H&R Sport Springs and Bilstein shocks?

[1997BMW328i]

I'm trying to decide between H&R oe sports and sports.. any pics??

Also in terms of daily driveability.. Ive been told oe sports is the way to go.. but I'm young, I dont mind a rough ride...

[mwood]

getting Billy B8 Sprint/Sports installed today... will know how they feel in a day or two

[cabdolla]

I'm trying to decide between H&R oe sports and sports.. any pics??

Also in terms of daily driveability.. Ive been told oe sports is the way to go.. but I'm young, I dont mind a rough ride...

spring rates are not a matter of you being able to stand a rough ride, it's that excessively high spring rates make the car drive like shit. You loose traction and handling. I think sports are fine, stay away from race springs.

[1997BMW328i]

getting Billy B8 Sprint/Sports installed today... will know how they feel in a day or two

which springs do you have?

spring rates are not a matter of you being able to stand a rough ride, it's that excessively high spring rates make the car drive like shit. You loose traction and handling. I think sports are fine, stay away from race springs.

I'm not interested in the race springs. Just looking for the difference in ride height between the oe sports and the sports

[carwiz008]

if your spine can take it, lower it

[mmark.]

OE sports are supposed to raise the spring rate, but retain the ride height.
The sports will lower the car 1/2" to 1" depending on the equipment level of the car.
With Bilstein Sport dampers, the car will feel "Busy", but rear grip and stability will be much improved.
The problem for me with the Bilstein sports is that the ride can be irritating, when I'm tired/not in the mood.. Otherwise I like them 90% of the time.


...And now, Cue the Bilstein Haters


m

[Level8drummer]

+1 for Bilsteins and H&R springs. Great on track, and good on the street. I run H&R race springs with my Bilsteins. Sport springs are much softer, and ride less firmly.

Bilsteins are the way to go for sure. Get Bilstein sports if you're lowering the car.

Level8Drummer

[image976]

I actually have Bilsteins (yellows) and H&R springs and I love how comfy the ride is ! It's not to aggressive at all and it hold it's own when u decide to drive it like u stole it. If it weren't for the fact that I want ride height adjustability I would probably keep this set up. But as of right now they are going to go up for sale in the classified section. So if you're interested hit me up.

[013137]

I had H&R sports with bilstein shocks before installing my coilovers, imo the spring rates were a bit too soft for the ride height, and the bilsteins made the ride pretty rigid over potholes. From what I was told (dont quote me on this), the bilsteins aren't valved right for e36 suspensions, they are more popular with the e30 guys

If I ever go back to a spring/strut setup, I will pair the H&R sport springs with the koni yellow shocks, from what I hear the koni yellows ride a lot better then the bilsteins.

[Level8drummer]

From what I was told (dont quote me on this), the bilsteins aren't valved right for e36 suspensions, they are more popular with the e30 guys

Yeah, I've heard that before too...from people who are wrong!

I've had both on my car within the last 2 years, I switched to bilsteins and am very pleased.

Really shock valving is very complicated. It involves the chassis, the motion of the wheel, the spring rate (linear vs progressive), the weight of the car, the weight of the suspension, the weight of the wheel and tire, and the surface you're driving on. For someone to state that a bilstein shock just flat out has the wrong valving for an E36 chassis...well that's pretty bold. And foolish really.

What works for some may not work well for others. The bilsteins worked better for me than the TCK koni's did...on the street and on the track.

If I ever go back to a spring/strut setup, I will pair the H&R sport springs with the koni yellow shocks, from what I hear the koni yellows ride a lot better then the bilsteins.

I would highly recommend you drive cars with both before you decide. You may like the koni's better.

Level8Drummer

[JDStrickland]

My car ('94 325) is on H&R Sports with Koni Adjustable shocks/struts.

[1997BMW328i]

I actually have Bilsteins (yellows) and H&R springs and I love how comfy the ride is ! It's not to aggressive at all and it hold it's own when u decide to drive it like u stole it. If it weren't for the fact that I want ride height adjustability I would probably keep this set up. But as of right now they are going to go up for sale in the classified section. So if you're interested hit me up.

How much would you be selling that setup for?

My car ('94 325) is on H&R Sports with Koni Adjustable shocks/struts.

That's just about the height im looking for. The gap i have now in the front just doesnt do it for me :s

[Moron95M3]

on my 95 M I have HR sports with billys. For just DDing I do think billys are a bit harsh, but I like them for really hard driving/autoX/track.

I will say that I seem to have a taller rear though than what it should...not sure why. (got some rake almost). I have yet to look at it, but I might pull out any spring pads or replace them if they're thicker.


tires - 245/40/17

[carwiz008]

Really shock valving is very complicated. It involves the chassis, the motion of the wheel, the spring rate (linear vs progressive), the weight of the car, the weight of the suspension, the weight of the wheel and tire, and the surface you're driving on.

Shock damping is determined using the driven-harmonic-motion linear differential equation:

m(t)x''+b(t)x'+kx=F(t,x)

where F is the force applied as a function of time and position (normal force).
m(t) is the mass suspended at each corner (car mass, but varies with time)
b(t) is the viscous damping coefficient (can be a function of time)
k is the spring constant

Aside from fancy shocks with adjustable rates that would provide a variable B coefficient, we can assume that the only variable dependencies are in the force equation and mass coefficient.

