Stock ride height E92 Msport N54...

[jon dee 500]

Been killing time by researching a few suspension options just is case I get lucky and can afford to freshen mine up. The Eibach/Bilstein B12 Pro-Kit looks like something that would work for me, so I am trying to figure how far down that will put me from stock. The car is already what I would estimate in my professional capacity to be... kind of low and I don't really see the need to go any lower.  I believe 100mm from the road surface to the lowest structural part of the car is the legal minimum, and if the Pro-Kit does lower the car by something over 25mm, that could get a bit dodgy come WOF time.

So, does anyone know what the wheel centre to fender lip measurements (front and rear) are for a bog stock E92 on factory rims and tyres ?? An equivalent off the floor measurement to the jacking pads or some other identifiable undercar point would do as well.  Car doesn't actually look that low going by the wheel gap but it could be leaning into the kerb. I'll do a bit of measuring tomorrow just in case I'm being old fashioned

Cheers...

[jon dee 500]

So I measured this... centre of hub to lip of wheel arch directly above; from the floor to the lip of the arch directly above the hub; and from the bottom of the jack pads to the floor. Because the wheel arch is curved and these are not the easiest things to measure, they are plus or minus a mm but otherwise pretty close. Looks like the rear is not bad for level but the the front right is about 10mm lower than the front left.

Note that the bottom row has measurements from the bottom rim of the wheel to the arch lip directly above the hub. This is much easier to measure and I found that BMW actually does (or did) provide this measurement for ride height on some cars. I found the measurements on another forum, said to be for an E92 M3 with 18" wheels and they were given as F: 610mm +/- 10mm and R: 594mm +/- 10mm. So it seems that my car is not unusually low... maybe I am just getting old  

Any ways... if you have a stock E92 coupe with 18" wheels I would like to get some comparisons. For the record I recently replaced the jacking pads so the measurements are from the floor to the lowest point of a fresh jacking pad.

Cheers...

 

[SmackJackTheCrackerMan 54]

I had an E92 M-Sport and that was always lower on the right hand side. I assumed that the suspension was getting a bit tired. 
move since got a E91 M-Sport and that is exactly the same. 
I wonder if they come like that from factory? 

[jon dee 500]

Dunno... I don't think BM would have designed it that way Could be that there is a bit more weight in that corner from the steering and turbos etc. If I replace the suspension it will be with something along the lines of the Bilstein/Eibach kit or the Koni/H&R equivalent. If/when that happens (depending on how the exchange rate looks next year) I shall also replace all the associated wearing parts to try and get a nice tight "as new" ride with a decent balance of comfort and performance. When I find a place that can install all that for me, I shall be asking for corner weights and an alignment to see what kind of numbers you get with a non-adjustable factory style setup.

I want something that is set and forget... does everything reasonably well without having to fiddle with with ride heights, damper settings and multiple sets of tyres. As it sits at the moment the ride height is about right for clearing driveways and speed bumps, but I have the feeling that a decent set of shocks and springs would help sharpen up the handling. In the end, short of being able to scrounge a ride in a car with the exact setup, it comes down to doing your research and then taking a punt that whatever you buy will meet your expectations

Cheers...

[SmackJackTheCrackerMan 54]

I'm also looking to upgrade my suspension early next year. I would imagine I will go with a decent set of coilovers, but as you say, I couldn't take it much lower then standard.

Upgrading to M3 arms kits seems to be a popular way to tighten everything up.

https://www.fcpeuro.com/products/bmw-m3-control-arm-upgrade-kit-e82-e88-e90-e91-e92-e93-bmwmcaktfr#description

A bit expensive but I would imagine this will completely change how the car feels.

[Herbmiester 924]

I found you can go about 20mm lower on the front before speedbumps etc become a hazard. The back seems a wee bit more tolerant. As the the M3 control arms its money well spent.

