[thegrinchboy]

Originally Posted by v1nc86

What D3, D4, D5, D6 refers to?

These refers to the markings on the BMW OEM Sport (ZSP) springs. D = Sport, C = Non-sport, I = x-Drive, etc. The number is different for different models e.g. E90, E91, E92, E93, as well as engine sizes, transmission and various options.

[v1nc86]

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(no rust at all, just yellow-ish after a wash)


Grocery List:

- Eibach Pro Kit "i" springs (PN: 2092.140)
- Bilstein Sport shocks (PN: Front Left: 35-142478, Front Right: 35-142485, Rears (same): 24-120425)
- Bump stops: rear E86 Z4M (PN: 3353 6770 350)

[C230AMG]

Originally Posted by v1nc86

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(no rust at all, just yellow-ish after a wash)


Grocery List:

- Eibach Pro Kit "i" springs (PN: 2092.140)
- Bilstein Sport shocks (PN: Front Left: 35-142478, Front Right: 35-142485, Rears (same): 24-120425)
- Bump stops: rear E86 Z4M (PN: 3353 6770 350)

How's the ride quality, cornering and going over bumps/potholes with this setup?

[thegrinchboy]

Originally Posted by v1nc86

Grocery List:

- Eibach Pro Kit "i" springs (PN: 2092.140)
- Bilstein Sport shocks (PN: Front Left: 35-142478, Front Right: 35-142485, Rears (same): 24-120425)
- Bump stops: rear E86 Z4M (PN: 3353 6770 350)

Are those performance brakes in the front?

[RaidersFan]

Great thread, plenty of useful info! Anyone know off the top of their head what the appropriate ZSP springs would be for a 335xi, 2011, w/Steptronic, cold, upgraded stereo, and Moonroof/premium package? I assume the AT and Moonroof would add the most weight.

I was wondering why some of the posters pics seem great with the Eibachs, and others are too low? Those first pictures with Eibachs seemed excessively slammed, the last set of photos (from the Gentleman up north in Canada) seemed exactly what I was looking for.

Huge tall ride height almost pushed me to purchasing a 335i. My wife talked me out of it though, she wasn't super happy driving the 328i in the snow, said we needed AWD on our next car. Is it just me, or does it seem ridiculous that BMW doesn't offer performance suspension on a 335, AWD or no? Is that no longer the case with the F30 series?

[thegrinchboy]

Originally Posted by dawgcatching

Great thread, plenty of useful info! Anyone know off the top of their head what the appropriate ZSP springs would be for a 335xi, 2011, w/Steptronic, cold, upgraded stereo, and Moonroof/premium package? I assume the AT and Moonroof would add the most weight.

I was wondering why some of the posters pics seem great with the Eibachs, and others are too low? Those first pictures with Eibachs seemed excessively slammed, the last set of photos (from the Gentleman up north in Canada) seemed exactly what I was looking for.

Huge tall ride height almost pushed me to purchasing a 335i. My wife talked me out of it though, she wasn't super happy driving the 328i in the snow, said we needed AWD on our next car. Is it just me, or does it seem ridiculous that BMW doesn't offer performance suspension on a 335, AWD or no? Is that no longer the case with the F30 series?

F30 xDrive does have (finally) available sports suspension. Given there are no (official) ZSP springs, it is a trial and error as well as personal preference. Also, E90 and E92 have different springs as wells. I have a 2011 E90 335i xDrive MSport with Nav and 6MT. As noted earlier in this thread, I started with Eibachs and then went to ZSP after a bit of research. The springs I used were D6 front and D5 rear. Search my handle if you are interested in pics. BTW, most E90 335i RWD with AT uses D7/D4.

[Baine]

Anyone use the Dinan springs?

[ajsalida]

Not sure where to put this update. I had originally thought I needed to get my ride height up from the too low levels from using Eibach pro kit + Koni sports. This was to avoid rubbing when some relatives came into town, driving them and their luggage around on some of the bumpier 2 lane blacktop up here in the mountains. I have 12/15mm spacers F/R on stock staggered 189's and was concerned the clearance was too tight. I had been considering swapping in some D6/D2 OEM sport springs.

Well I took my neighbors for a brief ride (about same weight) and no rubbing. So I decided to chance it with the relatives + luggage and full tank. No rubbing at all, on approx 500 miles of mountain driving. This was surprising to me.

