Dynamic / Adaptive chassis control (DCC / ACC)

**G-rig** · 30-05-2010, 10:48 AM

Great write up WJ, glad to hear you think its worthwhile. I haven't tested at what speed the steering gets heavier but dont mind sports mode either, and most roads are quite good up here. The steering may be a little heavy in sports mode for parking and slow driving but worth it over 60kmph.

**ddre78** · 30-05-2010, 01:12 PM

Thanks for taking the time to get that up WJ.

**WhiteJames** · 30-05-2010, 03:28 PM

Further info on DCC:

I may have led you guys astray on the previous WJ post.
Please allow me to clarify now that I have some additional miles sampling the DCC – Adaptive Chassis Control on the Mark 6 Golf GTI.

Route:

Bungendore – Tarago – Goulburn – Sydney.

Distance: 300km.

Types of roadways:

Dual carriageway (bitumen & concrete); good & medium B’grade single lane country tourist routes. Nothing as bad as Captains Flat Road.

Clarification:

I mentioned earlier that the steering in the Dynamic Chassis Control (DCC) equipped Golf GTI firms up at speed. This appears true for both ‘Comfort’ and ‘Normal’ settings.

The misinformation was that the steering in ‘Normal’ setting was put into ‘Sport’ mode by default at a certain speed (100kph @ +/- 10%).

This is not correct.

The DCC ‘Sport’ mode puts greater weight on the steering than ‘Normal’ mode. Sport mode steering is an entirely different weight to ‘Normal’ mode when driven at speed. Travelling on dual carriageway at 110kph it is now clearly evident that DCC put into ‘Sport’ mode puts the steering weight into another league – the extra weight is tangible.

The steering weight at 110kph in either ‘Comfort’ or ‘Normal’ settings is the same – it’s just the damping rate that changes, quickening or slowing the compression & rebound response times of the chassis.

Sport – Comfort – Normal:

DCC in Sport showed that the electronic steering wheel has greater resistance on your arms & hands and as a result, your body tends to firm up as extra physical effort is required to be applied to manoeuvre the Golf GTI around bends. The tenser state of body results in hustling the GTI a bit quicker than you normally would, well on the 110kph freeway anyway – it’s like a mind –v- body thing, but in reverse. Sport mode with the extra steering weight and tighter control of chassis movements, including less body roll, is very confidence inspiring at higher freeway speeds.

Sports mode brings the driver closer to the track car feeling, providing the roadway is smooth. Despite what the professional journalist state, the Mark 6 GTI still carries some slight to mild understeer, with the electronic XDS diff taking care of any incorrect steering movements or corner entry speeds – also makes a more clinical type of driving experience.

‘Sport’ mode contains the GTI chassis movements, reducing understeer, as the GTI chassis does not lean as hard or as much on the front outside tyre. The reduction in understeer with DCC in Sport is really noticeable at higher speeds, creating a greater sense of control from the driver’s perspective. This was really a highlight of the Dynamic Chassis Control system.

If you’re looking for the ultimate in a neutral chassis tune – better look towards a set of H&R adjustable solid aftermarket sway bars, if you’re not too concerned with ride comfort (not sure how aftermarket sway bars & XDS will work together). Me, I wouldn’t bother as a bit of slight to mild understeer is good for a street vehicle.

DCC in Sport constantly reminds you that DCC is in Sport setting, unlike ‘Comfort’ setting where it’s easy to forget that you left the GTI in ‘Comfort’. After about 3-4 bumps I think, “Damn Sport mode.”

Alternatively: after driving for 15 minutes only to look down at the console & find I’ve forgotten the GTI is riding in ‘Comfort’ mode. Comfort may not be good for driver attention as the better ride comfort allows your mind to wonder from the task at hand – Sport mode keeps you focussed after every damper compression with the GTI bobbing up & down over the minor road surface irregularities.

