2008 Spec.B Bilstein vs. Bilstein HD - damping data from Bilstein

[T-Rexky]

Good day,

 

I recently upgraded my Spec.B with Pinks and I have been somewhat disappointed with the insufficient damping of the stock Bilsteins. There is just too much bounce to my liking. I spent a considerable amount of time researching the various upgrade options and there seems to be many opinions and very little actual data. Touge Tuning and Racecomp Engineering have been extremely helpful in providing me with some data and indicating that the HDs are an excellent match for the Pinks - a huge THANK YOU for your help. The real bonus, however, is the information that I finally received directly from Bilstein that came with a permission to post it in this forum!

 

So, here is the actual shock absorber design data from the "horse's mouth", comparing the stock 2008 Spec.B with the Bilstein HD. Much to my surprise the difference in damping is much greater than I anticipated, which likely explains why the HDs are believed to be an excellent match for the Pinks, while the stock Bilsteins are a bit of a mixed bag. I hope this is useful to others trying, like me, to get the suspension just right.

 

T-R

[BAC5.2]

Good find.

 

When I installed my HD's, I was a bit shocked at how firm the ride was at first. I kept thinking "there is NO way a stock Spec-B is this firm". I thought all you people saying the Spec-B was too soft were on crack.

 

I love my Bilstein setup. I'll get their struts for any car I own in the future.

[1slowdriver]

Good day,

 

I recently upgraded my Spec.B with Pinks and I have been somewhat disappointed with the insufficient damping of the stock Bilsteins. There is just too much bounce to my liking. I spent a considerable amount of time researching the various upgrade options and there seems to be many opinions and very little actual data. Touge Tuning and Racecomp Engineering have been extremely helpful in providing me with some data and indicating that the HDs are an excellent match for the Pinks - a huge THANK YOU for your help. The real bonus, however, is the information that I finally received directly from Bilstein that came with a permission to post it in this forum!

 

So, here is the actual shock absorber design data from the "horse's mouth", comparing the stock 2008 Spec.B with the Bilstein HD. Much to my surprise the difference in damping is much greater than I anticipated, which likely explains why the HDs are believed to be an excellent match for the Pinks, while the stock Bilsteins are a bit of a mixed bag. I hope this is useful to others trying, like me, to get the suspension just right.

 

T-R

 

Great info! How would you describe the quality of daily driving comfort with your pink + bilstein setup, plus the Spec B's 18 inch rims? Are your local roads pot-hole ridden?

 

I'm also considering the pink/bilstein setup, and would consider mimicking your setup (read: copy/rip-off your setup).

[jagcars26]

Good find.

 

When I installed my HD's, I was a bit shocked at how firm the ride was at first. I kept thinking "there is NO way a stock Spec-B is this firm". I thought all you people saying the Spec-B was too soft were on crack.

 

 

Ditto for me as well.

I was running pinks with the stock struts fr about 2 years and then went with the HD Bilsteins/Pinks.What a difference!

Like Bac5 said it firmed it all up and was the missing link in my suspension program.I allready had all the Cusco bars and braces f/r along with upgraded endlinks and with the addition of the Bilsteins it all came together.

I'm also running Michelin Pilot Sport UHPAS which don't hurt either

[1slowdriver]

Ditto for me as well.

I was running pinks with the stock struts fr about 2 years and then went with the HD Bilsteins/Pinks.What a difference!

Like Bac5 said it firmed it all up and was the missing link in my suspension program.I allready had all the Cusco bars and braces f/r along with upgraded endlinks and with the addition of the Bilsteins it all came together.

I'm also running Michelin Pilot Sport UHPAS which don't hurt either

 

Nice setup - if you don't mind me asking, on your wagon, which sti pinks did you purchase? I'm still mired in doubt about which (JDM GT Auto Wagon vs GT-B) and have yet to find someone local to test ride. Which PN's did you go with?

[jagcars26]

I have no idea what the part #s are, Sorry.

It's been quite awhile since the original install of the springs (5years).I got the springs from Myles at RaceComp Engineering and I'm sure if you call them they can get you some part#s on the springs.

[omnicron]

Are the JDM Pinks with the JDM Bilsteins the same as the USDM Bilsteins with the JDM Pinks?

[1slowdriver]

Are the JDM Pinks with the JDM Bilsteins the same as the USDM Bilsteins with the JDM Pinks?

 

This thread states that USDM Bilsteins are identical to JDM GT Rev.C Bilsteins, but years/revisions for the JDM Bilstein struts differ (rev A,B,C)

 

This thread explains the differences in the STI Pink springs.

 

It gets rather confusing, and on this forum I've read several US Legacy wagons, GT sedans, and Spec B's, running different combinations of USDM Bilstein & Pinks. I'm attempting to sort through it all right now, and ask different owners on the board, their own experiences.

 

This thread is of particular interest as the information for the HD's is now available. As I'm clicking ever so closer to 60K miles, I anticipate a Bilstein HD & STI Pink purchase in the near future...

