3 components in the front suspension? Did the M3 struts mount to the 335i Knuckle? Also I don't think I will be going the custom controller mount or even the M3 center console trim (don't think M3s ever came with Walnut). I'm thinking of possibly just having the system activated with M Mode on the steering wheel and being adjusted directly in M Drive menu on the iDrive. I think this is possible but will require some custom coding (clearly) and possibly an emulator (to trick the EDC system into thinking it is installed in an M3). However I just need someone to confirm their front fitment (rears I have experienced bolt right in)

What was your final drop like? I have stock M-Sport suspension and honestly an extra .5-1" drop would be perfect. It's hard to tell in the front with your picture as the wheel is turned

Retrofitting EDC with factory controls into an M3 is a very very complex task. I have learned not to say that it is impossible for anyone to do it but it is basically impossible without a ton of research, skills, and access to information.

There is a thread on someone doing it on a 1M but it is very complex to get it working and not all of the details were known/given: https://www.1addicts.com/forums/showthread.php?t=794167

Fully active EDC requires adding many new sensors for YAW, different body computers, and is really outside of the scope for most people and the details weren't fully shared on the 1M that added it. I saw a note that they used an X5M module to get some of it working... The M3 steering rack is a complicated enough retrofit and it is nothing compared to getting factory EDC to work. Even if it was working tuning it to the 335i weight distribution (especially e93) would be even more complicated.... I think it would take weeks of work just to get the basics working and that assumes you already know how to code things in the car, swap modules from other cars, know which modules to swap, etc.

So with that... I went with the statically adjustable controller for the fronts and the rear. I was inspired by marconi118 who pioneered the work on his car and also had a lot of good advice about running M3 suspension on a 335i and what springs to run... With this we can soften the front and rear independently as desired but that dial changes both shocks on the front or rear and the car knows nothing about it.


Here is my experience with the M3 springs on a 335i with the full suspension swap front and rear (everything but the M3 front subframe which won't work due to different engine mounts).
I went with the M3 springs initially to get the car up and running again knowing that it would ride a bit high based on marconi118's experiences and advise....

M3 springs on an M3 suspension swapped 335i:

I used the stiffer and lower springs from a ZCP car. I also have a pair of the normal M3 springs marked X2/X1 but I never installed them.

The ride height with the M3 ZCP springs was a bit high which I was warned about. It was about 20-24mm too high in the rear compared to my 335i sport package target heights. The front was only about +10mm so it wasn't as bad and I did have the 3mm shims installed which could have been removed to drop it down to only +7mm from my 335i sport height target. This was with M3 ZCP springs marked X7 front and X5 in the rear.

Stock height targets were 599mm front with 19" wheels measured from the lowest portion of the rim to the fender (measured was 610) and 579mm rear (measured was 600 on one side and 605 on the driver side)

Some of this is because the M3 has larger tires than the 335i... The larger tires are 15mm taller in the front and 25mm taller in the rear (yes the rear M3 tires are 12mm larger in diameter than the fronts).

This means more sidewall and less fender gap so the M3 rides a bit higher (half of the tire size difference is the difference in wheel gap which is +7.5 and +12.5 when installed with 335 tire sizes). This works out quite close to what I observed...

The front actually raised up slightly more than the accounting for the tires probably due to the V8 with DCT being slightly heavier than the N54 with an automatic or manual (40-65kg overall by my research and weight bias is also a bit different given that the springs I got were from an E92 and my car is an E90).


1M springs on an M3 suspension swapped 335i

I just changed my springs (last night actually) to 1M Eibach springs. The 1M uses the M3 suspension but sits quite a bit lower. Eibach 1M springs are a full inch shorter than the Eibach M3 springs in the front based on what Eibach shared with me. I also shaved the upper mounts and used e36 M3 bump stops which is the BKM for the e90 M3 suspension.

