My TDV8 seemed to have slightly worse fuel economy than others have reported. Calculated mpg by brimfull to brimfull is about 21.6 and I've never seen much better than 23.5 average on the dash computer. So after cleaning the MAP sensors I bought some Miller's Diesel Power Eco Max and put 100 mls in a half full tank, brimmed it and re-set the 'mpg-ometer-. Now I don't generally believe in magic additives but a lot of people have said this stuff is actually good at cleaning the engine.

Next day 30 miles into a motorway trip it was reading 28 mpg and over the whole 200 mile round trip at mostly 70 mph or above (with a few full throttle accelerations once it was thoroughly warmed up to get the turbos working ) it was showing 28.8 average on the dash

So an improvement of just over 20%
For the cost of 100mls at about £2.70 that seems useful. Or am I just kidding myself? 2008 MY Java Black TDV8 HSE

Millers stuff is good. I wouldn't use any other additive in my Audi and their engine oil designed for classic minis is well known to preserve engines that share oil with gearboxes.
Sound like you have had an issue as mine would sit at 70-80 and return high 20's without bother and mid 20's towing a 27 ft caravan and I have a heavy right foot  2x TDV6. SE and HSE. Both returned to sender with issues👀
TDV8 Sport HSE...... Gone. Loved it but it didn't love me!!
Now rolling in MY10 Fullfat TDV8 Vogue. Slammed it to go round corners🙈
Cruising daily #56 mph in a Volvo V8. 😱
Lots of other toys in the cupboard...😜

I drive mine conservatively and struggle to get 23 with 80% A road driving

Might try the sensor clean. 2009 3.6 TDV8 HSE Santorini Black

mjbrr wrote:

I drive mine conservatively and struggle to get 23 with 80% A road driving

Might try the sensor clean.

That does sound very similar to mine before I started fiddling with it. Hopefully you saw my post today about how to find and clean the MAP sensors. If the car wasn't under a blanket of snow I'd be out there cleaning the MAF sensors - which is the next thing to try. 2008 MY Java Black TDV8 HSE

I got better MPG with a BAS remap But cant keep my right foot off the pedal cause of the grin factor so MPG back down below where I started Good if you can drive sensibly. RRS TDV8 (loving it)
Suzuki Bandit 1200 (For when the suns out)
Nissan 350z GONE

i have just put some forte diesel cleaner in mine and also put some egr cleaning throuhg it, might try cleaning my sensors next as i am always looking at ways to improve my mpg

Paddi wrote:

My TDV8 seemed to have slightly worse fuel economy than others have reported. Calculated mpg by brimfull to brimfull is about 21.6 and I've never seen much better than 23.5 average on the dash computer. So after cleaning the MAP sensors I bought some Miller's Diesel Power Eco Max and put 100 mls in a half full tank, brimmed it and re-set the 'mpg-ometer-. Now I don't generally believe in magic additives but a lot of people have said this stuff is actually good at cleaning the engine.

Next day 30 miles into a motorway trip it was reading 28 mpg and over the whole 200 mile round trip at mostly 70 mph or above (with a few full throttle accelerations once it was thoroughly warmed up to get the turbos working ) it was showing 28.8 average on the dash

So an improvement of just over 20%
For the cost of 100mls at about £2.70 that seems useful. Or am I just kidding myself?

It's a fair question. The computer is definitely showing the best average mpg I've seen. The computer is probably a bit optimistic but next time I fill up will calculate the actual consumption. Be surprised if it is not better than 21.6 which I was getting before cleaning the MAPs and putting Millers in the tank 2008 MY Java Black TDV8 HSE

i'll be watching this space for news.
ive just taken delivery of my TDV8. just finished a full tank with 400 odd miles, 90% motorway miles. trip reads 25mpg. im going to run another two tanks full of town driving and mixed driving before trying this. take it you just followed the instructions on the back of the bottle?

jack.bauer wrote:

i'll be watching this space for news.
ive just taken delivery of my TDV8. just finished a full tank with 400 odd miles, 90% motorway miles. trip reads 25mpg. im going to run another two tanks full of town driving and mixed driving before trying this. take it you just followed the instructions on the back of the bottle?

Jack, Should be using the rest of the tank this week on a long motorway run and will calculate on that. The Millers instructions are 50 mls to 50 litres or twice that if you want a quicker clean. I went for 100 mls in a full tank (84 litres). Probably worth pointing out before somebody else does that Millers is a cetane booster so may have a direct effect on mpg in addition to the indirect effect of cleaning the engine. BTW it smells very strongl and the fumes make your eyes smart so do not keep the bottle in the car. 2008 MY Java Black TDV8 HSE

Well it seems despite my (and others) scepticism the MPG is genuinely improved.

Just calculated the actual consumption over a 360 odd mile trip at the weekend using the time-honoured method of brimming the tank at the beginning of the journey, re-setting the trip meter and then brimming the tank again at the end of the trip.

And the answer is....... 26.54 MPG which compares favourably with the 21.6 MPG the car was returning before the MAP cleaning and adding Millers magic additive.

The computer dash display of average MPG was pretty constant at 29.0 to 28.8 which again compares favourably with previous average readings of about 23.5, but proving once again that the computer is a bit optimistic.

The journey was almost all motorway and 'A' roads so just cruising at 70 - 75 (we weren't in a hurry) with no hold ups at all.
I was hoping for slightly better economy but then I was with my mate who is bit of a lard-arse so I'm blaming him for the slightly worse economy! 2008 MY Java Black TDV8 HSE

i was thinking off putting my tdv8 on lpg, any one on lpg/

cossiedave wrote:

i was thinking off putting my tdv8 on lpg, any one on lpg/

Is it even possible to run LPG on a diesel engined car? 2014 L405 SDV8 RR Autobiography

2012 RRS SDV6 HSE -Orkney Grey with A/B bodykit - Now Gone
2007 RRS TDV6 HSE - Zermatt Silver - Gone

I have never heard of an LPG conversion on diesel cars.  2x TDV6. SE and HSE. Both returned to sender with issues👀
TDV8 Sport HSE...... Gone. Loved it but it didn't love me!!
Now rolling in MY10 Fullfat TDV8 Vogue. Slammed it to go round corners🙈
Cruising daily #56 mph in a Volvo V8. 😱
Lots of other toys in the cupboard...😜

There are some systems that use a mix of LPG and diesel - I'm not sure if they're in cars yet but some lorries have been converted.

You can't just run the engine fully on LPG because LPG needs a spark to ignite it and diesels don't have spark plugs. In the LPG/diesel system, the diesel ignites as normal and this then ignites the LPG. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed