Bilstein Science Experiment

[Fusion Works]

A friend gave me some Bilstein B6s since he converted over to Meisters. I was initially going to use them for dimensions to build my custom setup and then send them to another good home. For the rears I decided to go ahead and take them apart and dyno them and revalve them and put them to use. The fronts will probably be up for sale when I am done, although kinda want to cut one of them open to see what the deal is inside. I think its a twin tube, unlike the other Bilstein dampers for our cars. Its crimped heavily, so I may not.

Anyway on with the business.

Had to make up an adapter to fit the shock on the dyno. Bilstein uses a 8mm thread on the end of the shaft. No idea why Ford did this. Its smaller than every other damper I have dyno'd.

Yes I ran the part number and it comes back as a B6.

Yes Bilstein Crimped the seal head in place and its "non serviceable". Assholes.

"Non servicable" won't stop me, only slow me down. LOL
It is a MONOTUBE. The B6/B8/B14 is a MONOTUBE, not a twin tube. Here is the proof:

I dynoed the one that is assembled still. It has less than 100lbs of rebound force at the zero number. That is normal production car shock valving, nothing special. I haven't had a chance to compare to the OE Ford shock yet. It has 66lbs of gas pressure and probably needs more as I was seeing some cavitation/hysteresis at the 10-20in/sec range on the compression side.

These were kind of a pain in the ass as I had to vent the gas first, then use the lathe to part off the upper portion of the shock below the crimp. I shortened the body by 1.5in, which isn't a big deal on a lowered car.

 

[CarGuy]

I'd love to know the values for the stock Ford units, especially between the early 2014/2015 and 2016 and up struts/shocks.

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[Fusion Works]

I will dyno my OE Ford Parts when I take them off. It may be a couple of months though. I have to build a tool to hold the strut in the dyno since it doesn't come apart like my custom parts. The rear is pretty straight forward.

If you want to send me some earlier parts I can dyno them with my 2016 stuff.

 

[4nscguy]

They look so clean now Brett!

 

[kevinatfms]

Awesome. So that finally puts everything to rest.

What is the piston size? Type? Shim stack?

With that, Im wondering if the B8's are serviceable....it would make it easier to revalve the B8 rears for significantly higher spring rates.

The front B14 damper is the motorsports grade type from the looks of it so we already know that can be serviced.

 

[Fusion Works]

Its a 36mm, small body shock. Uses a COB piston. Its digressive. It has some shims. HAHA. I haven't measured them as its not really applicable to anything.

None of these are "servicable" per say. I will probably end up with a B8 length body when I am done anyways. The B8 would be even shorter because of cutting the crimp portion off.

Can someone measure the body length on a B8 or B14 rear shock? Just from the bump cap down the bottom of the mounting eye? This would let me know where I may end up comparably.

Its so odd that Ford used such a long shock. Its good for droop though and I suspect may help traction on the rear when the car is driven hard, by keeping the rear tire closer to the ground. The reality these cars can't be lowered that much anyways because of the suspension geometry limitations.

 

[M-Sport fan]

Most motorsport apps are 44mm, or even bigger yet?

 

[Fusion Works]

Yes Bilstein has this small body, its common for the A-body GM stuff. Its a front shock for those cars as well as some quarter midgets. They can generate a LOT of force with the small shocks. The more common is the 46mm (2.0in) tubes. I have a set of ASNs in that size, but they don't have anywhere near the stroke and length of these shocks otherwise I would use them. Then you can go bigger for some of the rally stuff and off road stuff goes 3in and bigger. Those is super specialized dampers though.

The cool thing with the Bilstein is their inverted struts, which are in reality a 46mm shock turned upside down with a polished body running in a bushed housing. This gives you a massive increase in camber stiffness for a strut car compared to the normal 21mm rods used by the Bilstein B6, B8, Koni, BC, etc.

 

[M-Sport fan]

Yes, that is exactly what the Bilstein R1 class rally Fiesta front coil overs use, albeit in a (externally) non-adjustable form.