Normal mode suspension setting also reminds you that you have purchased a GTI and can also be annoying on not so good B-grade country roadways. Normal setting also suggests that the non-DCC std GTI suspension is about as firm as you’d want for country touring on single lane roadways, concrete freeway or for city suburban commuting. The non-DCC MK6 GTI is almost at the point of having a tad too much rebound damping in respect to the spring rate.

Concrete freeways are the enemy of sport aftermarket suspension kits & large diameter/low profile wheel/tyre combinations. Concrete roadways tend to have small troughs & peaks in waves that make themselves apparent in Normal and Sport mode with DCC. Comfort mode helps in this regard, but does cause some loss of confidence with the wafting ride & less chassis body control. Sport mode works a treat on smooth bitumen, which tends to be flatter & softer and more 18” Detroit wheel/tyre friendly.

In town: Driving on roadways around my home suburb on Sydney’s South Coast – Comfort was the pick of the three modes. Comfort does feel a bit vague around town, but does a fine job of isolating minor low speed compression bumps that are so ubiquitous in Sydney. The GTI also dives & squats a little when stopping & starting, which is eliminated with the other two settings.

Normal transmitted a bit too much information & vertical movement into the cabin. Sport was not really an option for putting around the burbs. Having said that, the Normal and Sport settings in town are tolerable – but just not desirable, esp. if you have passengers on board.

It’s important to note that hard suspension ride improves at higher speeds when bumps are struck with greater velocity. Softer suspension rides better at low speeds, but tends to lose composure at higher speeds.

Cheers
WJ

**WhiteJames** · 30-05-2010, 07:31 PM

On a tangent to this thread:

While breaking-in the GTI, I stopped by the Marulan Driver Training Centre , Marulan South (MDTC), to check out the handling course & have a yarn with its owner, motor sport identity Gary Willmington.

The MDTC is a fantastic course. Gary Willmington used very small pebbles in the bitumen to make it super smooth – he also built in on/off camber, sometimes in the one turn with a few rises, dips & bumps thrown in to help replicate a public roadway.

The smoother asphalt, low speed tight corners, short straights and flowing nature of the course doesn’t kill the tyres, making for a cheaper day out for those looking to improve their skills on a budget. Gary reckons tyre wear on this course is way less than than Wakefield Park or Eastern Creek Raceway.

Highly recommend taking any sort of driving course & believe a basic & advance course should be mandatory for learner & provisional drivers. MDTC could be a good fore-runner to taking on Wakefield Park, then the superfast Eastern Creek Circuit - build your skills up in stages.

See link to MDTC:

Marulan Driver Training Centre | Home

Racing Car Driver Gary Willmington gives the GTI the thumbs up ... see pic in WJ S&W Thread.

Cheers.
WJ

**WhiteJames** · 04-06-2010, 07:41 PM

New MK6 –v- Old MK5:
The Mark 6 GTI has 4 improvements over the MKV GTI. The hollow rear anti-roll bar on the MK6 is 2mm larger at 24mm. Secondly – EDL which apportions torque to the outside loaded wheel/tyre coupled with XDS electronic diff that applies the brake to reduce understeer at higher speeds – most people called both XDS, although EDL works at lower speeds and XDS at higher speeds. There is no need for concern about the brake heating up or wearing out with XDS as there is a sensor that switches off the brake/traction control should this occur (i.e. track use, hill climb, mountain pass). Thirdly – slightly higher front spring rate which compensates to a degree for the upgraded rear anti-roll bar. The front anti-roll bar is the same for both the MK6 and MK5. Fourthly, extra damping rate front & rear. Lastly: The MK6 has some extra chassis stiffness over the MK5 GTI.

Changes in the MK6 cause the GTI to corner flatter than the MK5 GTI. The MK5 would roll onto it’s outside front tyre with positive camber change, scrubbing & tearing the outside of the tyre out. The larger rear anti-roll bar in cohort with the stiffer front springs has made a reduction in understeer on the MK6 GTI. The steering wheel on the MK6 requires less effort & stabs at it to corner and the GTI feels closer to the Aussie offerings of the Falcon/Commodore in terms of amount of understeer (although with no power oversteer). Steering around bends on the MK6 has a greater fluidity about it, with the driver being able to make a smoother arc around a bend.

