Bilstein
02-16-2010, 08:46 AM
#11
Former Moderator
Thanks
Bleed window? It's not a needle type adjustment. Usually if the clicks aren't defined enough to be accurate then I just count turns 1/4 turn or 1/2 turn. For a needle valve it doesn't matter where you are in the click and it usually nets better accuracy but I'm curious about the bleed window.
Do you run bilsteins?
Bleed window? It's not a needle type adjustment. Usually if the clicks aren't defined enough to be accurate then I just count turns 1/4 turn or 1/2 turn. For a needle valve it doesn't matter where you are in the click and it usually nets better accuracy but I'm curious about the bleed window.
Do you run bilsteins?
02-16-2010, 08:58 AM
#12
No I don't run Bilsteins. I have Penske's.
From Dennis Grant
In the Bilstein PSS9 adjuster, they've got a bypass passage drilled into the centre of the shock rod and a one-way check valve so that the bypass only functions in rebound - the same as Penske and a bunch of other shocks. But instead of a Penske-style needle and seat deal, the variable-flow section is a small cylinder with an angle cut across it and the angled section covering the outflow port on the shaft. The cylinder is, in turn, attatched to a shaft that runs the length of the shock rod - turn the shaft, and you turn the wedge/cylinder thingy, covering or uncovering the outlet port.
The shaft is indexed to the wedge/cylinder thingy by screwing a block with a captured detent ball sticking out of it on top of the shock shaft, and then a disk with a series of detent depressions cut into the underside is attached to the adjuster rod. As the disk is turned, the detent ball clicks in and out of the depressions in the disk, theoretically covering/uncovering progessively larger/smaller hole area as the disk is rotated.
Looks good in theory, but in practice, not so much:
1) There's only (if memory serves) 180 degrees of disk rotation between "hole fully covered" (full hard) and "hole fully uncovered" (full hard) which means the amount of hole area covered/uncovered is stupid sensitive to small amounts of disk rotation. Just a little bit of stiction in the detent ball can make a signifigant difference in the size of the hole opening, meaning that *which direction you adjust into* can change shock forces. ie, if you want a #3 setting, if you start at 1 and go 1-2-3 you get force A, and if you start at 5 and go 5-4-3 you get force B, and A != B.
2) While the area uncovered is roughly linear with the angle of rotation, the FLOW through the hole is a function of the SQUARE of the area (or maybe the cube...) anyway, it is nonlinear with area. So very small changes near full hard make huge differences, and very large changes near full soft make next to no difference at all.
3) The location of the detent ball is not keyed to the shock shaft at all, so getting the detent ball to line up in the same place on a set of shocks is damn near impossible. Full hard will be the same, and full soft will be the same (hole fully covered, hole fully open) but inbetween is an utter crapshoot. So all you can really count on is "full hard" and "full soft".
As an adjuster, it just plain sucks. The Penske needle and seat is much, much better (and Penske has does some neat tricks with the needle and seat profiles to make the force change per click linear across most of its range.
The shaft is indexed to the wedge/cylinder thingy by screwing a block with a captured detent ball sticking out of it on top of the shock shaft, and then a disk with a series of detent depressions cut into the underside is attached to the adjuster rod. As the disk is turned, the detent ball clicks in and out of the depressions in the disk, theoretically covering/uncovering progessively larger/smaller hole area as the disk is rotated.
Looks good in theory, but in practice, not so much:
1) There's only (if memory serves) 180 degrees of disk rotation between "hole fully covered" (full hard) and "hole fully uncovered" (full hard) which means the amount of hole area covered/uncovered is stupid sensitive to small amounts of disk rotation. Just a little bit of stiction in the detent ball can make a signifigant difference in the size of the hole opening, meaning that *which direction you adjust into* can change shock forces. ie, if you want a #3 setting, if you start at 1 and go 1-2-3 you get force A, and if you start at 5 and go 5-4-3 you get force B, and A != B.
2) While the area uncovered is roughly linear with the angle of rotation, the FLOW through the hole is a function of the SQUARE of the area (or maybe the cube...) anyway, it is nonlinear with area. So very small changes near full hard make huge differences, and very large changes near full soft make next to no difference at all.
3) The location of the detent ball is not keyed to the shock shaft at all, so getting the detent ball to line up in the same place on a set of shocks is damn near impossible. Full hard will be the same, and full soft will be the same (hole fully covered, hole fully open) but inbetween is an utter crapshoot. So all you can really count on is "full hard" and "full soft".
