The Koni Sport dampers, also popularly known as the Koni Yellows are a line of dampers intended to provide enthusiasts with more performance oriented ride and handling characteristics. They come with a lifetime warranty for the original owner. They are one-way adjustable dampers (rebound) to allow for matching with different spring rates. While the MK5 has pretty good body control stock, it is missing a little bit of extra rebound damping. The rear can get bouncy sometimes and the body can pitch quite a bit on choppy sections of highway. Big hits can take a little longer than I’d like to settle back down.
The problem I have with the stock dampers is that comfort can suffer from the lack of rebound. It makes rough roads a little softer but the choppy highway ride is what is really uncomfortable. It’s undesirable from the driver’s seat, imagine how much more for the rear passengers!
Replacing just the rear dampers made a big improvement in ride quality and control. Koni’s have a very smooth engagement and it makes the suspension feel a lot smoother in operation, despite their performance intentions. I installed the rears one night and did the fronts another day.
Koni Yellow Construction
Koni manufactures a variety of different damper types. They do monotube, and twin-tube hydraulic or low pressure gas. They usually reserve the monotube variety for higher spec racing dampers. You’ll find a lot of discussion regarding whether twin-tubes or monotubes are the better construction type. Theoretically, a monotube is better. Compared to a twin-tube, monotubes generally exhibit faster reaction time, less vulnerability to heat and can be installed in a variety of positions. If the body is damaged though, it will affect the performance of the shock or possibly take it out of service. In practice, and especially in a daily driven car, either one can be made to work well. Here’s a link to an excellent site that everyone should read: Autocross to Win – Shocks.
The Koni dampers for the MK5 are of the twin-tube variety. Bilstein, one of the largest producers of monotube dampers, also makes an excellent damper for the MK5 but I didn’t choose them for a specific reason. The quick response of a monotube can degrade ride quality quite a bit. A twin-tube damper has a slower reaction time, leading to a more progressive increase in the damping rate. This progressiveness is what gives the Koni’s their excellent ride quality. If you track your car, the Bilstein’s will handle better than the Koni’s but they won’t blow them out of the water either. If you do a little of both or want an upgraded damper for the street, the Koni’s would be my choice.
I’ve taken apart the suspension so many times that it’s easy for me now. The rears take about an hour for both side (replacing just the dampers). The front struts took me about 2 1/2 hours. The first time I tried to install springs and dampers on my car, it took me all day. There are several excellent suspension install DIY guides, I won’t try to make a better one. Here’s a good one-DIY Install. There’s nothing different about installing the Koni Yellows. The dampers will come with plastic washers, just be sure to place them between the damper and the bump stop. This keeps the bump stop from damaging the top seal. The Koni Yellows also come with a much larger location tab for the front struts, you may have to move the strut spreader to get the body to drop down into strut holder. A 1/4″ ratchet extension can work as a strut spreader in a few cases.
Be sure to check that both rear dampers are adjusted to equal positions. The rears require disassembly to adjust and you don’t want to remember after you’ve put everything back together. Set them at 1/4 turn from full soft for a few hundred miles to let everything work in. The fronts are externally adjustable, set them at 1/4 turn from full soft to let them break in as well. The reason for setting them a little off full soft is that the adjuster sometimes jams if left for a long time in the full soft position. I’ve never personally seen it but have heard a few stories regarding this.
I don’t have a photo, but I stood the Koni Yellows up next to the stock front strut. To my surprise, the spring perch is maybe 1/2″ lower or so, nothing drastic. I don’t see it mentioned anywhere but i’m positive it is different. It’s a slight difference but it is noticeable visually. Works out perfectly for me because my front end sat slightly higher visually. I really wish I had taken a photo.
These dampers are much better than the original Sach’s dampers. Sach’s makes great stuff but remember that OE dampers are spec’d to a price point. At the softest setting, the ride quality is better than stock, like buttery smooth. I don’t see how people would find the ride quality at full soft to be worse than stock. Bumps are absorbed with little drama and then the chassis settles back down. Roll is much smoother due to the higher rebound damping rate. Turn in is a lot more predictable and less upset by rough roads. The car feels lighter on its feet with the added chassis control. In terms of driving, these dampers offer improved dynamics with no cons.
What is the Correct Rebound Setting?
The correct rebound setting depends on the spring rates and driver preference. Koni provides the rebound adjustment to match spring rate and also to adjust for wear. Although there is an optimal setting, there is enough leeway back and forth for a driver to adjust the damper to personal preferences. As such I’m only going to say that you want enough rebound damping to control the spring after hitting a bump in the road. You want the chassis to take the bump, and then settle down after reaching the ride height. I’m oversimplifying this only because I can’t tell you what the best setting is.
The softest setting is the Koni recommended setting for stock springs. I find it very comfortable but body control is still messier than I would like. I ended up at the 1/2 turn setting for the rear. Better than stock comfort and ride control. You’ll be surprised by how large a factor the rear dampers are in terms of ride feel and handling. Having them correctly dialed in makes the car feel a lot more stable. Get the rear dampers dialed in first and then adjust the front rebound control to taste.
Remember that you are not attempting to stiffen the car with dampers. You are matching the rebound control with the spring rate. Springs and sway bars control how far the body rolls, dampers control the rate of roll. Rebound settings that are far too stiff will cause the suspension to jack down and not rebound after bumps. Stiffer than required rebound settings can lead to weird handling (washing out, sudden oversteer/understeer) and poor comfort. Rebound settings that are too soft result in less than optimal body control. Body control will feel somewhat loose.
If you are generally happy with the MK5’s handling and would like to improve on it, upgrading the stock dampers is an excellent choice. Tires and dampers make drastic improvements to the already competent MK5 chassis. You’ll be hard pressed to improve the handling further within a budget. Stiffer springs will destroy ride quality and lower springs will compromise the suspension geometry. I am on stock springs with the Koni Yellows and I feel that this is the perfect daily drive suspension. The slightly lower Driver Gear springs would make for a nice visual change and slightly improved roll control (slightly stiffer) but minus the wheel gap, the stock springs with Koni Yellows are an excellent combination. Very fluent in the corners and comfortable. The suspension geometry and travel are all kept within their optimized ranges. I’ve never been more in love with the way the car handles. After a few hit and miss suspension updates, I think I have finally found the perfect setup for my needs.
They are available from a variety of vendors. Check out the vendor list at the top of the site. Koni had an amazing sale on these last year but as of now they are around 600 dollars.