[jon dee 500]

Discovered that BM have a range of factory springs for the 3-series and fit specific springs to each model. The springs are tagged and the correct front spring for a Msport E92 N54 335i is a D6. Armed with this information I went and peered under the fenders and yusss... my springs are tagged D6. So, seeing as I am happy with the present ride height, there does not seem to be much point in going to lower, stiffer springs. b

Revised plan now is to get a set of Bilstein B4 OEM-Replacement Msport shocks and all the associated hardware that is recommended for replacement when the shocks are changed out. I'll see if I can squeeze M3 arms into the shipment and keep the total landed cost under NZ$1000. NZ Post have added a seafreight option to their North American forwarding service. That should work out quite well if I can get free shipping to Oregon from the vendor.

Cheers...

[jon dee 500]

Dayum boy.... researching suspension throws up some interesting stuff !!! Seems that the Bilstein B4 is a twin tube design and not the famous mono tube design that everyone knows and loves. So now I am looking at Bilstein B8's which definitely are mono tube. Haven't been able to find a definitive review of them when paired with the stock Msport springs, but from what I can glean from reading in many forums, is that (a) they are far too stiff and give a rough ride, or (b) they give a great compliant ride with much improved road feel and handling...  a little firmer than stock but quire acceptable for a "sports" sedan.

Anyone run the B8's with Msport springs (or similar mild lowering springs) and if you did, how did you like them ??

Cheers...

[Olaf 3317]

Not so sure everyone who knows the monotube design loves it... cue @3pedals for an excellent explanation of the benefits and flaws of said design.

PS: B6 = Sport, B8= shortened Sport.

Edited November 14, 2020 by Olaf
correct tagging of Billiam for this thread

[Olaf 3317]

or... just get the OEM Sachs Msport part and be very happy with the factory setup?  I appreciate that as you're punting the car around the track at motorsport events (more power to ya!) you may want more spring rate and a corresponding increase in damping... EDIT - and ARBs...

Edited November 14, 2020 by Olaf
added ARBs

[jon dee 500]

The biggest problem with selecting which suspension components are needed to meet ones own requirements is that virtually all recommendations or opinions found on the internet are entirely subjective. Put the same components on two identical cars for two different drivers and inevitably the impressions and opinions of the drivers will be different... sometimes radically different. If we consider that "comfort" and "performance" lie at opposite ends of the suspension spectrum, then it is not too difficult to identify the dominant components of shock and springs. But when it comes to trying to hit the middle ground of blending a firm but comfortable ride with decent performance, this is where driver opinions tend to diverge wildly.

And since we are dealing with opinions, I'll state mine From my somewhat limited experience with my E92, I consider that both the performance and handling are pretty damn good. BM have done a great job of hitting a middle ground that is well suited to the potential of the car without losing sight of the fact that it is a "luxury sport coupe" if I might use that phrase. In my view the ride height and spring rate are acceptable, but I feel that the shocks could stand an upgrade.

I'm not interested in in entering the wormhole and going down the path of upgrading every suspension component to achieve M-car handling in a non-M-car. That does not make sense to me when if you want that level of performance/handling you can buy an M-car. So I just started looking for some replacement shocks that would do a better job of keeping the wheels in contact with the road surface. In the past I have used Koni yellows and Koni Sports adjustables and found them to be a decent compromise for a road car. But legend has it that Koni has an edge in the comfort stakes while Bilstein does better on performance.

Hence my search for Bilstein shocks that will work with the existing springs without altering the ride height. Despite conflicting evidence to the contrary, I believe that B8's can work with Msport springs as they are classified as "lowering springs" when compared with non-Msport springs. In the end I think that my choice will be between Koni and Bilstein so I am keen to hear about anyone's experience with either when used with stock Msport springs

Cheers...

 

[Herbmiester 924]

M Suspension is essentially just control arms and shocks. Yes there are other parts like the sway bars but if you just did the M3 front end you would get big bang for your buck and that is a whole truck load cheaper than an M3. Shocks are consumables, replace every 80k or so. I used Koni yellows with M sport springs and they work fine. You can adjust the rebound of course so that allows you to get a pretty close match. That said Bilstein and Eibach kits seem pretty well matched according to the US forums and I did read a post by someone at Bilstein talking about how the Eibach/Bilstein kits are matched. What changes is when you add an LSD then you can play with the rear sway bar diameter because you will be getting you power down more effectively. 

