Bilstein B6 and B8 explained

[norcalpb]

Originally Posted by JIM THEO

Which points me to ask you another question, what is your opinion regarding the B6s paired with the original STI springs from the STI Bilstein kit? https://www.sti.jp/parts/subarubrz_z.../ST20330AS010/

I don't think there is much difference between the STI Bilsteins and the B6s, ok they are slightly longer and perfectly valved for the STI pink springs, but what about ride height, will the 15mm lowering from the STI kit correct the B6 height increase?
Or the lowering on the STI kit comes from the struts not the springs although they look similar with the B6s?
Ιt's easier for me to sell the tS pinks and replace them with the STI/Bilstein pinks that I guess will be slightly harder and better mated with the Bilsteins

I can’t remember where I heard this but I think these 2015 pink springs that come with paired with the STi bilsteins have a different spring rate than the 2013 pink springs. As usual could very much be wrong though.

However I had 2013 STi springs paired with B6 dampers and it felt awesome. Soft yet surprisingly retained its sportiness. I think you are on to something with pairing a stiffer spring with the B6 to match things up a bit better.

[JIM THEO]

Originally Posted by norcalpb

However I had 2013 STi springs paired with B6 dampers and it felt awesome. Soft yet surprisingly retained its sportiness. I think you are on to something with pairing a stiffer spring with the B6 to match things up a bit better.

I am searching exactly this, a stiffer spring not lower than 1,5-2cm, not too harsh, to mate the B6.
How much lowered compared with the factory height was with this setup, do you remember?
I guess the STI springs you mention were from the STI Bilstein kit not the STI Showa-pinks, nor the aftermarket STI pinks intended for the OEM shocks right?

[Racecomp Engineering]

Yeah it's certainly not just the bumpstops that make it feel that way!

FWIW I did not have a noticeable ride height change with my Bilstein B6. If there was one at all it was less than 5mm.

- Andrew

[wolffbite]

Originally Posted by LancePower

I have B8's paired with Eibach Pro-Kits and have the same observation.

Slow speeds or large imperfections are harsh, but the higher speed stuff feels more controlled.

How many miles does it take to break-in a shock? I still may not have hit that mark yet.

Based on your (limited) experience with that setup so far, do you recommend it?

I've got 140k kms on my original shocks and they are getting pretty tired. Considering upgrading to the B6's and keeping the Eibach pro kit.

Ride height change by a few mm isn't an issue to me. A little higher would probably be nice in some scenarios... I just barely get into my underground parkade as is without scraping.

[LancePower]

Originally Posted by wolffbite

Based on your (limited) experience with that setup so far, do you recommend it?

I've got 140k kms on my original shocks and they are getting pretty tired. Considering upgrading to the B6's and keeping the Eibach pro kit.

Ride height change by a few mm isn't an issue to me. A little higher would probably be nice in some scenarios... I just barely get into my underground parkade as is without scraping.

If you are looking for daily driver comfort, I'm not sure they are worth the money.

Best bet might be picking up some gently used SACHS. Negligible downgrade in performance and can probably had much cheaper.

I was expecting more for the price. Maybe they are better paired with H&R Springs or something else.

[ZDan]

Originally Posted by LancePower

If you are looking for daily driver comfort, I'm not sure they are worth the money.

Best bet might be picking up some gently used SACHS. Negligible downgrade in performance and can probably had much cheaper.

I was expecting more for the price. Maybe they are better paired with H&R Springs or something else.

Sachs weren't great for me. Stock, they were unduly harsh over bumps, classic too-much-high-speed-damping. Felt racy/go-karty in test-drives, but not the way good trackworthy damping works. When I got Swift springs, which lowered the car more than expected, in concert with Raceseng camber plates which lowered the front even more, about 35mm total, the front Sachs struts were just unbearable, with zero front bump travel. They were *hard* on the front bump stops statically. Even with front bump stops cut down and a 6mm spring spacer, they were awful over the smallest bumps. Bilstein B8s *transformed* the car. Way way WAY better damping, massively reduced harshness, and made the car able to swallow up bumps on the street and curbs at the track.

