Dynamic / Adaptive chassis control (DCC / ACC)

[Rob_R]

All this info is interesting. I never looked into all these changes that occur. Now I'll have to pay more attention when I change the settings.

[slam]

Thanks SilvrfoxX, I had to google it to find out what a sprintbooster is - never heard of it before.

Rob_R, you probably won't notice it in your DSG - the computer probably compensates for this. I doubt they would slow down the DSG throttle "blips" on purpose during downshifts when in normal or comfort.

[m_f]

Thanks SilvrfoxX, I had to google it to find out what a sprintbooster is - never heard of it before.

Rob_R, you probably won't notice it in your DSG - the computer probably compensates for this. I doubt they would slow down the DSG throttle "blips" on purpose during downshifts when in normal or comfort.

It does feel like a slightly different car though switching from Comfort to Normal. Those are the two modes I've tried most - I guess I just have to try the Sport one soon!

[T Go]

This article from the VW UK website confirms the throttle response and mapping is also affected.

I thought it was only the steering and suspension that changed on Sport.
Now that I know throttle response also changes, I might have to use it more often!
Good find.

[T Go]

Just a quick one (maybe for the tuning forum not piggy backed on this one??)

I am getting a bluefin unit for my car, and was wondering if people knew if ACC affected this?
From the VW UK link above:
Should the driver select 'Sport' mode the steering assistance is reduced, the damping is hardened and the throttle responses are sharpened as the mapping changes

So if ACC/DCC is set to Sport, is it just the throttle response thats increased? or is there a change in the fuel map? Does getting the car's ECU Flashed affect this?

I'm sure its probably not an issue, but just thought about it due to the situation.

[AdamD]

So if ACC/DCC is set to Sport, is it just the throttle response thats increased? or is there a change in the fuel map? Does getting the car's ECU Flashed affect this?

It's likely just using a more aggressive throttle map, and certainly won't relate to the engine tune. Because the Golf has an electronic throttle, pedal position doesn't link directly to anything mechanical (air/fuel delivery etc). The throttle can therefore be made more or less sensitive to physical pedal inputs.

[Mariani]

I seriously don't think the throttle response changes in ACC Sport mode. I think it's all in your head : )

Changing the transmission from D to S, now that makes a difference.

S combining the 2 you have the complete package. That is if you fancy S, personally I don't. Manual or D for me.

Mic

[T Go]

It was the official VW statement that said throttle response was changed, not me.
My transmission just changes from 1st through to 6th with the help of a pedal, I don't have fancy D and S settings

Anyways, I don't think that it'll be an issue as AdamD stated too. I was just curious about it.

[WhiteJames]

GOLF GTI: DCC v non-DCC

To DCC or not to DCC

Dynamic Chassis Control. Is it worth it?


EXHBIT ‘A’: Red Golf GTI – Non DCC

I had the pleasure of being able to take a out nice looking Red 3 door Mark Golf GTI with 18” Detroit Wheels for a blast from my local dealership at Sutherland down to the Boat Shed by the Hacking River inside the Royal National Park on the southern border of Sydney, NSW. The Red 3 Door Golf GTI was not equipped with Dynamic Chassis Control (DCC), rather having the standard spring and damper combo. This vehicle was driven from the North Toll Gate to the Boat Shed twice.

EXHIBIT ‘B’: White Golf GTI – equipped with DCC

In comparison, I also ran the same route in my own Golf GTI with Dynamic Chassis Control (DCC). My ride is a 5 door GTI also with 18” Detroit Wheels. The White DCC equipped GTI was driven along the same route from the Toll Gate to the Boat Shed twice – once in Normal mode – once in Sport mode. Tyre pressure on the DCC equipped White GTI may have been a touch higher than the demo Red non-DCC 3 door Golf GTI. The White GTI was running about 40psi as opposed to standard 38psi for one driver only.

Purpose

The purpose of the comparison is find out how a DCC and non-DCC Golf GTI behave on exactly the same roadway on the same day in a back to back comparison in addition to deciphering if the $1500 for the Dynamic Chassis Control is worth the extra coin.

