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Old 07-27-2011, 09:47 AM   #43
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Originally Posted by Bender View Post
Can one assume that a high-quality coilover has properly paired springs and dampers (an H&R for example)?

I know they might not be properly paired to our suspension, per-say, but at least engineered together?
Yes. That is the whole point. They are designed TOGETHER to effectively help aid in ride quality and performance.
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Old 07-27-2011, 09:47 AM   #44
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Continued

Enough chit chat....Lets continue. Again, I will keep this vague with as little mathematical derivation as possible. But, should you want to dive further I would definitely brush up on differential equations and basic physics.

I have found my interest lies within the damping aspect to determine my ride quality.

Relationship between spring and wheel rates

In general the relationship between spring deflections and wheel displacements in suspensions is non linear, which means that a desired wheel-rate (related to natural frequency) has to be interpreted into a spring-rate.

Suspension or motion ratio = Spring force/ Wheel force ******(Not the same as spring rates or wheel rates)

To find ANY motion ratio, jack the car up and let the suspension hang. Measure the spring length at this very moment. Then use the jack and deflect the wheel a given amount of inches. Once you do so record that and then measure spring length again. Use those numbers and relate it to this newly derived formula:

Motion ratio (R) = [Final spring length - Intial spring length] / Wheel deflection

Normally, you will know your spring rates. its as easy as searching on google. If you know your spring rates, then you can relate them to a spring energy formula....for the sake of no confusion I've derived it into its simplest form:

Wheel rate = Spring rate / [Motion ratio^2]

Motion ratio results from the same kinematic suspension analysis that gives camber gain and roll center. Note that R is usually greater than 1, so the wheel rate is less than the spring rate. R is not constant; it varies as a function of v. But on an front handling car, it will be close to the ride height value at both full bump and full droop. Once the desired kw is known, and R has been determined from a candidate suspension geometry, ks may be determined. Note that the spring’s own free length (i.e., under no load) corresponds to full droop and not to ride height.

Dampening and Natural Frequency

From Happian Smith:
Frequently called shock absorbers, dampers are the main energy dissipators in a vehicle suspension. They are required to dampen vibration after a wheel strikes a pothole and to provide a good compormise between low spring mass acceleration and adequate control of the unsprung mass to provide good road handling.

Might Wanna Look at Wiki too.....Click Me

Twin tube vs. Monotube


Good Read: Twin Tube vs. Monotube....CLICK ME

Basically Twin tube = comfort; Monotube = Performance

Back to the good stuff. While skipping the boring and tedious derivations, the undamped natural frequency is:

Nat. Frequency (omega) = Square root(wheel rate / sprung mass)

If the wheel rate is maintain constant, the natural freq decreases as the payload increases. It is possible to determine a variable wheel-rate which will ensure that the natural frequency ramains constant as the sprung mass increases. (More on that later)

Effective corner damping coefficients may be set by the damping ratio:

damping ratio (ζ) = effective wheel damping ratio / (2*omega*mass of the vehicle)

- Critical damping (ζ=1) is the boundary limiting oscillation after disturbance.
- Slightly overdamped (ζ=1.2) will keep the wheels hard-pressed to the ground.
- Slightly underdamped (ζ=0.6) will allow more rapid response to disturbance say rolling into a turn) without much oscillation.
- More underdamped (ζ=0.35) will allow rapid wheel deflection, such as necessary to follow a rough surface.

This part is hard because companies do not give these values. But you can calculate a critical damping ratio and go from there. You can see that there is A LOT of fine tuning that goes into this.

Look at this pic:

Normally you want to find that range of overshoot to not allow the car to go haywire when you hit a bump, but also you dont want to car to overshoot and bounce like a pogo stick when hitting a bump and returning on the rebound. Again, you can solve for which damping ratio you'd like and find a coefficient of damping and go from there. You might be able to ask companies for their values, but be warned, they might not give it to you.

Happian-Smith:
In dealing with road surface undulations in the bump direction (damper being compressed) relatively low levels of damping are required when compared with the rebound motion(damper being extended). This is because the damping force produced in bump tends to aid the acceleration of the spring mass, while in rebound an increased level of damping is required to dissipate the energy stored in the suspension spring.

What is the ultimate design? A controllable suspension (DCC) that electronically controls the adjustment forms of the basis of improving ride and handling. AKA Sport Standard and Comfort. Most companies design for the middle, but what the user wants to decide between tracking and daily driving? This system provails.