The MKV GTI/R32 was harder work in this regard when pressing on. Leaving the front sway bar the same size as the MKV GTI and upping the spring rate allows for greater independence of the front wheels of the MK6 GTI, improving grip levels of each wheel over irregular surfaces – in additional to EDL and XDS.

When the MK6 GTI feels like understeering, the EDL/XDS diff steps in to pull the GTI into the corner, taking the driver out of the equation to a degree. The experience leaves the driver thinking, ‘what just happened? Am I missing a couple of seconds of driving?”

Driving up steep tight bends, such as those found in Kangaroo Valley, inland of Wollongong, NSW – I noticed that the MK6 GTI does not spin the inside front wheel. Even at slow speeds, the inside wheel has less distance to travel around a bend than the outside wheel, causing the inside wheel to spin up at any speed. The lack of wheel spin in this type of driving would be attributable to the XDS electronic diff applying slight & imperceptible brake pressure to the inside wheel to stop it from losing traction in addition to forcing the torque to the outside wheel.

Note that although the GTI doesn’t feel like an AWD R32 or Tiguan – grip levels are enhanced considerably on the MK6 front wheel drive GTI. In 1500km of wet weather driving, I haven’t seen the traction control light appear – even when driving in the wet uphill through valleys.

Given that driving around a tight corner, you’d expect the inside wheel to spin up to a small degree as the outside wheel has to travel further around a larger arc, causing the inside wheel to unload. Not the case so far in the MK6 GTI. Bear in mind driving & throttle application have been gentle to date. The MK6 is definitely an improvement over the MK5 for ease of driving & grips levels.

Cheers
WJ

**hooba** · 04-06-2010, 09:25 PM

Keep posting about your experiences and adventures WJ, I love reading them.

**WhiteJames** · 04-06-2010, 09:37 PM

Which is the better drive?

The new MK6 GTI (DCC) –v- The old MK5 (KW V3/H&R)?

City:

Around town the Mark 6 DCC equipped GTI wins hands down. Being able to select ‘Comfort’ mode around town on the fly offer more comfort than either of the two aftermarket kits (Eibach/FSD – KW V3) on the old MKV GTI.

DCC in ‘Normal’ mode is similar to the Eibach/FSD combo and DCC ‘Sport’ mode gives firmer damping than the Eibach/Prokit package about the same spring rate (hard to compare progressive –v- linear OE springs).

KW V3 was in another league of firmness regarding damping & spring rates and not ideal for a daily cruiser imo.

Freeway:

DCC Mark 6 GTI wins by a very slight margin on freeway (more so concrete freeways) in a tightly fought contest. DCC has ‘Comfort’ for even concrete freeway joints and ‘Sport’ for the smooth bitumen. In other words, the DCC wins on its adjustability and ease of adjustability.

DCC also wins in the steering department with the steering being able to be firmed up considerably in ‘Sport’ mode. When heavier Sport mode steering is mated with the harder Sport damper setting with some factory induced understeer that is okay at higher freeway speeds, the MK6 DCC GTI feels very good indeed – confident, inspiring & reassuring at higher speeds. The MK6 GTI steering on Comfort and Normal modes is feels lighter than the MKV GTI steering. Steering on Sport mode is firmer than the MKV GTI/Comfort/Normal by a good margin.

The KW V3 would come in second place due to the higher linear cone shaped spring rate not suffering in ride comfort on smooth roadways as it does in the city or on terrible B’grade tarmac. This kit also offer supreme control, but can be firm & very telegraphic of roadway imperfections, even on smooth freeways.

Eibach/Koni FSD lagging behind in third place due to the hovercraft initial softness of the progressive rate strut springs, initial overdamping earlier in the spring compression rate and less overall chassis control. The Eibach Prokit/FSD combo can lean heavily on its outside front wheels compared to the MK6 DCC and KW V3 coil over.