[normality78]

Is Bilstein B 4, B6 and B8 same as the HD?

[T-Rexky]

To answer some of the questions, I spent a considerable amount of time researching the springs (Pinks) vs. the vehicle weights for the NA Legacy and the JDM Legacy. I decided to get the JDM 3.0R Auto front springs and GT Wagon rear springs. I am thrilled with the ride and the height, but the stock Spec.B Bilsteins are very underdamped for the stiffer springs and the lower ride height. I was frequently bottoming out the suspension on larger bumps on the highway and there was quite a bit of bounce to the ride over larger dips or bumps in the road.

 

The HDs are a SUBSTANTIAL improvement over the stock Bilsteins. The ride is quite a bit firmer, but I would not classify it as rough. It is somewhat similar to my stock Focus SVT, perhaps a bit firmer. It is perfectly dampened under all driving conditions I threw at it. Pavement seams can be felt quite a bit more, but neither myself nor my girlfriend would ever consider it uncomfortable. In fact we both love the way the car rides now. And the roads here around Toronto are really not the greatest nowadays - lots of pot holes, repairs and unevenness.

 

I also installed the Whiteline roll center and bump steer kit and I would highly recommend it even though the front drop was only approximately 1 inch. The car just did not feel settled on bumps when turning. It is much better now. Also note that I have installed the Rallitek sways on the front and the back. What is painfully obvious now on my car is how limiting the tires are - that will be the next upgrade.

 

The exact part numbers of the pinks and the photos of the car before and after are in the GB thread. Below is a quote from the relevant post. Note that I originally thought the bounce was acceptable, but over short period of time decided that it was not.

 

I finally got my springs installed a few days ago and I simply cannot emphasize enough how ecstatic I am with the outcome!

 

They are a HUGE improvement in handling: pitch and dive have been reduced to a perfectly acceptable level; there is almost no perceptible roll when cornering (combined with Rallitek sways); the ride quality is still EXCELLENT - slightly firmer, but no easily noticeable increase in harshness; and finally the car looks just awesome - at last it has a balanced stance. The factory Bilsteins are a reasonable match for the springs - there is a little bit more bounce, but it is perfectly acceptable. Slightly higher damping would be perfect, but IMHO not necessary.

 

For the benefit of others looking for STI Pinks for their Spec.B, my 2008 dropped exactly 1.0 inch in the front and exactly 0.4 inch in the back compared to the factory springs. The final distance from the ground to the edge of the folded metal fender on my car, measured perpendicular to the ground through the wheel centreline, is exactly 26 and 2/16 of an inch both front AND back. The springs I selected were P/N ST2033021000 for the front and P/N ST2038021010 for the rear. Attached are before and after photos.

 

TR.

[whitetiger]

im not surprised by this. bilsteins or not, the spec b shocks are still oem shocks and are not designed or valved to use aftermarket springs. i bet the stock LGT shocks are not far from the the stock spec b bils. it would be interesting to see that comparison.

[T-Rexky]

im not surprised by this. bilsteins or not, the spec b shocks are still oem shocks and are not designed or valved to use aftermarket springs. i bet the stock LGT shocks are not far from the the stock spec b bils. it would be interesting to see that comparison.

 

I can actually offer a bit of a subjective comparison, since I used to own a 2005 GT and switched to a 2008 Spec.B. My immediate impressions were that the Spec.B had a softer but much more controlled ride. It was actually hard to explain for me at the time, as the feeling was very contradictory. In retrospect I think that the 2008 Spec.B Bilsteins likely have lower damping than the 2005 GT KYBs, but are much better performing, hence the more "luxurious" ride that is better controlled at the same time.

 

As I said, very subjective and nonscientific, particularly since this has been three years ago.

 

TR

[normality78]

Hm... this is quite contradict with my experience on HD pair with Pinks which im currently having it.

 

I felt it is hard and bouncy. The only thing i'm not sure is which "type" of sti spring that i have and i don't even know there are different version of it. But i do have B6 for sure. So im not sure if it is the spring too hard or the HD. Also i don't think my sti spring is progressive type

 

http://a5.sphotos.ak.fbcdn.net/hphotos-ak-ash4/218150_10150172983633089_693408088_6783744_1004769_n.jpg

[chutrain]

Good to finally read this. I am running on Swift springs and the stock Bilsteins and the rear

is extremely bouncy. I thought at first it was the rear shock being blown, and I bought a

brand new pair for the rears to only be disappointed. I bought a set of adjustable Konis for

the rear that I can hopefully dial it in a bit.

[wpmarky]

i believe all springs for the LGT out there right now are progressive, even the pinks.

 

Gotta get coilovers to get a linear spring setup, and even with those some springs are quoted to be "more lineaer" than others (swift springs for the BC coils are more linear than the ones that come with them)

 

I've also had pinks on oem bilsteins & HD Bilsteins on my car. OEM is better for comfort, HD's handle much much better. The HD's feel more stiff than my 9k Tarmac coilovers.

