Bilstein Shocks

by **chrislak** » Tue Mar 24, 2009 8:12 pm

Has anyone carried out or thought about having their Bilstein shocks modified? I'm not sure whether the Bilstein shocks in the MY07 Spec B can be modded.

The Bilstein shocks i have in my XY were re valved and modified to a targa specification a few years back which gave a much better bump and rebound characteristics.

by **smythie** » Tue Mar 24, 2009 8:22 pm

I've been meaning to talk to the Bilstein distributors in Sydney about getting the dampers modified

by **Boxer** » Tue Mar 24, 2009 9:05 pm

Funny, was only talking to coyote about this today. I too am curoius about re-valving options in the 'steins.

I'd like to change the relationship between high speed and low speed damping on bump. I find rebound not too shabby.

Still a damper tuner worth his salt should be able to reap gains in re-valving

by **chrislak** » Tue Mar 24, 2009 9:41 pm

My past experience with re valving Bilsteins has been positive and there is many options, I'm getting some new wheels soon so i will inquire when getting the wheel alignment done.

by Q » Wed Mar 25, 2009 8:14 am

I'd be interested in this too. IMO the rebound is fine but there is far too much compression damping mixed in with a little stiction which results in a less than compliant ride over sharp edge bumps. I have emailed Heasemans a couple of times regarding revalving but have yet to hear from them....

by **Boxer** » Wed Mar 25, 2009 12:41 pm

Q wrote:I'd be interested in this too. IMO the rebound is fine but there is far too much compression damping mixed in with a little stiction which results in a less than compliant ride over sharp edge bumps. I have emailed Heasemans a couple of times regarding revalving but have yet to hear from them....

interesting!

is stiction a factor in 1500kg cars? I had never considered damper stiction playing a part in harsh struts. not saying you are wrong - just never considered it.

agree with your feedback on ride, which is why i'd likely less Hs damping whilst keeping the Ls damping to resist bottoming.

by **coyote** » Wed Mar 25, 2009 1:08 pm

Stiction is a massive problem with these Bilsteins. I've already regreased mine once as a precaution when the struts were off. Had not experienced any stiction though. The grease is secret and special Bilstein stuff ... and it costs a fortune.

Probably the best shock man in the country lives half an hour from you Goxer. If you are serious, just take the car to him, leave it there and let him decide what it needs.

http://www.dlook.com.au/business/161704 ... Automotive

I'll then wheel mine in for the same treatment.

by **Boxer** » Wed Mar 25, 2009 2:04 pm

there's a blast from the past Murray did the gearbox on my TX3

if stiction really is that bad (its a lot of resistance ) then it may alleviate the Hs harshness itself

by **Boxer** » Wed Mar 25, 2009 8:51 pm

Took the advice and spoke to Murray - but he has no real interest or expertise in road setups. Mainly gravel and some Targa work.

He did however confirm my suspicions with relation to the HS and LS compromise in the Bilsteins. They are setup to provide sharp responsiveness and excellent turn-in (which they do). But this creates a problem where it will feel harsh in square edges and bumps. It also trades off in the area of losing some support to the suspension when cornering and creates the tendancy to crash through and bottom out. This is due to the bleed and shim relationship - once the bleed flows and hits the shim, you are effectively at the max damping and further support under load is reduced.

They only have digressive valving. (the shim is a single stage - there is no progressive shim stack to help gain better LS damping and increase with travel)

He said you could play with it for days and try to get a better compromise but it will be exactly that. Changing the piston size will also help bottoming, but may lose sharpness again.

by **chrislak** » Wed Mar 25, 2009 9:04 pm

Ive been dealing with Heasmen's in Sydney for a very long time and used bilstein shocks in every modified car i have owned though never in stock form. The shocks in my Spec B just don't feel right especially over bumpy surfaces. I think ill need to get new sway bars and springs at the same time.

I'll go and see them in the next couple weeks to see what modifications their motor sports division have to offer.

by **Adrian2627** » Sat Mar 28, 2009 10:36 am

Boxer wrote:
Q wrote:I'd be interested in this too. IMO the rebound is fine but there is far too much compression damping mixed in with a little stiction which results in a less than compliant ride over sharp edge bumps. I have emailed Heasemans a couple of times regarding revalving but have yet to hear from them....
interesting!

is stiction a factor in 1500kg cars? I had never considered damper stiction playing a part in harsh struts. not saying you are wrong - just never considered it.

agree with your feedback on ride, which is why i'd likely less Hs damping whilst keeping the Ls damping to resist bottoming.

By Hs and Ls you mean (Hs) High speed damping and (Ls) Low speed damping don't you? Coming from tuning the suspension on downhill race bikes I would have thought that Ls damping would effect the ride over small bumps and Hs damping would control bottom-out. Is it different with cars?

by **BlackFZR** » Sat Mar 28, 2009 10:52 am

From a motorcycle background, HS Damping control sudden large suspension movements over very short periods (wheel drops into a pothole, speed bumps etc), while low speed damping is more the slower less agressive damping associated with weight transfer due to acceleration, braking, undulating roads.

Compression and rebound control bottom out.........

Although I don't know exactly what adjustment are available for the stock Bilsteins......

by **Boxer** » Sat Mar 28, 2009 7:23 pm

BlackFZR wrote:From a motorcycle background, HS Damping control sudden large suspension movements over very short periods (wheel drops into a pothole, speed bumps etc), while low speed damping is more the slower less agressive damping associated with weight transfer due to acceleration, braking, undulating roads.

Compression and rebound control bottom out.........

Although I don't know exactly what adjustment are available for the stock Bilsteins......

Correct - the high speed affects the performance for potholes speed bumps and the like. Low speed affect the bootm out on full load etc.

These are no seperate LS and HS circuits in the Bilsteins as i mentioned above (dont ya love bike dampers that have all the adjustments and progressive shim stacks to play with). However playing with any dampers bleed size, shim strength, shim stack, piston size etc will have different effects on each characteristic.

Bilstein Shocks

Bilstein Shocks

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