DCC Suspension Mod by installing the DSC Sport Controller

[Vorne Au hinten Weh]

Intro
Suspension performance can be measured with seat-adjuster vibration analysis, dynamic readings, track performance and on.
I do regular and spirited public road driving and have none of the measurement tools, other than my own subjective observations and comments passengers might make. Meaning this is about my personal impressions and how I got the suspension to work in ways that I like. My driving happens mostly in Ontario and the NE states.


My GTI's
My first GTI was a 2015 non-performance pack model without DCC (Digital Chassis Control = adjustable dampers). In 2019 I traded it for a 2019 Canadian Rabbit edition GTI (B-W differential lock, with DCC, no sunroof, no NAV system). On my cars I keep the complete suspension, wheels and tire size stock. Air pressure set cold at 37 psi.


What I did not like about the OEM suspension
I found the suspension of my (non-DCC) 2015 GTI o.k. but not great. Impacts were sometimes transferred harshly to the chassis. The suspension tended to crash on okay-looking road surfaces, occasionally, leaving me and passengers wonder if a wheel just got damaged. (for reference, our Honda Civic would travel across the same roads with just some thumping noises reaching the cabin, and no jolts or crashing noises).

Hoping the DCC feature on my 2019 GTO would improve things greatly I found it was not so. Only slight improvements. When overwhelmed still too harsh, still crashy here and there and still jolting people when transversing cracks with dips or pushed-up pavement bumps. Driving onto a road when there was, say, a 2” drop from the curb to the pavement always made the front end sound and feel overstressed.

Analysis
The DCC is described in the VW literature as a high-speed electronic damper tuning system, incorporating the input of three chassis accelerometers, steering angle, three chassis level sensors, brake pressure and car speed. While the three DCC settings (Comfort, Normal, Sport) certainly made a difference, my overall impression was that the system was not using all the inputs in a manner that really made the DCC suspension work much better than the non-DCC one. The programming did not seem to make much use of all the data the car generates on all the input channels. The DCC suspension still got overwhelmed in situations where other cars just thumped a bit.

I was not ready to replace springs, dampers and possibly sway bars with all the associated costs for parts, installation, any necessary alignments and camera/radar calibration. Then COVID came which really slowed down the amount of driving I could and needed to do.


Solution
In early March of this year I read in the Golf R section of this forum about a product that had just been released for use in Mark 7 and 7.5 Golf R and GTI. A plug-and-play replacement controller for the VW J250 Electronic Damping Control Unit. An intriguing idea. Simple install without shop involvement, simple uninstall.
Provided that this unit would have the advertised processing and output capabilities it appeared to be a sound engineering approach to suspension improvement.
Through discussions with the company (dscsport.com) it seemed to me they knew what they were talking about. Their website provides free software and the data tables loaded into the controller available. With these one can tweak the suspension to one’s liking by editing the data table and loading it into the controller.
They provide documentation and training videos online as well as phone and online support.

Each DCC damper in the GTI has a current-controlled oil-flow adjustment valve that is attached to the damper body. Which is more limiting in the range of oil flow control than, say, dampers with adjustment valves in the main piston which can adjust across a wider range of fluid flow. Or shocks with magnetic fluid which also have a wider range.
The Golfs also only have one rear axle chassis height sensor on the driver side, requiring a system to work without knowing where the rear right wheel is height-wise. Height data is used to calculate e.g. compression speed to add additional damping in high-speed movement situations. Yet DSC said they can make a considerable performance improvement and I decided to find out.

I installed a DSC controller unit in my car in the middle of this March. Zeroed the damper travel using their s/w. And went driving, just as the ground thawed and country roads around here were in their peak season for shifting and heaving. The car now stayed flat when cornering and no longer dived when breaking. Driving over dips and pushed-up cracks was much more pleasant and without trashy/crashing noises. For my personal feeling this was working much better than what VW had managed to do with their controller.

