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That advice is certainly questionable, even before entering into subjective experiences of car owners.
1) HJ was adamant that all WLTP/NEDC official figures were achieved on super fuels, usually Shell V-Power. Volvo categorically stated this to him.
2) Quite a lot of performance engines benefit from super fuels. Honda's 2.0VTEC in the S2000 was ran both hot and slower if not on 98RON.
3) Higher octane and higher cetane (diesels) create more torque, allowing increased efficiency. TC auto boxes will change up sooner, so in the hands of a careful driver, economy should improve.
Finally, our two cars, one petrol auto, one diesel manual, are quieter, smoother and more responsive on V-Power. The economy gains are hard to pin down, as no two journeys are the same, but occasional switches to 95RON, supermarket fuels is a marked difference.
Perhaps Shell could respond to the new advice in HJ section?
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That advice is certainly questionable, even before entering into subjective experiences of car owners.
1) HJ was adamant that all WLTP/NEDC official figures were achieved on super fuels, usually Shell V-Power. Volvo categorically stated this to him.
2) Quite a lot of performance engines benefit from super fuels. Honda's 2.0VTEC in the S2000 was ran both hot and slower if not on 98RON.
3) Higher octane and higher cetane (diesels) create more torque, allowing increased efficiency. TC auto boxes will change up sooner, so in the hands of a careful driver, economy should improve.
Finally, our two cars, one petrol auto, one diesel manual, are quieter, smoother anad more responsive on V-Power. The economy gains are hard to pin down, as no two journeys are the same, but occasional switches to 95RON, supermarket fuels is a marked difference.
Perhaps Shell could respond to the new advice in HJ section?
Where on earth is the evidence for your third paragraph?
Never heard of higher octane producing more torque.
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Quite simply higher octain contains more stored energy, when it ignites in the combustion chamber it creates a higher pressure on the piston crown pushing it back down the bore with more force, so in theory you shouldn't need to open the throttle as much for a given amount of acceleration using regular fuel.
That said I'm quite prepared to be shot down in flames......
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Quite simply higher octain contains more stored energy, when it ignites in the combustion chamber it creates a higher pressure on the piston crown pushing it back down the bore with more force, so in theory you shouldn't need to open the throttle as much for a given amount of acceleration using regular fuel.
That said I'm quite prepared to be shot down in flames......
You are shot down in flames.
NO difference in energy content. It is different additives in miniscule amounts...
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<< NO difference in energy content. It is different additives in miniscule amounts...>>
In molecular terms, the 'energy content' will be almost identical for different grades of petrol, because it derives from the bonds between carbon and hydrogen which are broken in the combustion process. The difference is in the branching of the carbon chains, which affects the rate of combustion in the cylinder. More branching makes for a smoother burn. When the Octane rating was first devised IIRC it was based on a figure of 100 for iso-octane, the most branched C8 easily available.
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The higher the octane number, the more resistant to knock (or pre-ignition), so an engine can run with the ignition with a greater degree of ignition advance (and a higher compression ratio) thus increasing torque output. Engines only produce torque (and heat), the PS or BHP is a contrived formula.
Edited by mcb100 on 09/07/2020 at 13:53
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3) Higher octane and higher cetane (diesels) create more torque, allowing increased efficiency. TC auto boxes will change up sooner, so in the hands of a careful driver, economy should improve.
Higher cetane doesn't have the same effect in diesels as higher octane does in petrols.
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But if all this was true about torque there would be loads of empirical evidence wouldn't there?
As the OP quotes, none exists!
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The key line in there is 'performance cars and some classics excluded'. If the engine mapping is designed to benefit from a higher octane number, then the science says that there will be an improvement in torque output.
They don't fuel F1 cars at Tesco for a reason.
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Personally, since moving to Colchester I have used Asda, They only sell one grade, so that's what it gets. When we were going to belgium I would fill up at the tesco just outside dover ,
Even the cheapo 91 ron petrol e10 in Carrefour at Dunkirk has never seemed to trouble whichever car i have been in.
I just try to use busy petrol stations...
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That advice is certainly questionable, even before entering into subjective experiences of car owners.
1) HJ was adamant that all WLTP/NEDC official figures were achieved on super fuels, usually Shell V-Power. Volvo categorically stated this to him.
2) Quite a lot of performance engines benefit from super fuels. Honda's 2.0VTEC in the S2000 was ran both hot and slower if not on 98RON.
3) Higher octane and higher cetane (diesels) create more torque, allowing increased efficiency. TC auto boxes will change up sooner, so in the hands of a careful driver, economy should improve.
Finally, our two cars, one petrol auto, one diesel manual, are quieter, smoother and more responsive on V-Power. The economy gains are hard to pin down, as no two journeys are the same, but occasional switches to 95RON, supermarket fuels is a marked difference.
Perhaps Shell could respond to the new advice in HJ section?