B-Grade Roadway:

Eibach Prokit/Koni FSD (or rather HPA KW SHS coil over) wins on the bad side of the B-grade roadway. The Koni FSD damper has it’s high speed compression setting giving a softer ride than the DCC in ‘Comfort’ mode. From Comfort – Normal – Sport the DCC modes vary slightly, but notably after being driven for extended periods of time. Changes in damping rates is nothing like turning up a KW V3 from 10% - 50% damping rate; where at 50% the KW V3 does not appear to move under harder braking, race car style.

I would not opt for the Eibach Prokit/Koni FSD kit due to the excessive noise of spring bind that they exhibit - Not on a 50 grand vehicle; although ProKit/FSD does offer supreme ride over harsh B-grade routes like Captains Flat Road (Go the HPA Motorsport KW SHS coil over or KW Comfort coil over instead for better NVH & linear front spring rates).

DCC comes in at second position as it does not soften up sufficiently enough to match the trademark Koni FSD carpet type of ride on rougher B’grade bitumen. The DCC suspension offers damper valving more in line with Sachs/H&R suspension (I think they are made by Boge-Sachs).

The sport focussed KW V3 being a distant third place (even when on almost full soft adjustment) as the slow speed compression is still firmer than the DCC in Sport, although high speed compression is somewhere between DCC - Normal to Sport - mode.

Tourist Drive:

The MKV GTI with the KW Variant 3 coil over and H&R sway bars is the better drive than the MK6 DCC GTI. The lower ride height, stiffer springs & damping is a factor, but not the biggest factor in the KW V3 win. The aftermarket H&R solid adjustable anti-roll bars with front on soft and rear on hard made the old MKV GTI near neutral in chassis tune. Nothing beats a near neutral chassis tune for the ultimate in driver connection & satisfaction. The KW V3 – H&R aftermarket kit makes for a fantastic drive, providing the tourist route is a reasonably smooth roadway (wet weather excepted).

The MK6 DCC GTI on ‘Sport’ setting with XDS electronic diff simply doesn’t provide the thrills & driver involvement that the old MKV KW V3/H&R GTI did. The KW V3 with H&R sway bars was more fluid to drive with a direct feel. Hustling the KW V3/H&R MKV GTI was a breeze on dry roadways.

When the XDS on the Mark 6 intervenes to tighten the vehicles line, the KW V3 with H&R sway bars would often be in trail braking lift off oversteer with the chassis turning from it’s central axis like a downhill skier. This makes for a more engaging drive, but at times unnerving when you find yourself steering in the opposite direction on corner entry. The KW V3/H&R MKV GTI, although inert under 7/10ths, really delivered from when leaned on from 8/10ths onwards.

Disadvantages of the KW V3 coil over suspension kit is that, like many sports biased suspension kits, they can be stiffed legged around town & on harsher B’grade roadways, sometimes pogo over high frequency undulations and be harsher when striking uneven concrete joints. With the KW V3 sports coil over kit – there certainly was a tangible trade-off in comfort for sports handling.

Cheers
WJ

**WhiteJames** · 05-06-2010, 11:14 PM

With a view to the breaking-in of the TSI motor, the GTI was taken for a run out from Sydney to Bathurst and Mount Panorama.

Additional time was spent sampling the different modes of the Dynamic Chassis Control (DCC).

The trip to Bathurst allowed some time to lean on the chassis through some nice flowing 60kph - 80kph bends in addition to driving on a variety of roadways and roadway textures in dry conditions with the temperature ranging from 8.0 degrees Celsius to 20 degree Celsius.