Adjustments
I found the base calibration setting DSC used for all four dampers a bit too hard for my liking. The VW dampers have an operating range of 240 mA (softest) to 2,000 mA (hardest). I dialled the softest setting for my dampers midway between the one DSC had chosen and the lowest possible setting. I reduced some of the compression settings as well. All good. It took a number of hours to study the controller input tables and the use of the s/w.
When installing the DCS controller with a USB cable plugged in it is easy to use a laptop for changing settings, doing live data recordings etc. The DCS controller installs in the same bracket as the VW J250 box. Inside the driver’s side rear quarter panel, right below the access flap in the carpet where one can undo a rear light plastic installation nut. Open the flap, pull out the USB cable and connect.


And now?
I am just using Comfort mode. I see no need to adjust modes no matter what driving I do. This system does a lot more adjusting, and over a wider damper range, than the VW box.
Seems the DSC Sport unit came with the same data table loaded for all three selectable modes. As I have no need for other settings I have left the other two modes alone.
As a side benefit, since the car no longer dives in the front while breaking, the rear discs get more of a workout and clean off the corrosion caused by all the salt and de-icing liquids used around here nicely now.


Related Findings
A VCDS scan found that VCDS cannot communicate with the DSC controller over the CAN bus. VCDS also reported the Steering Wheel Control Module showing a Level 2 communication error with the DSC box. There are no error lights or messages on the dashboard displays and no indications any systems are not working.


And here we are. I have used the controller for over two months now and am very pleased with the DCC suspension now. I’ll repeat, suspension performance is a very personal and subjective field and I am not saying this unit will make the GTI suspension work as desired for everyone. It costs a significant amount of $ but so do suspension hardware changes.

 

[Mosquito]

Unfortunate it still can't fully communicate with the can-bus. Specially considering how many modules it mediates for.

Also disappointed to find out all 3 modes carry the same settings within the DSC controller. It should enhance the modes.

Other than that. It sounds like an improvement from 2020s launch.

 

[Keehs360]

Glad it worked out for you but in normal mode my GTI with dcc doesn’t squat or dive on the street. And on track in sport mode even braking hard at almost 130mph till I reach 50mph I still get very very little dive. I’d check your front shocks for leaks

 

[scrllock]

Did you flash the controller or just zero it out? The tune they provide has some differences between normal/sport/track at least on the file I'm using. The difference is still noticeable between modes.

As far as the CAN bus goes, it's no different than using a DCC canceler as far as the rest of the car is concerned. ACC and ESC work fine. You'd need to use their software to scan the module properly, but that's typical of standalones (much like running a PM4).

 

[xXDavidCXx]

Glad it worked out for you but in normal mode my GTI with dcc doesn’t squat or dive on the street. And on track in sport mode even braking hard at almost 130mph till I reach 50mph I still get very very little dive. I’d check your front shocks for leaks

This has to be placebo, as a shock cannot determine dive or roll angles, only the speed at which the damper moves through the suspension arc.

 

[Keehs360]

This has to be placebo, as a shock cannot determine dive or roll angles, only the speed at which the damper moves through the suspension arc.

DCC equiped gti's have extra sensors and can absolutely determine those things. In fact, on a hard left I can feel both left front and rear shocks tightening up to prevent roll. On track I was surprised when I noticed that the DCC was actually keeping the cars weight from unsettling much too. I wish I could give you a more technical answer but I've no idea how the system does what it does. All I can say is that the system is so reactive and quick that it feels proactive. In fact it might even be proactive. I dunno.

Edit if you search there's this thread that explains all the parts you'd need to swap in the DCC stuff and have it up and running. Those are the parts I'm referring to. I'd argue that the DCC the GTI and R have is a better DCC system than what we see with the type r, another car I've driven on track but not mine. Belongs to my brother in law. The GTI DCC is adaptive too, like it knows I'm driving like an asshole and will tighten and loosen up when need be during a dick head event.

 

[xXDavidCXx]

DCC equiped gti's have extra sensors and can absolutely determine those things. In fact, on a hard left I can feel both left front and rear shocks tightening up to prevent roll. On track I was surprised when I noticed that the DCC was actually keeping the cars weight from unsettling much too. I wish I could give you a more technical answer but I've no idea how the system does what it does. All I can say is that the system is so reactive and quick that it feels proactive. In fact it might even be proactive. I dunno.

