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For awhile now I've been running on two leaking shocks, and it's starting to get a little bouncy over the bumps. So I'm going to wait until spring, but I'm hoping i can order some stuff now.
Here's what I'm thinking. Bilstein HD's front and rear with Eibach Sportline springs at 1.5" drop. What else shouyld/do I need to change when installing the new stuff, liek bump stops, spring perches, etc. etc.
Also, can anyone give me an indication how this will ride, at the moment it'll be on my A2 Golf with just the 14" rims and 195/60-14's for tires, with plans to upgrade later to 16"s
So any help can will be great, and maybe i can start collecting all the stuff to get this under way !
Thanks
Kritter
 

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Re: Need new susp...help me decide (Kritter)

Should ride pretty good on stock wheels and tires. Note that the suspension will make the handeling limits much more noticable of the stock tires. Yokahama AVS Intermediates and Falken Azenis are some good performance tires and affordable that come in 195/60-14. Replace the front strut bearings when you install the springs. Those have a pretty limited life span.. You might want to think about going with a bilstien sport instead of the HD. They are shortened for sport spring applications.
Aloha
 

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Re: Need new susp...help me decide (Kritter)

quote:[HR][/HR]Bilstein HD's front and rear with Eibach Sportline springs at 1.5" drop. What else shouyld/do I need to change when installing the new stuff, liek bump stops, spring perches, etc. etc. [HR][/HR]​
Bilsteins have built in bump stops, so you're just going to remove the stock ones. Rear shock mounts are often a good idea to replace. They're relatively cheap and they'll hold up better with the new stiffer suspension.
 

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Re: Need new susp...help me decide (Kritter)

You'll definitely want to get the Bilstein Sports instead of the HDs for this application.
I'm considering a new setup myself and went so far as to call the tech hotline at Bilstein and talk to their support folks. According to them, the HD and Sports dampers basically give similar damping rates. The Sports simply have a bit shorter shaft.
Bilstein's recommendation was that any drop equal or greater than 3/4" (~18mm) should use the Sport, anything less than 3/4" should use the HDs.
The 3/4" rule is easy to remember and follow but some folks (like me) are looking for a more in-depth explanation, in order to understand why the rule is what it is, and what happens if you violate it.
First, these are position sensitive dampers. As the shaft is driven deeper into the shock body, the compression damping rate increases. This is analagous to progressive rate springs, except here it applies to the damping effect of the shock and not the resistance to compression of the spring.
For example, at the beginning of a compression/rebound stroke the damper applies a minimum compression damping force, which increases (stiffens) as the suspension compresses, finally reaching the peak of a curve (or hitting a very abrupt plateau as the bumpstomp kicks in and the suspension bottoms out) and begins decreasing, now follwing the rebound dampening curve.
So, you've got a variable rate damper and maybe you've got a progressive spring as well. Each of these devices doesn't really have a single rate at all, it has a rate curve, with compression travel (inches or millimeters) on the vertical (y) axis and compression rate (resistance or stiffness) on the horizontal (x) axis. So, you can begin to see that matching springs and shocks isn't simply a matter of lining up a single spec printed on the side of a box.
Adding further complexity is the fact that the rate of damping is also sensitive to the upward velocity of the shaft. So a sharp, squared-off bump will generate a higher damping rate and not be taken up as smoothly as a gentle wave. This is due to inertia in the suspension and the way the oil in the damper reacts to changing forces.
Now, back to the original question: "Why shouldn't you mess around with the 3/4-inch rule?". For instance, what happens when you take a Bilstein HD and mount it with a 1.5-inch lowering spring? Well you've basically mounted the shock so that the shaft is about 3/4-inches into the shock body when it's at rest. So, when you hit a bump and the suspension compresses, rather than starting at the softest point in damping curve, you're already a good bit into the stiffer portion of the curve and into the section of the curve that is rising most sharply.
The net result is a harsher ride than if you chose the Bilstein Sport.
With the Sport shock, the curve has to rise from the same beginning point to the same ending point over a shorter stroke, so the curve IS somewhat steeper. But, the initial portion of the curve (say from the zero point of the stroke to the 3/4" point) will be noticeably softer than the portion of the HD's curve that you would be in if you had mounted them on the shorter springs (the 3/4" point of the stroke to the 1.5" point).
This first 3/4" or so of suspension travel is where most of the real world work is done. It's certainly where most road irregularities that produce what we'd call vibration or harshness are dealt with. This is why progressive rates springs can offer good cornering performance with reduced harshness.
The fact is that if a suspension has more travel, it can use less damping rate (damping force per unit travel) to get the job done. This fact is too often ignored, particularly when the currently popular fashion calls for cars to appear noticably lowered in order to seem "sporty".
So, don't fall into the trap of thinking Sporty=Firm=Harsh AND HD=Softer=Comfort, because in this instance, the Bilstein Sports will be the more comfortable choice, as well as giving you better handling and balance, due the fact that they are a better match for your springs.
--keihin
 

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Re: Need new susp...help me decide (keihin)

Interesting. I thought shocks were mainly velocity sensitive, and that position didn't play much of a role. I thought that was mainly the domain of springs... Do you know anything about the Eibach ProDampers? They are supposed to be softer than the Bilstein and Koni shocks, but still quite a bit better than the stock shocks. They warn you, however, only to use them with Eibach springs. Now, half of me says this is pure BS, whose purpose is nothing more to get to you buy Eibach springs too. However, the other half of me says there may be some validity to it... something to do with positional sensitivity or shaft length? An inability to handle the higher spring rate and more extreme lowering of some springs? Do you think they would be usable with the stock springs? I am worried that their shafts may be too short to be used with stock springs.
 

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Re: Need new susp...help me decide (catalytic)

quote:[HR][/HR]... Do you know anything about the Eibach ProDampers? They are supposed to be softer than the Bilstein and Koni shocks, but still quite a bit better than the stock shocks. They warn you, however, only to use them with Eibach springs. Now, half of me says this is pure BS, whose purpose is nothing more to get to you buy Eibach springs too. However, the other half of me says there may be some validity to it... something to do with positional sensitivity or shaft length? An inability to handle the higher spring rate and more extreme lowering of some springs? Do you think they would be usable with the stock springs? I am worried that their shafts may be too short to be used with stock springs.[HR][/HR]​
I don't know about the Pro Damper rods. However, I understand Eibach is the original equipment spring and sway bar supplier to VW and Sachs is the original equipment shock supplier to VW. Eibach created the Pro Kit springs to lower and stiffen the stock supension. Eibach created a different front sway bar and an additional rear bar to tune out body lean and increase rear stiffness. As to the Pro Dampers, Eibach worked with Sachs to get shocks with dampening matched to the Pro Kit springs. The Pro Dampers should be "like" stock shocks, but stiffer, heavier duty and designed for shorter than stock springs. While the Pro Dampers will work with any springs, they are matched, like coilovers, to Pro Kit springs. Since the Pro Dampers are matched to Pro Kit springs they will probably work better with springs similar to Pro Kits than with springs not like Pro Kits.


[Modified by dmkozak, 5:27 PM 12-9-2001]
 

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Re: Need new susp...help me decide (dmkozak)

I haven't used these in some time, but here's what I had listed in my files. Their new website indicates that they have moved, so the numbers may have changed. (probably less likely since these are 800 numbers...)
Here are my points of reference
Bilstein R&D dept.
1800-537-1085
contacts: Steve & Lou
Bilstein West coast customer service
1800-537-1085
contacts: Larry
Bilstein East coast customer service
1800-745-4636
contacts: Vinny
--keihin
 
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