So I'm shopping for shocks for the T2 car. Obviously Koni is my first choice, but the options for the STi are very cost prohibitive. I discussed with Lee and Koni-na trying to meander some inserts into the stock housing and thats still a possiblity. Other then that I've been looking at some other brand coilovers and noticed that everyone from Europe and Australia valves their shocks either progressively or linearly, while Japan and the US do digressive valving.

It would seem to me that for pretty much any application other then rally, you would want a digressive valve. It allows for a good amount of shock at lower shaft speeds, which is where a track car, or a road car spends most of its time. It also limits the shock at higher shaft speeds, so the car doesn't skip and bounce over bumps and isn't excessively harsh. It would seem to me that a progressively valved shock would not do jack for an autox slalom or for turn in or track out at a race track or for your toogay, while it would be non compliant over harsh bumps such as concrete slabs for autox, or curbing at a track. I could see how it would work well for rally as you probably need a lot of high speed valving to stop a car from bottom over a jump, something which a digressive valve couldn't do.

Can someone explain to me how DMS or Whiteline or KW or Ohlins shocks work? Do people only use them when they have a lot of spring or a lot of swaybar to control the initial reaction and body roll? If so, wouldn't the car be "bouncy" as there wouldn't be much low speed rebound or compression to prevent the car from coming back from a low speed roll?

Here is a fancy chart I made. It has a DMS shock, a Subaru STi OEM shock, a Koni Sport Insert for a WRX (which surprisingly has the same rebound at stiff/bump at 1/2 stiff as the 8611 race shock), a Tein Flex damper, and a KW Variant 3 (edit: added whiteline group 4 shocks)

http://www.trackmonkeyracing.c...W.gif

How can a) the DMS work, and b) the KW have less rebound then stock?

-Tom
confused, or maybe not?


Modified by trhoppe at 11:38 PM 2/15/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by trhoppe &raquo;</TD></TR><TR><TD CLASS="quote"> Can someone explain to me how DMS or Whiteline or KW or Ohlins shocks work? Do people only use them when they have a lot of spring or a lot of swaybar to control the initial reaction and body roll? If so, wouldn't the car be "bouncy" as there wouldn't be much low speed rebound or compression to prevent the car from coming back from a low speed roll?</TD></TR></TABLE>


I'd suggest you PM mikeskie38, He has knowledge on the DMS, and can explain (in his opinion) why they work. Or maybe he will chime in.

 

If you only have a damper to worry about then a digressive shock curve will generally maximize tire grip for both low speed body inputs and high speed road inputs. Shocks can be used for a lot more than that, and you'll find that certain applicaitons will require characterisitics depending on roads, rules, drivetrain layout, etc. (Cars with odd motion ratios, or hige amounts of travel seem to have more progressive curves).

It's not only the damping of ride motions, you have weight transfer effects, ride height "locking" (think aero), spring rate effects...

 

Just to explain further, I'm in a situation where I can only modify the shocks on my car. The rest of the suspension has to be OEM, so I cannot use springs/bars/bushings.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">


I'd suggest you PM mikeskie38, He has knowledge on the DMS, and can explain (in his opinion) why they work. Or maybe he will chime in.</TD></TR></TABLE>

In my opinion huh? I guess that is all I have to chime in with. I can say that since I have switched to a progressive spring and shock setup, I have 2 wins, a second and a third in 4 races in NorCal H4. And only one car the beat me in this stretch hasn't been running a progressive setup. I'm sold!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mikeski38 &raquo;</TD></TR><TR><TD CLASS="quote">

In my opinion huh? </TD></TR></TABLE>

well why you think they work might differ from other people's opinion

 

Theres an article on them in European Car this month.

 

Something to think about... DMS are valved to work with their progressive springs. Hence why their curve is uber-different from the linear-spring valvings.

The Koni, Tein and KWs are all digressive valvings, the KWs just less pronounced than the others. KW's valving philosophy seems to focus on using less spring rate and more low-speed bump. That said, have you looked at the valving on the KW 2-way race? Those are probably a bit stiffer than the V3.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote"> a Koni Sport Insert for a WRX (which surprisingly has the same rebound at stiff/bump at 1/2 stiff as the 8611 race shock </TD></TR></TABLE>

Tom can you point me in the direction of where I can find the details on this? I'm looking for something for the rear of my car and this sounds promising.

nm...I found out myself, they are versions of the 8610 inserts. Looks like I'm buying some WRX stuff for my SE-R

Anyway, I was reading what was said over on Nabisco and I would have to agree with what "adhowe" said that you definitely want a more digressive valving. The progressive type valving is tuned for a ton of droop travel, they probably have very tall internal droop limiters. Rally cars run relatively soft springs so in rebound alot of the valving effects are at a longer extension than normal. Does that make any sense? I mean you've seen a rally car in midair, I've never seen anything other than Baja trucks with that much suspension travel.


Modified by Wacked2882 at 9:36 AM 2/16/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Wacked2882 &raquo;</TD></TR><TR><TD CLASS="quote">nm...I found out myself, they are versions of the 8610 inserts. Looks like I'm buying some WRX stuff for my SE-R </TD></TR></TABLE>

Please read the IM. I think you are talking about crossing apples and oranges in hopes of growing bananas.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Wacked2882 &raquo;</TD></TR><TR><TD CLASS="quote">

Tom can you point me in the direction of where I can find the details on this? I'm looking for something for the rear of my car and this sounds promising.

nm...I found out myself, they are versions of the 8610 inserts. Looks like I'm buying some WRX stuff for my SE-R

Anyway, I was reading what was said over on Nabisco and I would have to agree with what "adhowe" said that you definitely want a more digressive valving. The progressive type valving is tuned for a ton of droop travel, they probably have very tall internal droop limiters. Rally cars run relatively soft springs so in rebound alot of the valving effects are at a longer extension than normal. Does that make any sense? I mean you've seen a rally car in midair, I've never seen anything other than Baja trucks with that much suspension travel.


Modified by Wacked2882 at 9:36 AM 2/16/2006</TD></TR></TABLE>

I'm running stiff progressive srings with little droop on my progressive shocks and I'm seeing great results.

 

Mike, do you have off the shelf valving? I was really just thinking about the wrc cars that i've seen on tv and what makes sense visually in my head.

Tom it might be worth doing some research talking to Mike and Chris about their DMS experiences if the STi stock springs are progressive (aren't most stock springs progressive?). I read through that whole DMS thread a month ago and it looks like they have been having great success.

I'm the epitome of measure once, then cut twice. In this case it was think once, then type twice.


Modified by Wacked2882 at 11:51 AM 2/16/2006

 

I want to thank Mike for talking to me for close to an hour last night. While I saw the light on how a DMS setup *could* work on a car with plenty of camber and a good swaybar/spring balance, I don't think the low, low speed damping could work well on my car which sucks ***** once it takes a set. We have no camber and our springs/bars induce understeer. We have to use our shocks to try to NOT use the springs/swaybars as much as possible

-Tom

 

Tom-

I don't have any useful information to provide, but just wanted to congratulate you on one of the best thread topics I've ever seen in the Honda-tech suspension forum. I've been pondering the same quandary.

I hope this thread develops into a tome of technical knowledge and not another ****-throwing party consisting self-professed racing heroes noting that their shock of choice is king because they won the last 5 races.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CelicaGTV6 &raquo;</TD></TR><TR><TD CLASS="quote">


I hope this thread develops into a tome of technical knowledge and not another ****-throwing party consisting self-professed racing heroes noting that their shock of choice is king because they won the last 5 races.

</TD></TR></TABLE>

Zing!