[WhiteJames]

1. Red Golf GTI – Non DCC

Steering:

The steering is very light for a hot hatchback. The steering weight is similar to the DCC equipped White Golf in Comfort and Normal mode, but appeared to be that little bit lighter. The immediate off-centre feel offers less resistance than any of the DCC modes (comfort, normal or sport). The lightness to the steering is not confidence inspiring. The steering is definitely a step back in terms of the meaty steering in the preceding MKV Golf GTI, which was a great little steering ride around this tight and at times undulating hill climb and descent. Driving into the hilly and twisty Boat Shed run, the Red non-DCC GTI required greater steering effort to position the vehicle into the corner and required greater skill and attentiveness of the driver to feed the nose of the vehicle onto the desired apex line. The steering does a good job of telegraphing what is happening under the driver, but never sufficiently weighs up for a truly invigorating drive. In this respect, the non-DCC Golf GTI failed to deliver in terms of hot hatch thrills. The lack of on-centre feel and initial steering feedback was the first striking difference between the non-DCC and DCC Golf GTI’s and was immediately noticeable on the first challenging corner encountered. The non-DCC Golf GTI also required a lot of repeated stabbing of steering input when hunting for the apex of each hill climb type of corner. The steering choppiness telegraphs a general understeer nature when not leaning on the Golf too emphatically.

Chassis Balance:

The non-DCC chassis balance would be described as mild understeer in nature. Muscling the non-DCC GTI into a turn involves tangibly greater driver steering effort with the chassis having momentarily more delay in following the higher degree of driver’s inputs. The non-DCC Golf was more challenging to tip the GTI into the corner with the driver very much more focussed on smooth inputs and a higher degree of trail braking to find that balance of front end grip. In a nutshell, the non-DCC GTI demanded greater steering and braking effort with less body reaction in terms of vehicle placement into and out of a turn. Up to about 7-8/10ths the steering choppiness is a prevailing demeanour.

Lean a little harder on the non-DCC Golf GTI and the stabbing and chopping of the steering inputs reduces as the movement of the rear sway bar comes into greater effect, giving the non-DCC Golf GTI some of that old-school agro about the way the rear end moves around mid corner. The non-DCC Golf GTI chassis, relying on it one size fits all spring and damper combo, starts to lean and roll to a much greater degree than that of my White DCC equipped Golf GTI. This in turn activates the rear anti-sway bar to a higher degree due to the body roll effect of the chassis leaning over, which provides greater effect to the trajectory of the non-DCC Golf GTI mid corner by working the rear sway bar harder & creating more rear end slip.

In other words, the rear sway bar of the non-DCC Golf GTI provides a greater effect to the suspension movement relative to the springs and dampers as the springs and dampers do not firm up as they do on the DCC equipped GTI. The rear sway bar working to greater effect relative to the softer damping rates was a highlight of driving the non-DCC Red Golf GTI, necessitating a higher degree of driver skill and interaction and providing a higher degree of driver enjoyment, albeit with a much softer edge than that of the non-DCC Golf GTI, especially in the steering department. The non DCC Golf GTI felt faster and made greater work of the driver, which was not the case in terms of absolute speed when pitted against the DCC equipped GTI that always maintains greater composure with less body roll, pitch and yaw. The non-DCC GTI offered up more understeer most of the time with and was generally softer overall package. Yes. This is the case whether the other White DCC equipped GTI was in either Normal or Sport mode as the dampers constantly adjust relative to driver inputs and speed on the DCC equipped GTI.

Transient Behaviour:

This involves stringing a series of corners together while simultaneously taking account of roadway undulations that can often upset chassis arc of trajectory – the Boat Shed run is a good little piece of roadway with predominantly low to middle speed undulations around different parts of their turns. On corner entry, there is definitely a delay between steering input and pointing the noise into a corner on the Red non-DCC Golf GTI, which is a sure indication that the modern day Mark 6 Golf GTI is refined but a little underdone, being on the softer side of the hot hatch equilibrium. The nose of the Red non-DCC Golf GTI seems unresponsive to the driver inputs for that half a second to one second on initial turn-in. The non-DCC just does not want to turn into a corner as quickly or sharply as the DCC equipped GTI, with the non-DCC Golf GTI in suspended animation for that brief period of time, requiring the driver to lock extra amounts of steering lock to tighten the corner entry line.