[jon dee 500]

Yes... I have no argument with progressively improving a car based on the careful evaluation of each modification and ensuring that it will work in harmony with previous or future modifications. I also recognise that we are all different and each owner will have their personal preferences and goals when modifying their car... wouldn't have it any other way It is possible that further down the road I will look at adding selected M-car components if I feel that there will be worthwhile benefits for the use I am making of the car.

Presently I am focusing on shocks and while I like Koni yellows there is no chance I will ever change the setting on the rears once they are installed !!! Even when I had top adjustables front and rear in my Corolla, once I found a sweet spot I never changed them again. I understand that the factory sets the rears at the midpoint of the adjustment... what did you end up with on yours ?

As a matter of interest, the first set of bottom adjustable Konis I bought for a Corolla were model specific and factory tuned for the AE86 (came with a set of Koni springs). The instructions that came with them indicated that the adjustment was to compensate for wear. Seemed reasonable, as I don't think tearing a strut apart to tweak damping is much of a sales feature !!!

[Herbmiester 924]

For my Koni rear shocks I dialed in more rebound damping, approximately 3/4 towards full firm. This works at motorway speeds but is a but crashy around the rough roads in the Valley. I have Tein springs which are progressive and firmer than M/Sport. Reasonably happy but not sure its any better than linear but slightly softer Eibach's or H&R's. If I did it again I would probably go Bilstein  B8 if staying with lowered springs of B6s if staying with factory M sport springs. The Bilstein monotube design is superior to a twin tube setup but there are other factors like quality of manufacture and as mentioned damping vs spring rate. Koni adjustability will allow you to get those two things right for your application. All that being said I had some Koni Strt (orange) on one of my old E36's with some King springs (They were on the car when I bought it) and the setup was really good. 

[jon dee 500]

Interesting... and basically you are describing the dilemma that faces anyone looking for that "ideal" setup Having spent many hours now poring over hundreds of old  posts on many different forums,  the one factor that becomes clear is that there is no one setup that will make all owners happy. What I might describe as firm and supple, someone else will call harsh and uncomfortable. This makes it virtually impossible to draw any conclusion from reading reviews. Poor selections, mismatched components, run flats vs non-run flats, too much drop, not enough drop, insufficient bump travel, worn bushes, wrong bump stops... there are a hell of a lot more ways to get it wrong than there are to get it right.

If I was starting from scratch with a non-Msport car, I would also likely go with the Eibach/Bilstein B8 combo based on the some of the more favourable reviews and the reputation of these two companies. Plus, once they are in they are there to stay with no fiddling possible. However, having looked at all the options and bearing in mind that all I want is to do is refresh the shocks and related mountings/bushings etc without changing the spring rates or ride height, I'll probably settle on the B4's. Bonus being that I don't have to explain what those coloured things are behind the wheels.

One of the hallmarks of a quality vehicle is the absence of intrusive NVH, and this a key part of my approach to modifications. The builders of up market vehicles put a lot of effort into tuning the suspension to minimise NVH while still providing a smooth and well controlled ride. Rubber bushings and mounts play a big part, and while they are popular modifications, I would not replace rubber with poly bushes or pillowballs in my cars. Oui for race cars no problem, but non for road cars. I am not prepared to downgrade the pleasure of driving my car every day just for some minor performance gains that only come into play at the limit of adhesion, but annoy me every time I hit a manhole cover. But that's just me

Cheers...

[Herbmiester 924]

Having used Poly bushes on a few cars now I dont believe there is that much of a trade off on NVH, but it depends on how many bushes you replace, where they are fitted etc. Personally Running an E92 on standard tyres (not runflats) with M3 control arms (Stiff bushes) the ride is probably better. I dont think you can apply blanket generalizations like poly for race rubber for road. and considering you do a bit of motorsport in your I cant see the problem.

 

[jon dee 500]

Yes... generalisation for sure... most of my opinions are pretty general unless talking about specific items. I was trying to draw the line between people who buy a poly bushing kit that replaces every rubber bush on the car, and those who select poly bushes for certain places that can benefit from them without generating excessive NVH. On my Corolla I bought a TRD hard rubber bush set and replaced every bush on the car But the only place I used poly was for rollbar drop links. Of course the BM suspension is a totally different to an old live axle Corolla, so different rules may apply.