I did one other thing, and that was I took out the camber pins in front strut hats, got another 0.5 degree neg camber. Very nice and wakes up the turn-in feel significantly. Used the method suggested by someone here (brilliant) of dremmeling a slot in the pin for a screwdriver, then loosening all 3 top nuts. Pins came right out.

So now front camber is sitting at approx. -1.7 deg both sides, which is much closer to what you want on McP strut car for performance oriented handling without too much tire wear. Will drop the rear down to near that next and evaluate.

[SLOWER]

Originally Posted by v1nc86

Grocery List:

- Eibach Pro Kit "i" springs (PN: 2092.140)
- Bilstein Sport shocks (PN: Front Left: 35-142478, Front Right: 35-142485, Rears (same): 24-120425)
- Bump stops: rear E86 Z4M (PN: 3353 6770 350)

Does an LCI car change this formula at all? You didn't have to change the bump stops in the front?

Your car looks great. The every day comfort of the ride is good?

[cloudconnects]

Originally Posted by SLOWER

Does an LCI car change this formula at all? You didn't have to change the bump stops in the front?

Your car looks great. The every day comfort of the ride is good?

Wondering same thing...

[v1nc86]

After 2 months of driving my e90 335xi on the combo Bilsten Sport and Eibach Pro Kit "i" springs, here's what I think: the drop is perfect for my taste, the front sits as low as the rear (no rake look anymore), but the bad thing is the suspension is way too stiff, no more ride quality anymore. Not sure how long i gonna keep them on.

[v1nc86]

Originally Posted by SLOWER

You didn't have to change the bump stops in the front?

No shorter bump stops required in the front if you go with the Bilsten because they do have front internal bump stops. If you go with Koni you need to get the shorter bump stops in the front.

[ajsalida]

Another update here. Before winter I had wanted to experiment with I rear springs on my XI car. Currently have eibachs and the rear seems a bit low, in the following sense: the wheel well gap to top of tire shoulder in back seemed narrower than in front. When you measure the fender lip to ground is almost exactly the same front vs back, but it looks low because the gap is non existent in back. Had a set of ZSP springs lying around, got them from someone here used couple of years ago, but not any numbers I've seen before. D6 front and D2 rear.

Put the D2's on the rear just now and did some measurements. Gained 3/8" passenger side and 7/16th other side give or take. Now the lip to tire gap is identical front to back (except driver side rear which is always a bit higher without driver). Visually it looks perfect, funny how the eye can pick up something that small and process it.

So to recap this is a 335xi e92 AT, now with eibach pro kit front only springs, D2 ZSP OEM rear springs, koni sport SA shocks. Pins removed from front strut hats for more camber, 12/15mm spacers on OEM staggered 18's stock size tires (DWS contis). Whiteline rear subframe bushing inserts and OEM M3 rear sway bar. Trimmed rear bump stops (1") and e36 M3 front stops. Whew!

Test drive was nice, but a bit odd it seemed like the new rears were stiffer when I know they aren't. Should let it settle a bit and re-evaluate. I could feel the extra ride height as weird as that may seem. Def felt tilted forward a tiny bit. I set the eccentric camber bolts at the same point they were at before, so I need to go back and align it right, get some more camber going.

So anyway, if the # convention means what we think it means, D6/D2 is off a car with MT and no sunroof, or at least lighter than cars that had D7/D3 for example. 328? who knows.

I think I will leave it like this I do not want to raise the front and find the gap is off again. Unless it settles a lot but I doubt it will.

Carry on.

edit: I also confirmed for myself that to swap rear springs you do not need to remove anything other than the inside lower control arm bolt (eccentric), and drop down the arm. Driver side you need to remove the ride height sensor bracket, that is all. Pretty easy but time consuming. You must pay attention to the rubber spring pads and make sure they are aligned correctly on the spring (top and bottom) and in the lower control arm itself (bottom).

[thegrinchboy]

Originally Posted by ajsalida

Another update here. Before winter I had wanted to experiment with I rear springs on my XI car. Currently have eibachs and the rear seems a bit low, in the following sense: the wheel well gap to top of tire shoulder in back seemed narrower than in front. When you measure the fender lip to ground is almost exactly the same front vs back, but it looks low because the gap is non existent in back. Had a set of ZSP springs lying around, got them from someone here used couple of years ago, but not any numbers I've seen before. D6 front and D2 rear.