Mid corner hits to the suspension from undulations are smoothed over rather than dealt with crisply or with absolute adroitness as is the case with many of the aftermarket suspension kits esp. coilover kits. From a driver’s point of view, the non-DCC Golf GTI is more about caressing the hatchback into a corner with greater, definite, but smoother driver inputs to ensure the whole shebang follows a smooth arc around the bend. The low speed damping rate is appears to be less than that of the DCC equipped Golf GTI. The non-DCC Red Golf GTI did not telegraph as much of the minor low speed roadway undulations than that of the constantly variable DCC equipped White GTI – the different is barely perceptible of only a very minor degree and could be put down in part to variances in tyre pressures.

The mid speed damping on middle sized bumps actually feels to be firmer than that of the DCC equipped GTI, which make sense in a one size fits all damper. The DCC equipped GTI softens up the mid-speed middle sized bump damping, making for an improved ride, but creating a feeling of being underdamped for that ¼ of a second or more if a series of high frequency wave of bumps in the low to mid-speed damping range are struck in quick succession. The firmer mid-speed damping of the non-DCC was a surprise and this appears to be the case with the non-DCC Golf R after sampling both DCC and non-DCC Golf R’s.

[WhiteJames]

Body Control:

You notice the additional low speed damping pitch and roll of the non-DCC Golf GTI. The low speed compression driving on local roadways – both in town and on the highway at higher speeds, conveys a feeling of less low speed compression and rebound rates relative to spring rates than that of the DCC equipped GTI. The non-DCC GTI feels that bit more relaxed on the highway with a smoother more refined feeling. Crossing a set of railway tracks at 80kph showed the non-DCC GTI to have very well judged mid-speed compression and rebound damping that offered pretty much the same vertical body movement as that of the DCC equipped GTI.

The body control is let down to a degree when punching the non-DCC Golf GTI around the undulating tight twisties between the Boat Shed and Toll Both. In particular, when a series of low to mid speed bumps are struck one immediately after another in a higher frequency fashion, the non-DCC Golf GTI tended to float over a short series of bumps, rather than deal with them speedily and adroitly. Alternatively, the softer feeling of the non-DCC Red Golf GTI does offer more driver adjustability in terms of balancing the vehicle on either the throttle or brake, which makes for more driver involvement and fun. With DCC, you lose some of that throttle & brake adjustability and driver involvement as the dampers are pro-actively reacting to the inputs of the driver. The non-DCC Red Golf GTI had a feeling of mum and dad’s type of family hatchback rather than an all out super firm hot-hatch, with the non-DCC wafting along and over roadway bumps rather than short sharp vertical chassis movement that the DCC equipped GTI offers when in ‘Sport’ mode.

The high compression hits are smoothed over with a general sense of refinement and that are never jarring or uncomfortable. On my two test runs driving over the Boat Shed low lying concrete bridge in a northerly direction at varying speeds, the large high compression bump immediately adjoining the bridge just as the non-DCC GTI is commencing a left hand turn offers an ideal assessment of how well a chassis can cope turning and absorbing bumps simultaneously.

On both occasions, the Red non-DCC Golf GTI front right 18” Detroit Tyre rubbed on the top fender screw. On a past drive review, the Golf R on 19” wheels did not rub in this location, although the Golf R had DCC in ‘Sport’ mode on the previous test. The rubbing of the tyre onto the inner mud-guard on the non-DCC was very surprising given that it’s running on only 225mm wide tyres. Both GTI’s in this test run on the heavier 28-29lbs Detroit wheel, which works the suspension harder with greater un-sprung weight.

The DCC equipped GTI did not rub the tyre on the mudguard in either “Normal’ mode or ‘Sport’ mode. This is suggestive of the fact that high speed compression damping in the non-DCC Golf GTI is softer than was expected – perhaps even softer than the previous MKV Golf GTI. Overall, the body control of the non-DCC Golf GTI is not up to par with the DCC equipped GTI, as all chassis movements either laterally or vertically take longer with additional floatiness, waftness making for a slower change in direction and requiring greater effort form the driver for a lesser end result. The chassis requiring greater driver skill and input is viewed as a good thing from an enthusiast’s point of view, so it’s not all bad with the non-DCC Golf GTI.

I would describe the body control of the non-DCC Golf GTI being similar to the DCC equipped GTI in ‘Normal’ mode until such time as the roadway becomes rougher in terms of bumps, pot-holes, high frequency bumps, etc ... or when you are leaning on it on a smooth roadway ... where the non-DCC suspension tune seems to settle somewhere between DCC ‘Normal’ and DCC ‘Comfort’ modes.