The force equation is continuously variable and relies on how fast you're driving, over what.
A critically dampened system satisfies, b^2 - 4*m(t)*k = 0, but only works when the mass is a finite constant (sitting still on flat ground)

Now if you use a variable viscous damping coefficient, b(t)...

b(t)^2 - 4*m(t)*k = 0

You can see how another function of time would allow for critical damping across a range of masses, even when the car isn't static and the weight is shifting around.

disclaimer: for clarity of explanation I've ignored the spatial dependency in the b and m parameters, keeping the Diff EQ in linear form. Also, to include the mass of the suspension you would need another spatial variable to show how the suspended mass varies with height.

TL;DR
Basically this all shows that you will never have a critically damped system except in very specific situations, unless you have variable damping. The required B value changes when the Mass shifts around corners. So get over the shock valves unless you're throwing down for the good stuff. It really comes down to how tight you want it.

[image976]

i'll probably post them up for around 300-350 obo.... they're in good shape no leaks of any kind. if you'r interested lmk

[1997BMW328i]

i'll probably post them up for around 300-350 obo.... they're in good shape no leaks of any kind. if you'r interested lmk

Yeah im interested. have any pics of the car with them/of the shocks/springs themselves? Andgould@comcast.net

[cabdolla]

Shock damping is determined using the driven-harmonic-motion linear differential equation:

m(t)x''+b(t)x'+kx=F(t,x)

where F is the force applied as a function of time and position (normal force).
m(t) is the mass suspended at each corner (car mass, but varies with time)
b(t) is the viscous damping coefficient (can be a function of time)
k is the spring constant

Aside from fancy shocks with adjustable rates that would provide a variable B coefficient, we can assume that the only variable dependencies are in the force equation and mass coefficient.

The force equation is continuously variable and relies on how fast you're driving, over what.
A critically dampened system satisfies, b^2 - 4*m(t)*k = 0, but only works when the mass is a finite constant (sitting still on flat ground)

Now if you use a variable viscous damping coefficient, b(t)...

b(t)^2 - 4*m(t)*k = 0

You can see how another function of time would allow for critical damping across a range of masses, even when the car isn't static and the weight is shifting around.

disclaimer: for clarity of explanation I've ignored the spatial dependency in the b and m parameters, keeping the Diff EQ in linear form. Also, to include the mass of the suspension you would need another spatial variable to show how the suspended mass varies with height.

TL;DR
Basically this all shows that you will never have a critically damped system except in very specific situations, unless you have variable damping. The required B value changes when the Mass shifts around corners. So get over the shock valves unless you're throwing down for the good stuff. It really comes down to how tight you want it.

There should be no spatial dependency on a damper, the damping depends on the speed of the pistons movement, not its position during the stroke. Also, the suspended mass does not vary with height. It is what it is - rigid body.

I don't agree with you that mass varies over time. The mass is that of the moving components: tire, wheel, rotor, shock. These are all a fixed value. When the car has load transfer, that changes the forces felt at each corner of the four tires, not the mass.

Good analysis, none the less.

And I absolutely disagree with your first reply, "lower it as much as your back can take". Again, handling will become pitiful when the rates become too high. Lowering the car - inherently - requires a larger spring rate. Larger spring rates mean the car cannot keep up with irregularities in the road surfaces of real world roads. A real world road is nothing like a smooth track.

[carwiz008]

Is a damper really constant across the entire actuation? If it is I guess the spatial dependence would only define limits of motion and be redundant.

The mass and driving force should be at opposite ends, right? I used the wheel's normal force for F, so the car mass is what the spring is oscillating.

The total mass doesn't vary, you are correct. But I'm going to stick with my argument that the mass at each corner varies. The mass is being influenced by each corner simultaneously, so the relative mass at each corner is dependent on what each spring is doing.

Sum[ m(t) ] == M.

Think about this: the mass that the spring supports is really only the strut tower, and everything else is just a collection of forces exerted by the rest of the car (and springs). Those forces vary with time, so the relative mass the spring is supporting (oscillating) varies as well.

To adequately model all four diff EQ's you would need 4 linearly dependent mass equations.

Recheck my first reply, I did not say "go as low as you can take it." I meant that if he can deal with the sport lowering springs, get them. They handle and ride acceptably. That was the question: daily driveability. I didn't mean to suggest the race springs for street driving.

[mwood]

Just got the car back from the shop after having some routine service and the Bilstein B8's installed.

How do they feel? Surprisingly they are nowhere as harsh as I had thought they would be. On the contrary they are very comfortable, yet provide good rebound for taking any corner at any speed. Here in Helsinki downtown is all cobblestones, and bad ones at that, (plus trolly tracks). The B8's suck them up like butter, not harsh, very stable.

Front end sits about 1/2-3/4 inch higher, but hopefully they will settle and I will get my ride height back.

Recommend for anyone wanting to get some good struts/dampers without worring about a harsh ride. B8 are reccomended for those with lowering springs. ( I think they are the same as the B6 but shorter )

Will write more as I drive more!