Touring SLS delete.

[Nick.Hay]

My Touring has knackered SLS in the rear, and I'm looking at deleting the system in favour of some Bilsteins and lowered springs.

I've done a bit of searching, but I am still confused about which springs to use. I know that the shocks are standard sedan items.

Can I just use lowering springs for the sedan? I read that the Touring is heavier in the rear, but is it really that much heavier that sedan springs would be insufficient?

I'm looking to use "Kings" brand springs (I had them in my 535i, and in my Volvo with no issues), and they are 30mm lower and 30% stiffer.


Advice??

[shogun]

LAD springs are softer than standard shock springs, maybe you try the LAD springs in your new shocks, I assume the rear will go down a bit.

[allalpinweis]

This is a long answer, but I have done a lot of reading and questioning about this subject. I've performed the SLS delete, installed non hydraulic shocks and found the ride to be quite nice, not too stiff or soft. The real question is what type of ride are you after? how are you using the Touring? I have done extensive suspension work on two different 92' 525it's and it all comes down to what you want in the end.

Green 525it - SLS Delete, new Sachs strut, stock spring front, new sachs non hydraulic shocks and matched springs rear, no significant lowering, nice smooth ride very similar to stock, less body roll than worn out crap. Car used for typical family carting, dog, homeowner type hardware store purchases.
Alpine 525it - Lowered on H&R Sport springs with Bilstein Sport struts front, Stock SLS on rear, other mods to rear, new foam bump stops, shock mounts, Nurburing Sway and new bushings, new dog bones and through bleed of system.
The Alpine is my DD, my work truck, my drive the **** out of it car. I love the stiff ride along with the ability to put 500 lbs in the back. It's jarring with a lot of weight in it but very responsive and agile with just me and a 100 lbs or so of tools and gear. I also have 235/45/17's which definitely affect it's handling.

You could definitely use the lowering springs on the touring however I'm not so sure you'd like the ride.

There is not a lot of info out there on this subject, enough if you poke around.
This is mine after all mods above.
8213

[Nick.Hay]

Love a 'long answer'... :)

My Touring won't be getting loaded with much stuff. Certainly nothing over 100-150kg TOPS.

It currently sits about the same as your white iT, however it is jarringly stiff in the back! The front has 30mm lower springs and Bilstein B6 (known as HDs in the USA), which is firm, but AOK with me.
I'm thinking that if I do the SLS delete, I'll go with Bilstein B4 (standard-spec 'black' gas) shocks and Kings 30mm lower springs. Its the identical rear shock/spring combo I have in my 240 Volvo wagon, and that thing is brilliant!!

[genphreak]

Nick, the Volvo settings are very different, so YMWV on the e34...

Best with a lowered spring is the Koni Sport, followed by Boge/Sashs 'Turbo/Sport' (red), Bilstein Sport, HD, Boge/Sashs 'Automatic', then a KYB,, Bilstein 'Touring', Boge/Sashs std, and other stock valved shocks etc.

Remember it is either made for reduced travel or not. If it isn't, it won't dampen the spring as well as it could. The first three above are exactly that. Now that doesn't mean the ride will be bad... just, well you know, it can be really good in an e34... :)

[Nick.Hay]

Hmmm... I'll just continue doing the research before I commit to anything. A few other things are required first!!

[mattyb]

just had a mate get back from Tassie yesterday, I have a set of sls rear springs from Eibach I bought last year by mistake, my mistake that is, I put them on knowing id made a mistake to see what the difference was and them took them straight off as they are shorter than non sls. you can have them if u want to pay the postage. they are brand new still, still in the boot wrapped up in fact; recommended fitting with bilstein HD's, great combo as I did this when I got the right eibach springs for the rear and did the front at the same time, takes about 15 minutes each wheel. may as well do strut mounts while ur at it. FCP euro was a good way to go and has discount international shipping at the moment. get the lemforder mounts not \\meyle (file://\\meyle). remember the bilsteins come with all the spacers and other bits which I also bought and still have. let me know

regards mattyb

[RockJock]

A raft load of my naïve and technically inept questions:

When you guys are talking about SLS are you referring to a LAD system or an EDC system? Are the two entirely different animals? (i.e. did some E34s come with both LAD and EDC flavored versions of SLS?).

Also, why delete instead of rebuilding/replacing (cost)? In one of his threads Shogun mentions that there are safety aspects to keeping the LAD system—what are they? Better stability at high speeds?

If one decides to delete what are the advantages of coilovers vs. springs and dampers?

Thanks guys...

[allalpinweis]

SLS - Self leveling suspension, general description of technology.
LAD - Load Adjusting Damper, specific component of system, chassis and year dependent. Not a system
EDC - Again a more general term for technology used on specific chassis
Specific models of E34's and E32's came with a version of SLS which incorporated the rear dampers controlled by hydraulic fluid. There are no front end components of this systems sans the Pump and reservoir.

I deleted the SLS for one owner because of cost. He did not want to invest any more than necessary. The dampers are expensive new and labor heavy to rebuild. Replaced with stock springs and shocks. Perfectly decent ride and ride height remains close to original. Only lose auto adjusting height aspect. Slightly stiffer spring rate which most people do not notice.

Opinions galore on advantages/disadvantages.

I choose to retain and maintain my SLS. I load mine up with all sorts of things. After much reading and research I agree that the SLS system is superior when cared for. Coilovers for touring are challenging to source and my opinion the SLS is a better adjustment method. The advantage of a coilover in general is ride height adjustment and spring rate changes.

I'm not an expert, but have done my share of research, hands on technical work and testing with different setups. I currently have lowering springs on the front and my SLS intact and I love the ride. It's not for everyone however.

Hope this helps.

[RockJock]

Hope this helps.

Excellent post, you nailed all my questions, thanks so much. I guess the cost/economics of keeping the SLS intact comes down to expensive dampers and possibly hoses, accumulators and the regulator?

[allalpinweis]

Thanks, all parts of the system are expensive relative to other suspension components.

[shogun]

Compared to EDC (especially EDCIII) SLS/LAD is very simple.
All hydraulic, in the front there is the power steering pump, with LAD it is a double vane pump, that is the only difference. Then the hydraulic line to the rear axle where the regulating valve it which operates mechanically, and from there it divides into 2 lines to the rear accumulators aka bombs and from there into the LAD rear shocks, the return line goes again back into the engine bay to the Pentosin container.
Detailed info with diagrams on my website and here http://www.bmwe34.net/E34main/Maintenance/E34Touring/Suspensions.htm . The only electric component is the camber warning switch, which just gives a warning in the CC.
What can brake on LAD systems? hydraulic hoses, bombs, leaking regulating valve, leaking LAD shocks. All can be repaired DIY.

[genphreak]

... Hope this helps.
Yep x2, I'm the same. Love the SLS, but it is costly. Need to use the right fluid, maintain the shocks as they always leak a little bit and eventually wear out. Nitro bombs et al, you have to be prepared to look after it...