[BAC5.2]

Odd. Mine are BUTTER smooth.

 

I just did orange-dot Pinks today. Fantastic setup, though a little low.

[normality78]

Good to finally read this. I am running on Swift springs and the stock Bilsteins and the rear

is extremely bouncy. I thought at first it was the rear shock being blown, and I bought a

brand new pair for the rears to only be disappointed. I bought a set of adjustable Konis for

the rear that I can hopefully dial it in a bit.

 

 

Exactly what happen to my rear. Front is still ok, but rear was extreme bouncy. I even had a back passenger puke after 30mins ride

[normality78]

I'll replace with H&R spring by this week and let me see how big different. I still not sure if the culprit is spring or absorber.

 

Anyway, my other complain with pink is not drop low enough hence regardless, pink will still have to go.

 

let me come back with "new" review but will take 2 weeks

[BAC5.2]

I bet it's bouncy because you are hitting the rear bumpstop.

[T-Rexky]

Hm... this is quite contradict with my experience on HD pair with Pinks which im currently having it.

 

I felt it is hard and bouncy. The only thing i'm not sure is which "type" of sti spring that i have and i don't even know there are different version of it. But i do have B6 for sure. So im not sure if it is the spring too hard or the HD. Also i don't think my sti spring is progressive type

 

 

Out of curiosity, what do you define as 'bouncy'?

 

When I said that the pinks with stock Bilsteins were bouncy I was highlighting that the stock Bilsteins do not have sufficient damping for the pinks with the mass of the Spec.B. As a consequence the ride was underdamped and suspension disturbances would result in a decaying oscillatory bouncing before settling down.

 

With the Bilstein HD setup the suspension is much firmer riding and much better damped. Any disturbances settle down much faster and there are no oscillations.

 

When you define it as bouncy, are you perhaps just referring to more road unevenness being transferred into the car chassis? Because this is exactly what happens when the suspension is stiffened by increasing the damping on the shocks.

[normality78]

I bet it's bouncy because you are hitting the rear bumpstop.

 

sorry, i think bouncy is the wrong word. I should say hard. As i dun think my absorber compress that much at all (or damper). So i can almost certain never reach bumpstop at all

[normality78]

Out of curiosity, what do you define as 'bouncy'?

 

When I said that the pinks with stock Bilsteins were bouncy I was highlighting that the stock Bilsteins do not have sufficient damping for the pinks with the mass of the Spec.B. As a consequence the ride was underdamped and suspension disturbances would result in a decaying oscillatory bouncing before settling down.

 

With the Bilstein HD setup the suspension is much firmer riding and much better damped. Any disturbances settle down much faster and there are no oscillations.

 

When you define it as bouncy, are you perhaps just referring to more road unevenness being transferred into the car chassis? Because this is exactly what happens when the suspension is stiffened by increasing the damping on the shocks.

 

 

i corrected in above post. Should not say bouncy as i dun think mine damper that much.

 

Mine was hard rock. Just like coilover on hard setting. It hopped along over speed strips

[wpmarky]

The harshness is the struts, not the springs. I had coilovers with springs that are more than twice as stiff than Pink springs, but were as comfortable as stock.

 

I think the HD's are fine for daily driving, but if you want more comfort try the stock Spec.b bilsteins. I like the performance handling improvement of the HD's over spec.b bilsteins.

[normality78]

I've bought the H&R spring and let see which is the "culprit"

[SBT]

This is great info. Really wish we could see the collapsed/extended lengths on the factory Spec B (Rev C) Bilsteins. It's been mentioned before, that the HDs have a shorter rod length so that information would be helpful to confirm.

 

I have Spec B (Rev C) Bilstein struts with Swift wagon springs. Like this combination, but for reasons mentioned above, mostly under-dampening (not nearly as under-dampened as the stock KYB/Spring combo) but, over time, have come to realize that the Rev Cs are just a bit too soft in that area.

 

One thing I noticed right away with the Rev Cs is that the car would hobby-horse (rock back and forth) horribly. To fix this, I did the Bilstein bump-stop mod which helped considerably. I also did the LCA bushings and the Roll Center Bump Steer kit as well because of the huge gain in static camber from the Swift drop. If you are on lowering springs, that drop you more than 3/4", I'd recommend doing the bump-stop mod to regain additional suspension travel without the incidental loading/unloading from the bump-stops. If you're dropped more than an inch, I'd recommend the RCBS Kit.

 

So, I've bought a set of HDs which I'm getting ready to install with the Swifts and a set of 3/8" butt spacers at the rear. Will be using the RCE bump stops in place of the cut-down Bilstein stoppers. Will post up my results once I get them installed.

 

Do plan to send the Rev Cs to Bilstein in Poway, CA and have them re-valved to Sport settings for another application, so will also post up how that goes.