Alfa Romeo Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
253 Posts
Discussion Starter #1
Although I like to think I'm a fairly spirited driver in my 2.4 159, enjoying my weekly italian tune up (no DPF, EGR mapped out etc). However, I have never found the limit when the traction control would kick in (perhaps a good thing).

But I would like to know if anyone can advise just what is this little VDC/ASR button actually doing! All I see is the display warn me when it is deactivated (by me) but I have never felt it operate in any way. Does it really operate only under extreme conditions, over a certain speed perhaps?

Any thoughts most welcome. Even in snow last year I did not feel any difference.
 

·
Registered
Joined
·
3,138 Posts
I only got mine to work when I first bought the car and it had new but terrible wanli tyres on it, the traction control would work when pulling out on a greasy junction, I could feel the power being limited along with a light on the dash flashing.
I guess it works the same as the 156 That I was driving when it snowed last year, with the button left alown it would get up quite a steep him with my foot flat down with the computer sorting out the wheel spin, with the button pressed and the system off it wouldnt get anywhere close to getting up the same hill, I think it also applies the brake to a spinning wheel.
Whilst messing about in our car park in work with the handbrake it also brakes the front outside wheel to stop the car from spinning round.
 

·
Registered
Joined
·
238 Posts
It flashes a yellow triangle in the speedo (or rev counter, can't remember) when it's activated. I'm surprised you haven't invoked it yet, I can get it to cut in with 4WD during a bit of roundabout drifting (when I've forgotten to turn VDC off).

Ian A.
 

·
Registered
Joined
·
1,637 Posts
The ASR definitely works, although on a dry road, straight line acceleration in a 159 doesn't usually create a wheelspin problem. The software on the 159 seems to allow a certain amount of wheelspin in any event. On a 2.4 the additional engine weight would make wheelspin even more unlikely.
On an icy driveway 2 years ago with ASR engaged my car wouldn't go anywhere - it sat there with the light flashing and the wheels slowly rotating and no amount of throttle changed this - the ASR over-rode the throttle. Mind you, with the ASR disengaged it didn't go anywhere either! lol

The VDC is a different kettle of fish - this is only disengaged with a sustained press of the button. This feature will brake single wheels under the influence of various accelerometers, speed and yaw sensors etc to keep the car under some semblance of control. I have felt this cut in on a couple of occasions - once when tanking round a roundabout and finding some slippery spilt diesel - there was a sense of a giants hand pulling the car back into line. It works.

As Jon156 has mentioned, the same system incorporates the Q2e electronic diff feature on cars from MY2008, which will brake the front inner spinning wheel when cornering hard, thus diverting drive to the outer and gripping wheel and force the car into the bend. This DOES work, albeit at only about 50% of the efficiency of a mechanical limited slip differential. There have been many discussions on what this does - with a number of noted disbelievers who think it is just a different name for anti-skid. The difference is that the ASR systems usually cut drive to the spinning wheel by limiting throttle input - the driven wheel gets no further drive until the spinning wheel drops its speed to that of the driving wheel. On the Q2e system, by braking the spinning wheel the torque is transferred to the driving wheel which gets MORE drive - increasing stability and driving the car into the corner, significantly reducing understeer.

The same system also provides the Hill Holder, by controlling the brakes in conjunction with throttle position and speed and torque sensors.

These systems pop up on more and more cars these days as they are standard features of Bosch ABS systems, so they are not unique to Alfa Romeo.
 

·
Registered
Joined
·
716 Posts
It flashes a yellow triangle in the speedo (or rev counter, can't remember) when it's activated. I'm surprised you haven't invoked it yet, I can get it to cut in with 4WD during a bit of roundabout drifting (when I've forgotten to turn VDC off).

Ian A.
Can beat a bit of 4 wheel drifting on roundabouts ;)
 

·
Registered
Joined
·
7 Posts
my brera 32 4wd has impressive grip on pirelli's but i am dissapointed that i cant get the wheels to spin with vdc off. it makes me think having vdc is pointless unless on wet roads. seems it is a safety thing rather than a feature which is necessary due to the performance of the engine.

unless my brera is not putting out the power it should. its service was ok. can anyone get any wheelspin from a 32 brera?
 
1 - 8 of 8 Posts
Top