Or to put it another way; if I found that the best way to solve a handling problem with the BM was to use poly bushes, I would use them... providing they did not generate an objectionable (to me) increase in noise inside the car. NVH is the reason I have never used coilovers with camber plates. Once again, if I was building a race car I would be prepared to overlook the down side to gain the benefits.

Cheers...

[Herbmiester 924]

M3 control arms;  Best advice I can give you.

[jon dee 500]

This kit ? That's all I need ? https://www.fcpeuro.com/products/bmw-control-arm-kit-5-piece-m-upgrade-bmwmcakit

Edited November 16, 2020 by jon dee

[Herbmiester 924]

Yes thats the one. Do it.

[jon dee 500]

OK... ordered that Looking at the pieces it seems that the kit can be installed without disturbing the struts or installing new shocks. But I already have a set of discs and pads waiting to be installed, so I figured I might as well collect up all the new bits (shocks, bushes, spring pads, mounts etc) and get the whole lot installed at one time. My current goal is to get get the car riding like it did when it left the showroom (except without the run flats)  Maybe better if these arms are as good as you say. Then I can drive it for a while and see if I think it needs Eibachs and B8's. That would be phase two

Cheers...

[Herbmiester 924]

12 hours ago, jon dee said:

OK... ordered that Looking at the pieces it seems that the kit can be installed without disturbing the struts or installing new shocks. But I already have a set of discs and pads waiting to be installed, so I figured I might as well collect up all the new bits (shocks, bushes, spring pads, mounts etc) and get the whole lot installed at one time. My current goal is to get get the car riding like it did when it left the showroom (except without the run flats)  Maybe better if these arms are as good as you say. Then I can drive it for a while and see if I think it needs Eibachs and B8's. That would be phase two

Cheers...

Good plan, FWIW I am taking my Tein S Techs  out and going back to M Sport springs. Well I think I will  

 

Edited November 16, 2020 by Herbmiester

[jon dee 500]

One of the things I learned when messing around with short stroke suspension on my Corolla was that it is critical to keep the shock in the correct part of its stroke with the weight of the car applied. Rule of thumb for me was 2/3rds of total available stroke for bump and 1/3rd for rebound. That's why I am reluctant to change the OEM ride height without having a lot more information on the springs. .

This also highlights the one worthwhile advantage of decent coilovers (as far as I am concerned) in that ride height and damping can be adjusted without changing the spring preload. Still not enough to talk me into using them on a road car.

Cheers...

[Herbmiester 924]

Bilstein make it pretty clear that the B8 is for lowered springs like Eibach H&R etc while the B^ is for stock springs inc the M sport springs. 

Quote

The Bilstein B8 Performance Plus Kit includes two rear shocks. These shocks are for use with lowered springs such as from H&R or Eibach. We do not recommend that you use them with any factory spring, including factory sport package springs. With the increased damping rates from stock you will have much more control over body motions. These will give a much more buttoned down and taut feeling with lowering springs compared to stock shocks.

 

 

[jon dee 500]

Yes... I've noticed that it is one of the hotly contested fittings on the internet. Turner Motorsport offer the B8 for the E92 but don't recommend that they be used with Msport springs. Bilstein list B8's for the sedan with Msport which leads me to think that maybe the sedan has stiffer springs or greater mass than the coupe. Turners suggest using H&R or Eibach springs if you want to use B8's on the coupe, and that seems reasonable if the spring rate and ride height maintain adequate bump and rebound stroke.

Interestingly enough, Bilstein do offer the B8's for the 2012-13 E92 with Msport and they are the same shocks as offered for the 2007-11 sedan. Again, there could have been a spring change between the early and later coupes. Too many unknowns for me to want to take a punt on the B8 setup. Even the B6 has a few concerns relating to raising the ride height

All of which helps persuade me that the B4 setup is the way to go with Msport springs. The B4's are reputed to be valved about 10% stiffer than OEM, so that should work well with the extra 0.5 degrees of negative camber that the M3 arms bring to the party.

Cheers...