The fact that they are inverted, and their diameter, mandates that the base, non-ST Fiesta front uprights/knuckles be used with them in order to clear the FiST's (or any other heavier duty than base Fiesta front axles), so any FiST using those must be retrofitted to the base deals.

I cannot even imagine what they are using in those Class 8 and up, SCORE desert trucks, or the Dakar/rally raid rides.
They must be enormous, despite them running up to FOUR PER CORNER!

 

[Fusion Works]

I see no reason why you can't use a regular Bilstein inverted damper on a ST knuckle. I am going to. I just have to weld the brackets to match the ST knuckle on the tubes I built. Then my custom insert goes in with no changes to the OE suspension system. They obviously sell the inverted damper for the Fiesta ST, its called the B14.
I built these for a Focus SVT and its just a matter of adding brackets for a Fiesta to the tubes instead of the round end.

 

[bhmax]

Can you confirm there’s no internal bump stop?

 

[Fusion Works]

On the shock there is no internal bump stop, just a plastic droop limiter. On the front inverted struts there is a bumpstop inside the housing, but not inside the shock.

 

[draxxus131]

[emoji897][emoji897][emoji897]

Finally they added butter!

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[Fusion Works]

I finally got my hands on a set of B14s and dyno'd them. Boy howdy, that was eye opening. Not sure what the hell is going on over at Bilstein, but they need to update their shock valving design strategies. I finally figured out the reason everyone says, "these ride better than the stock setup", even though they have 100lbs more spring rate front and rear.

Their valving is "garbage". The nice thing is, they can easily be fixed. The stock Ford valving is in Yellow and the Bilstein is in blue. These are the Front Dampers.

Not totally sure why Bilstein did this, but I am guessing they are stuck on the past way of setting up suspension. Gone are the days of slapping really stiff springs on the car and using soft valving. Modern race and track chassis setup is vastly different.

I also compared the B14 rear shocks, (which Bilstein claims are the same as the B8). The Stock dampers are stiffer as expected. What I didn't expect, the B14 rear dampers are valved the same as the B6 rears I dynoed. Figured Bilstein used the same parts. The B8 is a bit shorter than the B6 as to be expected. They are NOT twin tube. They as all the same parts and I have worked out a way to revalve the rear dampers. They will end up being a bit shorter for obvious reasons. The B6 and probably the B8 front damper is a twin tube with a crimped top, No easy revalving on those. Still want to get a hold of a B6 or B8 to cut them apart and see if they could modified with an insert style damper.

 

[the duke]

We've known the OEM dampers were over-dampened however. Too high a rebound rate and the car doesn't settle on weight transfers after the spring compression and that can cause stability and twitchiness that many won't want. The OEM dampers contribute a lot to the "Go-Cart" handling as they just aren't compliant.

With that said, this isn't the first time I've heard that Bilsteins dampening strategy is considered less than convention/contemporary.

I've got a set of drop-in B6s on OEM 2014 springs that'll be headed to Pitt Race on the 20th. I'm interested in seeing how they react to weight transfer, partoculary corner 1, the switchbacks, and the kink after the waterfall.

 

[M-Sport fan]

For whatever it is worth (or they themselves for that matter) the 'techs' at Bilstein USA I've spoken to directly about the B14s informed me that these dampers are valved to the PROGRESSIVE RATE springs included in their full kit.

(YES, as much as so many on here swear up and down that these are linear rate springs in this setup, their own people have told me MULTIPLE TIMES that they are in fact PROGRESSIVE RATE springs!)

They told me this after asking them if I could use the B14 coil overs/dampers from this kit and install some LINEAR RATE springs in their place (IF I could even find any), and questioned them about what rates these could possibly handle.

They said "DO NOT do that!" quite emphatically.

Of course, they were taking for granted i was not going to open them up and re-valved them at all.

 

[Fusion Works]

We've known the OEM dampers were over-dampened however. Too high a rebound rate and the car doesn't settle on weight transfers after the spring compression and that can cause stability and twitchiness that many won't want. The OEM dampers contribute a lot to the "Go-Cart" handling as they just aren't compliant.