Put the D2's on the rear just now and did some measurements. Gained 3/8" passenger side and 7/16th other side give or take. Now the lip to tire gap is identical front to back (except driver side rear which is always a bit higher without driver). Visually it looks perfect, funny how the eye can pick up something that small and process it.

So to recap this is a 335xi e92 AT, now with eibach pro kit front only springs, D2 ZSP OEM rear springs, koni sport SA shocks. Pins removed from front strut hats for more camber, 12/15mm spacers on OEM staggered 18's stock size tires (DWS contis). Whiteline rear subframe bushing inserts and OEM M3 rear sway bar. Trimmed rear bump stops (1") and e36 M3 front stops. Whew!

Test drive was nice, but a bit odd it seemed like the new rears were stiffer when I know they aren't. Should let it settle a bit and re-evaluate. I could feel the extra ride height as weird as that may seem. Def felt tilted forward a tiny bit. I set the eccentric camber bolts at the same point they were at before, so I need to go back and align it right, get some more camber going.

So anyway, if the # convention means what we think it means, D6/D2 is off a car with MT and no sunroof, or at least lighter than cars that had D7/D3 for example. 328? who knows.

I think I will leave it like this I do not want to raise the front and find the gap is off again. Unless it settles a lot but I doubt it will.

Carry on.

edit: I also confirmed for myself that to swap rear springs you do not need to remove anything other than the inside lower control arm bolt (eccentric), and drop down the arm. Driver side you need to remove the ride height sensor bracket, that is all. Pretty easy but time consuming. You must pay attention to the rubber spring pads and make sure they are aligned correctly on the spring (top and bottom) and in the lower control arm itself (bottom).

NICE. Would like get your input on the ride/handling after some time. Also, did you have to realign the car after the rear spring swap?

[ajsalida]

Originally Posted by thegrinchboy

NICE. Would like get your input on the ride/handling after some time. Also, did you have to realign the car after the rear spring swap?

In principle, if you mark the washer locations on the eccentrics prior, and set them back to that after, you wouldn't need to re align for such a small increase in ride height. IMHO. But I will go ahead & re align because I need to adjust rear camber more negative anyway, to match the extra neg I got in front from pulling the strut pins.

So I just set it back to the marks I had before (on the eccentric bolt washer) for now. This will give me a little less camber than optimal and a little more toe @ the higher ride height. I'll probably do a full alignment in a couple of days, dial the rear camber back down from wherever it is to what the front is now (-1.7 or so).

Initial impressions off a short 50 mile test drive were positive. Felt like a tad more weight on the front wheels and not so squat-prone in back, even a bit stiffer. As I said above you can really feel 1/4" raise on one end. I did not thrash it or get aggressive, just a pleasant drive up in the mountains on 2 lane sweepers with some serpentine side side every so often. Feels good. Currently have the konis set at 1 full turn off soft in front and 1/2 turn off full soft in back. After doing the rear sway bar and subframe bushings, the rear felt far stiffer than the front so I stepped the front up 1/4 more turn from 1/2, then another 1/4 to get at least transient stiffness feeling a little more balanced. Briefly thought about tunring the rears up but decided not to, lazy plus did not want to be doing too many things at once. Science demands we change only one variable at a time.

Really curious how a UUC front bar would feel like you got.

More after I put some miles on it to settle and then align it again.

[thegrinchboy]

Originally Posted by ajsalida

Really curious how a UUC front bar would feel like you got.

More after I put some miles on it to settle and then align it again.

The UUC bars did make the car flatter. The body roll is noticeably lessened dramatically. As noted before, I rolled the DWS tires on the on ramp. Something had to give I guess... Last weekend, I also firmed up the front Konis another 1/8 turn to 1/2 way in between Firm/Soft, as the front end felt soft, and not as quick with the UUC F/R installed. Now it is much better. Since I installed both F/R at the same time, I don't have a perspective on how much benefits the front UUC brings, but to me it was definitely worth it.

[ajsalida]

Nice to have adjustable shocks eh? I see they sell the front bar separately now.

Wanted to mention something I will probably start a new thread on this. I was looking at the front D6 ZSP springs I have lying around. Was comparing them to the I4 OEM 335xi fronts I also have.

They are exactly the same in terms of overall height, number of coils, coil diameter. The only difference is wire diameter, I4's are slightly thicker. I was doing this comparison because I noticed the rears (C3 I think) were also the same size # of coils etc as the D2, except for wire diameter. The eibachs (rear) were shorter with fewer coils but thicker wire.

