Beginner’s Guide / Tips for Buying a Street-Based Suspension

[UwU_demon]

And you will continue to bottom out with shorter springs even though the rate is a touch higher than stock...as the springs get shorter so does the bump travel. Lowering springs are mainly for looks I'm afraid to say (I run them too). A stock suspension with an upgraded RSB and good tires will handle excellent.

I know, thats why I was considering pairing them with the B8s.

 

[scrllock]

Well I dont feel like the stock suspension is supportive enough. I have bottomed it out a plenty of times when driving on back roads and I dont like the amount of body roll I get. Basicly I dont feel like the stock setup is supportive enough. So I want to improve it a little.

I might get some autoX time in, but not track time, I am worried about crashing...

just pick a track without barriers. most likely scenario is you hit someone's leaking fluids and slide into some grass/dirt in most of the turns at my local tracks.

 

[tigeo]

I know, thats why I was considering pairing them with the B8s.

And that will help for sure but again, you are losing bump travel and the springs/B8s will still bottom once in a while...which is fine but just saying. I run B8s w/H&Rs, nice ride but I'd rather have a bit stiff spring.

 

[GIACUser]

I know, thats why I was considering pairing them with the B8s.

I ran the b8s on my MKV GTI they are quite a bit stiffer than stock. A good chunk of comfort is given up with these. I used the car as a daily and some track time.

 

[UwU_demon]

I ran the b8s on my MKV GTI they are quite a bit stiffer than stock. A good chunk of comfort is given up with these. I used the car as a daily and some track time.

From what, Ive read bilstein made them softer for the mk6 and even softer for the mk7, so I dont think it'll be that bad.

 

[tigeo]

B8s are not overly firm dampers.

 

[GIACUser]

B8s are not overly firm dampers.

The concept of firmnes is subjective. I liked the B8's but I don't mind the stiffness. When carrying passengers I did get complaints about stiffness. I sold them to another forum member who lived in my state and he complained that my assessment of the comfort level was way off. He said they were not at all comfortable. My point is that while you and I may say they are not overly firm, others will say that they are significantly more firm than stock dampners, which they are.

I just recently replaced my stock suspension with a set of YCW coilovers which I took to a raceshop to have them custom valved to B8 specs and I love them but like my actual B8's they are much firmer than stock. On my MKV the B8s with a mild spring (Eibach Sportline) did very well at the track which is an indicator to me that they are likely a lot stiffer than stock.

 

[mrmatto]

Great discussions in here. Here's what I'm thinking for my DD setup that I occasionally toss into autocross:

• OEM springs. I think the ride height and general stiffness is appropriate
• Koni Special Active dampers. A bit softer where I want it (small bumpy stuff) and a bit firmer where I want it (cornering, maneuvering)
• EuroSport camber mounts. Adds ~0.8* of front camber
• Rear sway bar and rear bracing. Already done. Great upgrades that made the car more responsive and easier to rotate in tight autox elements.

In my view, this setup would address a few key goals of mine:

1. Smooth out and add composure to the stock jittery ride. Stock suspension feels quite unsettled over rough stuff, especially at 65k miles. Around town, it doesn't always feel like a quality vehicle.
2. Reduce body roll. SA's stiffen up a decent amount in cornering, from what I've read.
3. Add some much-needed front camber to aid with turn-in and reduce some understeer.
4. Big key: None of these things take the car too far in any direction or drastically change the nature of the car I love. This car is my daily, first and foremost. I just want to tweak it to make it better.

Notes:

