What do Tesco do to their fuel??

I have always been very sceptical about the value of fuel additives, but I am now being forced to reconsider this after seeing a significant (over 5%) jump in fuel economy with BP Ultimate Diesel.

My car has done about 92,000 miles, about 24,000 of which have been driven by me since buying the car. I've run it almost exclusively on Morrisons diesel, apart from a few tanks of Shell Fuelsave diesel during which I noticed no change in mpg. I obviously have no idea what fuel previous owners used.

Given the age (8) and mileage of my car I thought I'd try some BP Ultimate just in case there was anything to the engine cleaning claims. I have now run a couple of tanks of Ultimate. Over the weekend I filled up on Saturday morning, then drove about 350 miles of mostly motorway driving at 60 mph on Saturday and Sunday before refueling again on Sunday evening. I averaged 70.7 mpg. The previous best I have ever managed in my car is 65.8 mpg for similar driving, and this was in very hot summer weather (i.e. optimal conditions). Full data here:



This jump in mpg is much more than BP would claim. So where I'm at now is to either wonder what may have coincidentally changed with my car, or to consider that this fuel must have improved the performance of my car, I assume primarily by cleaning the injectors. (Yes the fuel has a higher cetane number, but that wouldn't have such a big effect, and the Shell Fuelsave I tried is also a higher Cetane fuel that made no noticeable difference when I tried it.)

The one complicating factor is that in June 2012 I did have one short trip (157 miles) for which filling up before and after indicated an economy of 72.3 mpg. I have always discounted this as nonsense and the result of a fuel pump stopping early. If this was actually real then I'd love to know why my car is very occasionally capable of such good mpg!

I am confident about the above 70.7 mpg as it agrees with my accurately calibrated ScangaugeII, which indicated 70.8 mpg.

Oh, and as for whether my car is running better or quieter, I think it might be, but not obviously enough for me to be confident this isn't a placebo effect. The mpg change certainly isn't though.

The dilemma I now have of course is has this fuel now cleaned my engine such that if I switched back to a cheaper fuel I would still see higher economy...

The moral of this thread is still that modern diesel engines are not sufficiently rugged in design to be considered fit for purpose.

It's interesting that Mitsubishi were absolutely caned in the late 1990s for their GDI petrol engine, a lump that was specified by the company to only be run on high-octane fuel. People ran it on standard 95RON unleaded, the engines got coked up, and people blamed the engines for being poorly designed.

Here we have a series of engines which are failing to run on fuel that the manufacturer specified -- and people are running to the defence of their engines.

Rather sums up the thought processes of some people out there.

goonarmy wrote: »

Yep this^^.
Recovery technician mate of mine has taken petrol back to them and put lit matches in it to show it wont burn.

No offence but he's not very good then. You've always been able to put matches out in petrol.

http://youtu.be/vln5-HZpgcA

Also, for reference, Tesco are supplied by Greenergy who er... count Esso as a customer http://www.greenergy.com/news/

They were also looking to buy total and Murco's forecourt business at one time (not sure if they did) but again, Tesco don't make petrol any more than they make baked beans so chances are you are filling up on similar base materials whatever you do. It is purely the additives that make any difference.