Edit if you search there's this thread that explains all the parts you'd need to swap in the DCC stuff and have it up and running. Those are the parts I'm referring to. I'd argue that the DCC the GTI and R have is a better DCC system than what we see with the type r, another car I've driven on track but not mine. Belongs to my brother in law. The GTI DCC is adaptive too, like it knows I'm driving like an asshole and will tighten and loosen up when need be during a dick head event.

What I mean to say by determine, is not "know the suspension movements" I mean, a shock cannot limit suspension travel. A shock is a timing device. Mid-corner any given suspension will reach max roll based on grip and g-forces and some other stuff.

 

[Keehs360]

What I mean to say by determine, is not "know the suspension movements" I mean, a shock cannot limit suspension travel. A shock is a timing device. Mid-corner any given suspension will reach max roll based on grip and g-forces and some other stuff.

I get that. But manipulation of the oil path in the shocks can offset those very forces by a bit. If you ever have a chance please test drive a Veloster n. Of all the cars I've ever driven the n's DCC set up has been the best by a large margin. Take it to 20 and hit the brakes. Then do it again in n mode

I've never driven an n on track but during a test drive I left very impressed. You'll see what I'm getting at. Sorry I can't articulate past what I can feel. I honestly am not sure exactly how the tech works btw. If you're near Denver u can drive my car and see for yourself?

 

[Chillout]

If you want, it's possible to flash the DCC module to the Passat/Arteon 2021 firmware and dataset, which enables a range of 16 modes (from 0 to 15), where 0 is more comfortable than just comfort, and 15 is more stiff than sport.

 

[Vorne Au hinten Weh]

Did you flash the controller or just zero it out? The tune they provide has some differences between normal/sport/track at least on the file I'm using. The difference is still noticeable between modes.

As far as the CAN bus goes, it's no different than using a DCC canceler as far as the rest of the car is concerned. ACC and ESC work fine. You'd need to use their software to scan the module properly, but that's typical of standalones (much like running a PM4).

To zero the height sensors I connected to the controller and used the "Zero Travel" command in the "Settings" page of the s/w.

I am not worried about the CAN bus coms. The controller and all critical communications work. I noted it because installing the DCS controller impacts the VCDS scans. Something to know, that is all.

 

[Vorne Au hinten Weh]

If you want, it's possible to flash the DCC module to the Passat/Arteon 2021 firmware and dataset, which enables a range of 16 modes (from 0 to 15), where 0 is more comfortable than just comfort, and 15 is more stiff than sport.

Now that is interesting. I heard that VW has made some strides in some models to give the DCC more intelligence.

 

[Vorne Au hinten Weh]

I get that. But manipulation of the oil path in the shocks can offset those very forces by a bit. If you ever have a chance please test drive a Veloster n. Of all the cars I've ever driven the n's DCC set up has been the best by a large margin. Take it to 20 and hit the brakes. Then do it again in n mode

I've never driven an n on track but during a test drive I left very impressed. You'll see what I'm getting at. Sorry I can't articulate past what I can feel. I honestly am not sure exactly how the tech works btw. If you're near Denver u can drive my car and see for yourself?

Interesting discussion. A bit beyond my areas of knowledge. The DSC controller box has a feature to set shock travel stops, for each shock, in mm of travel. It would, I imagine, require a car with travel sensors on each wheel to really make that work. And shocks as well as shock install points that can take the loads.

 

[Daks]

I've never taken my GTI out of sport mode since I bought it two years ago

 

[burgerkong]

As a side benefit, since the car no longer dives in the front while breaking, the rear discs get more of a workout and clean off the corrosion caused by all the salt and de-icing liquids used around here nicely now.

Huh?

Are you suggesting your rear wheels were airborne before? Just how spirited are you driving on public roads? Are you threshold braking with the stock pads? Unless you've lost contact with the road, how does stiffening the shocks cause your rear brakes to work more? Shock stiffness while it does affect weight transfer, it does not CHANGE the amount of weight being transferred - stiffer shocks (all things being equal including spring rate) just allow for transfer to happen quicker and thus your tires reaching max contact patch under max loading quicker (hence braking efficiency increases). What it does NOT do, is change brake bias, or increase braking force.

So after suffering through what looks half like an advertisement, we've reached the creme de la creme - placebo.

Edited for clarity.

 

[Acadia18]

I've never taken my GTI out of sport mode since I bought it two years ago