• I'm unsure how Koni SA's perform when you hit bumps while cornering hard. They can't be both stiff and soft at the same time, so which takes over in that instance? Also, how does less rebound damping actually help the ride -- isn't poor rebound damping what the OEM dampers suffer from?
• I considered Bilstein B6's. I haven't totally ruled them out because the Bilstein quality is unbeatable. But, I would lose the softer damping from the SA's and easing the ride is a key goal for me.
• I considered Koni Sports, but even though they're adjustable, they have to be practically uninstalled to be adjusted. In my view, that makes the adjustability pretty pointless for my needs. (Ideally I could adjust them soft for daily'ing, and firmer at the track).
• I recognize my tires may be contributing to some of the poor ride quality I'm experiencing. But it's hard to parse out how much if that is the tires and how much of that is worn stock suspension. But by most accounts, the stock suspension isn't up to the task, regardless of tires.
• I considered downsizing to 17's.
  • I think 18's look better on these cars at stock ride height.
  • That might help soften some impacts from bumps, but wouldn't necessarily solve the jittery, unsettled nature of the stock dampers.
  • Right now, since I'm just a casual autocrosser, I'm using the same wheels and tires for both daily and track. Street tires with a taller sidewall = flimsy rubbery roll on the courses with no feel

I'm curious if anyone feels differently or strongly on any of the above, or if I have any bad info. Thank

 

[GIACUser]

From what, Ive read bilstein made them softer for the mk6 and even softer for the mk7, so I dont think it'll be that bad.

I used MK6 b8s. The Mk5 version was overly stiff and not suitable for a daily.

 

[xXDavidCXx]

Great discussions in here. Here's what I'm thinking for my DD setup that I occasionally toss into autocross:

• OEM springs. I think the ride height and general stiffness is appropriate

I would run 400in/lb rear with the OEM front springs. That is my non-race setup. It feels fantastic.

• Koni Special Active dampers. A bit softer where I want it (small bumpy stuff) and a bit firmer where I want it (cornering, maneuvering)

I would run the Koni Yellow, and deal with the difficulty of adjustment, but once you get it right, you are done adjusting.

• EuroSport camber mounts. Adds ~0.8* of front camber

I would look into the 034 fixed strut mounts, they give -1.5. More is better.

• Rear sway bar and rear bracing. Already done. Great upgrades that made the car more responsive and easier to rotate in tight autox elements.

Not a fan of bracing, but I know it's cheap.

I'd look into a front bar, too. You are already in STH with the camber mod, so why stop with just a rear bar? Adding just a rear bar is hardely reducing body roll since the stock Front roll couple % is rather high, like 70%, which means most of the roll is happening at the front. All you've done is locked the rear tires together more and you unload the inside tire earlier (off the ground). It may feel fast, but there are better ways.

In my view, this setup would address a few key goals of mine:

1. Smooth out and add composure to the stock jittery ride. Stock suspension feels quite unsettled over rough stuff, especially at 65k miles. Around town, it doesn't always feel like a quality vehicle.
2. Reduce body roll. SA's stiffen up a decent amount in cornering, from what I've read.

The special actives don't "stiffen up". The name is misleading, it just has a bump blow-off feature in the high-speed shock shaft range. In lower speed shaft movements, there is some amount of stiffness in rebound, probably less in bump, like the Koni yellow.

1. Add some much-needed front camber to aid with turn-in and reduce some understeer.
2. Big key: None of these things take the car too far in any direction or drastically change the nature of the car I love. This car is my daily, first and foremost. I just want to tweak it to make it better.

My full tilt STH build is not a dramatic change from stock, just a little stiffer, with a specific alignment, and better equipment.

Notes:

• I'm unsure how Koni SA's perform when you hit bumps while cornering hard. They can't be both stiff and soft at the same time, so which takes over in that instance? Also, how does less rebound damping actually help the ride -- isn't poor rebound damping what the OEM dampers suffer from?

High shaft speed blow-off, like I mentioned above. A shock does not see corners, only shaft speed. So the body leans, the shock dampens the initial movement, then all things being equal, nothing is happening in the shock during the smooth corner. When a bump is hit, the shock shaft moves up in compression, and if the shock shaft speed meets a speed threshold, separate oil passages open up to allow the oil to be displaced without going through the normal valving route. Then the suspension rebounds via the potential energy stored up in the springs. The shock is now moving in extension or rebound. Some amount of rebound damping is happening in the shock to smooth out the extension so the car does not bounce back and forth.

Poor rebound damping can be not enough at high shock shaft speeds after a bump is hit, and the rear of the car bounces more than 1.5 times per bump. Your rear passengers will hate you. Or too much rebound and the car is skittish and skates over bumps, not giving the tire time to stay in contact with the ground.