The rear Eibach M3 springs (685lb/in) are also MUCH stiffer than the Eibach 335i rear springs (457lb/in) and the 1M Eibach springs are 7mm shorter than the standard 335i Eibach springs and are progressive (399-598lb/in). The 1M springs are on a fire sale from Eibach right now so they are a great deal that I could not pass up... But they only fit if you have a non M e90 with the front M3 spindles struts, M3 sway bar links, and M3 inner tie rods which are needed to match the M3 spindles. I did see a post this morning about how even with M3 front control arms the 335i knuckle geometry isn't quite perfect for them which I hadn't heard before but everyone seems to have good results with it anyway

I just got these springs on the car and haven't even had a chance to drive it yet!

Right after install of the 1M springs (before settling) the rear is now 587 and the front is the same 587mm. So it is currently +8mm in the rear and -12mm in the front with the 1M springs... I will see how it settles out but I can always add in a small spacer (or camber adjustment plate) in the front to raise it enough to even it out if I decide to. Eibach springs shouldn't settle much so I will probably want a bit of a front spacer. This is still better than the M3 springs would have been given that the desired height is in between the two and without cutting that isn't possible on the M3 springs.

I have gotten suggestions that cutting 3/4 to 1 full turn off from a non sport 335i rear spring and using that for a the rear is a good match on this kind of swap. It is a nice option but given the deal I got on the 1M springs I had to give them a go. I will see in the upcoming weeks how it works out.

-Rich

[Runnin'Rich]

Massive respect that you managed to make this work. Lots of perseverance and patience must have gone into the conversion. Hats off to you!

[GnomeChild]

Originally Posted by rbryantaz

The rear Eibach M3 springs (685lb/in) are also MUCH stiffer than the Eibach 335i rear springs (457lb/in) and the 1M Eibach springs are 7mm shorter than the standard 335i Eibach springs and are progressive (399-598lb/in). The 1M springs are on a fire sale from Eibach right now so they are a great deal that I could not pass up... But they only fit if you have a non M e90 with the front M3 spindles struts, M3 sway bar links, and M3 inner tie rods which are needed to match the M3 spindles. I did see a post this morning about how even with M3 front control arms the 335i knuckle geometry isn't quite perfect for them which I hadn't heard before but everyone seems to have good results with it anyway

Rich

Thank you for your exhaustive post and offering your experience with this swap. If it is possible, which it seems like it is, it will come in handy later. That being said; this was the only part of the post that really pertained to the mechanical aspect of the swap. The coding/electronic parameters can be researched and fine tuned later but any research into this area is useless if it is not mechanically viable or too mechanically involved that I'd rather not continue to pursue this retrofit

From what I understand, you are saying that the front struts are not simple plug and play with the 335i spindles/knuckles, correct? Even with having fitted M3 Control Arms and an M3 rack, fitting of the M3 EDC Struts would require additional supporting mods such as, what I can gather from the post: M3 Knuckles, M3 outer Tie Rods, and M3 Sway Bar Links? Do the M3 top hats plug right into the 335i strut towers without modification? Are the outer tie rods direct fitment to 335i inner rods or should I just order complete M3 tie rods? I just ordered new 335i tie rods for my M3 rack... but I will make the sacrifice if need be. I have lifetime alignment on my 335i so I can fine tune and upgrade suspension components to my hearts content

That being said, what did you end up doing with the front Brakes? Did you just end up upgrading to the M3 ones? Or can the 335i brakes be retained (and subsequently bolted onto the M3 spindles without additional hardware)?

Also good call in the Eibach 1M springs: a full set is not even $100 ordered from Eibach at this time. Hopefully I can wrap my head around the supporting mods that are required so I can make a concise decision and order a set from Eibach before the deal is gone forever

[rbryantaz]

Originally Posted by GnomeChild

Rich

Thank you for your exhaustive post and offering your experience with this swap. If it is possible, which it seems like it is, it will come in handy later. That being said; this was the only part of the post that really pertained to the mechanical aspect of the swap. The coding/electronic parameters can be researched and fine tuned later but any research into this area is useless if it is not mechanically viable or too mechanically involved that I'd rather not continue to pursue this retrofit

From what I understand, you are saying that the front struts are not simple plug and play with the 335i spindles/knuckles, correct? Even with having fitted M3 Control Arms and an M3 rack, fitting of the M3 EDC Struts would require additional supporting mods such as, what I can gather from the post: M3 Knuckles, M3 outer Tie Rods, and M3 Sway Bar Links? Do the M3 top hats plug right into the 335i strut towers without modification? Are the outer tie rods direct fitment to 335i inner rods or should I just order complete M3 tie rods? I just ordered new 335i tie rods for my M3 rack... but I will make the sacrifice if need be. I have lifetime alignment on my 335i so I can fine tune and upgrade suspension components to my hearts content

That being said, what did you end up doing with the front Brakes? Did you just end up upgrading to the M3 ones? Or can the 335i brakes be retained (and subsequently bolted onto the M3 spindles without additional hardware)?

