rally valving for Bilsteins

[GRMPer]

Ok, since I need one Bilstein, I might as well upgrade to 900 rears and revalve all of them to real rally specs. What should I tell the folks at Bilstein about this valving that I want?

"I want it better than this $16 Gabriel....."

[Jordan]

Front: 390 rebound/160 compression
Rear: 300 rebound/ 120 compression

[paulh]

so are the rally specs softer or firmer than what you get with the regular bilstein HD's?

Paul

[GRMPer]

I would think firmer. thanks!

[Geoff]

I know different people run different valving. Jordan, where did the valving you posted come from (Luke, ScanWest, or...)?

The valving that came with the shocks that came with my car were "rally valve + 10%" in the front and I think "rally valve" in the rear. Whatever that means. I'd guess that the fronts are probably similar to what Jordan posted, maybe 10% stiffer. I have no idea on the rear.

Team RallyHo (and maybe Groo too?) was running 300/100 (or 125?) front and 425/100 rear. I know the front shocks that came on my car are significantly stiffer than the ones that came off the RallyHo-Mobile. Do you guys know where that baseline for valving came from?

I think with all of these shock valvings they were based around S&R or similar springs (SPG with spacers).

I wish I had a larger capacity load cell (unfortunately they're about $2500) for the machines at work so I could measure my shock valving.

[Jordan]

I wrote it down from somewhere, I have a few sets of bilsteins I was going to get revalved... Probably from Luke or from some S&R literature. I guess it would be interesting to see what the factory HD shock dyno would show, I wonder if they are fairly application specific, or more universal internally.

[SteveP]

Any new numbers or information on valving ? I am running ScanWest springs on a 89 .

Thanks

[steve99w]

Don't forget that the factory Bilsteins had thick shafts compaired to std, The shocks off Blomqvists car i couldn't push down with two hands and my body weight 70kgs , compared to std ones,
I would be interested to know if anyone has the factory spring and shock rates.. including length and diameter?
My thoughts also on this is that this was 30years ago and how much testing with springs and shocks was carried out back then!! not alot i feel.

[Geoff]

Don't forget that the factory Bilsteins had thick shafts compaired to std, The shocks off Blomqvists car i couldn't push down with two hands and my body weight 70kgs , compared to std ones,
I would be interested to know if anyone has the factory spring and shock rates.. including length and diameter?
My thoughts also on this is that this was 30years ago and how much testing with springs and shocks was carried out back then!! not alot i feel.

That description sounds like the shocks that were on the front of my rally car when I got it (we weigh the same and I had a really hard time getting them to compress with my body weight, I think I used the weight of the car to compress them so I could get them back on!). If mine were based off of the specs that Jordan posted they might have been 430lb rebound/176lb compression ("rally valve + 10%").

The standard Bilsteins usually have an 11mm shaft. 14mm tends to be their large shaft. Is that what was on the shocks you have/had? If you have them you might be able to find someone with a universal testing machine who could put them into it and compress/rebound the shock and take measurements of their rates. I think the rates are given when the shock is compressed/rebounded at a rate of 1 inch per minute.

I used to have a spreadsheet that had calculated spring rates on it including the S&R front springs. But I can't find it right now...

[Luke]

The Bilstein ratings that are given are Newtons (convention is to quote #s as 1/10 to shorten them ie. a 300/100 shock is really a 3000/1000 in terms of actual force) at a speed of .52 m/s ... or about 20" a sec... fast!
Unfortunatly although its fun to talk about how hard it was to compress a shock by pushing on it by hand... it gives little bearing or indication as to how the shock will perform in use as its mostly influenced by the nitrogen preload and stiction.
Also, the std numbers used for referance, say 300/100 are a middle ground... and show only how effective the shock is at one velocity. Its possible to have 2 shocks that are both measured the same at .52 m/s but have very difference characteristics at the other ends of the spectrum. To get an accurate view one needs to look at the entire force-velocity graph for all effective shaft velocities...

Don't forget that the factory Bilsteins had thick shafts compaired to std, The shocks off Blomqvists car i couldn't push down with two hands and my body weight 70kgs , compared to std ones,
I would be interested to know if anyone has the factory spring and shock rates.. including length and diameter?
My thoughts also on this is that this was 30years ago and how much testing with springs and shocks was carried out back then!! not alot i feel.

That description sounds like the shocks that were on the front of my rally car when I got it (we weigh the same and I had a really hard time getting them to compress with my body weight, I think I used the weight of the car to compress them so I could get them back on!). If mine were based off of the specs that Jordan posted they might have been 430lb rebound/176lb compression ("rally valve + 10%").

The standard Bilsteins usually have an 11mm shaft. 14mm tends to be their large shaft. Is that what was on the shocks you have/had? If you have them you might be able to find someone with a universal testing machine who could put them into it and compress/rebound the shock and take measurements of their rates. I think the rates are given when the shock is compressed/rebounded at a rate of 1 inch per minute.

I used to have a spreadsheet that had calculated spring rates on it including the S&R front springs. But I can't find it right now...

[Geoff]

that makes things easy...

[steve99w]

that makes things easy...

So do we agree that 30years ago they maybe to hard !! which would be why they tear off the lower shocker mount,upper mount and as it passes through the body if not strengthened !!
I have reinforced all areas on mine, a 6x4 inch plate welded over the upper as it passes through the body,The factory car has a 7 inch crack here which they didn't plate back then .
i run the upper outer s&r suport,+ i straped the upper inner around the spring tower as well as straping the lower to the control arm.
Have any of you played around with different settings for maximum grip etc?

[Geoff]

I've run 3 different shock vavlings on the front of my car but I've only run the same valving on both front corners for a few events. After those first few events I have run a number of different valvings ("rally valve + 10%" on RF, "rally valve" on LF and now "rally valve" on LF and 300/100 on RF). I think the valving I've liked the best is the "Rally Valve + 10%" but of course I can't be positive what the numbers are for that.

I have no idea whats on the rear but it seems to work....

As for the S&R spring rates, the calculated spring rate for my front springs (which are either S&R or the S&R ones that ScanWest reproduced) is 408 lb/in. I don't have rears, just a set of 900 rear springs.

[Geoff]

Some more stuff I've dug up:

I found this on my computer, file date was 1/27/2002. I don't know who it came from, could have been James Fox...
"on the front we have 530/240 front and 300/140 rear IIRC
the actual bilstein codes are:
09209350 rear
09204350 front"


Also, the shocks that came off the former RallyHo car (which are nicely labeled) are 300/100 front, 425/100 rear