[328iFitz]

Got a full set of B4's and installed them in my 07 328i sedan last weekend. I had put new lowering springs in but the back was a little much. I swapped the rears back to stock and they're a bit bouncy now haha I'm wondering if the M sport springs from my same car (but the M) would be better? I found a set on eBay for $56 so I did buy them but I haven't received them yet. I've tried looking through threads cause I heard the coils of a 330i could potentially work but then found that set of rear M series springs at a decent price so I just got em anyway. Will they work with the B4 shocks I just installed?

[relative4]

B4s are for stock height. B8s are good for lowering springs.

[bluewater328]

The sports springs would be fine with B4. But you don't want to put aftermarket (lowering) springs on the B4, it will give you some issues (speaking from experience here).

As stated, B8 will pair with the lowering springs better (also speaking from experience). B8's are a little rougher on the ride. B8s + Eibach Pro Kits = B12 which is a designed and matched system. And if you dont mind rougher than that, buy B14s for about the same price and you can adjust to the height you want on a system designed together.

[328iFitz]

Originally Posted by FCobra94

False - front struts blew in fairly short order when going from Non-sport springs to sport springs on B4 on my car. With the same sport springs and B8 now, absolutely no issues...exactly why Bilstein only recommends B4 for non-sport configurations now.

Correct.

Correct.

False - only difference between B4 and B8 is shaft length. Slamming into bumpstops w/ B4 leads to an obviously "rougher" ride.

"Designed and matched" is a stretch here. Just because they're sold together as a kit doesn't mean that there aren't better springs out there to pair B8 dampers with. Why anyone would choose to lower their car on springs that have the same exact spring rates as stock (Eibach Pro Kits) is absolutely counterproductive, but to each their own...

Fcobra, I was under the impression the b4s were sport, atleast that's how they were advertised that's why I picked em up. The rear shock/spring pairing is what I'm most concerned with right now. As I had put in the OP I went ahead and bought those "M sport" springs cause of the price but would shocks such as the Sachs be more suitable from a budget stand point? If nothing else I could get the B8's but I'm not spiriting as much as I am just daily driving it. I'm going to try and attach the link to the springs I got..

[328iFitz]

Fcobra, now I did not buy THIS kit.. I was researching and stumbled upon it. As it states in the description the "b4 sport" so I just ordered the shocks/struts and F/R mount kits (not from this site). I also did not use the Dinan springs either. Just wanted to show my source for the "sport" I assumed were the b4s.

[328iFitz]

Hey Bluewater, what sport springs did you run on yours? Or what sport springs are you and Fcobra speaking of just in general? I just don't know how to search correctly I guess. I've searched spring codes, different model e90s and just can't seem to come to a conclusion

[Welcome to NBA Jam]

Originally Posted by FCobra94

False - only difference between B4 and B8 is shaft length. Slamming into bumpstops w/ B4 leads to an obviously "rougher" ride.

Are you sure you're not mixing up B6s and B8s? The B4s are designed to be similar to OE whereas B6/B8 use inverted monotube struts and are harder than stock. B8s are shorter shaft versions of B6s.

[bluewater328]

Originally Posted by 328iFitz

Hey Bluewater, what sport springs did you run on yours? Or what sport springs are you and Fcobra speaking of just in general? I just don't know how to search correctly I guess. I've searched spring codes, different model e90s and just can't seem to come to a conclusion

I ran the OE "Sports" springs that came with the car as part of the "sports" package that most E92s came with. They were fine. Maybe Fcobra has rougher roads or drives more aggressively than I do, but I was fine with B4s. I've had other people recommend oem sports springs with the B4s. You just can't run lowering springs on them: Part of it is it's not valved at the right ride height. So the dampening is inefficient at the wrong spots.

B6 are the ones that are actually the same valving as B8, but longer. B6 work well with stock springs. B4s are closer to OE.

Bilstein could have picked a half a dozen partners for a B12 but they picked Eibach. I'm sure they put no effort into trying to match specs a little {sarcasm} ....I mean they could have picked H&R or Sprint but they didn't. Each have partners and each car/driver has certain needs; partnerships or business relations, what have you. But I doubt there was no effort put into it.

[bluewater328]

Originally Posted by Welcome to NBA Jam

Are you sure you're not mixing up B6s and B8s? The B4s are designed to be similar to OE whereas B6/B8 use inverted monotube struts and are harder than stock. B8s are shorter shaft versions of B6s.

This. B4s can be paired with stock length sport springs for an OE "feel." B6 is the beginning of the performance line for Bilstein (=stiffer monotube design).

[328iFitz]

Originally Posted by bluewater328

This. B4s can be paired with stock length sport springs for an OE "feel." B6 is the beginning of the performance line for Bilstein (=stiffer monotube design).