Also good call in the Eibach 1M springs: a full set is not even $100 ordered from Eibach at this time. Hopefully I can wrap my head around the supporting mods that are required so I can make a concise decision and order a set from Eibach before the deal is gone forever

The shocks are completely different on the M3 as are the springs and spindles. The spindles are needed for the brakes and the shocks, shock hats, tie rods, and springs are needed for the spindles.

I think it is the inner tie rods that are different rather than the outers as I originally posted. There is a thread somewhere about swapping the M3 steering rack that details what tie rods are needed for the M3 spindles. Rockauto had a branch of M3 inner/outer tie rod combo kits for cheap on closeout... If you ever think about doing the M3 spindle swap it would be smart to buy them I think they are only $5 or so per side for inner and outer on closeout.

I am using everything from the M3, suspension wise only the front subframe is from the 335i (and the springs are 1M eibachs now). The 1M eibachs probably need a 12mm spacer in the front to level out with the rear given the large drop that eibach put on the 1M front but it is fully drivable with just the 3mm strut saver shim.

It actually settled in an extra 5mm or so from this picture:



I was able to take it out and even drive over some rough spots with it after the install and it was fine. I think it rides better than on the M3 springs.


-Rich

[GnomeChild]

That is quite the sweet up Rich

Looks like like I'll have to add "source M3 front struts + hubs assemblies" to my list of future mod plans now
Now I suppose my rear M3 end/LSD will have a matching setup in the front. Wish I never sold my EDC rear shocks that came with the rear M3 K though; would have a setup effectively "50%" at this point. Will probably actually use the M3 brakes now as a consequence, and may spring for an M3 brake master cylinder as well

[rbryantaz]

Originally Posted by GnomeChild

That is quite the sweet up Rich

Looks like like I'll have to add "source M3 front struts + hubs assemblies" to my list of future mod plans now
Now I suppose my rear M3 end/LSD will have a matching setup in the front. Wish I never sold my EDC rear shocks that came with the rear M3 K though; would have a setup effectively "50%" at this point. Will probably actually use the M3 brakes now as a consequence, and may spring for an M3 brake master cylinder as well

Yes you need the M3 spindles on the front and rear to run the brakes. They aren't a huge upgrade over the 335i but they run the lighter (much more expensive) rotors, etc.

I also initially was going to return the EDC shocks as not useable but then decided that they could be a nice setup with some work.

I decided against the M3 LSD. It is a big heavy beast that has axle clunk issues due to uneven axle lengths on that unit. And then there is the hassle of making a custom driveshaft....

I think the 335i 215mm with a helical diff is a better option. I ended up just rebuilding a 188 diff with mfactory LSD but probably should have changed to the 215. Everyone I talked to claimed that the weak point was the input shaft and there wasn't much of a strength difference overall in the 215 and 188. I was concerned that I would need new axles and drive shaft if I changed to a 215 but I have since found lots of people that have interchanged them on the same driveshaft and axles.

Even if I need to eventually replace the 335i axles with upgraded ones I think I still like this Helical LSD better than the M3 clutch LSD. Several people have worn them out with the increased torque on a 335i compared to an M3.

I also sold my M3 LSD on ebay for more than I paid for the entire front and rear setups from the local dismantler... (I did pay an additional $340 for the front and rear shocks).

