Does ACC ride the brakes?

[WeeDram]

I know ACC applies the brakes if traffic in front slows down. What I'm wondering is if it rides the brakes, causing unnecessary wear and annoying drivers behind with constant flashing of the brake lights? There's not a lot of compression braking from the engine. When I'm controlling the throttle myself I can anticipate traffic patterns and back off the gas pedal early, but ACC is more reactive. It sure feels like it's riding the brakes but without having someone drive behind me to check it's hard to be sure.

 

[dragon]

I'd be interested to hear the answer as i've wondered the same!

 

[cuke2u]

TC rides the brakes...

 

[WeeDram]

TC rides the brakes...

Yes but only when losing traction which is an occasional event. I'm talking about continuous braking while in heavy traffic, which without ACC I generally avoid by lifting off the accelerator early unless it's a stop-and-go jam.

 

[jungle650]

You can alter the distance control setting from 3 or 4 car lengths to shorter (2 is a good option) when in heavier traffic. This eliminates a fair bit of the constant braking and helps to reduce the number of people pulling out into your space betwen u and the car infront. I use the ACC a fair bit on a run and find it generally pretty good.

I have even found that it actually brings you to a complete stop at traffic lights then accelerates u back up to your chosen speed. Which i was not expecting.

Jungle

 

[WeeDram]

Not sure if it affects the amount of braking but I find the shorter distance settings result in much harder braking, near panic braking on occasion, given the way people drive around here. I find myself adjusting the distance setting regularly as traffic patterns change to keep people from cutting in front on the one hand and being launched through the windscreen with each stop on the other hand. On a long trip yesterday in blinding torrential rain it worked very well on the max distance setting since hardly anyone was foolish enough to change lanes.

 

[Helifella]

It must ride the brakes as many a time when I've used it on A & B roads, once at the destination the brakes are stinking, seemingly the rears.

I wonder if the ACC overly trail brakes if the limit is set to 60 for instance on an A-road but traffic is 45-50 as this is where I seem to get the strongest whiffs once I have arrived.

On a journey down to Falmouth, I rendezvoused with my sister in her A5SB at Bridgwater and she followed me on the dual carriageway. So I rang her up and she said there was no brake light illumination at the points where it felt it should be.

I got the car in December last year and took it in February time - they suggested it could still be bedding in, but if I was unhappy to book it in. I'm now at the stage where I'm leaning towards it being investigated further.

 

[Helifella]

Well mine is currently in Harrogate Audi for a drivers seat creaking and ACC investigation.

It went in on Tuesday morning and the Master Tech who I have a great relationship with wants to keep hold of it a bit longer. I don't really mind as the loan car is a bit of a gem - a 3.0 tdi Quattro with 272bhp A7 black edition.

Will keep you posted on the ACC outcome.

 

[Ignition1]

Ha! I'd leave the A3 in the garage for as long as possible if that's the loan car you've been given...

 

[Helifella]

Had a lovely three days with the A7 and the masterTech could not replicate my burning smell, so gonna keep monitoring.

 

[Ignition1]

Had a lovely three days with the A7 and the masterTech could not replicate my burning smell, so gonna keep monitoring.

Did they drive it at distance though? Tricky to prove things to master techs sometimes. I took mine in because I felt the throttle response was poor (felt like there was a dead zone in the pedal) but he was driving it and said it seemed fine. Although one comment he said was "it feels pretty close to normal."

I don't want "pretty close". I just want normal!

 

[Helifella]

Yes he drove it twice for longer than I stated I experienced it, to really give it chance to smell. Both journeys were half hour plus.