So would a set of sport springs, those of an e92 sit right on my e90 sedan? Of course if I they were out of a sedan as well? I would hate to have to buy another set of shocks/struts to achieve the small goal I'm in search of, but I guess if I have to than I will. I recently got a smokin deal on some AR1s that I just dropped off yesterday for powder coat (the were black w/polished lip-gross) they're getting powdered in "polished aluminum". At any rate they're 18x8 front and 18x9 rear et40 front and 45 rear. I'm currently running 15/20mm spacers with my 162s and I'm just looking to close the wheel gap in the rear slightly more. Not trying to slam or stance the car in that sense. After reading all your replies last night/this morning, and after a few days of driving, I gave a good push down on the front of the car (w the lowering springs still currently) and there was NO movement. With that being said I'm going to most likely be hunting down a solution/different option today. It does sit nice and the bounce is most definitely not coming from the front while driving it absolutely the rears that's why I'm trying to solve that issue most importantly.

[328iFitz]

Originally Posted by 328iFitz

So would a set of sport springs, those of an e92 sit right on my e90 sedan? Of course if I they were out of a sedan as well? I would hate to have to buy another set of shocks/struts to achieve the small goal I'm in search of, but I guess if I have to than I will. I recently got a smokin deal on some AR1s that I just dropped off yesterday for powder coat (the were black w/polished lip-gross) they're getting powdered in "polished aluminum". At any rate they're 18x8 front and 18x9 rear et40 front and 45 rear. I'm currently running 15/20mm spacers with my 162s and I'm just looking to close the wheel gap in the rear slightly more. Not trying to slam or stance the car in that sense. After reading all your replies last night/this morning, and after a few days of driving, I gave a good push down on the front of the car (w the lowering springs still currently) and there was NO movement. With that being said I'm going to most likely be hunting down a solution/different option today. It does sit nice and the bounce is most definitely not coming from the front while driving it absolutely the rears that's why I'm trying to solve that issue most importantly.

I just looked at my stock front coils. They're labeled D5. Not sure what that would make the stock rears if it would be D4 or D6? I was doing a little more reading about the e92 coils I was asking you about, I see some people went with D4/D3 combo.. would something along those lines work with the b4s while bringing the ride height down a bit as well?

[The Nightman]

Originally Posted by FCobra94

False - front struts blew in fairly short order when going from Non-sport springs to sport springs on B4 on my car. With the same sport springs and B8 now, absolutely no issues...exactly why Bilstein only recommends B4 for non-sport configurations now.

Do you have a source for this? It seems that Bilstein still specs different B4 dampers for standard and sport springs:

https://cart.bilsteinus.com/results?...43698366115210

Standard:
22-136572
22-136589
19-303574 (rears)

Sport:
22-135032
22-135049
19-303581 (rears)

[328iFitz]

Originally Posted by freedomfries

Do you have a source for this? It seems that Bilstein still specs different B4 dampers for standard and sport springs:

https://cart.bilsteinus.com/results?...43698366115210

Standard:
22-136572
22-136589
19-303574 (rears)

Sport:
22-135032
22-135049
19-303581 (rears)

The rears I got were advertised as sport and they are 19-135052's.

[Bimmer_Engineer]

Originally Posted by bluewater328

I ran the OE "Sports" springs that came with the car as part of the "sports" package that most E92s came with. They were fine. Maybe Fcobra has rougher roads or drives more aggressively than I do, but I was fine with B4s. I've had other people recommend oem sports springs with the B4s. You just can't run lowering springs on them: Part of it is it's not valved at the right ride height. So the dampening is inefficient at the wrong spots.

B6 are the ones that are actually the same valving as B8, but longer. B6 work well with stock springs. B4s are closer to OE.

Bilstein could have picked a half a dozen partners for a B12 but they picked Eibach. I'm sure they put no effort into trying to match specs a little {sarcasm} ....I mean they could have picked H&R or Sprint but they didn't. Each have partners and each car/driver has certain needs; partnerships or business relations, what have you. But I doubt there was no effort put into it.

Figured i'd jump in to this one since it looks like it's time for new shocks. I have factory sports suspension and I was looking at getting the B4 kit that's listed as being for vehicles with sports suspension...

https://www.ecstuning.com/b-bilstein...t/22-135049kt/

I'm looking to just get the suspension back close to where it was stock...will this get me there?

[328iFitz]

Originally Posted by Bimmer_Engineer

Figured i'd jump in to this one since it looks like it's time for new shocks. I have factory sports suspension and I was looking at getting the B4 kit that's listed as being for vehicles with sports suspension...

https://www.ecstuning.com/b-bilstein...t/22-135049kt/

I'm looking to just get the suspension back close to where it was stock...will this get me there?

They are the oem replacement. I got the sport as I have non sport. Unfortunately my spring intentions were not thought out well enough but they are supposed to be a C hair stiffer than the oem. I am rather overwhelmed with the amount of information on what spring combo for F/R I should go with alone and then pairing that combo to the B4s haha

Originally Posted by freedomfries

Do you have a source for this? It seems that Bilstein still specs different B4 dampers for standard and sport springs:

https://cart.bilsteinus.com/results?...43698366115210

Standard:
22-136572
22-136589
19-303574 (rears)

Sport:
22-135032
22-135049
19-303581 (rears)

Nope. I meant B6...it was a typo. Going back to edit my reply now.

But yeah, there are 2 different versions of B4: sport and non-sport.