DPF Economy

[SteveBray]

I previously had a 2004 1.9 CDTi 16v Vectra and typically got almost 48 MPG with my usual driving and while touring Scotland got a little over 54 MPG, these are genuine figures and not the fuel computers idea.

I now have a 2006 1.9 CDTi 16v Signum and typically get 43 MPG and 48 MPG at best if driven very carefully, quite a difference which I can only assume is due to the DPF?

Any one else found the same results, is this normal, does the DPF reduce economy and sap power?

[Big Sig]

it only uses fuel when on a regen cycle. As far as I know, it shouldn't sap power or otherwise reduce the mpg.

[Signum_CDTI]

However, when it is on the regen cycle.... which with mine is about every 2k, it drinks the fuel like a 3.2 V6, I kid you not!

[Kcs]

I traded in my 56 plate 150 cdti hatch for a 07 150 cdti estate xp, used
to get 48 mpg combined, but now only getting 40.5 ! im not very
impressed at mo ! the book states it should get around the same as
the hatch, even with the 19" wheels !

[Signum_CDTI]

What sort of mileage are you doing in it - and is it mainly motorway or city driving?

[Kcs]

What sort of mileage are you doing in it - and is it mainly motorway or city driving?

I do a mixed type of driving, cover about 380 miles a week !

[Signum_CDTI]

If it is like mine and regens every 1500 to 2k miles, then you will notice a drop in economy from car to car - have you done the airbox mod and ghanged to K&N filter??

After doing this, at 70 ish mph i was averaging 52 ish mpg!!

[Kcs]

If it is like mine and regens every 1500 to 2k miles, then you will notice a drop in economy from car to car - have you done the airbox mod and ghanged to K&N filter??

After doing this, at 70 ish mph i was averaging 52 ish mpg!!

Yep done the air box mod and K&N, i have noticed that it runs
rough at about 2k from time to time, not sure what it is, because
some days it runs so sweet !

[DenisCB]

I average 45 mpg from my Signum with a lot of mixed mileage, including a fair thrashing on the motorways. Looking at the way mpg falls away with higher speed, I suspect this thing has the aerodynamics of a brick. I was on the M11 last week, and in traffic could only do a fairly steady 60 mph. At that speed, mpg was 52-53. But at 82-85mph, it drops to around 42 mph. I never noticed anything like that sort of variability with my previous petrol Vectra B, which I suspect was a lot more slippy through the air.

[learoy69]

how do you know when it is on regen
get 38mpg round town in my estate
at average 19mph