Bi-Turbo Turbo Lag?

[Fasteddy]

I'd assume it's to do with the engine ecu and gearbox ecru when in Dpf mode where as you're travelling in a lower gear in auto mode
eg. When in cruise control 30mph the car will easily remain in 5th gear maybe reduce to 25mph before it drops to 4th however when in dpf mode it will stay in 4th maybe up to 35mph before it changes up an gear
so I'd imagine it would only be a perception that the car is quicker in dpf mode as you're already in a lower gear

[Rassi]

How is your fuel economy? Read about a BiTDI on a French forum that had appalling fuel economy and random lacklustre performance, which was traced to DPF regeneration every 200 miles or so, rather than 800 miles (+/-).

[ChuckMountain]

How is your fuel economy? Read about a BiTDI on a French forum that had appalling fuel economy and random lacklustre performance, which was traced to DPF regeneration every 200 miles or so, rather than 800 miles (+/-).

It's all relative I guess. I have something like 35-36mpg over 2,500 miles though need to check. I must admit I have a heavy right foot and at a lot of that mileage was in France at 80mph where I would get 38-40mpg or so. I am expecting it to go down a bit because I am doing a lot of short journeys at the moment so the tank is saying 475 miles full (was around 535-550 before local traffic) which is 73L compared to my old 2.0TDI mulitronic which was around 525 on a 65L and that was around 36mpg overall a much longer period.

I have never been anywhere close to the claims but to be honest you would have to drive slower than Miss Daisy to get them

I would say also that if you drive the car moderately or fast then you are not going to get anywhere near the status. I have had under 20mpg on one trip when I had my foot down

[Scott K]

Your economy isn't too bad. Mine was about 38 mpg for the first 5000m and has now settled at 40 mpg. The computer reckons about 5% more but mine is worked out brim to brim.

[robbyg]

I think there are two elements to the answer IMHO.
1. during DPF regen it certainly hold back the gears and i agreed with fasteddy re 5th or 4th at 30 is an easy way to spot regen in progress. Obviously it will respond quicker and not need to kickdown if already in a lower gear.
2. (i beleive) one of the ways modern adaptive gearboxes operate is to measure how fast yo press the pedal. eg if i am driving at 30 then reach the end of the 30zone and it becomes national speed limit: in 5th ease the pedal slowly from 5% travel to maybe 50% it will stay in 5th and pull gently and smoothly using the lovely low down torque. move the pedal quicker from the same 5-50% and it will drop to 4th or 3rd and give it more beans. Jab the pedal hard to 50% and it will probably grab 2nd. How you drive makes a big difference to how the autobox respons. A jab=delay then big response, and easing = instant but smoother response.

[Bar Shaker]

It's also worth remembering that the gearbox learns your driving style.

If you very rarely ask for fast gear changes, it may learn to do them slowly and more smoothly.

I tend to use the paddles if I need to move quickly.