Super Diesel.. any better ?

[esgyrndafydd]

Originally Posted by Kaiser Bill

I take it that Shell vpower has the new anti-corking additive then?

A bit late but still...

Shell V-Power - Wikipedia, the free encyclopedia

[devilmaycare]

The characteristics of these fuels have been available for some time now, well at least since I started using them after I acquired my car in 2006. My original interest was in using the cleanest possible fuel available and trying to avoid problems with DPF, EGR and swirl flaps. So far, this ploy seems to have been successful, but should there be problems, I won't be able to blame poor quality fuel. As a bonus, there does seem to be a small benefit in fuel efficiency and a noticeable improvement, albeit difficult to quantify, in acceleration (compared to the odd occasions when I have to resort to "regular" fuel).

[esgyrndafydd]

Originally Posted by devilmaycare

The characteristics of these fuels have been available for some time now, well at least since I started using them after I acquired my car in 2006. My original interest was in using the cleanest possible fuel available and trying to avoid problems with DPF, EGR and swirl flaps. So far, this ploy seems to have been successful, but should there be problems, I won't be able to blame poor quality fuel. As a bonus, there does seem to be a small benefit in fuel efficiency and a noticeable improvement, albeit difficult to quantify, in acceleration (compared to the odd occasions when I have to resort to "regular" fuel).

I assume that the car won't need to regen as often and less carbon is also a plus. Have you noticed that?

[devilmaycare]

Difficult to know when regen has taken place, unless stepping out of the car just as it has stopped (burning smell and creaking exhaust). Can't really comment on carbon, other than no obvious problems as a result of carbon build up. No tell-tale signs around the exhaust outlets, but that might just indicate the DPF is doing its job.

[esgyrndafydd]

Shell V Power seems to get slightly better press that BP [in second place] so it's probably worth a try. There's a bit about the constituants here-

<http://en.wikipedia.org/wiki/Shell_V-Power#V-Power_Diesel>

I'm a bit undecided at the moment as despite shopping for price my fuel economy has suddenly increased since the cold weather started...

I noticed the last couple of times I filled up that it's gone from just over 32mpg to just under 37. Quite a difference considering that during this time I've not really done any journeys longer than say 25 miles or so.

[devilmaycare]

All engines should become more efficient in cold weather. Cold air is denser than warm air so the cylinders are charged with more air mass and hence more oxygen, for combustion. This is why turbochargers, superchargers and intercoolers are used. However, superfuels made using gas to liquid technology, are less dense than regular fuels and seemingly contradict this theory, but the inherent efficiency of superfuels more than compensates for this drawback. Another advantage is that a tankful of superfuel results in lower weight to haul around. I'm not sure whether this completely explains your dramatic improvement in economy, but it will help. You may have also adjusted your tyre pressures recently, as these can have a pronounced effect on mpg.

[esgyrndafydd]

Originally Posted by devilmaycare

All engines should become more efficient in cold weather. Cold air is denser than warm air so the cylinders are charged with more air mass and hence more oxygen, for combustion. This is why turbochargers, superchargers and intercoolers are used. However, superfuels made using gas to liquid technology, are less dense than regular fuels and seemingly contradict this theory, but the inherent efficiency of superfuels more than compensates for this drawback. Another advantage is that a tankful of superfuel results in lower weight to haul around. I'm not sure whether this completely explains your dramatic improvement in economy, but it will help. You may have also adjusted your tyre pressures recently, as these can have a pronounced effect on mpg.

Agreed, cold weather should help. But, to move on to your other comments the fuel used has been bog standard Tesco - there was nothing else open the last couple of times I filled up - and tyre pressures have been the same.

As I said, I'm at a loss to explain this sudden bonus and my only thought is that it's the car responding - at last - to some maintenance. When I bought it the mileage was just on 35,000 and it had only done 3,000 in the past two years. The tyres needed replacing and the EGR valve was sticky. I had the valve and the tyres done and ran it like that for a while - up to 37,000 - and then had it fully serviced [the oil was really grim] including coolant and brake fluid replacement etc. so perhaps it's now responding to actually being used?

It's a 56 plate touring so even now with just over 44,000 on the clock it's hardly been over used although it's piling the miles up quite quickly at the moment.

I'm going to give the V-Power a try from this week, there's a nifty phone app which gives fuel prices for all garages within 10 miles of your location so I'll give it a try.

[devilmaycare]

A sticking EGR valve wouldn't do much for economy, so fixing that would help a lot. Having good quality oil would also help, as would a new air filter. Still, 37mpg for short runs is impressive and on supermarket fuel too. I would only achieve that on long motorway trips, with 32mpg (or even less) being more realistic for short trips.

[esgyrndafydd]

Originally Posted by devilmaycare

A sticking EGR valve wouldn't do much for economy, so fixing that would help a lot. Having good quality oil would also help, as would a new air filter. Still, 37mpg for short runs is impressive and on supermarket fuel too. I would only achieve that on long motorway trips, with 32mpg (or even less) being more realistic for short trips.

It's certaily impressing me...

The EGR valve was so bad I had it replaced rather than just cleaned as it was REALLY badly carboned so presumably that will be OK for the future.

I keep waiting for something to go wrong, coming back tonight the ECM is reading 38.7 but that always reads high. I'll fill up at the end of the week and see how it's done. It's mostly round trips, Monmouth to Avonmouth via Chepstow and the old bridge and then the back roads so 50/60 is about the most you can do with all the other traffic, wagons etc. so that probably helps but I've found normally the car is mre economical at a decent speed.

[devilmaycare]

Originally Posted by esgyrndafydd

The EGR valve was so bad I had it replaced rather than just cleaned as it was REALLY badly carboned so presumably that will be OK for the future.

To avoid future problems I would stay with good quality fuel.