Strange increase in MPG

[BruceT]

I've been tracking my fuel usage since I got the HDi at the back end of August and the spreadsheet is slowly being populated. Im filling up with about £30-40 worth Diesel about every 4 weeks.


From August to Feb my MPG has been around 36-38 REAL world mpg. From my calculations the on-board computer undereads by about 2-3MPG.

Example, 35.2mpg reading on the on-board computer is realy about 37.7mpg. It would be more, ofcourse, but I dont ever empty the fuel tank.

Now, call it odd, but since adding 250ml of 2-stroke oil my mpg on the on-board computer was 40.4 mpg on the first week (Lighter traffic), second week dropped to 38.4mpg.

Now, take into account the on-board computer under-reading, id have a guess in 'real world' terms its nudging a good 40mpg.

Route has stayed the same, my driving has stayed the same, only differences are:

New front pads and discs.
2-stroke in diesel
slighly warmer weather.

Whatever it is, I hope it stays as its very welcome!

[DiscoPol]

could well be the weather, the HDI is well known to drop a few mpgs in cold weather, due to the "cold running enrichment programme" or what ever its called.

have you checked and topped up your tyre pressures recently?

it can make up to 3-4 mpg difference

and the big one is always driving style, if you drive like an old man like me you can well push it up by up to 10-15 mpg, if your interested in getting big numbers try some *Millers fuel additive its what i use on the long journeys its not cheap but it really helps get the most out of a tank of diesel, it also allegedly cleans the injectors and all that jazz.

Got to love the HDI for the fuel consumption if nothing else

* other fuel additives are available, its just this one is the one i plumped for.

[BruceT]

I always keep on top of tyre pressures

I have the EGR blanked off to, which probably doesnt help up with heating things up!

I think its probably because the old front brake discs where badly worn and causing drag, maybe some warmer weather. Unsure about the 2-stroke though.

The front wheels when in the air on axle stands do rotate easier now.

I think ill check the back wheels rotate freely but fear the rear braking system and handbrake (Mine has rear discs)

I also having a leaking flexi section of my exhaust, so this could also be affecting my mpg a tiny bit.

[DiscoPol]

The leaky flexi is a problem i have too so not sure if thats such an issue, but the driving style is the key, I had a BMW 740 before i got the 406 and it satisfied my need for speed for life i think

so now im happy to potter on the motorway at a very steady 65-70, not everyones cup of tea i know

but keeping just under 70 mph makes the world of difference and unless you have clear roads and no traffic it makes very little difference to the journey times, honestly give it a try you will be amazed.

[neildavies]

could well be the weather, the HDI is well known to drop a few mpgs in cold weather, due to the "cold running enrichment programme" or what ever its called.

.

Glad you said that, I've lost about 3-4mpg on my computer's average in the last few months, and in fainess, we have had some rotten weather.

But I'm going to get some additive, I used to use Forte on my old 2.1TD, shich chucked out masses of smoke, then was clean as a whistle after adding forte. For a short while anyway.

[jasper5]

My HDi 90 Expert van was using £40 of diesel to 290 miles, with the bad weather it dropped to 230, now the weather is better, i'm back up to 280.

The only thing wrong with my van is the bloody reverse gear selector cable has broken again