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Reamer
So the high dollar shocks can adjust low speed and high speed do you know what or how they adjust?

Most of the shocks out there are more or less some version of De Carbon style shocks. Below is a very general description as there are lots of variations available out there and I have never taken apart any of the fancy rally things to see how each one works but i am sure someone who services them could tell you which manufacturers do what.

External adjusters generally allow you to control the following:
Rebound damping is controlled by a needle valve in the shaft that allows oil to bypass the shim stack

Compression damping is controlled by valves that allow displaced oil to flow into the reservoir either with a needle valve (controls low speed damping) or poppet valve (high speed control) or both.

Your first 2 sentences and the last sentence did not read well for me so i dished it back. Lets move on from that.

I will get some picks.

Im wondering how they can adjust high and low speed separately from the out side of the shock? With the stuff Im used to you can adjust high speed but not low speed. Maybe gas pressure?

Shocks are just part of the big picture. I realize there are other aspects to go fast. Being new to rally I dont expect to win. But I do want to learn as much as possible on my down time.

Is a poppet valve set by spring tension? And the needle going to the canister must have a by-pass or something to stop from adjusting rebound correct? Thanks I havent seen a poppet valve.

http://lmgtfy.com/?q=poppet+valve&l=1

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john vanlandingham
Except show us a top mount that there's room for a fucking schrader valve sticking out the side, or angled out the corner..

How feasible is it to drill down through the pin and put the schrader valve on the top of the pin? Thats where all those fancy pants shocks have their connections for the remote reservoirs, so maybe a schrader valve could go there? Or one of those bolt thingies that you fill with a needle?

I just like the idea of not having to send a shock on a 4600 mile trip if all it needs is a $10 seal or an equally cheap o-ring.

when I was working at Öhlin's way back then Kenta said the gas pressure really makes virtually no measurable, detectable difference in function.
I have no idea how many shocks I rebuilt and just for shits and giggles have gasses up from 90 PSI to 200 PSI.

Never noticed a thing different.

As for exatly how they're doing the adjusters
Not sure.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

I agree I never felt to big of a change from 50 to 100 psi. My stop watch at the track showed almost 3 tenths of a sec faster from 100 down to 50 psi. Im sure I could have changed the balance on the car and been able to leave the higher pressure but it worked so I left it.

Im sure you could drill a small hole threw the top it wouldnt have to be very big. I dont know how much weeker it would make the end. It sounds like they already bend easy.

The gas is there to stop the shock from cavitation and to take up the space when the shaft is out of the tube. If you have no air there will be a big gap between comp and rebound. If you fill the body to full of oil the shock will hydraulic because theres no where for the oil to go on compression.

Shocks seem to be a big mystery to people. I can tell you for 100% after you take one apart a few times It gets a lot easier. At least to clean and inspect. confusion starts after you want to change something. Thats why some of us like to mess with them.

Thats a good google on the poppet valve not sure if that would work so well on a shock. Would like to see one related to what were talking about.

Just to point out for people asking how the knobs and shit work, look at Penske's tech manuals, at http://www.penskeshocks.com/Downloads.php or specifically http://www.penskeshocks.com/files/Adjustable_Manual.pdf which explains in nice detail how the adjusters, canisters, and various piston shapes work. Pretty much everything with clickers, aside from oddballs like Ohlin's TTX shocks, works on some slight variant of exactly the same way, and even the TTX just moves the shims and needles and shit to a different position in the fluid path.

Here's the Ohlins literature for their lancer 4 group N shocks, from AMF's site:
http://www.amfmotorsports.com/pdf/mit_evo.pdf
It has a "how the shock works" section as well as exploded parts diagrams.

From looking at the parts diagram it appears that they use something similar to a banjo fitting on the pin to connect to the remote reservoir on the front shock, not drilled down through the top of the pin like I had mistakenly remembered, unless the subaru n12b shocks are different (which are what I have experience with).

Heres some RS&SP literature with parts diagrams as well, from rallispec
http://www.rallispec.com/rssp_sub.pdf

The RS&SP's reservoir connection is through the top pin on the rear, however its not a mac strut so the pin doesnt (hopefully) see the same side loads as the front would. The rs&sp's front reservoir is set up kinda funky, being that the reservoir is at the bottom even though the insert is inverted. To replace the grease you take the insert out the bottom of the body, and that big gland nut can be a pain in the ass.

