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Question for petrol experts

PeteHall

Moderator
Cantclimbtom said:
Got to be honest, that subtle performance edge that premium fuels supposedly gives is lost on me.

I once did a bit of a (not very scientific) test to see whether it was worth the extra cost of premium petrol in terms of improved MPG. I had driven my wife's Renault Clio from Bristol to Durham on regular petrol and recorded my MPG for the journey. Before I returned, I filled up with premium petrol and made the same long steady journey the other way and recorded my MPG.

My theory was that over two long and more or less identical journeys, I could work out a comparable ? per mile for both regular and premium petrol.

As it was, I never bothered working out the cost per mile, as the MPG on the return journey was identical; the premium fuel made no difference at all to my fuel economy.
 

tomferry

Active member
The last time I worked my mpg out for the 1987 Landrover 110 2.5na was 18mpg to go from Northamptonshire to Conwy.

I have tried Asda ,bp and shell  they all get inbetween 16-20mpg depending on the journey I have never noticed a single bit of difference.

According to me it?s still the best engine Landrover ever built !  :eek:
 
Years ago, I tried it in my Saab. I got an approximate 5% improvement in mpg, a negligible difference in acceleration and a 10% increase in petrol bills. The Saab then lost an argument with a white van and I switched to a Honda Accord. Premium fuel made no difference at all (apart from the increase in bills). Unless the additives make a significant difference to the life of your engine, I don't see the point.
 

aricooperdavis

Moderator
I remember doing a bit of research on this when I learned to drive, but there seems to be very little hard evidence about premium fuel use and a lot of personal preference.

The first complexity is what is meant by premium fuel. If you're just talking octane then you should use the fuel recommended by the manufacturer because your engine is designed to be combusting fuel at a certain temperature. So, as expected, using too low octane fuel can reduce performance and fuel efficiency, but so can using too high octane fuel!

Whether or not the additives make a difference is even harder to research, because each one is different and most of the research is funded by the manufacturers and not released in full. There's a 2016 report from AAA which suggests that using fuels without additives can be detrimental to performance and longevity, but the authorship conflict of interest makes me doubt its value.

For me, I'll happily put the cheapest possible fuel (of the appropriate octane) in my car, because pulling away from traffic lights doesn't need the extra 2% bhp that even the creme-de-la-creme of petrol can give, and I'd rather replace my intake valves 1 month earlier than give Shell/Esso/BP a penny more than I have to.
 

ttxela2

Active member
Annoyingly my motorcycle isn't on the published government list. Despite having bought it brand new this year the maker won't release definitive advice saying it's Ok to use E10. The best I've seen is a rather wooly statement saying it 'should' be ok but 'most owners will prefer to use the best fuel available'.

Whatever that means..... I wonder if they are hedging their bets in terms of warranty claims 'well you didn't use an approved fuel...'

Fortunately it's a pretty frugal machine so filling it with premium doesn't cost a significant amount more.

I wonder how long premium fuels will be around for in E5 form. Lead replacement Petrol didn't seem to last very long........
 

Paul Marvin

New member
PeteHall said:
Cantclimbtom said:
Got to be honest, that subtle performance edge that premium fuels supposedly gives is lost on me.

I once did a bit of a (not very scientific) test to see whether it was worth the extra cost of premium petrol in terms of improved MPG. I had driven my wife's Renault Clio from Bristol to Durham on regular petrol and recorded my MPG for the journey. Before I returned, I filled up with premium petrol and made the same long steady journey the other way and recorded my MPG.

My theory was that over two long and more or less identical journeys, I could work out a comparable ? per mile for both regular and premium petrol.

As it was, I never bothered working out the cost per mile, as the MPG on the return journey was identical; the premium fuel made no difference at all to my fuel economy.

My Caddy van not only runs better and crisper but does do more to the gallon on Premium diesel and  I have worked it out very precise ( sado )  :LOL: Petrol it probably does not make much difference, diesel definitely does, the ecomap I had put on it made a whopping difference    ;)
 

Ian Ball

Well-known member
PeteHall said:
Cantclimbtom said:
Got to be honest, that subtle performance edge that premium fuels supposedly gives is lost on me.

I once did a bit of a (not very scientific) test to see whether it was worth the extra cost of premium petrol in terms of improved MPG. I had driven my wife's Renault Clio from Bristol to Durham on regular petrol and recorded my MPG for the journey. Before I returned, I filled up with premium petrol and made the same long steady journey the other way and recorded my MPG.