I found the OEM rear shocks to lack enough rebound, and the springs were too weak, causing way too much rear bouncyness.

• I considered Bilstein B6's. I haven't totally ruled them out because the Bilstein quality is unbeatable. But, I would lose the softer damping from the SA's and easing the ride is a key goal for me.
• I considered Koni Sports, but even though they're adjustable, they have to be practically uninstalled to be adjusted. In my view, that makes the adjustability pretty pointless for my needs. (Ideally I could adjust them soft for daily'ing, and firmer at the track).

You need one setting for a given sprung weight, which won't change too much unless you constantly have a changing passenger load. If it's just you, set it and forget it.

I think there is a way to modify the fender liner to gain access to the rear adjuster.

• I recognize my tires may be contributing to some of the poor ride quality I'm experiencing. But it's hard to parse out how much if that is the tires and how much of that is worn stock suspension. But by most accounts, the stock suspension isn't up to the task, regardless of tires.

It's almost entirely the rear shocks and springs.

• I considered downsizing to 17's.
  • I think 18's look better on these cars at stock ride height.
  • That might help soften some impacts from bumps, but wouldn't necessarily solve the jittery, unsettled nature of the stock dampers.

True.

• • Right now, since I'm just a casual autocrosser, I'm using the same wheels and tires for both daily and track. Street tires with a taller sidewall = flimsy rubbery roll on the courses with no feel

I don't think your assessment of 17 vs 18-inch tires is correct.

In fact, I'm moving to a 17-inch tire after my current tires wear out.

I'm curious if anyone feels differently or strongly on any of the above, or if I have any bad info. Thank

I guess I feel differently

 

[mrmatto]

I would run 400in/lb rear with the OEM front springs. That is my non-race setup. It feels fantastic.

That's nearly double the OEM spring rate. What would be the benefit in doing this? Wouldn't it make the ride stiffer?

I would run the Koni Yellow, and deal with the difficulty of adjustment, but once you get it right, you are done adjusting.

I would literally adjust them outside the car then install them and that's it. I know myself. If the fronts are easy to adjust I’ll do those, but not the rears. I'm not going to mess with that. What's the great benefit of Koni Sports adjusted soft vs. B6's or SA's?

I would look into the 034 fixed strut mounts, they give -1.5. More is better.

More is indeed better, but they're 50% stiffer than stock. Doesn't that translate into NVH? My goal for this is to make the rider nicer.

Not a fan of bracing, but I know it's cheap.

I'd look into a front bar, too. You are already in STH with the camber mod, so why stop with just a rear bar? Adding just a rear bar is hardely reducing body roll since the stock Front roll couple % is rather high, like 70%, which means most of the roll is happening at the front. All you've done is locked the rear tires together more and you unload the inside tire earlier (off the ground). It may feel fast, but there are better ways.

Yeah, I'll probably get a front bar some day. It's on the list.

The special actives don't "stiffen up". The name is misleading, it just has a bump blow-off feature in the high-speed shock shaft range. In lower speed shaft movements, there is some amount of stiffness in rebound, probably less in bump, like the Koni yellow.

I meant "stiffen up" compared to stock. The base rebound damping for the SA's are higher, and then like you said, some of that rebound damping gets blown off or bypasses during high-frequency events.

High shaft speed blow-off, like I mentioned above. A shock does not see corners, only shaft speed. So the body leans, the shock dampens the initial movement, then all things being equal, nothing is happening in the shock during the smooth corner. When a bump is hit, the shock shaft moves up in compression, and if the shock shaft speed meets a speed threshold, separate oil passages open up to allow the oil to be displaced without going through the normal valving route. Then the suspension rebounds via the potential energy stored up in the springs. The shock is now moving in extension or rebound. Some amount of rebound damping is happening in the shock to smooth out the extension so the car does not bounce back and forth.

That makes sense I think, thank you.

I don't think your assessment of 17 vs 18-inch tires is correct.

How so? Even with a 235/40r18 summer tire, I have to run ~40psi or more in the front to keep them from rolling over too much. That problem would only get worse if the sidewall was taller, and I would end up with less steering feel. I'm not talking track tires here. I'm talking summer street tires. How do you plan to counteract/prevent this problem? You don't agree?

