super dooper fuels

Just acquired a new diesel motor and wondering if BP Ultimate / Shell Extra etc are worth the extra pennies for the claimed benefits?

And are the supermarket fuels really different (i.e. poorer) than standard BP / Shell / Esso and other premium fuels? Something to do with additives?

Had a nosey on a few car forums without success. They also keep talking about 'Millers additives' and other enhancements for the discerning driver. Are opinions on different fuels akin to those on hifi cables? Or do you just need a 5.0ltr V8 to exploit the benefits of these super fuels?

cheers

 

not sure - but I've just been to asda and paid 76.9 a litre of their stuff...

 

76.9 a litre...... LUXURY.....

UL = 82.9 a litre here... Llandrindod Wells.... 75 litre tank = £62.175.....Bugger.

 

yeah, that is cheap (asda), it noormally cost around 80.9 just now, but there is a hotel (with a built in garage - or is it the other way round..? hmm...) anyway, they're selling petrol at 96.9 litre...blimey, thats on the a68 towards Corbridge (from weardale)...

 

To answer cookie's question...

Yes, there is a difference with fuels. Whether you'll notice it or not is another matter. A few tanks of optimax in a 30k+ engine will clear out some of the gunk and make it run a little better. With a japanese engine (where they use 100+ RON fuels) the octane boosters in optimax will give you a noticeable difference at high revs (caught me out once on one of the few tanks of optimax I've run). With a big lazy engine (say a 3.8 litre GM V6, 170bhp) I think any difference will be very minor indeed.

Is there significant difference between supermarkets and branded fuels? There are about 7 oil refineries in this country. ALL of the fuel comes from them, no matter whether it's sold through sainsbury's or shell. Shell put in various additives. Sainsbury's don't. The hydrocarbons come from the same place.

If you maintain the car properly then with the odd dose of something like fuel injector cleaner or valve cleaner (which are about £5 a dose each, once every few tens of thousands of miles) then there's no real reason to buy the fancier fuels.

Note some performance cars require high-grade fuel.

 

Thanks.

Mainly curious as this is my first diesel, and didn't know if they benefit more from 'better' fuel.

It's only a Fiat Punto 1.3 Multijet. More concerned about economy and protection of the engine than performance.

Quite a cool little engine (133 lb/ft @ 1750 / 70bhp @ 4000 ). Achieved just over 62mpg off its first full tank with normal driving! Hopefully will get more as the engine breaks in. Got 25-30mpg off the last car, so well pleased with that.

I'm mainly restricted to BP round here anyway, so i'll probably just stick to their ordinary stuff then. Middle of the road.

 

Cookie,
Long time no see. How are you? If you have come here we could have help you find out. All you need to do is ask your wife to fill the car up with an unknown type of fuel for a few weeks before she change it with another brand. Then all you have to do is drive around and decide whether there is a noticable difference. Now before anyone ask this is not a BLIND test. That is totally not advisable under the circumstances as driving around with a blind fold would be very dangerous indeed.

 

As long as she doesn't put petrol in it....

A brand new diesel... Diesel engines last, so don't worry about "protection" of the engine. The car will have fallen apart long before engine wear becomes an issue.

 

Apparently the Civic Type-R is supposed to be filled with High Grade Unleaded for better performance (does it really need it??)

 

batfink - It will probably run on normal unleaded. You won't get the advertised performance and you may encounter knocking. It's generally japanese performance cars (although not exclusively) that carry this stipulation because of the higher fuel grade available in japan where they are tuned.

 

In Portugal Shell Optimax (which is called V-Power everywhere but the UK ) is 98 RON just like all other "super" unleaded petrol (it seems like the UK is the only place in Europe to get shafted with 97 RON) but it does have the cleaning additives in it which I beleive are worth it, at least every now and then.

BP Ultimate in Portugal is 100 RON so it's the highest octane petrol available but I haven't noticed any difference using it in my M3.

I do try to stick to Shell V-Power or BP Ultimate though.

Michael.

 

michaelab - it was only a 5500rpm overtaking manoeuver that it had a noticeable impact on. If you're not pushing it hard then it won't be apparent.

You can buy (in the UK and europe, but only from specialists) 76 Cool Blue fuel, which is 106 RON. However, it's several times the price of Optimax... mostly it's used by enthusiasts on track days or at santa pod.

 

You can obtain up to 120 Octane fuels for racing(and the chap who built my Escort also built an RS200 for the Pikes Peak Hillclimb that ran on that stuff and delivered 850bhp from 2.2L ).

For more mundane motors(and including most turbo engines....not talking about diesels here) the Super unleaded that's now slowly being phased out was perfect....moderate benzene content,hence the higher octane rating,and perfect in fairly high boost turbo engines(mine ran 2 bar,and it's predecessor ran 2.5 bar on this,with no problems,on an everyday basis).

Whilst both would run on 95 Octane fuel,it certainly wouldn't allow the use of decent boost levels for long....for most of us though,and certainly for my diesel runabout,the presence of detergents in the fuel makes no difference at all as far as I can see.

 

I'm not a sceptic about everything Isaac . I didn't mean to imply that I thought that superfuels were bollox, just that from a purely subjective test with 100 RON I didn't notice an obvious difference. I'm fairly sure I they do make a difference

Michael.

 

As you say,they can and do make a difference,but only with engines that require a higher than average octane rated fuel to prevent pre-ignition,i.e. high compression and/or high boost turbo engines.

 

Alex, my BMW M3 (E36 version) recommends you use 98 RON fuel allthough it will work fine with 95 RON but with some loss of performance (according to BMW). Will 100 RON fuel theoretically give more power or will the ECU "manage" that away?

Michael.

 

In general,the ECU will retard the ignition slightly if preignition begins to occur,and the end result will be a loss of power.
Higher octane fuels in non turbocharged engines will not necessarily give a great deal more power,but will certainly enable the ECU and thus engine to run at a less retarded setting,and therefore deliver the rated power.

With a turbocharged engine,the story is different,as the fuel/air mixture is inducted under pressure,varying from not much above atmospheric in relatively low tuned engines,to 2 to 3 times atmospheric in some(mine included in that)and higher still in the old F1 engines,where up to 5 bar was used in qualifying.
At those pressures and with raised air temperatures due to compression in the turbo,pre ignition is always a problem,and requires the use of higher octane rated fuels,and other methods such as intercooling to reduce air temperature,water injection,and in the case of the old F1 engines,to describe the fuel as petrol would be stretching it a bit....most were custom made mixes of a petrol base,heavily laced with toluene.

So...after all that,for normally aspirated engines,as long as the fuel being used is matched to the ECU's map adequately,the engine will run fine.

 

Cookie, Honest John who writes for the telegraph is always on about this. His columns are available online. basically he reckons with cheaper fuels especially diesel you get clogging of the injectors. very expensive to put right. I use Esso as it's around the corner and has the detergents in. I get excellent fuel economy and the car seems to run well. I shan't be using Tesco etc. Maybe I'm believing the hype but rather that than risk a £1000 repair on mine

 

I must admit, although Tesco is handy for me (just around the corner), there have been a couple of times when I've had dodgy fuel from them and the car ran really rough for a while.