As an adjuster, it just plain sucks. The Penske needle and seat is much, much better (and Penske has does some neat tricks with the needle and seat profiles to make the force change per click linear across most of its range.
From Dennis Grant
02-16-2010, 09:24 AM
#13
I just called Bilstein's Circle Track group to get some information on the new DA Shaft they have.
Its significantly different that the PSS series adjuster. Its adjustable from 0-6 and on a 40/40 shock (typical digressive valved circle track shock) - this gets you about 200lbs of force at 10"/sec for both rebound and compression. He said you can set this up to get 140lbs of adjustment across the sweep of the adjuster. Thats a pretty decent chunk of adjustment.
He didn't know if a pin top mount (like we would need) is available, he's only seen it in the rod end type. Typical price runs around $130 just for the shaft and you can do Rebound only, Compression only, or both.
I know LG Motorsports is using this shaft in conjunction with the ASN Series shocks for the C5/C6 Corvette's right now. I can't seem to find any pictures and I seem to remember the price point being really high though.
Its significantly different that the PSS series adjuster. Its adjustable from 0-6 and on a 40/40 shock (typical digressive valved circle track shock) - this gets you about 200lbs of force at 10"/sec for both rebound and compression. He said you can set this up to get 140lbs of adjustment across the sweep of the adjuster. Thats a pretty decent chunk of adjustment.
He didn't know if a pin top mount (like we would need) is available, he's only seen it in the rod end type. Typical price runs around $130 just for the shaft and you can do Rebound only, Compression only, or both.
I know LG Motorsports is using this shaft in conjunction with the ASN Series shocks for the C5/C6 Corvette's right now. I can't seem to find any pictures and I seem to remember the price point being really high though.
02-16-2010, 09:35 AM
#14
Originally Posted by TheNick,Feb 16 2010, 09:15 AM
Shaikh.
The damping adjustment is valid though too, its just not that great. You basically have ON or OFF. The bleed windows aren't indexed very well inside the shaft and depending on which end you start at for adjustment, you might get a different window when you turn the adjuster.
The best way to treat a PSS9 is one "race" setting and one "street" setting. Full hard and full soft.
The damping adjustment is valid though too, its just not that great. You basically have ON or OFF. The bleed windows aren't indexed very well inside the shaft and depending on which end you start at for adjustment, you might get a different window when you turn the adjuster.
The best way to treat a PSS9 is one "race" setting and one "street" setting. Full hard and full soft.
it is quite difficult to accurately set them if not full on or full off
i use a marker but even then it is tricky
for street full off is pillowy but good control
for time attacks full on is stiff but falls slightly short of what i want
overall though a very good street/track setup
02-16-2010, 09:55 AM
#15
Former Moderator
Wow, interesting, I wonder why bilstein did something like that for the adjustment.
I'm going to guess you like your Penskes? I'm pretty sure I would
Did you have to have them revalved at all or were they good from the get go? Two or three way? Spring rates?
Sorry for all the questions but I would like my next suspension purchase to be my last. So far the only suspension I've been happy with was my ohlins 3way on my bike.
I've had SRC's on the S and don't really care for the lack of low speed damping and the insane high speed damping on the rear.
I'm using a friends KW V3 CS's and they for the most part don't feel too bad but maybe release a bit too much on the high speed end and the change from med to high doesn't seem very smooth in the transition but at least they're compliant compared to the SRC's.
I've driven a car with JRZ's that weren't properly setup and have been in an S with motons (cs?) at thunderhill. The Motons felt like they would be good but as a driver they may feel different?
Have you been on SRC's, KW's or Motons? if so how do they compare with the Penskes.
I'm going to guess you like your Penskes? I'm pretty sure I would
Did you have to have them revalved at all or were they good from the get go? Two or three way? Spring rates?
Sorry for all the questions but I would like my next suspension purchase to be my last. So far the only suspension I've been happy with was my ohlins 3way on my bike.
I've had SRC's on the S and don't really care for the lack of low speed damping and the insane high speed damping on the rear.
I'm using a friends KW V3 CS's and they for the most part don't feel too bad but maybe release a bit too much on the high speed end and the change from med to high doesn't seem very smooth in the transition but at least they're compliant compared to the SRC's.
I've driven a car with JRZ's that weren't properly setup and have been in an S with motons (cs?) at thunderhill. The Motons felt like they would be good but as a driver they may feel different?
