Bilstein Science Experiment

[Fusion Works]

Compress them and strap them down?

 

[kevinatfms]

Compress them and strap them down?

Got a box with an intake kit for my F150. Will be using that. Should have them protected and sent by tomorrow mid-day through USPS. Will send tracking number the minute they go out.

 

[Fusion Works]

Roger that. Looking forward to working on them.

 

[Rutschpartie]

Roger that. Looking forward to working on them.

did this already happen - I would be very interested in seeing the results!

 

[Fusion Works]

Haven't gotten time to start dynoing dampers. I have the ones from Kevin and my pile to do. Probably gonna spend a day doing damper testing.

 

[Fusion Works]

Just got a spreadsheet from Bilstein that gives me a sortable listing of strut inserts to compare lengths, extended and compressed. So I can actually build a front strut with more travel than stock. So yes its possible to build a proper off road damper for stock or even slightly higher ride height.

 

[the duke]

Did you dyno a b6?

 

[Fusion Works]

Not yet. I have to pull my dampers off my car and put 8 dampers on the dyno. Kinda have to set aside some time for that. Been so busy at work for the last couple of months, haven't gotten freed up to do it. Might pull my car down this week since its suppose to rain all week and I can just drive my truck all next week.Too bad gas went back up.

 

[Fusion Works]

Tomorrow is the day. Taking all of these and some others over to dyno and get some solid no BS charts on these.

I have the following dampers to dyno
B8 Front and Rear
B14 Front and Rear
Stock Front and rear
Brett's custom Front and rears
Ford Focus Rear
and some other race dampers

 

[Fusion Works]

Ok here is a slight preview. I ran out of time to sort out the software and figure out how to come out with pretty fancy graphs I can post, but the software wasn't straightforward like that. So I printed the graphs and have to take pics of them since my scanner came over on the Ark with Noah and won't work with Winblows 10.

This is a graph of the Stock Fiesta ST front strut and the Bilstein B8 strut.

 

[Fusion Works]

The four lines are both sides of the football chart. If you ran these shocks and plotted both the opening and closing of each section of the valve you would get a football shaped chart with opening on the left and closing on the right. This version of the graph is them overlaid on top of each other. Hence the slight disparities in the stopping and starting numbers of each damper.

 

[the duke]

Interesting. I was under the impression the Bilstein was softer than OEM. I also thought the OEMs were more digressive and the Bilsteins linear, wheres it's backwards?

For that matter, who even makes the OEM struts? I can't remember seeing a stamping on the bodies when I removed mine.

 

[Fusion Works]

Lets start with the Front dampers. Keep in mind I am testing the following:

OE Fiesta ST front with 40kish miles.
Bilstein B8 Replacement damper
Bilstein B14 insert
Brett's Custom insert.

The B14 and My struts use a monotube insert, where as the B8 damper is non serviceable twin tube damper. I am going to open one up and see what it looks like inside, but consider it a bolt on only piece.

Stock Front Damper:

B8 Front damper:

B14 Front insert:

Stock vs B8 vs B14

 

[Fusion Works]

Now here is my custom valved damper compared to stock, B8 and B14. The weird little notch in all these graphs is related to my mounting setup. I think something was a bit loose and you can see it when the dyno reverses shaft direction. I see it more on the rears.

My Front Insert

My biggest complaint with my damper is the low speed rebound is too high I think. I need to put some bleed in to allow a little more compliance on big low speed bumps/dips/rises. It tends to toss the car around a bit too much.

 

[the duke]

So what springs are used on the B14 kit to warrant such a drop in damper force? I can't remember, but is the B14 kit ST specific or is it a fiesta kit with rates lower than an OEM Fiesta ST spring?

Bravo. This is is some good work.

 

[Fusion Works]

Interesting. I was under the impression the Bilstein was softer than OEM. I also thought the OEMs were more digressive and the Bilsteins linear, wheres it's backwards?

For that matter, who even makes the OEM struts? I can't remember seeing a stamping on the bodies when I removed mine.

Why would the Bilsteins be linear? Almost no OE street car shock is linear.

I suspect the OE dampers are made Tenneco automotive. Basically Monroe. They are a Teir 1 damper manufacture (as well as other components). The valving is developed by Ford of Europe and America, then copied a zillion times by the main manufacture. They are a normal twin tube shock similar to the Bilstein.

 

[Fusion Works]

So what springs are used on the B14 kit to warrant such a drop in damper force? I can't remember, but is the B14 kit ST specific or is it a fiesta kit with rates lower than an OEM Fiesta ST spring?

Bravo. This is is some good work.

This is the bizarre part. The B14 kit uses a 274/223ish spring setup. So they use less valving and more spring. Its a stupid way to design a damper setup, but it lets them keep a squishy ride and you think it handles great because they prop the body up with the springs. Yes I am about to install the B14 kit on my car to compare to my current setup.
Have no idea if it is specific to the ST or not. Kinda doesn't matter. The spring and damper rates are what they are.

 

[Fusion Works]

Lets talk rear dampers. For some reason I didn't get the individual graphs of the B8 and B14 printed out. I also didn't print the comparisons with my custom rears. I wasn't paying attention when I printed everything. I will be going back at some point so I can print those and maybe figure out some more options for displaying charts. I did dyno all of the shocks except the Focus B8 Rear. It was a different size lower mount and I had to make an adapter at the dyno shop.

Stock Rear (yes I know I left off the "a")

You can see the slack in my upper mounting adapter, circled in this picture.

Stock vs B8

Stock vs B14

 

[Dialcaliper]

Interesting and thanks for doing this testing. It looks like the B14 is oddly soft compared with the B8. Is yours from the Fiesta kit, or an off the shelf insert?

What it suggests to me is that the B14 kit, spring rates and damping were designed as an upgrade to the base model Fiesta. It looks like that might not be true of the B8 (maybe B6?)

I’d also still maintain that the OE spring design uses the bumpstops (which are remarkably long) as a spring aid, and is effectively stiffer than the B14 setup once they come into play (which is pretty quickly especially in the front on a lowered car)

And it also fits with the harsh ride quality that’s pretty much a hallmark of high rebound and assymetric damping. It’s certainly a valid way to tune, and characteristic of most OEM “sport suspension”. Because sporty.

I have a feeling you’re going to be fiddling and dissatisfied for a long time if you are having issues with the ride quality. With the tuning strategy you are using, the high rebound is your body control on a smooth road/track. If you reduce it, or reduce spring, you are going to sacrifice some handling. The problem is even harder when you remove the bumpstops as part of the control, as you’re effectively reducing the spring rate there too.

I know you disagree with the “old school” higher spring rate + less rebound + more compression damping strategy, but you’re always going to sacrifice street manners trying to wring handling out of a sub <1.8Hz front frequency setup by adding rebound.

Pull back on rebound as your instinct is telling you, and you’ll be able to increase the front spring rate back to 300-350 lb/in to get the front frequency back in the 1.8-2.0 Hz range to get the handling you want without so much of the bone crushing ride.

 

[Fusion Works]

I need to check on the Fiesta Kit. A friend picked it up from someone used who said it was for a Fiesta, but meh, who knows crackheads on Marketplace these days.

The part number I have for the front damper is 35-242055. That corresponds with what Bilstein says is the ST kit not the base and Mazda 2 kit.