I am no boffin when it comes to the science behind all this. I only speak from experience and that indicates that I get lower fuel consumption when using premium diesel. Never bothered with it in my old Skoda Superb 1.9tdi PD130 but my new Volvo appreciates the difference. I went from approx 43mpg to 48mpg when I switched. I do a similar long run a few times a year to North Yorkshire from Kent and this allowed me to judge the different fuels. As for smoothness; the car is a TC auto 8 speed and the engine is the latest design so they are quite smooth anyway. I also tow a 1450Kg caravan from time to time. I only do approx 8-10K miles per annum so the premium price doesn't bother me that much. IMHO it is worth it but understand other points of view.
Cheers Concrete
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I love this old chestnut. It never fails to cause debate.
Edited by groaver on 09/07/2020 at 17:13
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I love this old chestnut. It never fails to cause debate.
That sounds like the words of a sceptic. This is a regular topic which always illustrates the old dictum that most people just believe what they want to. Some of them will carry on doing that even when shown strong scientific evidence. As my earlier post says, I am not suggesting any great benefits of super-fuel, but I see nothing wrong in spending an extra quid or two to clean up an engine occasionally, especially just before a MoT test, for example.
On the other hand, if the only consideration is to spend as few ££ as possible, basic supermarket stuff is the way to go.
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I love this old chestnut. It never fails to cause debate.
That sounds like the words of a sceptic. This is a regular topic which always illustrates the old dictum that most people just believe what they want to. Some of them will carry on doing that even when shown strong scientific evidence. As my earlier post says, I am not suggesting any great benefits of super-fuel, but I see nothing wrong in spending an extra quid or two to clean up an engine occasionally, especially just before a MoT test, for example.
On the other hand, if the only consideration is to spend as few ££ as possible, basic supermarket stuff is the way to go.
I use super unleaded exclusively.
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I love this old chestnut. It never fails to cause debate.
That sounds like the words of a sceptic. This is a regular topic which always illustrates the old dictum that most people just believe what they want to. Some of them will carry on doing that even when shown strong scientific evidence. As my earlier post says, I am not suggesting any great benefits of super-fuel, but I see nothing wrong in spending an extra quid or two to clean up an engine occasionally, especially just before a MoT test, for example.
On the other hand, if the only consideration is to spend as few ££ as possible, basic supermarket stuff is the way to go.
I use super unleaded exclusively.
To give a alternative view I will never use super unleaded again unless the manufacturer specifically specifies it (unlikely on the cars I buy). Tried it in the Focus 1.8 petrol back in about 2003 for about 3 tanks. Did not notice any change to the way it ran but it did appear to do a few extra miles between fill ups. But towards the end of the 3rd tank it started to run poorly (just over 4 years old, probably 50,000 miles) and when I checked the plugs they were black. Cleaned them and refitted and filled with a tankful of Asda, seemed fine. After another 3 tanks of Asda checked them again and still fine. Ran car for another 5 years or more mostly of Asda and never had another issue.
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Our other car gets regular unleaded exclusively, supermarket or whatever is cheapest.
The Superb's manual states it should be used as does the inside of the fuel cap.
Do I notice a difference?
I've never used anything else so cannot say.
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That's interesting, I've not heard of 'mainstream' car specifying exclusively premium fuel. Which engine is it?
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That's interesting, I've not heard of 'mainstream' car specifying exclusively premium fuel. Which engine is it?
2.0 litre turbo'd VAG engine.
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Does it state an octane number requirement? Regular 95 is called Premium.
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I love this old chestnut. It never fails to cause debate.
That sounds like the words of a sceptic. This is a regular topic which always illustrates the old dictum that most people just believe what they want to. Some of them will carry on doing that even when shown strong scientific evidence. As my earlier post says, I am not suggesting any great benefits of super-fuel, but I see nothing wrong in spending an extra quid or two to clean up an engine occasionally, especially just before a MoT test, for example.
On the other hand, if the only consideration is to spend as few ££ as possible, basic supermarket stuff is the way to go.
I use super unleaded exclusively.
To give a alternative view I will never use super unleaded again unless the manufacturer specifically specifies it (unlikely on the cars I buy). Tried it in the Focus 1.8 petrol back in about 2003 for about 3 tanks. Did not notice any change to the way it ran but it did appear to do a few extra miles between fill ups. But towards the end of the 3rd tank it started to run poorly (just over 4 years old, probably 50,000 miles) and when I checked the plugs they were black. Cleaned them and refitted and filled with a tankful of Asda, seemed fine. After another 3 tanks of Asda checked them again and still fine. Ran car for another 5 years or more mostly of Asda and never had another issue.
I'm wondering if that issue was because you used a superunleaded supply that was E10 an not E5, as older engines (possibly that 1.8 petrol) may not like the higher ethonol content - this was highlighet in media reports when it was (erroneously, in my view) proposed that all fuels have their bio-fuel content upped from 5 to 10%.
There was a list of cars that included engines designed or prodcued in around 2004 (I think) and older, that would need to keep using a more limited supply of E5 (rather like old leded petrol when we changed over 25-30 years ago) filling stations or use special additives instead.