Brakes, Motor and Ergonomics:

The newer Red non-DCC Golf GTI had only 2,800km on the odometer. The brakes felt pretty much the same as my older White DCC Golf GTI with closer to 28,000km. Their appeared to be a slight rattle in the rear of the demo Red non-DCC Golf GTI and the motor felt a bit lazier when prodded compared to the well-run-in motor in my White GTI with 28,000 that was methodically run-in that does not use any oil.

[WhiteJames]

2. White DCC equipped Golf GTI:



2. White GTI with DCC:

Driving the non-DCC GTI had me gripping the steering wheel with both hands tightly and concentrating intently on hustling the Red Hatchback around the tight twisty hill climb and descent. Sometimes half as much or more steering lock was required in the non-DCC Golf GTI to point the nose into a corner with a tanbile delay in having the front end point from straight ahead into a corner. The White DCC equipped GTI was the complete opposite. Punting the White DCC GTI was a breeze with minimum driver inputs in steering, throttle and braking. Miss the apex, not problem, just tighten the line and let the dampers firm up accordingly. No need for a high degree of skill and driver involvement, a dummy could drive the DCC equipped GTI in a hurry with the minimum of fuss.

The DCC equipped GTI required less driver skill and involved to gain the best from it and was generally faster in every aspect. The DCC does rob the GTI of some throttle and brake adjustability due to the less pitch and body roll. On the super tight turns down the bottom of the hill, you could feel the rear sway bar working it’s magic in shifting the trajectory of the GTI’s rear end, but not to the extent of the Red non-DCC Golf GTI. The DCC equipped GTI did not fall over itself during cornering, limiting understeer or lift over oversteer. The end result is a faster hatchback, but ultimately a less rewarding drive.

The steering on the DCC equipped was better in all modes. There is little difference in ‘Comfort’ and ‘Normal’ modes, esp. around town, but around the hill climb route, the steering felt a tad meatier and had improved on-centre feel than the non-DCC Golf GTI. This may be an inadvertent benefit of the continuous semi-active adjustment of the dampers, having the firmer chassis and more secure chassis create positive feedback into the steering. The amount of steering input in both Normal mode and Sport mode of the DCC equipped GTI required much less driver input. There is less delay between the driver’s steering input and the chassis response – in this respect the DCC provides for a more reactive, but less adjustable chassis tune.

The stabbing and choppiness of the steering inputs inherent in the Red non-DCC Golf GTI was not present in the White DCC equipped GTI, making it a lot easier to spank the GTI from corner to corner. The steering is a class above the non-DCC Golf GTI, the feedback of each GTI is about the same – part’n’parcel of the modern day electronic steering systems. The steering in ‘Sport’ mode offers a tangible reduction in servo assistance and is a must for any challenging roadway or hill-climb, making for less pronounced driver effort and creating a more direct race-car type of feel. In comparison, the too-light steering of the regular non-DCC Golf GTI was nervous in straight ahead position on the freeway and less responsive to driver inputs around the tight twisting corners of the hill-climb. The standard non-DCC steering is a major let down of the modern Mark 6 Golf GTI. The steering adjustment on the DCC equipped GTI is worth half the $1500.

If the chassis balance of the non-DCC is a 7.5/10, the DCC chassis balance is a 9.0/10 when in ‘Sport’ mode. Both steering predominantly from the front, but the DCC equipped GTI simply gets on the with the job of negotiating turns in a flat composed way, rather than leaning over the front outside tyre, forcing a positive camber change of the tyres, ultimately resulting in understeer as in the case of the Red non-DCC Golf GTI. The DCC equipped GTI has the electronic suspension keeping the GTI flat in turns when pushing on in corners. Changes of direction are done with less chassis movement and greater crispness and alacrity, offering the driver a greater degree of control and enhancing confidence levels. The DCC equipped GTI just seems to maintain a slight understeer chassis balance through the spectrum of cornering G’s. Roll and pitch are banished to a greater degree over that of the non-DCC Golf GTI. The DCC equipped GTI does not having any sort of negative aspect to its handling apart from trading driver involvement and reward for a synthetic driver experience – faster but ultimately less fun.

