[Mike.]

yeah yeah, I know

So i have a 328xi, and want to get a spring/shock "i" combo. Now the "i" spring is rated about 200lbs less than what the xi weighs (for the xi)... so in my infinite wisdom I thought to combat this I by going with the 335i eibach prokit since the springs are rated for more weight.

For comparison:
335i ~3594
328xi ~3605
328i ~3362

Now, my question is, will 335i springs work? Will they fit--and give a nice drop? (Which they should--double checking if my idea will work) Since I would be going with the 335i spring, theoretically that would mean even less stress on the shocks/struts correct?

[ajsalida]

Couple of things. Your intentions are good unfortunately there are other factors. First of all any non-XI e9x springs will fit XI. Plenty of people here have put non-XI Eibach springs on XI, myself included.

The problem is the rear tends to sit too low. Lot of debate why but it appears the front lower spring perch on an XI is higher than on a non-XI, so when you put the springs in it sits higher than the rear. Drives a lot of people crazy, do some searches.

This will be worse with your idea, because the extra weight on a 335XI is mostly in front. So on a 328XI it may sit even higher.

One option is to use OEM ZSP springs. Look for a thread titled "i springs on xi" lot of this is discussed there. What you may want therefore is a set of 328i sport package springs, with the D-code springs (read the thread).

I eventually could not stand the low rear ride height on eibach pro-kit on my 335xi coupe. I swapped in a set of rear ZSP springs which were just a but higher than the rear eibachs, but kept the fronts. So far so good.

[Mike.]

Originally Posted by ajsalida

Couple of things. Your intentions are good unfortunately there are other factors. First of all any non-XI e9x springs will fit XI. Plenty of people here have put non-XI Eibach springs on XI, myself included.

The problem is the rear tends to sit too low. Lot of debate why but it appears the front lower spring perch on an XI is higher than on a non-XI, so when you put the springs in it sits higher than the rear. Drives a lot of people crazy, do some searches.

This will be worse with your idea, because the extra weight on a 335XI is mostly in front. So on a 328XI it may sit even higher.

One option is to use OEM ZSP springs. Look for a thread titled "i springs on xi" lot of this is discussed there. What you may want therefore is a set of 328i sport package springs, with the D-code springs (read the thread).

I eventually could not stand the low rear ride height on eibach pro-kit on my 335xi coupe. I swapped in a set of rear ZSP springs which were just a but higher than the rear eibachs, but kept the fronts. So far so good.

interesting..I'll start reading...thanks man

[ajsalida]

Originally Posted by Emozoo

interesting..I'll start reading...thanks man

Sure mon. One other thing is OEM XI springs are a lot stiffer than I springs, in terms of effective spring rate. You'll find this out yourself if you try to compress them to get them them off shocks.

They look almost identical in terms of # of coils etc but have thicker wire. So even ZSP springs and eibachs are softer springs, and much of the lowering effect is from that. Nobody really knows what BMW was thinking with the XI suspension, it is kind of screwy.

So you will get lowering and a smoother ride, but tend to bottom out esp if you don't trim bump stops. Lowering an XI is not straight forward. Lot of threads on this.

On the other hand H&R are very stiff, you get about the same lowering, but many people have found them to be far too harsh.

[Mike.]

Originally Posted by ajsalida

Sure mon. One other thing is OEM XI springs are a lot stiffer than I springs, in terms of effective spring rate. You'll find this out yourself if you try to compress them to get them them off shocks.

They look almost identical in terms of # of coils etc but have thicker wire. So even ZSP springs and eibachs are softer springs, and much of the lowering effect is from that. Nobody really knows what BMW was thinking with the XI suspension, it is kind of screwy.

You get lowering and a smoother ride, but tend to bottom out esp if you don;t trim bump stops. Lowering an XI is not straight forward. Lot of threads on this.

theoretically could I just swap my front/back springs with 328i zsp springs instead of mixing with eibachs?

[ajsalida]

Originally Posted by Emozoo

theoretically could I just swap my front/back springs with 328i zsp springs instead of mixing with eibachs?

Correct, lot of people do that. Cheaper too. Read that thread, there are some nuances to picking the right combo of D-code springs.