If I were to spend a bazillion bucks on suspension I'd go with RS&SP. They seem to hold up to abuse pretty well as far as adjustable shocks go, except that all my experiences with Rallispec have left a lot to be desired, and I've heard likewise from many. But luckily for me I'm cheap, so I won't be spending $6k on suspension.

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mekilljoydammit
Pretty much everything with clickers, aside from oddballs like Ohlin's TTX shocks, works on some slight variant of exactly the same way, and even the TTX just moves the shims and needles and shit to a different position in the fluid path.

And the Twin Tube Ohlins TTX and Double Barrel stuff seems pretty silly for the most part. Why would you ever need to independently control high and low speed REBOUND damping? The rebound force and shaft speed is determined by your springs so unless you have some crazy (and I mean really crazy) super rising rate spring setup, the shaft speed will always be controllable by only ONE of the adjusters.

Sure, the Twin Tube stuff allows more oil to be metered by the adjustable valves than a typical setup. This just means you can more easily get the settings very badly wrong rather than just doing some fine tuning to some OKish starting point.

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Carl S

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john vanlandingham
Except show us a top mount that there's room for a fucking schrader valve sticking out the side, or angled out the corner..

How feasible is it to drill down through the pin and put the schrader valve on the top of the pin? Thats where all those fancy pants shocks have their connections for the remote reservoirs, so maybe a schrader valve could go there? Or one of those bolt thingies that you fill with a needle?

I just like the idea of not having to send a shock on a 4600 mile trip if all it needs is a $10 seal or an equally cheap o-ring.

I was considering that when I looked into building my own triple adjustable shocks for the Civic. Planned on doing a progressive build. Start somethin with either no adjustability, or having single rebound/compression adjustment by using a Hotbits rod in bilstein body. Was going to drill/tap the bottom of the shock where the gas charge normally sits, add a schrader valve to start for self recharge and later thread some sort of external reservoir. If I wanted to stick to 2 way, hotbits rebound rod with external can. If I wanted to go $bling$ I could have added a Penske remote reservoir.

Cost range of Bilstein kit w/ no adjustability was ~$1500 (shocks, rebuilds, drill/tap, springs, coilover sleeves), adding the 2 way adjustable (same as custom, but added hotbits rebound rod + external can) came out to ~$2500. Going 3 way adjustable came out to ~$4500 range.

With the Double Adjustable Hotbits off the shelf kit being $2280 I decided to just go with it, custom ordered my spring rates/length and requested larger reservoirs for more fluid capacity at no extra charge. Plus, Hotbits US distributor Larry Parker is a 15 minute drive from my house so when I need rebuilds, it costs the same as a Bilstein to do so. I also got triple use from these with the adjustability. Softer spring rate and full soft setting for Sno*Drift, standard spring + damping setting for gravel. Top end of damping + higher springs for Rally TN tarmac setting. I wanted to do all three surfaces, so for $280 more I saved myself $4000 in a bunch of specific suspension for each surface.

If you're not so much running snow/tarmac you can just run your same suspension (I ran my gravel setup in my VW for both track and snow, wasn't horrific).

In contrast, all other kits I found were in this range:
JVAB $2000
RS&SP double adjustable $3500 (no external reservoir, thus limits shock travel)
RS&SP triple adjustable $6000 (external canned, still costly rebuilds but still local so quicker turn around in theory, I'm sure they still need to have their parts shipped from overseas that they don't stock)
Proflex triple adjustable $6000 ($800 quote cost for simple teardown and fluid replace for all 4 and overseas parts turned me off of these)

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john vanlandingham
when I was working at Öhlin's way back then Kenta said the gas pressure really makes virtually no measurable, detectable difference in function.
I have no idea how many shocks I rebuilt and just for shits and giggles have gasses up from 90 PSI to 200 PSI.

Never noticed a thing different.

As for exatly how they're doing the adjusters
Not sure.