With that said, this isn't the first time I've heard that Bilsteins dampening strategy is considered less than convention/contemporary.

I've got a set of drop-in B6s on OEM 2014 springs that'll be headed to Pitt Race on the 20th. I'm interested in seeing how they react to weight transfer, partoculary corner 1, the switchbacks, and the kink after the waterfall.

They are not "over damped", they are fine for the stock spring rates and even the spring rates of stiffer springs. They would be fine with the Bilstein spring rates. Do you want a Cadillac or a car that handles well. Can't have both.

The valving built into my new dampers is pretty much double the OE rates across the board. Also has a lot less bleed in the lower end of the curve than the OE or even the Bilsteins. It is definitely not a couch and 250lb springs feel harsh for street use, but on track they are magic.

The OE dampers are a compromise for the 90th percentile. They have to be. There is no reason for the Bilsteins to have even less control. That is just poor shock valve selection.

Why do you think the B6 damper will be better than the OE in a track application? It is softer, thus allow the vehicle to flop around more.

For whatever it is worth (or they themselves for that matter) the 'techs' at Bilstein USA I've spoken to directly about the B14s informed me that these dampers are valved to the PROGRESSIVE RATE springs included in their full kit.

(YES, as much as so many on here swear up and down that these are linear rate springs in this setup, their own people have told me MULTIPLE TIMES that they are in fact PROGRESSIVE RATE springs!)

They told me this after asking them if I could use the B14 coil overs/dampers from this kit and install some LINEAR RATE springs in their place (IF I could even find any), and questioned them about what rates these could possibly handle.

They said "DO NOT do that!" quite emphatically.

Of course, they were taking for granted i was not going to open them up and re-valved them at all.

The Bilstein Techs barely know more than the part numbers and some basic tech data. They are not ride control engineers or shock valving specialist. I would never ask them for shock valving or setup advice (the people in Poway CA at the Aftermarket side of Bilstein).

Yes the Bilsteins are progessive. I can measure the springs, but I don't really care what they are beyond what Bilstein claims they are. They won't really be used in this application for this customer.

 

[Sam4]

Its amazing what can be determined and done with availability to major equipment (drool). Here's two questions based on your data - 1) would it be reasonable to assume B6s could be toast after 50K? 2) Daily driver, oe height/spring - use Motorcraft OE struts and shocks?

 

[Fusion Works]

Not necessarily. The OE shocks I dyno'd had 40Kish on them, they were fine. Bilstein builds some extrememly nice shocks from a component standpoint. They have one of the best seal heads in the business. A friend dyno'd a 20+yo Miata Bilstein and it was within a few percent of the Original specifications when it was built.

Like many OE type shocks, the Bilstein street shocks don't build enough force to really hurt the components inside. Now that all said the B6 and B8 dampers are a twin tube like the stock components and are built differently than the monotube and motorsport dampers. I see no reason if they aren't leaking that they should be worn out at 50K miles.

 

[the duke]

They are not "over damped", they are fine for the stock spring rates and even the spring rates of stiffer springs. They would be fine with the Bilstein spring rates. Do you want a Cadillac or a car that handles well. Can't have both.

The valving built into my new dampers is pretty much double the OE rates across the board. Also has a lot less bleed in the lower end of the curve than the OE or even the Bilsteins. It is definitely not a couch and 250lb springs feel harsh for street use, but on track they are magic.

The OE dampers are a compromise for the 90th percentile. They have to be. There is no reason for the Bilsteins to have even less control. That is just poor shock valve selection.

Why do you think the B6 damper will be better than the OE in a track application? It is softer, thus allow the vehicle to flop around more.



The Bilstein Techs barely know more than the part numbers and some basic tech data. They are not ride control engineers or shock valving specialist. I would never ask them for shock valving or setup advice (the people in Poway CA at the Aftermarket side of Bilstein).

Yes the Bilsteins are progessive. I can measure the springs, but I don't really care what they are beyond what Bilstein claims they are. They won't really be used in this application for this customer.

In my case it's because my OEM dampers were shot after 70K miles in NEO.