Aha you say! Since we all know the formula for spring rate looks like

constant * wire diameter^4/(# active coils*coil diameter^3)

What does this mean? It means XI springs are stiffer than ZSP! A lot stiffer. No wonder that spring compressor was so hard to compress the front springs (I broke a set of spring compressors on my front XI springs trying to compress them). It turns out that the bottom spring perch on Xi strut is also higher by 12-15 mm on the strut.

So it looks like what BMW may do for ride height between different models and weight is vary the wire thickness, and leave overall spring dimensions the same. It is simple of you know what you're doing. Then on the XI front they raise the bottom spring perch. This has important implications esp for XI folks, some of which are:

1. ZSP's are softer than OEM XI. By a lot.
2. Possibly XI are stiffer than EIbachs.
3. Problems with ride height off F/R can be traced to this combined with the taller front strut.

To me it was a huge surprise that front and rear ZSP and OEM XI springs were exactly the same dimensions except for wire diameter. If you think it through this explains a lot but it also means many of our previous assumptions about ZSP vs Eibach vs OEM XI are wrong.

edit: Also if the REAR eibachs are indeed same rate as OEM non-XI, as they claim, then clearly the rears are also softer than OEM XI. Think about all this for a minute, we've swapped out tall OEM for SOFTER lowering spring. Wrong wrong wrong! No wonder we got so much larger drops on XI. And since the front bottom perch is higher, no wonder the rear droops.

Hint at where I'm going with all this. It may be the right suspension for XI, slightly stiffer all around and lower, with no rake, is trim a half coil off OEM front springs and maybe 1-1.5 coils off rears. Need to run the numbers and cogitate. Also need to take out the front Eibachs and confirm or refute they are softer than OEM Xi.

[thegrinchboy]

Originally Posted by ajsalida

Nice to have adjustable shocks eh? I see they sell the front bar separately now.

Wanted to mention something I will probably start a new thread on this. I was looking at the front D6 ZSP springs I have lying around. Was comparing them to the I4 OEM 335xi fronts I also have.

They are exactly the same in terms of overall height, number of coils, coil diameter. The only difference is wire diameter, I4's are slightly thicker. I was doing this comparison because I noticed the rears (C3 I think) were also the same size # of coils etc as the D2, except for wire diameter. The eibachs (rear) were shorter with fewer coils but thicker wire.

Aha you say! Since we all know the formula for spring rate looks like

constant * wire diameter^4/(# active coils*coil diameter^3)

What does this mean? It means XI springs are stiffer than ZSP! A lot stiffer. No wonder that spring compressor was so hard to compress the front springs (I broke a set of spring compressors on my front XI springs trying to compress them). It turns out that the bottom spring perch on Xi strut is also higher by 12-15 mm on the strut.

So it looks like what BMW may do for ride height between different models and weight is vary the wire thickness, and leave overall spring dimensions the same. It is simple of you know what you're doing. Then on the XI front they raise the bottom spring perch. This has important implications esp for XI folks, some of which are:

1. ZSP's are softer than OEM XI. By a lot.
2. Possibly XI are stiffer than EIbachs.
3. Problems with ride height off F/R can be traced to this combined with the taller front strut.

To me it was a huge surprise that front and rear ZSP and OEM XI springs were exactly the same dimensions except for wire diameter. If you think it through this explains a lot but it also means many of our previous assumptions about ZSP vs Eibach vs OEM XI are wrong.

edit: Also if the REAR eibachs are indeed same rate as OEM non-XI, as they claim, then clearly the rears are also softer than OEM XI. Think about all this for a minute, we've swapped out tall OEM for SOFTER lowering spring. Wrong wrong wrong! No wonder we got so much larger drops on XI. And since the front bottom perch is higher, no wonder the rear droops.

Hint at where I'm going with all this. It may be the right suspension for XI, slightly stiffer all around and lower, with no rake, is trim a half coil off OEM front springs and maybe 1-1.5 coils off rears. Need to run the numbers and cogitate. Also need to take out the front Eibachs and confirm or refute they are softer than OEM Xi.

Interesting... Definitely would like to see a separate thread on this.

BTW, after looking at the Eibach vs. OEM XI, my installer initially suggested, in an offhanded manner, that he could cut the OEM XI springs, assuming that they are linear springs, as an experiment. I considered this briefly, but didn't go through with it due to cost/effort, and the unknown factor (linear vs. progressive). Keep us posted!

