Hi all.

Having always thought my car was a bit rubbish MPG wise due to the DPF, I have had a recon engine, front wheel bearings, dpf delete and a economy and performance hybrid map done. I just did Suffolk to London down motorways 70 mph 6th gear and it averaged 35 mpg. I assume this is about 10 mpg down on what others are experiencing am I right?

I recently drove from Anglesey to Gloucestershire via near Chester, Shrewsbury, Bridgenorth, Kidderminster and M5 and didn't drive for economy.  Mpg was 51.8 on maxi-dot and 49.3 when corrected for known maxi-dot over-read.  Approximately half journey on motorway or dual-carriageway and the rest in mainly 60 and 50 limits.

 

I know my car has a different engine to yours but as you say I would have thought you should see at least mid-40s?

That's what I thought. I'm going by what the maxi dot says though. But I can't figure out what could be causing the poor mpg. If it was over fuelling or boost leak I'd expect to see black smoke with no DPF

Edited 18 April, 201511 yr by whitep

That is awful MPG. For me, I have averaged 47mpg over 50,000 miles and it often hits 57 on a run.

DPF delete and Shark remap here

M3/M25/M20 run to channel ports last Sept saw 43/44mpg @ similar 65-70 in 6th with my TSI, so I'd say that 35mpg from the diesel should be a lot better.

 

My old PD130 Fabia VRS would routinely show 52/53mpg on 250 mile North/South Mway runs, smaller car I know.

Same journey I usually see low to mid fifties

Something definitely not right

?

So who's Performance & Economy map did you get to go with the DPF delete?

 

Did it actually give more performance, & did you need more performance or was it efficient running you wanted,

because surely the car was already able to do 70mph plus easily with a DPF, or has it failed to do the as well,

it certainly does not seem to have helped Economy, 

Maybe best to run a Standard Map & the DPF delete seems to have failed to achieve what you thought it would.

It was cap before the dpf was removed. It was half the reason why I took the damned thing off. But it made no difference.

Does anyone have any idea what might be wrong? There isn't much more left to change

Have you checked the basics... tyre pressures (can make a huge difference) brakes binding slightly etc?

 

35MPG is pretty shocking, who’s map is it?

Are you just going on the mid readout or have calculated the actual fuel consumption?

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Just the readout tbh

You pay for the fuel and know how many litres go in the car and then the miles covered,

 (Gallons have not been delivered at UK Pumps for a long time now, we never went to km though, we stuck with miles.)

4.546 Litres to a Imperial Gallon incase anyone forgets)

 

it is actually sensible to see how much fuel you do actually use over the distances covered.

Day to day short, or longer up to heat journeys.

You pay for the fuel and know how many litres go in the car and then the miles covered,

(Gallons have not been delivered at UK Pumps for a long time now, we never went to km though, we stuck with miles.)

4.546 Litres to a Imperial Gallon incase anyone forgets)

it is actually sensible to see how much fuel you do actually use over the distances covered.

Day to day short, or longer up to heat journeys.

Like George says, work out the actual consumption, it may be very different. Given the engine swap it may not be a surprise if something isn't correctly calibrated.

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That economy is so far out I doubt it will just be the difference between computer figures and calculated figures

So the idea is to see how far you can actually drive on say 45 litres or so, 

Brimmed tank before a trip,

then once you have covered near 350 miles does it need 45.46 litres to Brim again.  

Or if there is enough fuel in maybe leave it longer until you brim it.

If it takes '10 gallons to fill up, after you went 400 miles, you were getting 40 mpg out of that fuel.

Not rocket science.

Edited 19 April, 201511 yr by goneoffSKi

That economy is so far out I doubt it will just be the difference between computer figures and calculated figures

Mine is over 10mpg out, the computer is way over optimistic.

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Mine is over 10mpg out, the computer is way over optimistic.

Most tend to be over rather than under

Not that you are liable to get 10% misreadings, but you can get not far off, 

but what tyre size is on the car ?  

Not the size on the Side wall but actual measurement side by side with the Standard Tyre Sizes.

Then Brand / Compound / Pressure can make a few mpg difference.

 

http://kouki.co.uk/utilities/visual-tyre-size-calculator

35MPG from a diesel tells me something is wrong, possibly the DPF delete map is at fault or something has happened and despite there being no DPF the car is possibly trying to regen and thus injecting more fuel.

 

My 3.7 V8 Petrol manages 32MPG on a run (calculated), so something must be from for a 2.0PD170 to only be getting 35. IIRC my old PD140 DSG superb ran in the mid to high 40s, and that had a shark remap but retained the DPF.

I have 225 40 18's on. Bridgestone potenza are the tyres. To be honest I get better mpg down country roads with tight bends constantly changing gears.

I will do some maths though. I brimmed the tank yesterday and zeroed the trip counter so let's what comes of it.

I don't think there is anything wrong with the map because it was just as bad before the dpf was taken off

Although not the same engine, my 1.9pd with shark's stage 1 (140bhp). with a boot full of equipment will happily do 55mpg plus all day long, (usually 57-59). And thats foot flat acelleration and 70 (ish) on motorways. Definately something wrong with your car whitep. To be that far out though makes me think something major. How is the performance?

I strongly believe there is nothing wrong.

 

When I was in the middle of my PD170's demise (immediately after the VOSA injector recall) my dealer had the car for weeks trying everything to fix the issues I was experiencing.

 

Whilst not fixing any of them the car was returned to me with the Maxidot showing very poor MPG, significantly worse than when it went in.

 

The initial panic was replaced with annoyance, a manual calculation (brim to brim) revealed the fuel consumption was spot on (49-50mpg), the Maxidot however was miles out (35mpg).

 

The dealer as you'd expect denied that anything they did could have affected it. It never improved. A few weeks later the car was gone.

Edited 19 April, 201511 yr by silver1011

I must admit my fuel gauge is showing 1/8 of a tank used at 150 miles...