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View Full Version : Eibachs/Bilsteins not a good match?



kermac
03-06-2007, 09:02 PM
G'day

Long-ish post. Stick with me[drive]

I wonder if anyone has any knowledge of revalving or adjusting Bilstein shocks?

Background

I have a B5 (2000 model) 1.8TQ Sport (we call them GP Series Down Under). The factory Sports suspension seemed abormally high, especially at the front. A friend offered me a set of used Eibachs off his '98 model.

I thought I would follow the advice of the gurus and upgrade my shocks at the same time [:D], which would help prepare the car for the occasional track day.

No one was able to tell me in advance how much the Eibachs would lower the ride height as there was no way of telling whether the stock springs were atypical or from a bad batch, or perhaps there was a problem with the height of the spring perches? I checked with the owner's handbook and found they were indeed Sports springs, not Heavy Duty or Cross Country. Truth is, the car looked like a Toyota LandCruiser at rest [:o]

The Choice

I wanted a shock that was both height-adjustable and had (at least) rebound adjustment. Of course, No one makes such a beast.

I'd had Yellow (Sports) Konis and Eibachs on my previous A4TQ. The original owner of the car had fitted them right out of the box without adjusting the settings, so they were....well.......soft. I bought a Koni adjusting key and went out one mild Saturday morning to tweak 'er up. PROBLEMO: you have to take Konis off the car to adjust them [rolleyes]. Anyway - the end result was pretty good. I just didn't feel like paying a suspension fitter another $300 each time I wanted to tweak them a little to get them to my exact requirements.

So - I deleted the Konis from the list this time round.

The only other entry on the (very short) list was Bilsteins. These can have grooves machined on the body so you can move the circlip that locates the spring perch, thus altering your ride height up or down by up to 20mm [:)] BUT - Bilsteins are non-adjustable for stiffness [mad]

The purchasing and fitting experience

I live in Australia's capital city, and although small, we are lucky to have a suspension genius who managed the whole thing. He even got the Bilstein agent to ring to enquire what sort of springs I was using, and how I wanted the shocks set. "Reasonably firm", I said, "but not enough to rattle the kidneys. And I'll be doing the odd track day, so plenty of control if you please."

"No wukkas, mate*" said this eloquent fellow.
*Aussie argot for "no wukkin' furries, my good man"

So the suspension genius got the shocks the next week, I left my car with him for the day and all was well witht he world. I marvelled at the new ride height when I picked up the car, and drooled over the negative camber at the front. So we'd certainly got it right in the looks department.

Driving impressions

At first, the car seemed so much better to drive - really good turn-in going into corners, seemed to stick to the road like glue. But after a bit I realised I hadn't tested the suspension out properly by taking her for a hard drive on poorly-surfaced country roads.

The picture changed completely. On bumps or potholes, the front suspension would crash and jar your teeth. On large bumps or undulations, the back would wallow and pitch and take several cycles to settle. The I had to do a bit of a crash stop where the surface was a bit rough, nothing special, and the car was all over the road. Rounded a corner with a bump in the middle and the back end wallowed and started oversteering.

In short, these shocks are only good on smooth roads. On rough roads, they're far too soft both on compression and rebound (although I'm not certain whether the crashing at the front might not be caused by the fronts being too stiff on compression. The suspension guru thinks otherwise).

The problem (you still with me??)

I've discussed this with said guru, and agreed the Bilsteins need revalving. The problem is - revalved to what? How do you quantify your needs and convert this into valve settings on both compression and rebound? There is, you see, a price to pay (like life, really). $300 or thereabouts each time you have the shocks removed and replaced (luckily I kept the old shocks so there won't be too much downtime).

How do you make sure that you get something close to what you need without repeated visits to the guru?

I should add that I finally realised just how soft my rear shocks were when I went for a track day with a friend and his B6. He has coilovers with relatively hard springs (I think he said 800 kg/cm front, 1200 rear) and the rebound setting on the dampers close to the max. His handling was brilliant (both to look at and from inside the car). The back of the car was almost rock-solid. On mine, I could grab the towbar and bounce it up and down like a baby's stroller.

Needless to say, I haven't yet had my car on the track [mad]

Ideas, anyone? Is there any sort of database on axle weights / spring rates / damping force??

Thanks for staying with me [:D]

kermac
Canberra, Australia

deolu
02-08-2008, 07:55 PM
Damn someone should have at least leave a comment with the whole typing he did. LOL

SeanF
02-08-2008, 08:16 PM
i had factory valved bilsteins with an eibach prokit, and with the neuspeed rear swaybar, it was a VERY good combo IMO. i had no track duty though.

ratty
02-09-2008, 06:14 AM
I think some posts were lost - I definitely recall replies, even one from me.

The problem ended up that the Bilsteins had never been revalved in the first place. After many apologies and a round trip for the dampers, all was resolved when the original request was used for reference.

Oh, btw I'm the friend with the B6 [:D] Just a couple of weeks ago took the lead in the NSW VAG Motorsport series by beating an RS4 (B7) around the most power based track we have in NSW (except for Bathurst, but racing there is practically impossible).