-Rich

[GnomeChild]

Well Rich



You've thoroughly convinced me
And I couldn't sit on my hands long enough and let this deal pass me by

A shame about the M3 diff NVH; I never knew about the axle clunk issues and yes, I know the clutch packs tend to wear faster on higher Tq n54 builds but I may be running stock DME/"bolt ons" for quite a bit while I dial in my research/wait for future developments on other mods. You'd think these little nuances would be discussed more in depth unless they already have and it is just me not digging nearly deep enough


That being said, do you think it would be safe to run the EDC setup with no electronic controllers/link to the EDC module? As in, have the setup installed as a "proof of concept" to be sure the setup works/clears/settles properly before installing/dialing in the electronics/coding. Were you running your setup controllerless before adding in your controllers?

[rbryantaz]

Originally Posted by GnomeChild

Well Rich



You've thoroughly convinced me
And I couldn't sit on my hands long enough and let this deal pass me by

A shame about the M3 diff NVH; I never knew about the axle clunk issues and yes, I know the clutch packs tend to wear faster on higher Tq n54 builds but I may be running stock DME/"bolt ons" for quite a bit while I dial in my research/wait for future developments on other mods. You'd think these little nuances would be discussed more in depth unless they already have and it is just me not digging nearly deep enough


That being said, do you think it would be safe to run the EDC setup with no electronic controllers/link to the EDC module? As in, have the setup installed as a "proof of concept" to be sure the setup works/clears/settles properly before installing/dialing in the electronics/coding. Were you running your setup controllerless before adding in your controllers?

I always ran the controllers. If you don't it will just be really stiff and possibly wear out the shocks faster.

I run them at 1.6 out of 2 amps (listed as the max soft by BMW) most of the time on the street for casual driving which is where I setup my dial to max out

I might increase it to 1.8amps to see how much more comfy it is. Unfortunately some modifications are required to the controllers or they can hit 3 amps or so at 100% duty cycle so it has to be limited to 66% or less which requires a resistor change on most PWM controllers (which are otherwise under $10 each). I did a bunch of work to add motorcycle volt/amp gauge to sanity check them and an over current limit board that alarms and shuts them down if they go over 2amps. They are all activated by a relay on the accessories so that they don't' draw the battery dead.

I got a 2 year degree at a community college where I studied a lot of electronics before I transferred to a university many years ago. So it was a fun project to revisit up on some old knowledge.

-Rich

[GnomeChild]

I see
If that's the case, this may be a project I will have to sit on parts for much longer than expected. Par for the course on most of my mods recently

[streetpro]

Originally Posted by rbryantaz

I always ran the controllers. If you don't it will just be really stiff and possibly wear out the shocks faster.
-Rich

I can only confirm this after practical experience with an Audi A8 4H (which has air suspension plus 3 settings for electronic dampers), where I accidentally reset the chassis control unit to an empty setting. So I drove for a couple of days with the default high (which was fine), but the electronic dampers at max damping (no current), which meant a really rattling ride.

[feuer]

Originally Posted by GnomeChild

I see
If that's the case, this may be a project I will have to sit on parts for much longer than expected. Par for the course on most of my mods recently

Are you goin to install these Pro Kit BMW 1 Series M springs with non M struts and shocks?

[rbryantaz]

Originally Posted by feuer

Are you goin to install these Pro Kit BMW 1 Series M springs with non M struts and shocks?

Yea these need to be with M front struts and mounts.

The 1M eibach pro front springs are pretty short. I ended up adding a spacer to raise the car 5/8" to level it (the OE bad road spacers without the 3mm shim which I might put back in) out and get the front up to the normal sport ride height of 600mm. 16mm lower in the front isn't too far out of line compared to how some kits lower more in the front than the rear but I was also about 5-6mm higher in the rear compared to the normal 335i sport spring alignment specs at 584mm so I spaced it up a bit in the front.

So there is a downside of the lost 16mm of travel with these. It would be better to have a longer spring and no spacer but I also used the Dinan style shaved mounts and shorter e30 bumpstops.

Eibach said the 1M front spring is about 1" shorter in the front than the M3 kit.

-Rich

[GnomeChild]

Originally Posted by feuer

Are you goin to install these Pro Kit BMW 1 Series M springs with non M struts and shocks?

No, I intend to install the 1M springs on full M3 struts

[langsbr]

Thread revival - when you converted to full M3 front suspension (especially the knuckles) how did it affect track? Did you need to get different wheels or did everything work normally?