Premium fuel == con? - David Horn
My dad filled his 2.0 Daewoo Leganza up with BP Ultimate Unleaded as an experiment prior to driving down from Manchester a few days ago. A trip he usually does on 3/4 of a tank this time involved him nearly having to stop at a service station to get more petrol.

He's not impressed, and since this was a good 5p more expensive, the journey cost him a lot more than usual too! Has anyone had a positive experience with "premium" petrol?
Premium fuel == con? - BobbyG
If you do forum searches for Ultimate and Optimax to name but a couple, you will find loads of similar threads on the matter.
Premium fuel == con? - Statistical outlier
There was a test on this on one of the TV motoring programmes, I can't remember which one (5th gear?), but I'm sure someone on here will.

With petrol, the basic upshot was that depends on your car whether you'll see any mpg improvement. I think it was a Clio, a small engine, where they found that Optimax made no difference at all, whereas on an Impretza they saw an increase in power of nearly 40 hp. It appears that the engine must have sensors to allow it to adjust the ignition timings before you will see benefit. If this isn't the case, then I believe the only benefit is in the larger amounts of the detergent in the more expensive petrol.

I'm now running a diesel, and I've found that the premium diesel does seem to make a noticeable difference in low revs power. It also gives me about an extra four or five miles per gallon. I think it's worthwhile, although since someone on this forum alerted me, I'm trying to use Shell as their standard diesel appears to be of the premium and variety.

Hope this helps, and I look forward to various people correcting their mistakes in the detail of this posting.

Gord
Premium fuel == con? - Red Baron
I second the above statement by GM...

My 1997 Alfas ignition management system is obviously clever enough to account for a higher octane petrol as I get 3mpg more if I use Shell optimax over anybodys standard fuel. 3mpg justifies the extra expense.

Have also used Shell diesel extra on my TDCi. Can't yet say whether I get more mpg, but there are fewer particle clouds out the back under acceleration.
Premium fuel == con? - Murphy The Cat
I hate myself for saying this because I so wanted to tell everyone that BP Ultimate Diesel is rubbish, but since I've gone over to it I have found that my Chrysler 300C is quieter, more responsive, smoother and quicker, so for the time being I think that it's good stuff. I haven't done enough miles yet to comment on mpg.

MTC

p.s. Before using BP Ultimate, my 300C already was quite, responsive, smootth & quick, its now just a little bit more of each.
Premium fuel == con? - TheOilBurner
I was always skeptical of using higher octane petrol and was never 100% sure of the benefits. However, now I've got a diesel (Vectra 1.9 CDTI) I thought I'd give BP Ultimate Diesel a go recently.

The difference was amazing. From an average of 48mpg (on Shell Diesel) over 3,500 miles, I'm now averaging 52mpg over 1,000 miles so far. Performance *feels* a little better and the car *seems* a little quieter and smoother, especially when cold.

So, I'm paying 4% extra over BP regular diesel but getting more than 8% better fuel economy! Talk about a win-win situation...

No going back for me - this Ultimate stuff really works, in my engine at least.
Premium fuel == con? - David Horn
Have been meaning to try BP Ultimate diesel as I found the Shell premium diesel made an improvement in my car, but I rarely come across BP garages in Devon and those that are there don't usually stock the ultimate diesel.
Premium fuel == con? - Dipstick
For my part, my Lexus GS300 was no smoother or quieter (well not surprising really), but did do a little better in the mpg department. However, the extra cost/mpg gain balanced so there was little point.

My current replacement Jaguar S-type shows no improvement in any area, including mpg, so again, no point in this car for me.

These tests were done with both Optimax and Tesco 99 super.
Premium fuel == con? - jacks
I use Optimax in my petrol BMW 323 (T reg) and definately get an improvement in mpg (+ 3mpg is usual), the 6p/litre price premuim is just about covered by the extra mpg although sometimes I've been to garages who charge 9p extra for Optimax and then I don't bother & use std. U/L.
Premium fuel == con? - Group B
They did a test on 8 different brands of petrol in Evo magazine a few months ago. Some of their comments were:
As stated above, higher octane petrol will only make a difference if your engine has knock sensors so it can adjust the ignition timing.
Petrol deteriorates if stored for too long, so the most important thing is to use a busy petrol station; the more petrol they sell, the fresher it should be. (Supermarket ones are usually busy so fresh petrol).
Most cars will run better on some fuels than others, so find which one your car goes best on and stick to it. eg. Imprezas run best on Optimax, Mitsubishi Evos run best on BP Ultimate. (I think it was that way round, I dont have the mag with me.)

The article was performance oriented, not long term running, so did not mention detergent additives, etc.

Premium fuel == con? - turbo11
I gain around 3mpg(41/42 mpg) using Optimax in my mazda,otherwise its 38/39 mpg using shell unleaded.The extra cost of optimax is negated by the increase in economy,let alone the slightly better responsiveness.
Premium fuel == con? - kithmo
I only get 1 or 2 mpg increase with Optimax on my V6 Mondeo but low speed torque is better and the engine internals are being kept clean with the "improved detergents" in it. The engine feels even more torquey with cheaper Sainsbury's super unleaded but the mpg goes down and after a few tankfuls I get a slight hesitation on pick-up (which clears on returning to Optimax).
Premium fuel == con? - malteser
Here in Spain we now have availability of Shell VPower diesel. I understand that it is not marketed in the U.K. under that name, if at all. Apparantly it is at least partially composed of synthetic diesel produced from gas rather than crude oil. It is claimed to have a higher percentage of cetanes and to be lower in sulphur.
Is this the same as the Shell "Extra" diesel, which is available in the U.K., or not? Is BP "Ultimate" similar in formulation?
The Shell VPower is priced at a substantial premium compared with their regular product, at about 5 euro cents per litre more.
Smug mode "on"
"Cooking" diesel is hovering around 0.95.5 Euros a litre - about 0.65 GBP equivalent, so we at least have some advantage here!
Oh - our car tax equivalent for the year is + - fifty quid for a 1.9tdi.
smug mode "off"

Roger. (Costa del Sol, España)