[ajsalida]

Quick update on swapping out eibach rear pro kit sprigs with D2 OEM ZSP's.

On some more aggressive low speed driving it was clear the rear was stepping out a bit too aggressively. So I shut it all down and went to align. Sure enough rear had over 1/4 degree of POSITIVE toe out. Combined with the stiffer rear sway bar + higher rear ride height it was a bit scary.

So I aligned it and it is fine now. The best this car has felt handling wise since I got it 3.5 years ago. I think I will stop messing with it for this season, unless I can find a front bar.

OK so the point is after swapping rear springs by dropping the control arm you MUST re-align. Setting it back to index marks I had made on the eccentrics is not good enough, not even close.

Had no idea it would be off by this much. I guess part of the issue is with the rear Eibach pro kit being so low on an XI, you are way into a part of the 5-link parameter space where small changes in ride height make for large changes in camber & toe. I recall I had a very hard time getting it to where camber was not hugely negative with the right toe settings. For those of you not familiar, there are two eccentrics at the inside bolt location of two links, one is called the camber link and one toe link but they (the eccentric settings) interact with each other. Both affect camber and toe, and you have to go back and forth. Getting it right on the eibachs took a lot of back and forth, initial was -2.4 deg camber! Looked absurd esp since front would not go lower than -1.1 or so.

It is presently set at -1.4 to -1.5 deg neg camber and 0.15 deg total toe in. Front is set at zero toe and -1.5 to -1.7 deg camber.

[ajsalida]

Quick update on two things. One, I put in a UUC front sway bar, see this thread. post #48

http://www.e90post.com/forums/showth...5#post14905405

Second I did look at the front Eibach pro kit springs. They are indeed softer than the stock XI I4 springs (thinner wire by a lot), but a tiny bit thicker than front ZSP D6 springs. I did not take apart the struts so I cannot vouch for this, but it looks like all these front springs have 5 turns give or take, and 4 active coils. The remaining variable needed to caculate ride height would be dead length, which I would not be able to get unless I took them apart.

Anyway, now we know front ZSP D6 is FAR softer than front stock XI I4, and Eibach front is a little but stiffer than front D6.

[thegrinchboy]

Originally Posted by ajsalida

Quick update on two things. One, I put in a UUC front sway bar, see this thread. post #48

http://www.e90post.com/forums/showth...5#post14905405

Second I did look at the front Eibach pro kit springs. They are indeed softer than the stock XI I4 springs (thinner wire by a lot), but a tiny bit thicker than front ZSP D6 springs. I did not take apart the struts so I cannot vouch for this, but it looks like all these front springs have 5 turns give or take, and 4 active coils. The remaining variable needed to caculate ride height would be dead length, which I would not be able to get unless I took them apart.

Anyway, now we know front ZSP D6 is FAR softer than front stock XI I4, and Eibach front is a little but stiffer than front D6.

Out of curiosity, do you know if the XI springs are linear or progressive?

[ajsalida]

Originally Posted by thegrinchboy

Out of curiosity, do you know if the XI springs are linear or progressive?

It looks like all rear springs I've examined are linear. ZSP and XI OEM identical shape (dead length, # coils, coil diameter) only difference being wire thickness, XI a lot thicker (so stiffer). Eibach has fewer coils, shorter dead length, and thicker wire than either. They have stated it has the same rate as OEM ZSP. SO it is the same rate but shorter dead length, that is how it gets lowered. OEM XI has thicker wire but same dead length and # of coils as ZSP so it is stiffer than either.

It looks like all front springs individually have uniform wire diameter (so no progressiveness from diameter taper in other words). The only thing that would make the fronts progressive is the slight variance in coil diameter, narrowing near the bottom needed to fit into the standard sized BMW upper and lower strut perches (or actually the pads that fit into the perches).

IOW it looks like the 3 types I've looked at, ZSP, Eibach ProKit, and OEM XI, are all mildly progressive in front, with the shape or curve of the progressiveness of rate identical due to the fact that the spring shape is identical. The only difference being wire diameter. It looks like the Eibach is the same shape as the others but I did not have it out. I have looked at pictures and they seem to all have 5 coils +/- small fraction of a coil.

I think it would be hard to get a significantly different rate curve into this form factor. It looks like only 4 active coils and not much of a diameter change from top to bottom.

I have some thought on what you said in the other thread on UUC bars, will PM you tomorrow. Answering the door for trick or treaters right now, and catching up on Walking Dead via Netflix.