Anyway I have a set I would sell for a lot less than used Bilsteins. Because they aren't *nearly* as good, on the street or at the track. Not even close...

[RToyo86]

For comfort the base 17-20 shocks ride quite nice. Probably go that route if you wanted comfort.
The 2022+ shocks are apparently even softer for the street, that could be an option too

[tekno]

Originally Posted by Racecomp Engineering

We've received lots of questions lately on the Bilstein B6 and B8 dampers, so I thought I'd do a rundown on these two fixed perch shocks. I just got a set in for my own car (because I really like them!) so I thought it was good timing.



Short version
The Bilstein B6 (formerly called Bilstein HD) dampers are an OEM fitment replacement, fixed perch, monotube damper with inverted front strut. The Bilstein B8 (formerly called Bilstein Sport) have a few differences and are specifically intended to be used with lowering springs, but have the same valving as the B6 dampers. I recommend the B6 even with lowering springs. We'll talk about that more later.

These are excellent as a replacement for your high mileage OEM suspension or as a performance upgrade with lowering springs. Both work with lowering springs. They ride well and they're durable.

Is a monotube like the Bilsteins better than a twintube?
Sometimes. Monotubes and twintubes each have their advantages and disadvantages, and either one can be good or bad. Monotubes are generally more responsive and sometimes better on bigger bumps, sometimes at the expense of a "busy" ride over smaller bumps. Bottom line, Bilsteins are good and the valving is really nice.


......




Should I get B6 or B8?
Bilstein B8 are supposed to be paired with lowering springs...but we still recommend B6 instead. The difference between B6 and B8 is NOT in the valving. That's identical. The B8s have slightly less droop, or extension travel. The idea is that shorter lowering springs don't need the droop travel or wouldn't be fully secure with longer travel. In reality, all lowering springs for this car are designed around the OEM dampers dimensions so this simply isn't needed and actually droop travel is good. So, get the B6s. The B8s are still very good if you have them.


- Andrew

Hello Andrew, what's the highest spring rate the B6's can handle?

Andrew

[Racecomp Engineering]

Originally Posted by tekno

Hello Andrew, what's the highest spring rate the B6's can handle?

Andrew

I'd say about 5 kg/mm front and 6 kg/mm rear is as high as I would go.

- Andrew

[tekno]

Originally Posted by Racecomp Engineering

I'd say about 5 kg/mm front and 6 kg/mm rear is as high as I would go.

- Andrew

Much obliged, sir!

[JIM THEO]

Originally Posted by norcalpb

I can’t remember where I heard this but I think these 2015 pink springs that come with paired with the STi bilsteins have a different spring rate than the 2013 pink springs. As usual could very much be wrong though.

However I had 2013 STi springs paired with B6 dampers and it felt awesome. Soft yet surprisingly retained its sportiness. I think you are on to something with pairing a stiffer spring with the B6 to match things up a bit better.

According to this video (at 56"):

Pink STI springs from the Bilstein/STI kit are 25% harder than the base 2013 BRZ springs rates: 27Nm front - 34Nm rear!
So actual spring rates or I'd say "wheel spring rates" for the Bilstein/STI kit are 33,75Nm front - 31,8Nm rear, not bad for my use, while my current springs from the 2018+ tS are 26Nm front - 28,35Nm rear!

[RToyo86]

What kind of durability is expected out of these? I've got about 70,000km on my set now. 99% daily use.

Suggestions for places to service them as needed?

[Pat]

100,000 with ease

Sent from my Pixel 7a using Tapatalk

[strat61caster]

https://bilstein.com/en-us/contact/

Contact Bilstein for service, last I checked they referred me to PSI in Sonoma.