Tackling series of turns with mid corner bumps had the DCC equipped GTI dealing with the chassis movement in a much faster manner, keeping the chassis taunt and firm, and when in Sport mode with heavier steering, inspires confidence to press-on. Alternatively, the continuous adjustment of the damping has the chassis always in a state of readiness, rather than relaxing entirely. This is not so apparent in a straight line, but noticeable when cornering in any mode (sport, normal or comfort). This can often present as a brittle feeling ride esp. on 18” wheels and 40 series tyres when bumps are encountered. The 18” wheels on the DCC equipped GTI seemed to have a brittle feeling over and above the non-DCC Golf GTI in the low speed compression damping.

I have no reservation that thrown into a corner hard enough, even the ‘Comfort’ mode would firm up in a fraction of a second over and above that of the non-DCC Golf GTI. In this respect, the DCC equipped GTI in ‘Comfort’ mode has the capacity to out-handle the non-DCC Golf GTI. Another perceived negative is that when a series of high frequency bumps are encountered, the DCC reduces the damping rate, which can at times, esp. at lower speeds, create the sensation of under-damping similar to that of a worn out set of shock absorbers. At times I find this slight annoying and would like to bump up the damping another 5-10% in the all modes in the mid-speed compression and rebounding damping.

The Saleswoman at the dealership indicated to me that DCC is not a popular option and that she would not recommend the option as here in AUS we don’t drive fast like they do in Germany. For local driving around town, I’d agree with her, but when it comes to some fun around the tight twisties, DCC makes a tangible difference, esp. in the steering department, where the stand non-DCC Golf GTI fails to deliver (if you don’t believe me, drive a Megane RS250). Fitting a set of aftermarket comfort/sports coilovers such as KW Comfort or HPA Motorsport tuned KW SHS coilover kit would bring the standard non-DCC Golf GTI closer to the DCC equipped GTI in terms of handling ability, but it doesn’t solve the issue of the too light steering that robs the driver of enjoyment and confidence.

[WhiteJames]

Summary:


The DCC –v- non DCC comparison leaves me with a real quandary.

The non-DCC Golf GTI is softer in the suspension and even softer in the steering department. The softer suspension tune I could live with as it offers extra comfort for extended drives of greater than 2 hours. The softer steering is a disappointment that I would find difficult to live with. It leaves me thinking that Volkswagen has pandered to the largest market outside of Europe and Americanised the steering, making it lighter. For drivers looking for improved handling, Volkswagen have tactfully introduced a DCC option that gives both steering and suspension a harder edge. Another part of me takes that view that Volkswagen is attempting the pitch the standard non-DCC Golf GTI to a wider audience, in other words: Toyota-rising their product to in an attempt to be everything to everyone, broadening the definition of the hot-hatch.

The DCC equipped Golf GTI on the other hand offers a sporty & agile chassis and with a touch of a button, a more comfortable ride or somewhere in between if you desire. But there is a trade-off for all this electronic wizardry – the driver’s skill & inputs become a lesser factor in obtaining the best from the great little Golf chassis. Substituting the driver’s ability & skill to adjust the chassis attitude with clinical & technical efficiency leaves me a little cold in respect to the DCC. The efficiency is great for user friendliness, long trips and for those that are uninitiated in the art of muscling around a little hot hatch, but fast doesn’t necessarily mean fun when driving on public roadways. Is the DCC equipped GTI a better car to own? Yes ... but not necessary a better car to drive in the context of driving as an art-form.

Cheers.
WJ

[WhiteJames]

Pictures:

Red 3 door Golf GTI (DSG)
White 5 door Golf GTI (DSG)

Don't know how to post pics on this site.
Posted pics on WJ Suspension Review site on other forum.
The White GTI is not my GTI - it's a demo Manual version that is for sale apparently as is the Red 3 door GTI non-DCC.
You have the luxury of test driving a manual and DSG back to back if your desire.
The final pics of the Silver Golf R and Red Golf ED35 are also apparently for sale at Sutherland.

http://golfmkv.com/forums/showthread.php?t=100863&page=18

Cheers.
WJ

[Candyman]

Ran a GTI with ACC this weekend (loaner for our daughters 21st)

Flicking between the modes, I can't see anything I am missing on my R without it other than a button to play with (a lot of placebo effect as well). Unless Sport mode is your thing and the difference in that mode could be useful on track.

Kept it short.