The biggest is when you chose a static spring and shock setup that has to balance the two: Comfort and Sport. Thats where multivariable input shocks such as Koni FSDs come into play. Basically just a valve that has high limits that soak up the major bumps in the road, but at slow compressions, such as during turns, they act as a performance shock. Still....when does the valve open? Thats left for some interpretation and subjective reasoning to deteremine "ride quality"

An objective approach to ride quality will be discussed further, when I can collaborate my notes a little better....Stay tuned.......
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Old 07-27-2011, 11:52 AM   #45
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I've had multiple suspension setups over the years. from coilovers to cup kits to seperate spring and shocks. The coilovers rode very nice, but I didn't have them slammed like some people do. They were in the middle to higher end of the adjustment. I just wanted to get rid of the gap without being too low either. had alot of travel and it was a good handling and ride quality. The only thing is that once I found the perfect height for me, I never touched them again.

On the mk6, I think the best setup would be DG springs with either sachs GTI shocks or Koni yellow sport shocks.then add some swaybars if you want to push it more. If you can't find the GTI shocks at a good price you could always use the new koni strt shocks too.

I think with the DG and koni sport you would have a pretty good setup for handling and ride. you can fine tune the ride with the rebound adjustment. The springs lowers just enough to give you a nice look without looking too low. Anyways too low is bad for handling. I also want to retain some ground clearance because the winters are harsh here. another good thing with the konis is that as you rack up the miles, you can turn up the stiffness to compensate for wear of the shocks. When a shock wears down, you always lose some dampening.
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Old 07-28-2011, 10:05 AM   #46
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I really feel that the Neuspeed + FSD set up would work well for me as a countermeasure to the stiff ride that I share with my bilsteins. I've heard multiple people say that I need to do coilovers because they are mated up during design and are adjustable. While I do agree, I also feel there are spring shock setups that can get you close enough to bare with the ride. I dont care about taking a turn at 80mph on the off ramp. I dont care if my aft, dive, squat, heave, and bounce motions are affected. A performance shock will give me better than stock performance from the get go.

I havent slid coilovers off the table yet, they just cost too much for my to judge it as a worthwhile mod. I'd say I'm 65-75% happy with my current setup and I'm sure I'd be fine with stock, but the wheels wouldnt look right if I didnt have at least a 1inch drop on it. Thats why I need a shofter shock. I could always use the stock shock, but I've diminished the life of the shock and would have to change it out in a year. who knows....

Theres always the low and show guys and the hardcore tracking guys. Wheres the middle aged married men with childern that want some drop and minor performance upgrade? I dont need a stiffass suspension to justify my love for the car. I agree DG springs and koni yellows would work, but I dont care at all about adjusting. I'll end up setting it and leaving it there. Why not get a shock that you dont have to worry about? I KNOW there are people who share the same feeling I do.
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Old 07-28-2011, 10:15 AM   #47
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Originally Posted by grambles423 View Post
I really feel that the Neuspeed + FSD set up would work well for me as a countermeasure to the stiff ride that I share with my bilsteins. I've heard multiple people say that I need to do coilovers because they are mated up during design and are adjustable. While I do agree, I also feel there are spring shock setups that can get you close enough to bare with the ride. I dont care about taking a turn at 80mph on the off ramp. I dont care if my aft, dive, squat, heave, and bounce motions are affected. A performance shock will give me better than stock performance from the get go.

I havent slid coilovers off the table yet, they just cost too much for my to judge it as a worthwhile mod. I'd say I'm 65-75% happy with my current setup and I'm sure I'd be fine with stock, but the wheels wouldnt look right if I didnt have at least a 1inch drop on it. Thats why I need a shofter shock. I could always use the stock shock, but I've diminished the life of the shock and would have to change it out in a year. who knows....

Theres always the low and show guys and the hardcore tracking guys. Wheres the middle aged married men with childern that want some drop and minor performance upgrade? I dont need a stiffass suspension to justify my love for the car. I agree DG springs and koni yellows would work, but I dont care at all about adjusting. I'll end up setting it and leaving it there. Why not get a shock that you dont have to worry about? I KNOW there are people who share the same feeling I do.
You never tried Eibach Pro System? Those lower the car by 1.2" and comes with Eibach Dampers. I read some good reviews in Vortex! I'm gonna give them a try.
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Old 07-28-2011, 10:45 AM   #48
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You never tried Eibach Pro System? Those lower the car by 1.2" and comes with Eibach Dampers. I read some good reviews in Vortex! I'm gonna give them a try.
You mustve missed my build thread. I purchased the car with Neuspeed+Bilsteins already on the car (2008.5 MKV) I'm not looking to buy a whole new kit. I've already got lowering springs.
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Old 07-28-2011, 11:13 AM   #49
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Quote:
Originally Posted by grambles423 View Post
Theres always the low and show guys and the hardcore tracking guys. Wheres the middle aged married men with childern that want some drop and minor performance upgrade? I dont need a stiffass suspension to justify my love for the car. I agree DG springs and koni yellows would work, but I dont care at all about adjusting. I'll end up setting it and leaving it there. Why not get a shock that you dont have to worry about? I KNOW there are people who share the same feeling I do.
I am REALLY close to feeling this way (though I would probably go the DG Springs with the FSDs) BUT I am tempted by both the HR SS SP Kit and the Cup Kit...
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Old 07-28-2011, 12:08 PM   #50
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Quote:
Originally Posted by grambles423 View Post
I really feel that the Neuspeed + FSD set up would work well for me as a countermeasure to the stiff ride that I share with my bilsteins. I've heard multiple people say that I need to do coilovers because they are mated up during design and are adjustable. While I do agree, I also feel there are spring shock setups that can get you close enough to bare with the ride. I dont care about taking a turn at 80mph on the off ramp. I dont care if my aft, dive, squat, heave, and bounce motions are affected. A performance shock will give me better than stock performance from the get go.