1. DCC Sport:

DCC in Sport mode as the default setting for motorways: M4, M5 and M7. With exception of the motorways, about 1/3 of the trip could be driven in Sport mode. The majority single lane highway was smooth enough to allow for this, as was the Mount Panorama. Sport mode also became the preferred setting for tight bends running through the great dividing mountain range. The GTI really began to impress with the chassis sitting flat, with the larger rear anti-roll bar and EDL/XDS making a notable reduction in understeer in the mountain bends. This is the first completely dry day that the GTI has driven in – the earlier drives were in wet or damp roadway conditions. I did get caught out on in Sport mode on a section of rutted roadwork that was initially not pleasant until I managed to fumble out Comfort mode. On smoother roadways and travelling around 100kph and above, the Sport mode is the setting to have, keeping the GTI firmly planted to the roadway, especially when it came to overtaking slow moving vehicles. The firmer Sport mode steering also assists in this regard as the steering is more direct and requires less driver input to achieve the same or better result than the two softer modes. Sport mode did offer too heavy steering for suburban roundabouts; the heavy Sport steering improves with speed.

2. DCC Normal:

The in-between Normal mode was chosen for 1/3 of the country drive. This was for when Sport was too punishing and Comfort felt too loose and uncontrolled. Steering could still do with a tad more weight in Normal. All roadways being equal in smoothness & texture, Normal mode is good for speeds between 60kph and 100kph. At lower speeds the damping can be a tad firm, with Normal at higher speeds not as confidence inspiring or stable as Sport.

3. DCC Comfort:

Comfort was the default setting for Bathurst City. This country city had rough roadways in the centre of town, which had me thinking about ditching the 18” Detroit Wheels for 17” Denver in addition to running DCC permanently in Comfort mode. In Normal mode in Bathurst CBD, the relationship with the GTI was becoming strained with the GTI being to feel nuggetty & stiff legged: GTI + Normal Mode + 18” Wheels = Too Firm for Bathurst Country. Comfort mode was also the default for any road works encountered along the way and was used intermittently throughout 1/3 of the trip when the roadway quality deteriorated or was very undulating. The low-speed compression and rebound of Comfort mode in riding over a series of continuous bitumen patchwork along was fantastic – not quite a carpet smooth Koni ride, but not far off on the Great Western Highway . All roadways being equal – Comfort mode is great at speeds under 70kph – but any more than 70kph and comfort does compromise handling, agility and steering with less vertical body control , chassis roll in corners exhibiting extra understeer over Normal or Sport– this does rob the driver of some confidence.

Result:

On a trip from Sydney to Bathurst and return – each setting was used for about 1/3 of the time (M4, M5 and M7 excepted).

Other Issues:

The B-pillar plastic strip around the seat belt strap holder has developed a squeaking noise, which was also a problem with the old MKV GTI. A plastic rubbing against plastic type of sound. Disappointing that Volkswagen did not correct this. Some noise could also be coming from the base of the passenger’s front seat.

Oil Temperature ranged from 93 degrees to 105 degrees for the duration of this drive.

Fuel consumption was 6.9 litres per 100km – already better than the MKV GTI.

The Mark 6 GTI requires 38 psi in the Bridgestone RE050A tyres – the old Mark 5 GTI only required 35-36psi (extra weight of the MK6).

Don’t miss the leather interior at all – money well spent on Bi-Xenon’s & Park Assist. Cloth has added support & comfort.

The exhaust scavenging resonating sound between 2400rpm-2500rpm was heard intermittently on this trip. The rougher coarse chip bitumen drowns out the hissing sound. The resonation is easy to hear when driving around Mount Panorama that is bordered by concrete walls.

At sea level with humid air, the Mark 6 GTI feels sluggish. At higher altitude with cool dry air, the GTI feels more powerful with greater crispness to acceleration.

The GTI does have a hint of torque-steer, esp. in the higher gears (3-6) and compared to the MKV GTI. This suggests to me that more than 280Nm of torque is being put through the front wheels – perhaps more like @ 300Nm.

Old EA113 Mark 5 GTI motor felt more crisp and linear, esp. off boost. New EA888 Audi developed TSI motor in the Mark 6 GTI has greater punch in the mid-range, but feels slightly retarded in spark timing (maybe due to being 95RON compatible instead of 98RON).

Bathurst’s Mount Panorama always has the element of the unknown – like coming across an EMU on approach to Skyline on top of the hill.

See images of Bathurst on W&J Suspension Thread:

Cheers
WJ