BP Ultimate--worth it?

Placebo effect.

Is the right answer.

A Primula is in no way set up to take full advantage of 'special' fuels.

Agreed, it's completely psychological. Remember that a subconscious psychological effect of monitoring your fuel usage is that you're likely to be more light footed, amongst other things.

The increase in MPG is negated by the fact the fuel costs more. I've been driving at around 58mph on the motorway recently, allowing a bit more time for my journeys, and generally been much more easy going with my driving.

42 Litres of petrol got 387 miles, which is 6 mph over what I usually get. Slow progress can be irritating, but you get used to it. Some may say that 'labouring' the engine in this way, ie: not high revs, etc, can actually have a negative effect on the engine. Just try plan more, and be more careful and aware of the speed you're doing, and you'll notice a decrease in fuel consumption.

Note that it also calms you down a bit as well, there's no 'rush' to get to

70, around 60 is fine, and it's generally better for the mechanical components in your car too.

If you feel paranoid about it, just do this: stay at a constant speed, and note the cars that fly by you. Wait 5 minutes. Watch them as they appear in front of you in the far left hand lane, having used up loads of fuel for no particular reason.

Give it a bash, using a car as a fast penis extension is pretty sad anyway :-)

only use the higher octane / cetane value fuels if your vehicle is designed for them otherwise your wasting your money

Struggling to get up not very steep banks in a 1.8 diesel van has it's good points as all the dick heads from the factory some miles down this rural jaunt get to build up a massive head of steam and tailgate almost everything in their path in order to relieve themselves. Right up to the last moment they are overtaking on blind spots then almost immediately treading on the middle pedal to slow down for a sharp corner into their work's car park.

This is nominally Muller's in Market Drayton. I don't know what they put in their food there but it stupifies the brain and enlarges the adrenal glands. I bet it happens on the way to factories up and down the land.

What is it that they do that makes them want to rush into to work like that? I work on barn conversions and spend most of the day out in the country enjoying the weather cold or hot. I couldn't imagine a job with more satisfaction. And yet I can't see the reason for speeding just to get to bloody work.

Coming home we go to the pub straight from work. Still no need for speed in my 'umble. What difference will getting my pint 5 minutes earlier make to me? I will still be sitting down doing something I enjoy. Or is it that they hate driving? Rushing to get it over with?

In message , David Wood writes

I would be surprised if that's a real effect. I found a small, statistically significant increase in mpg with Optimax over 95RON in my Civic Type-R, but that was based on almost 20,000 miles worth of data. There's a tremendous amount of scatter and as a result the trend is barely visible by eye.

In my case, it wasn't worth it, as the increase in mpg was outweighed by the difference in price.

I'm just wondering though, is it any better for the engine?.....In any way at all,........

That's more or less what I found with the Pug 406 2 litre. I tried running it on the more expensive brands of petroleum fluid for a month (1800 miles). It made 1mpg improvement on my normal mpg (33) but cost me loads more.

If it's an older Primera with a distributor you can advance the timing and get more power with these fancy fuels. Or at least the acceleration is measurably better which is the same thing. I doubt if you'd ever see any difference in mpg because if there's extra power you always use it don't you?

Nope...last 37mpg probably because its just been Easter hols with a lot less traffic on the road and less queueing.

Don't think you've checked the MPG correctly. If it were 5 mpg better it would be a bargain and advertised as such.

I won't be using it again. I use Shell Optimax in my Triumph Vitesse because the higher octane prevents it pinking. When I once filled it up with Ultimate, it pinked away as though it was just ordinary petrol.

Any of the high octane ones seem fine in my SD1 - I usually get it from the local tesco Express which IIRC is Esso.

Had to fill up on the A1 yesterday. 103p a litre. Hope they didn't clone my card...

If you're going to run an SD1 you can't really complain at petrol costs.

Tescos 99 is the best if your car needs it, from my experience. I run it in one of my other cars too just because it might do something. The Carlton just gets regular though.

It averaged 27 mpg yesterday over some 300 odd miles. Including crossing London twice - early in the morning was fine but coming back was pretty clogged due to the marathon. The rest a mixture of motorways and B roads with some quite spirited driving. ;-) So not bad for a 3.5 auto.

With LPG at 40p per litre, aren't you tempted to have it converted?

Hmmm, I borrowed a 2.6 once and I could actually see the fuel gauge drop while driving....

In message , adder1969 writes

Tesco's 99RON fuel's octane rating is boosted by the addition of 5% ethanol. Although it has a higher octane rating, ethanol has a lower calorific value than petrol. I haven't seen a measurement of the calorific value of Tesco 99 versus ordinary unleaded, but it's been widely speculated that it will be lower as a result of the 5% ethanol.

If that's true, then putting it in a car which can't improve efficiency by advancing the timing to take advantage of the higher octane rating will result in a decrease in power and economy relative to ordinary

95RON fuel or to competing super unleaded fuels which don't use ethanol.