I havent slid coilovers off the table yet, they just cost too much for my to judge it as a worthwhile mod. I'd say I'm 65-75% happy with my current setup and I'm sure I'd be fine with stock, but the wheels wouldnt look right if I didnt have at least a 1inch drop on it. Thats why I need a shofter shock. I could always use the stock shock, but I've diminished the life of the shock and would have to change it out in a year. who knows....

I agree DG springs and koni yellows would work, but I dont care at all about adjusting. I'll end up setting it and leaving it there. Why not get a shock that you dont have to worry about? I KNOW there are people who share the same feeling I do
well Neuspeed sells the sport springs with the FSD and people who have that setup are pretty happy. But I also heard the FSD likes to blow up after a while when paired with lowering springs. I've seen numerous reviews online of blown shocks. Thats why they advised me to go with the yellow. I think the yellows are pretty good because you can really set them the way you like for ride and handling. start full soft and adjust them till you find a setting that you like. Yes once you find the setting you like you won't touch them , but the ability to be able to adjust them the way you like is what makes it good about them, + if you keep them a long time, you have the ability the turn up the dampening to compensate for shock wear over time that is if you keep them a long time.


I also thought of coilovers. If you look at the new ST coilovers which are the same as KW V1 coilovers minus the stainless steel housing. they are selling now for 799$ and are really comfortable drive from people who have them.
the range of adjustment on a GTI is 0.4 to 1.6 inch lower. so you can set them at a similar height like the neuspeed, but have a setup that is designed to go together. The FSD shocks alone are close to 700$. so for a bit more you get a complete setup. either way , your not losing so much as you can always sell your bilsteins or neuspeed/bilstein setup and recoup some money so the new setup ends up cheaper.
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Old 07-31-2011, 04:58 PM   #51
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Quote:
Originally Posted by grambles423 View Post

Theres always the low and show guys and the hardcore tracking guys. Wheres the middle aged married men with childern that want some drop and minor performance upgrade? I dont need a stiffass suspension to justify my love for the car. I agree DG springs and koni yellows would work, but I dont care at all about adjusting. I'll end up setting it and leaving it there. Why not get a shock that you dont have to worry about? I KNOW there are people who share the same feeling I do.
Great thread, Thats the same feeling I have, I want the minor drop, but I love the way my GTI drives as is, but would like the european level suspension stiffness. I guess I'll be watching this thread to see what direction you go. I was thinking of going driver gear springs, but what worried me was that sound people were experiencing in that thread.

Though I am wondering, how much a difference between between the suspensions on a 4door, 2door, DSG and manual are between the US models. I noticed at a local meet between 3 different MKVI configurations all on stock suspensions, my 4door 6spd sat lowest, and it was low enough that it causes me to second guess whether I do really want to lower it, since it doesnt look that bad, not like the 2door dsg where all my fingers fit in the wheel gap vs 3 on my 4 door.

I did notice a lot of that thread from vortex by teched, reminded me of a few posts or stuff I read a long time ago by Dick Shine, from Shine racing, with the suspension they offered not lowering any of the car and actually slightly raising it up a bit. I think in the case of the MK1 VW's there was only 4in of suspension travel, and dropping it really affected the suspension.

Im gonna have to read up on suspensions one of these days, and make the right choice for my car.
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Old 08-17-2011, 10:03 AM   #52
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Old 09-21-2012, 04:00 PM   #53
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Thumbs up

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Old 12-12-2012, 03:51 PM   #54
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Big bump. Z you might want to include some of these articles in your post.

These are hugely technical, but broken down into easy to understand verbatim. With all the people bringing up the MOAR LOW = better handling topics, this needs to be propagated more.

http://www.modified.com/tech/0506_sc...1/viewall.html

Article 1 out of 6
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Old 12-12-2012, 03:54 PM   #55
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Stickied. We'll use this the channel what suspension questions people will have. Feel free to ask anything you'd like.
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Old 12-12-2012, 03:57 PM   #56
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