I would think that going to a higher PSI helps when you're getting high shock temps and speeds to help with cavitation. But your compressed nitrogen is a spring itself. AutoX weenies in stock classes, who are allowed to change shocks, typically run extra high PSI to effectively increase their spring rates when they're not allowed to change springs. Since we can change springs, it doesn't make sense to do this for us.

But then there's those fancy rod-through-body designs I've seen popping up on race cars that look interesting. Rod those through the shock, so there's no displacement from rod movement, thus no need for nitrogen reservoir. But I've only seen $names$ attached to those shocks, so nothing a weekend rally figher could afford.

gawd i get tired of the confident repetion of tired "truisms".
Billy--- Next you are going to tell me about how much the gas "lifts' cars up, huh?
Auto cross are weenies because they fail to understand that the cars and all their work and all their incessant yapping about their dreams about how things both work and how that effects their "Results" is all a construct to compensate for their lack of social skills.

What they're really doing is constructing a way to meet and schmooze--and for many--and importantly show off and boast about how much they have spent (to drive in a fucking parking lot) and how much they imagine they know (which they glean by talking to others in ever increasingly unsubstantiated levels about ever more pointless shit).

The fact that auto-cross do anything is damning proof that whatever it did is probably USELESS.

Do you really think that autocrossers---ordinary guys who in an entire "race career" have have 1 or 2 hours of driving time under their belt--- actually know anything? Anything applicable here?

Sorry.
The dividing piston pushes on the oil.
The oil pushes ON BOTH SIDES of the PISTON when the suspension is installed on the car.

If the tiny amount of force generated by a few cc of gas at whatever pressure is pushing on BOTH SIDES of a piston pull of fuckin holes
then the imagined force is BALANCED..Push up balanced by the oil on top pushing down.

The fact that that does not INSTANTLY jump out as a glaring fault in auto crosser "logic' shows that no critical examination occured, but rather repetition is supposed to be a "social marker"....


Good god.
Sweet bleedin Jeeezuz.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

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Josh Wimpey

Quote
mekilljoydammit
Pretty much everything with clickers, aside from oddballs like Ohlin's TTX shocks, works on some slight variant of exactly the same way, and even the TTX just moves the shims and needles and shit to a different position in the fluid path.

And the Twin Tube Ohlins TTX and Double Barrel stuff seems pretty silly for the most part. Why would you ever need to independently control high and low speed REBOUND damping? The rebound force and shaft speed is determined by your springs so unless you have some crazy (and I mean really crazy) super rising rate spring setup, the shaft speed will always be controllable by only ONE of the adjusters.

Sure, the Twin Tube stuff allows more oil to be metered by the adjustable valves than a typical setup. This just means you can more easily get the settings very badly wrong rather than just doing some fine tuning to some OKish starting point.

I suspect they're there to bandaid weird effects of weird spring rates on prototype cars, which is where they showed up first. That, or standardizing the spools across compression and rebound both... or, at the risk of being cynical, "hay look, moar clickers!" Seriously though, independent high and low speed adjustment first showed up in F1 and has stuck around, so I'd wager it's actually useful for *someone* under some circumstances...

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john vanlandingham
The dividing piston pushes on the oil.
The oil pushes ON BOTH SIDES of the PISTON when the suspension is installed on the car.

If the tiny amount of force generated by a few cc of gas at whatever pressure is pushing on BOTH SIDES of a piston pull of fuckin holes
then the imagined force is BALANCED..Push up balanced by the oil on top pushing down.

The fact that that does not INSTANTLY jump out as a glaring fault in auto crosser "logic' shows that no critical examination occured, but rather repetition is supposed to be a "social marker"....


Good god.
Sweet bleedin Jeeezuz.

That's almost correct. The internal gas pressure is acting on the tiny imbalanced area of the piston where there is a shaft sticking out one side and not the other. That's why the shaft is always sticking out when they're sitting on the shelf. As long as you have enough nitrogen pressure to prevent cavitation increasing the pressure just causes more seal stiction and fattens the nose of the shock curve.

I didn't say autoX knowledge is the bible. I just said what they do, since they can't change spring rates. I even called them weenies. I Only listed two things I've heard for increasing gas pressure. While, yes, they get something silly like an hour of seat time in 1 minute intervals but I wouldn't say they suck at driving. It's like roundy-round or drags. Apples and oranges as far as setup, style, etc.