First off, sorry for the hiatus. Turns out grad school is hard? Weird stuff, I know. Despite that, I have still be on Facebook entirely too much and have answered a lot of miscellaneous questions here and there. I thought this might be great opportunity to take it from the top and address a lot of different tidbits with one rambling article. Enjoy the ride!
Springs vs. Cup Kits vs. Coilovers
When it comes to upgrading shocks and struts, there air the three main options. I guess air too, but that's not for this blog. Go to BMPTuning for that ricey shit (Love you Autrey). Springs are a good jumping off point for newer cars, because while miles are down, the shocks are working like new and can handle a bit more spring. Springs give the car a better stance, and often times better [feeling] handling. People that are just getting into cars should often look into springs.
So... what are the downsides? Firstly, shock wear is accelerated, and this often results in a poor ride over time. As the shock loses dampening, it can't control the spring very well. The ride can start to feel "bouncy" or "lofty" (often times I think people describe the same feeling these two very different words). Secondly, suspension works best when all components are matched. Many aftermarket springs work well with shock dampers (for some period of time) but many, particularly ones with more lowering, are too stiff for factory struts. Lastly, comes the price of entry. If you can do it yourself, springs are cheap. But if you can't, spring installs range from $300-500, and require an alignment. You spend $200 on a part and twice that on labor. Ouch.
So cup kits then? If you don't know, cup kits are basically after market springs and dampers purchased together, often bundled by a shop. An example would be H&R Springs with Koni Yellows, or Bilstein B8s and VWR Springs. The after market shocks are generally damped firmer, and are often matched closer to after market springs. Because of this, they also don't experience the accelerated wear of stock shocks with aftermarket springs. Firmer dampening usually results in a "more planted" ride, but once dampening gets too stiff, the car will become unresponsive to bumps. Generally speaking, you won't have this issue with cup kits.
Coilover overs. People often think that the moment you go with coilovers, you're automatically sacrificing ride quality for performance, and the ride will be harsh. This simply isn't true. Some coilovers, take KW V1's for example, are very geared toward street comfort. While it's true that the ride is about 10-15% firmer, but the well matched dampening will result in minimal differences in comfort while making the car feel significantly better. However, one must be careful. BC Racing coilovers, for example, are sprung about 100-150% stiffer than stock. Hence, the ride changes will be significant. Overall, my opinion is that coilovers are the best option, but you should spend a lot of time thinking about what you want in a suspension.
This subject truthfully desires it's entire article but let me just throw in a quick two cents here, particularly, related to Mk7's. The generally function of sway bars is to stiffen either the front or rear of the vehicle. In general:
Stiffer Front = More predictable, more understeer.
Stiffer Rear = More rotation, more oversteer.
By default, almost all factory cars are tuned with an understeer bias. This makes them easier to drive at the limit and also much safer. (Turns out oversteer is a lot harder to correct... I think there's a whole sport just for oversteering?) Anyhow, the Mk7 platform is no exception. For example, the GTI comes factory with a 25mm front sway bar, and a 20mm (or 21.3mm for some earlier production models). Looking at the numbers is a good jumping off point to see the bias. While in truth there is so much more (seriously, can't stress that enough), the point is upgrading the rear bar should be one of the first mods you do to bring the car to a neutral state (in my opinion anyway).
Another common thing I see people do is upgrade front bars on our cars. I'm not a fan of this -- and let me share why. Like I said in the earlier example, we had a bias towards understeer. Upgrading the rear bar was our solution to make the car neutral. If you upgrade both the front and the rear, say front 25->29mm, and rear 20->24mm, yes, you've reduced roll. But you haven't really changed the bias. Also, while increasing this stiffness, you've made the independent suspension that much less independent. Softer sways = more response to road imperfections. While generally these effects aren't particularly noticeable, I recommend only adjusting sway sizes to play with the overall bias of the car on our platform, and use spring rate tuning to get the roll levels to the right level for you.
TL;DR: Just upgrade you rear sway bar to a nice 24-26mm bar and call it.
Getting a "Dialed" Alignment
Okay, so you've got the hardware, what about actually tuning it? A bad alignment or poorly setup coilover can make good hardware feel cheap. That being said, it doesn't take much to get things figured out. Firstly, go get an alignment. Here's a quick guide I've found works well. A hair toe in or toe out is really just that. Means you want the margin of error on that side of things. Camber wear on our cars seems to be borderline non-existant up to -2 camber, by the way. Oh -- and in case you haven't heard: camber doesn't typically cause wear, bad toe does. Camber just extenuates wear caused by bad toe.
Simply put, the goal of a good alignment is to maximize the contact patch of the tire to the ground. In street driving, we're spending most of our time going straight. So we put minimal camber because most of the time the car is standing straight up. Inversely, on track we're spending most of our time in a corner. By adding camber, we're maximizing the contact patch during the corners. Adding toe-out up front changes the slip angles, often maximizing mid corner grip. Adding toe-in increases stability. This quickly distills a lot of info to make it digestible. To be clear -- by no means am I trying to overshadow the detail that goes into a great track alignment. However, the generaly 80/20 rule applies here. 20% of the effort nets you 80% of the benefit.
Adjustable Shock Dampening
If you've ever installed a coilover kit or even an adjustable shock kit, it can be as overwhelming as exciting. Where to start? How often to adjust? How important is keeping all the adjusters the same? Let's dive in a little. Firstly, the best place to start on any setup is the simply "the middle". You may have some assumption that softest setting = least grip, most comfort and firmest setting = most grip, least comfort. In fact, very rarely is that true.
An unresponsive suspension is both harsh and prevents a suspension from doing it's main job: Keeping the wheels on the ground. Likewise, an underdampened shock results in a poor ride, just like blown struts. Starting the middle affords you the opportunity to drive your car and think about it.
Another common question that pops up is adjusting front and rear dampening separately. Not only CAN you do this, I recommend it. It's kind of like getting adjustable sway bars for free. The bias is nearly identical to sway bar bias tuning as well (for the scope of 99% of readers). One thing to keep in mind though is working in small increments. A few clicks can mean a big difference.
Anecdotally, I first tried my BC's (30 clicks in total) at 25 front, 28 rear on track. My first corner on my first lap I went around the corner station with about 30 degrees of counter-steer, praying to not get black flagged. I drifted more that session than while autoX'ing my friends 240. Putting the setup back to 25/25, the car felt very neutral and very composed.
The point is, I recommend starting neutral (again). Then, adjust in no more than 10% increments. If you have 30 clicks like the BC's, 3 clicks up or down can be a big shift. If you have ~2 rotations like Koni yellows, try 1/4 turn increments. If you have 10 clicks, try just 1. You'll be surprised how big the difference is when you put the car in the corner.
This one I definitely know the least about, but let me try to paint a picture. You hit a bump. Suspension compresses. You finish traveling over bump. Suspension must expand. In fact, before suspension expands, we aren't even really gripping the road. Preload helps push the suspension back to the road, faster. Preload also helps keep springs in place. For preload, I recommend starting per manufacturer specifications. From there, try increasing in small increments if other adjustments aren't working to fix your ride issues.