I really appreciate you taking the time to give a thorough reply!

 

[xXDavidCXx]

That's nearly double the OEM spring rate. What would be the benefit in doing this? Wouldn't it make the ride stiffer?

It does make the rear stiffer, but I think the rear is un-sprung from the factory. With enough rebound from an adjustable shock, the rear bumps get dampened properly. It does not feel stiff, it feels properly dampened.

I would literally adjust them outside the car then install them and that's it. I know myself. If the fronts are easy to adjust I’ll do those, but not the rears. I'm not going to mess with that. What's the great benefit of Koni Sports adjusted soft vs. B6's or SA's?

The sports give you the rebound you need. Special actives probably don't. Don't pay any attention to their marketing graphs. They don't make any sense. I have Koni Special actives on the front right now, but I won't be autocrossing on them. What the Koni Sport can't do is blow off bumps. But it's bump valving is pretty low, so it's kind of evens out. I don't know anything about the B6 except they seem to be reviewed as stiff.

More is indeed better, but they're 50% stiffer than stock. Doesn't that translate into NVH? My goal for this is to make the rider nicer.

It will hardly matter. What gives much more NVH is the offset front lower arm bushings, holy cow, huge difference. Remember, the shock is in line with the shock mount, so it takes up the additional NVH.

Yeah, I'll probably get a front bar some day. It's on the list.

I meant "stiffen up" compared to stock. The base rebound damping for the SA's are higher, and then like you said, some of that rebound damping gets blown off or bypasses during high-frequency events.

I'm not sure of the valving. I've never seen a proper shock dyno of Koni Special Actives or Sport shocks.

Bump forces is what gets blown off, not rebound.

How so? Even with a 235/40r18 summer tire, I have to run ~40psi or more in the front to keep them from rolling over too much. That problem would only get worse if the sidewall was taller, and I would end up with less steering feel. I'm not talking track tires here. I'm talking summer street tires. How do you plan to counteract/prevent this problem? You don't agree?

Run more pressure in autocross and less on the street. Easy.

I really appreciate you taking the time to give a thorough reply!

Anytime!

 

[mrmatto]

Bump forces is what gets blown off, not rebound.

That’s what I thought, but Koni themselves told me otherwise.

“The FSD valve system used in the Special ACTIVE dampers works in the rebound stroke of the shock, not the compression stroke. In the instance of driving down the road or through a corner the FSD still works the same. In normal smooth conditions the dampers are firm for greater body control, and then when encountering a large bump, or a crack in the pavement the FSD valve allows for the rebound damping to essentially “blow off” to a much softer damping force so that the imperfection is absorbed with much less force.”

Run more pressure in autocross and less on the street. Easy.

I’m already running 40psi at autocross with 18s, though. How much higher can I go before the tire is losing grip,,,

 

[xXDavidCXx]

That’s what I thought, but Koni themselves told me otherwise.

“The FSD valve system used in the Special ACTIVE dampers works in the rebound stroke of the shock, not the compression stroke. In the instance of driving down the road or through a corner the FSD still works the same. In normal smooth conditions the dampers are firm for greater body control, and then when encountering a large bump, or a crack in the pavement the FSD valve allows for the rebound damping to essentially “blow off” to a much softer damping force so that the imperfection is absorbed with much less force.”

Okay, after further reading, it appears to blow off both directions for short stroke high force movements.

I’m already running 40psi at autocross with 18s, though. How much higher can I go before the tire is losing grip,,,

Don't over thinks this. It's not complicated and may require a few PSI change. People run on 17's all the time and are popping tires off the rim.

 

[mrmatto]

Okay, after further reading, it appears to blow off both directions for short stroke high force movements.

Where did you find that info? Koni is telling me otherwise — just the rebound. TireRack also describes it this way: "The Special Active dampers also have a fixed compression setting, but instead of allowing the user to manually adjust the rebound, the internals of the Special Active dampers automatically adjust the rate and shape of the force curve (when plotted on a graph) on the fly, responding immediately to the frequency of the damper's movement."