Fuel

Its to do with the percentage of ethanol in the fuel I think. The thing with rubber seals etc.

So some cheaper higher octane fuels might actually be worse for an old engine than a more expensive 95, because they will boost the RON with more ethanol?
 
[TW]Fox;30069634 said:
This is a very interesting debate but Joe says I'm not allowed to join in :(
Click to expand...

I can't handle it if you don't call me an idiot every time theres a debate about this. :(

I got an extra 30 miles out of a tank on my base spec Polo when using Momentum 99 ;) ;)
 
Iamzod said:
I usually fill it right to the top, then wait 5 seconds & I can usually trickle another litre or two in until I can see it in the filler neck.

Not sure how much it costs to fill up as I use the fuel so it is irrelevant and never pay any attention to the pump, I always use V-Power diesel and usually get 675 - 750 miles to a tank, usually with me filling up when the trip computer reads 10-30 miles remaining (MK3 Mondeo Diesel)

I don't use V-Power for any performance benefit, just to keep my moon mileage engine clean, a recent EGR removal revealed next to no crud build up. :)
Click to expand...

My Focus 2.0 TDCI didn't like V Power Diesel. With standard Tesco diesel I get around 480 before it reads zero on the miles to empty. With V Power I only got 420 and actually ran it to almost empty (it was coughing) another 40 miles later. Didn't plan on this, but it was in the middle of the night driving from Pembrokeshire to Anglesey and the computer stated I had 220 miles of range to do the 160 mile trip. Pretty much just made it, probably the hairiest trip I've had, and not got V Power since
 
Yeah I was lucky! Started fine when I got to the pump, and have changed the fuel filter since too. That's a nasty job on these as they lack a lift pump.

I was around 2 miles from the 24h Tesco after I'd passed other Tesco and Morrisons in the search of fuel, when it started coughing at me. Crawled along for those two miles, fortunately some of it down hill, with very little throttle input. Never went straight to my destination after that fill up either, took it down the A55 for a bit just to make sure she was OK!
 
When I replaced the fuel filter on my Octavia, the old one had so much crap in it that I didn't have enough diesel to fill up the new filter before fitting it.

It took a worrying amount of cranking to get it going. I thought I'd killed it. :p
 
Acme said:
Its to do with the percentage of ethanol in the fuel I think. The thing with rubber seals etc.So some cheaper higher octane fuels might actually be worse for an old engine than a more expensive 95, because they will boost the RON with more ethanol?
Click to expand...
Very much so, yes.

LadFromWales said:
the computer stated I had 220 miles of range to do the 160 mile trip.
Click to expand...
I wouldn't take that as gospel, as the actual value can vary greatly depending on your driving, the traffic and many other factors.
I wonder if the V-Power cleaned so much cack off the engine that it started affecting the vehicle?
 
When I got my Corsa 1.7Dti, it produced no smoke on startup nor when booting it but it had a noticeable flat spot between 3-4k rpm, I tried changing the fuel filter to no effect so then decided to use BP Ultimate diesel for every fill up.

Gradually over a couple of months the hesitation vanished and on its last big run down to Taunton and back it ran perfectly and had no issue whatsoever maintaining progress at motorway speeds - bang in that rpm range - I can only assume the additives helped clean out the fuel system as it certainly ran far better after a few months of Ultimate.

My 2.5d Volvo shows no such signs of running rough and therefore it's on the cheap supermarket stuff which it seems fine with, I've added a bottle of diesel treatment to it to give it a clean out (176k) and have noticed its kicks out much less smoke now when booting it, I'm not inclined to run it on Ultimate as I doubt it has any performance benefits but I don't doubt its cleaning abilities.
 
Last edited:
Acme said:
When I replaced the fuel filter on my Octavia, the old one had so much crap in it that I didn't have enough diesel to fill up the new filter before fitting it.

It took a worrying amount of cranking to get it going. I thought I'd killed it. :p
Click to expand...

You'd just introduced an air lock (the new filter) to its fuel system hence ,as I'm sure you now know, the need to fill the new filter with fuel! :)
 
Scania said:
You'd just introduced an air lock (the new filter) to its fuel system hence ,as I'm sure you now know, the need to fill the new filter with fuel! :)
Click to expand...

I knew that you are supposed to fill the new filter, but I filled it about 3/4 and hoped it would be OK... Clearly not so I know not to do it again! :D

Took a good minute of on and off cranking and then a little bit of encouragement with the throttle to get it to come back to life after that. :p
 
Regarding the difference between 'super' diesels, there is certainly an argument to be made for cleaner running in the long term. For example Shell V-Power diesel contains a proportion of Perl GTL (liquified natural gas), which inevitably means a lower portion of 'dirty diesel' combusting in the chambers. Exhaust emissions are also therefore supposed to be lower as a consequence. If you actually look at the spec sheets for regular FuelSave diesel and V-Power diesel, there's not much in the actual numbers however.

FuelSave diesel spec.
V-Power diesel spec.

The density is comparable, but if anything the regular diesel has the higher cetane number for better and cleaner combustion. On modern high pressure systems with multiple injections per cycle that's less of an issue, though. The V-Power will also have a higher proportion of detergents, but again how useful that is is debatable.

Perhaps more relevant for diesel users is BP Ultimate. Rather than the usual up to 7% fatty acid methyl ester (FAME) biodiesel content, they use instead hydrolysed vegetable oil (HVO). HVO is much cleaner during combustion and doesn't have the possibility of varnishing the system as does FAME. It also results in less ash and deposits in the DPF, and won't foul the oil with fuel (increased oil levels until runaway in modern diesels, anyone?) as can FAME based fuels.

So yes there are arguments to be made, but looking just the the numbers there's really not so much in it. It just comes down to detergency and other additives, and how much you think they're worth. If I ran diesel then I'd either stick to one of the above two for the (hopefully) long term cleanliness, or just buy the cheapest I could find that met spec, and dose it with Millers detergency package at about 1-2ppl extra.

Luckily my car takes super unleaded, and can actually use it. Oh and Acme, you're an idiot. ;)
 
You must log in or register to reply here.
Back
Top Bottom