Is premium petrol cost effective?

[kwakdonut]

That's not my understanding.

We were always told it was to do with knocking.

Higher octane meant ability to run at higher compression and also better ignition control.

That was pretty much my understanding too - RON is a rating, the higher the number, the more resistance to detonation. This must go back to at least when we had 2,3,4 & 5 star petrol. 2* being, I think, 91 RON and 5* being around 99/100, maybe more.

I don't believe the petrol has any more energy, just better control for, as you said, higher compressions etc

 

[crankiejohn]

i was told by a fuel tanker driver that supermarket fuel is the same fuel as named brands,with less cleaning agent so mine just gets a good thrashing now and then to try and stop the carbon building up to much

 

[fredT]

That's not my understanding.

We were always told it was to do with knocking.

Higher octane meant ability to run at higher compression and also better ignition control.

the reason why it detonates (knocks) less is because it burns slower (or longer as described above).

ie a low octane fuel all explodes with the piston at tdc, but a higher octane starts burning at tdc and continues to burn for some of the pistons way down..

therefore you can run higher compression and more precise ignition timing with highr octane fuel


on topic, i have never seen any mpg benefit from using premium fuels

 

[gIzzE]

I have seen a benefit using Shell hi octane, especially in the M3, in both pick up and mpg.

I think it was Thorney Motorsport who did a test over 6 months or so using different fuels and the Tesco 99 stuff did best.

You have to remember that refineries share fuel as well, just the additives that are different.

I use regular shell diesel though and Millers for day to day use on the E320cdi.

 

[Ted]

That's not my understanding.

We were always told it was to do with knocking.

Higher octane meant ability to run at higher compression and also better ignition control.

That was exactly my understanding too.

 

[219]

Since I used to live near the BP refinery in Grangemouth , and at one point worked for a company who were the official photographers to the refinery , hence was in there quite a lot , I can confirm that ALL the major brands , supermarket chains etc fill their tankers up there for distribution throughout Scotland . Drivers fill up the tankers with the base fuel then mix in their company's additive pack .

I expect the situation is the same for other refineries elsewhere in the UK .

 

[bigjim]

Every fourth tank, I use Diesel, just to give the engine a good clean through. Works a treat and keeps my fuel bills down.

 

[Charles Morgan]

I topped up last week with a quarter tank of 99 octane VPower, as the garage was out of unleaded, and the W124 was really very responsive today. Probably an illusion, and now petrol seems to be back on tap I hopefully won't do it again, but it just felt really alive.

 

[fuzzer]

Its like bottled water , you get the same out the tap but youre buying a lifestyle

unless the car actually needs it. Fuel is dear enough without messing about without buying a lifestyle.

 

[Charles Morgan]

No chance, I'm way too mean to pay more and it doesn't need it. This was a fill up in case of panic one off.

I also only drink Chateau ThamesWater at home.

 

[Stratman]

No chance, I'm way too mean to pay more and it doesn't need it. This was a fill up in case of panic one off.

I also only drink Chateau ThamesWater at home.

Which did embarrassingly well in a blind tasting a few years ago.

Why is bottled water so expensive? Spell 'Evian' backwards.

 

[jonm]

did a little test myself in a 200K a couple of years back. Over a few tank fulls the cars reported average was around 10% better with Esso 'carlos fandango super wide' sports petrol rather than with the normal stuff.

My conclusion was that it costs in and was actually cheaper (as in few %) but you need to really watch the price difference to be sure.

The result being that I couldn't be bothered and when push came to shove, paying more to fill up than I need to was a step too far;-)

Jon

 

[welland99]

Wow guys. I've never started a thread that created so much interest. Interesting to hear a few differing views.

Since my nearest Tesco where I usually fill up is selling the momentum 99 for only 3p per litre more than regular, I feel that I must test it out.

Like many of you, I think petrol is expensive enough without making it unnecessarily more expensive. But if the fuel is no more than 5% more expensive and the mpg is increased by more than this, then it will be worth it. And since I live in a rural location where there are not many petrol stations, the extra MPG will give added convenience (If I find them). I'll report back.

Also interested to hear that some cars are recommended to use premium fuel. Anybody know what's recommended for mine (E280 W210) - too cold to go outside looking for the handbook at this time.

 

[markjay]

Wow guys. I've never started a thread that created so much interest...

Thy any of the following topics:


Are premium fuels any good?

Which oil is best?

Should Winter tyres be used in winter?


These are always sure to start a very lively (and inconclusive) debate!