Have you been on SRC's, KW's or Motons? if so how do they compare with the Penskes.
02-16-2010, 10:20 AM
#16
No comparisons. I actually haven't driven on the Penske's yet. The car just came down off jackstands last night.
I spec'd the valving on my Penske's - I'm still not exactly happy with the rebound side but we'll see what happens when I get the car on the street. Its significantly different than the OTS Penske's this particular builder would supply. The dyno's look similar to Moton's.
The boat that most shocks miss out on is low speed compression and they use way too much rebound across the board.
I spec'd the valving on my Penske's - I'm still not exactly happy with the rebound side but we'll see what happens when I get the car on the street. Its significantly different than the OTS Penske's this particular builder would supply. The dyno's look similar to Moton's.
The boat that most shocks miss out on is low speed compression and they use way too much rebound across the board.
02-16-2010, 10:59 AM
#17
Former Moderator
Originally Posted by TheNick,Feb 16 2010, 11:20 AM
No comparisons. I actually haven't driven on the Penske's yet. The car just came down off jackstands last night.
I spec'd the valving on my Penske's - I'm still not exactly happy with the rebound side but we'll see what happens when I get the car on the street. Its significantly different than the OTS Penske's this particular builder would supply. The dyno's look similar to Moton's.
The boat that most shocks miss out on is low speed compression and they use way too much rebound across the board.
I spec'd the valving on my Penske's - I'm still not exactly happy with the rebound side but we'll see what happens when I get the car on the street. Its significantly different than the OTS Penske's this particular builder would supply. The dyno's look similar to Moton's.
The boat that most shocks miss out on is low speed compression and they use way too much rebound across the board.
The penske dyno matches which moton line? club sport or their motorsport? I'm assuming the motorsport line.
So off the shelf penskes are not quite as nicely valved as the Moton's OTS
Is there any reason why you went with Penskes over Motons? Is it because of the shock builder you deal with for the revalves?
I think for a twin tube KW did a very decent job with the low speed compression. I've been told that twin tubes usually lack low speed damping.
Sorry for all the questions and I really appreciate the answers
02-16-2010, 11:43 AM
#18
The Clubsport and Motorsport are generally valved exactly the same (glagola1 could elaborate on that I think) except that the Motorsport have more adjustments within the range.
Mine was based solely on price. I supplied Fox racing canisters and did SA 8300 Penske's for $2500. Clubsports with slight adjustments to the valving would have been near $4600.
I've been told that the KW's are exactly the same internally as a Koni although they seem to valved a little bit better. Other than that I don't know a whole lot about them.
What I like about the Penske's is how modular they are. You can start with a SA shock that is Rebound, Compression or both on one knob. Upgrade to the 8300 canister for $350-360 a corner. Or to the 8700 series canisters for $600 each at any point you want. You could even go to the Regressive piston used in the F1 cars right now for $1700. Moton's have one piston and one canister and it costs $250-300 per shock to revalve (not like you would really need to though). That being said - Moton's piston is very different than the Penske and you don't need all kinds of different designs to get different characteristics, you could just change the size of the springs or valves. I think they are very similar to the Koni 28 Series shocks that use cartridges instead of a "piston".
Mine was based solely on price. I supplied Fox racing canisters and did SA 8300 Penske's for $2500. Clubsports with slight adjustments to the valving would have been near $4600.
I've been told that the KW's are exactly the same internally as a Koni although they seem to valved a little bit better. Other than that I don't know a whole lot about them.
What I like about the Penske's is how modular they are. You can start with a SA shock that is Rebound, Compression or both on one knob. Upgrade to the 8300 canister for $350-360 a corner. Or to the 8700 series canisters for $600 each at any point you want. You could even go to the Regressive piston used in the F1 cars right now for $1700. Moton's have one piston and one canister and it costs $250-300 per shock to revalve (not like you would really need to though). That being said - Moton's piston is very different than the Penske and you don't need all kinds of different designs to get different characteristics, you could just change the size of the springs or valves. I think they are very similar to the Koni 28 Series shocks that use cartridges instead of a "piston".
02-16-2010, 12:37 PM
#20
Originally Posted by TheNick,Feb 16 2010, 01:24 PM
I know LG Motorsports is using this shaft in conjunction with the ASN Series shocks for the C5/C6 Corvette's right now. I can't seem to find any pictures and I seem to remember the price point being really high though.
$7700 w/springs
I think that must have something to do with the custom aluminum bodies.