[jwrag2000]

I recently bought an e93 330d, while it's engine and step auto gear box are fantastic, I can't really come to terms with the 19inch wheels and stiff and I suspect lowered suspension. So I've come up with the solution to get a set of OEM 17s to replace the optioned 19s and put some 50 or 55 profile tyres on. I also am thinking about changing the springs all round as the car seems lower than it should be (by 1/2 inch) and I want at least stock height if not a little (20mm higher). With the inherent body flex and extra weight of a convertible an e93 is never going to be the last word in handling anyway, better off to maximise the cruiser feel. Discuss?

Where can i get slightly longer springs that are the same stiffness if not slightly less stiff than the stock e93 SE suspension? What is the spring rate and stock ride height of a SE 330 e93 anyways?

[Tambohamilton]

Remind me some other time and I'll go through this for you. I've calculated the rates of most stock springs and have data on fitment and length, so I should be able to recommend something that works (if there is an OE part available). I suspect that because you're e93 and SE already, that you won't have any options within the e9x OE offerings. You'll probably have to look at springs from the X3 or something.

What are your current spring codes?

Given that you're an auto E93, it's likely already got the stiffest factory springs ever available.

No big deal though...as you mentioned, run a taller tire:
225/50/17
245/45/17
Etc.

Also find the right combination of OEM front upper perches and OEM rear spring spacers to raise/level front and rear to perfection.

[MightyMouseTech]

No need to change springs. Can get the parts for the "rough road package" which adds spacers to the springs and raises the car up.

[tlow98]

E30 spring perches get you 12mm increase in the front, all else equal.

E36 spring cup spacers in the rear get you anywhere from 10mm-25mm depending on which pad you use.

For Tambohamilton's advice, you'll apparently have to come back during normal business hours. It will be worth the wait :-)

Highly recommend some taller 17 inch tires for sure!

[Tambohamilton]

I think the best 'fixes' will be taller tyres (smaller wheels if poss) first. Then spring cups to raise the suspension on your standard springs as others have suggested. This raises the suspension off the bump stops ('auxiliary springs') which are normally engaged at ride height. The trade off will be more body roll and less responsive handling.

The springs on your car should be C8, front and rear. These are the longest stock springs for the e9x platform, but also the stiffest of the non-sport ones (other than some e91 rear springs); front 365mm and 144lb/in, rear 340mm and 550lb/in. So none of the stock springs will be able to maintain current ride height and reduce spring rate. You could go with softer springs, but you'd just end up running deeper into the bump stops which would be counter-productive.

I can't seem to find any other OE(M) springs which would work for you, so I think wheels/tyres and spring cups are your best bet

[Baldfox157]

Some useful info in here
https://www.e90post.com/forums/showt...ck+ride+height

[bantam]

Originally Posted by Tambohamilton

I think the best 'fixes' will be taller tyres (smaller wheels if poss) first. Then spring cups to raise the suspension on your standard springs as others have suggested. This raises the suspension off the bump stops ('auxiliary springs') which are normally engaged at ride height. The trade off will be more body roll and less responsive handling.

The springs on your car should be C8, front and rear. These are the longest stock springs for the e9x platform, but also the stiffest of the non-sport ones (other than some e91 rear springs); front 365mm and 144lb/in, rear 340mm and 550lb/in. So none of the stock springs will be able to maintain current ride height and reduce spring rate. You could go with softer springs, but you'd just end up running deeper into the bump stops which would be counter-productive.

I can't seem to find any other OE(M) springs which would work for you, so I think wheels/tyres and spring cups are your best bet

I am somewhat similarly interested in raising my rear suspension in particular, but I would not be opposed to a stiffer spring, as I am expecting to carry a fair bit of extra weight in the rear.

My car is a 2009 e90 335i M sport with auto trans

I have looked into this previously but have not had success in positively identifying a suitable spring.

Thanks in advance for any suggestions you have to offer!

[Tambohamilton]

How about e91 m-sport springs? These should give you minor increase in ride height with reasonable increase in stiffness. They're intended to take the extra load that the e91 has room for (along with slightly higher rear vehicle weight).

You should currently have D4 or D5 in the rear, which are really the same spring but for slightly different applications. They are around 550lb/in.

You could try a K2 or K3 spring (again the same thing just like D4/5). These are the sport e91 spring for low spec models, and have around 570lb/in rate. Ride height should be almost unchanged, from my calcs.

Or K4 at ~590lb/in and 0~1/4" ride height gain. K5 would be ~614lb/in with similar height as the K4.

If you want similar for the front, you probably need to look at e93 335i springs. I can dig out some data on that if needs be.

YMMV with all of that. It's all data from calcs based on spring measurements from various catalogs, along with load data from BMW specs and MR from fe1rx. In other words, I haven't tested it; use it at your own risk! (but it should be close because it makes sense and I used numbers...and I hope it helps!)

Let us know what you choose and how it goes.

[bantam]

Originally Posted by Tambohamilton

How about e91 m-sport springs? These should give you minor increase in ride height with reasonable increase in stiffness. They're intended to take the extra load that the e91 has room for (along with slightly higher rear vehicle weight).

You should currently have D4 or D5 in the rear, which are really the same spring but for slightly different applications. They are around 550lb/in.

You could try a K2 or K3 spring (again the same thing just like D4/5). These are the sport e91 spring for low spec models, and have around 570lb/in rate. Ride height should be almost unchanged, from my calcs.

Or K4 at ~590lb/in and 0~1/4" ride height gain. K5 would be ~614lb/in with similar height as the K4.

If you want similar for the front, you probably need to look at e93 335i springs. I can dig out some data on that if needs be.

YMMV with all of that. It's all data from calcs based on spring measurements from various catalogs, along with load data from BMW specs and MR from fe1rx. In other words, I haven't tested it; use it at your own risk! (but it should be close because it makes sense and I used numbers...and I hope it helps!)

Let us know what you choose and how it goes.

Thanks for the information! How would one go about finding the part numbers for the K4 and K5 springs?

I do not anticipate needing front springs, as my goal is to use a combination of weight reduction and ballast to shift the weight bias towards the rear to improve traction (Currently 48% rear).

I have tried all of the usual remedies and remain unsatisfied.

(M3 rear control arms, solid subframe bushings, aftermarket toe arms, LSD, differential lockdown brace, ADE two way adjustable drag shock kit, and semi-slick tires)

I am not quite ready to put smaller rear wheels and drag radials on yet...

[Tambohamilton]

No need; the K4 or K5 is enough to identify them. But here they are:
K3 = 6773597
K4 = 6773598
K5 = 6773599

[bantam]

Originally Posted by Tambohamilton

No need; the K4 or K5 is enough to identify them. But here they are:
K3 = 6773597
K4 = 6773598
K5 = 6773599

Thanks for the info, look forward to trying them!