Looking for Air Suspension info

[Urluz3n]

Hello
I am trying to find if any one has added an Air Suspension to a Z4M Coupe. I would love to be able to raise and lower my '07 M Coupe. Does anyone have any information or know of anyone who has done it? I had a flat last year and when the tow truck came to get me the fangs on the front dragged and my cans in the back rubbed as well. If I can raise the car an inch, I won't have these problems again.

[SHOR3N]

Hey,

I've been researching for the same thing. I found these two options, but they are not air-based and pricey..
Also not sure if they'll work on the Z4M.

Anyone here with this type of setup or more info?

http://www.ramliftpro.com/

http://kw-suspension.com/us/kw_hls.php

[psygnosis]

Why do you want to make a Z4M slower?

[seank]

m-powerm3 is on air or he wouldn't be able to drive his car

[psygnosis]

But he didn't ruin an M, of which there are less then 1,300 examples of in the US

[SHOR3N]

Originally Posted by psygnosis

But he didn't ruin an M, of which there are less then 1,300 examples of in the US

How will it ruin the car?

[seank]

Originally Posted by SHOR3N

How will it ruin the car?

Most bmw guys/gals aren't into it. That also includes: chrome wheels, spinners, 22" tires, etc.

[SHOR3N]

Originally Posted by seank

Most bmw guys/gals aren't into it. That also includes: chrome wheels, spinners, 22" tires, etc.

Oh I see, no I'm not into that either. I'm just looking for a practical add-on really, as the OP mentioned there are times when being able to raise the front can come in handy.

[beta]

I've heard good things of the KW hydraulic lifters from a Porsche owner. You still get all the performance of coilovers, but you can raise the clearance a bit when needed.

I think the concern above is that if you bag the suspension, you'll lower the performance. From searching around, some people do track cars with air suspension (no z4ms that I can find, but mustang/wrx) and have had good results, but since I have zero personal experience I can't say.

[GuidoK]

I've also thought about this problem: bumpers scraping on speedbumps, carparks, toetrucks etc.
The KW HLS kit (very expensive) and the ramlift system use hydraulics, but there are also similar systems that use air:
Umbrella design: http://www.umbrellaautodesign.com/co...vrh_suspension
and
Stance solutions static+: http://www.stance-solutions.co.uk/1

Hydraulic sets could give you (in theory) a system that drivable at any height. Oil isn't compressable so when you pump the riser half full with oil it should give you half height no matter what the load is. I don't know if these systems are that advanced.
There is also a downside and that is leakage. A lot of hydraulic suspension systems (like citroen) have a diaphragm around it to catch oil if leakage occurs and guide it back to the oil reservoir. These sets don't have that (the diaphragm around the kw set is there to protect the system from dust etc). so leakage like this....
With air.... it doesn't matter as long as the pump can handle it (leaking air of course isn't supposed to happen but it won't result in a really messy situation).

Also it looks like the air systems take up less height in the height range from any existing coilover, but it is limited to what springs are used (and off course inner shaft diameter).

That static+ system is pretty cheap (about $500 or so) but that excludes compressor/tank and lines etc. But loads of that stuff on ebay. (normal air lift stuff needed with tanks etc)

I have no idea what works better. The hydraulic sets seem to have been around longer I think. But an air lift system will be faster as you can use a pressure tank.

Those air systems with the height adjuster on the top obviously dont work with coilovers like this:
http://www.zpost.com/forums/attachme...1&d=1263923411

[nekky]

Modern air suspension has come a long way... I've had some friends looking into Airrex and Accuair. Both expensive, but high quality. Broadway Static also builds air cups. There's lots of info out there; I just don't think anyone has done it to a Z4M yet.

As far as taste goes, usually people who do air ruin the car with the wrong type of wheels or something. Air can be very useful and quite aesthetically pleasing if it's done properly. As an example, I think Stefan's car (the silver coupe w/ the AC Schnitzer Type II's) looks fantastic, but I could NOT go that low where I live. For a static setup, he's dumped. It's quite literally an impossibility. The streets here suck. But I'd love to be able to dump it for shows etc.

[Urluz3n]

An air suspension isn't as practical as hydraulics. With an air suspension you will need a compressor and a tank, but with hydraulics no tank is needed. With a M Coupe having a pump/tank isn't practical. I just have to find someone to install it for me.

[GuidoK]

You don't need a tank, it's a convenience.
You only need a compressor, which is the full equivalent from the pump you need with hydraulics. You can buy small compressors especially made for air reinforcement systems for like $150 on ebay. That will do the job in the same way.

So on that area they're the same. Air just gives the possibility for a tank (quiet fast operation), something you can't do with hydraulics (or at least it's very difficult)

If something goes wrong an air system will be cheaper to fix I think. There's no possibility that oil can become polluted (with result that the pump gets damaged), and if it leaks the system just doesnt work (depends on the amount of leakage).
With hydraulics any leakage will shut down the system (I dont think there's a large fluid reservoir) and you get a big mess (oil&dirt)
The HLS system seems to be nicely shielded, but that ramlift system looks like an unshielded system (well there's an o ring obviously), and upside down, so that dirt falls in the cilinder. That's a sure way to ruin the system (that's why KW probably installed shields....)
The air systems have the cilinder upside down, so dirt has to fall upwards to clog the system. It also looks that you can shield it much better yourself with a bumpstop or so.

Too bad the HLS system is 3 or 4k (so parts will be really expensive too), it looks better engineered than the ramlift.