My theory was that over two long and more or less identical journeys, I could work out a comparable ? per mile for both regular and premium petrol.

As it was, I never bothered working out the cost per mile, as the MPG on the return journey was identical; the premium fuel made no difference at all to my fuel economy.


What are the variables that aren't identical here Pete?

I can think of:
road surface
topography
wind
traffic volume

I honestly had a belief that the premium brands had some sort of diesel injector cleaning properties.  Useful for a hard blast up and down the dual carriageway before an mot emissions test.
 

Paul Marvin

New member
Ian Ball said:
PeteHall said:
Cantclimbtom said:
Got to be honest, that subtle performance edge that premium fuels supposedly gives is lost on me.

I once did a bit of a (not very scientific) test to see whether it was worth the extra cost of premium petrol in terms of improved MPG. I had driven my wife's Renault Clio from Bristol to Durham on regular petrol and recorded my MPG for the journey. Before I returned, I filled up with premium petrol and made the same long steady journey the other way and recorded my MPG.

My theory was that over two long and more or less identical journeys, I could work out a comparable ? per mile for both regular and premium petrol.

As it was, I never bothered working out the cost per mile, as the MPG on the return journey was identical; the premium fuel made no difference at all to my fuel economy.


What are the variables that aren't identical here Pete?

I can think of:
road surface
topography
wind
traffic volume

I honestly had a belief that the premium brands had some sort of diesel injector cleaning properties.  Useful for a hard blast up and down the dual carriageway before an mot emissions test.

Forgot tyres Ian and inflations    (y)  ;)
 

tony from suffolk

Well-known member
Ian Ball said:
PeteHall said:
Cantclimbtom said:
Got to be honest, that subtle performance edge that premium fuels supposedly gives is lost on me.

I once did a bit of a (not very scientific) test to see whether it was worth the extra cost of premium petrol in terms of improved MPG. I had driven my wife's Renault Clio from Bristol to Durham on regular petrol and recorded my MPG for the journey. Before I returned, I filled up with premium petrol and made the same long steady journey the other way and recorded my MPG.

My theory was that over two long and more or less identical journeys, I could work out a comparable ? per mile for both regular and premium petrol.

As it was, I never bothered working out the cost per mile, as the MPG on the return journey was identical; the premium fuel made no difference at all to my fuel economy.


What are the variables that aren't identical here Pete?

I can think of:
road surface
topography
wind
traffic volume

I honestly had a belief that the premium brands had some sort of diesel injector cleaning properties.  Useful for a hard blast up and down the dual carriageway before an mot emissions test.
You forgot the obvious variable - when going to Durham you're going uphill, then back down to Bristol.
 

Paul Marvin

New member
tony from suffolk said:
Ian Ball said:
PeteHall said:
Cantclimbtom said:
Got to be honest, that subtle performance edge that premium fuels supposedly gives is lost on me.

I once did a bit of a (not very scientific) test to see whether it was worth the extra cost of premium petrol in terms of improved MPG. I had driven my wife's Renault Clio from Bristol to Durham on regular petrol and recorded my MPG for the journey. Before I returned, I filled up with premium petrol and made the same long steady journey the other way and recorded my MPG.

My theory was that over two long and more or less identical journeys, I could work out a comparable ? per mile for both regular and premium petrol.

As it was, I never bothered working out the cost per mile, as the MPG on the return journey was identical; the premium fuel made no difference at all to my fuel economy.


What are the variables that aren't identical here Pete?

I can think of:
road surface
topography
wind
traffic volume

I honestly had a belief that the premium brands had some sort of diesel injector cleaning properties.  Useful for a hard blast up and down the dual carriageway before an mot emissions test.
You forgot the obvious variable - when going to Durham you're going uphill, then back down to Bristol.

:clap: :clap: :clap:


 

ZombieCake

Active member
The journey needs to be repeated with the Clio both laden and unladen, and with respect to velocity, as that is what those wise in the ways of science would have done.
 

pwhole

Well-known member
Well as a non-driver, I was hoping to find out a little more about Stihl strimmers and their performance on luxury fuels, but no such luck. Mind you, I don't have a garden either. Staring out of the passenger window again. But of course artists don't drive, they're driven. :halo:
 
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