My Mazda3 1.6 petrol wasn't on the list as far as know, but I suspect it only *just* was new enough, as that engine first appeared in late 2003 I think. I would rather keep to E5 if I can. If I recall, some of the superfuels (not Tesco), probably only at some branded filling stations, have no biofuel content, and is perhaps why some owners of older/classic cars may be force into paying a huge premium (pardon the pun) to keep their car useable.
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All through my car driving life, I keep detailed fuel usage records.
I have tried premium fuel on every car I owned. With one exception it made no difference to fuel consumption or engine running. The exception was a 1963 Lotus Elan S3 tuned to Sprint performance + a bit 130bhp. It ran best on premium fuel
As for cleaning? Used She Super Expensive Diesel on Yaris Diesel. Made zero difference at MOT time : to pass the soot test it still required 20 miles at 5,000rpm (low mileage town journeys)
So on the basis of my own experience only - I treat with disdain claims made without detailed records ##- I say only required where stated or for performance cars. Cost wise, it is just added expense with no return...
## Claims made on the basis of mpg readouts on car displays can be dismissed out of hand..
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Claims made on the basis of mpg readouts on car displays can be dismissed out of hand..
I don't see why, if fuel-mpg comparisons are made on the same car. There should be no extra variables, unless superfuel improves performance so much that your driving style changes. The absolute values may be wrong, but the comparison should be valid.
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Claims made on the basis of mpg readouts on car displays can be dismissed out of hand..
I don't see why, if fuel-mpg comparisons are made on the same car. There should be no extra variables, unless superfuel improves performance so much that your driving style changes. The absolute values may be wrong, but the comparison should be valid.
If its one owner and one car using different fuels its possibly OK but if 2 owners are comparing notes than its likely to be total nonsense.
To keep things totally consistent and worthy of comparison several tank to tank fill ups are necessary but even then you should use the same garage, same pump and be pointing in the same direction (cross gradients for drainage make a huge difference to the amount you can get in) plus stop at the first click each time (hoping it stops at exactly the same point in the filler neck).
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<< To keep things totally consistent and worthy of comparison several tank to tank fill ups are necessary but even then you should use the same garage, same pump and be pointing in the same direction (cross gradients for drainage make a huge difference to the amount you can get in) plus stop at the first click each time (hoping it stops at exactly the same point in the filler neck). >>
I have never believed in the brimming method, partly because of the reasons you give, and partly because I don't like having a full tank anyway, especially in warm weather. I buy fuel in units of 10 litres (i.e. 20 or 30 at a time) to simplify calculations, and if I feel really keen I plot a graph and calibrate my odometer against km-posts on the motorway - tho those aren't always in the right place after road work. My daughter works in Trading Standards and used to do filling station checks, so I take pump accuracy at face value. I think pump fraud died out some time ago.
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I'm wondering if that issue was because you used a superunleaded supply that was E10 an not E5, as older engines (possibly that 1.8 petrol) may not like the higher ethonol content - this was highlighet in media reports when it was (erroneously, in my view) proposed that all fuels have their bio-fuel content upped from 5 to 10%.
The issue I had was in about 2003. Did E10 petrol actually exist back then? And the garage was a Shell station, very expensive stuff at the time.
Since the E5 or E10 topic hit the radar I have yet to see a garage selling this mysterious E10 petrol. All the sites I have used (mostly supermarkets with small sites on holiday) have the pumps clearly labeled E5. Even Morrisons, which some posters on other sites insist is poor quality E10 petrol label the pumps E5 and I have never had an issue using it.
For the record the handbook in the Nissan and the Skoda clearly state that E10 petrol is fine but any fuel with more than 10% ethanol will damage the car.
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I brim the tank if going on a long journey and set the trip. I then let the tank go as low as practical and brim again and then do the calculation which is good enough to check if fuel consumption is dropping off for any reason. More accurate obviously over a few fill ups. I never buy premium and always go for cheapest fuel.. Never had any fuel related problems
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Definitely more torque from Tesco Momentum in my 2003 Forester X
Going up the A3 Hogs back I can do it in 4th gear on Momentum at 50mph but need to peg it down to 3rd on 95 octane.
I normally use Momentum or BP 95 but years ago put a tankful of Jet in. I thought my car was due a service or something was going wrong as the car felt awful. The next tank of BP sorted it out and back to normal. It's a low performance, non-turbo engine but fuel makes a huge difference for some reason.
Incidentally, I own a S2 Etype that seems to run as well on 95 as 99, though I usually use Momentum.
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Definitely more torque from Tesco Momentum in my 2003 Forester X
There will be if its a Turbo because as if I remember correctly Subaru specified high octane fuel for the turbo models. Not sure about the N/A models but i doubt it would make much (if any) difference in those even if it was recommended.
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Definitely more torque from Tesco Momentum in my 2003 Forester X
There will be if its a Turbo because as if I remember correctly Subaru specified high octane fuel for the turbo models. Not sure about the N/A models but i doubt it would make much (if any) difference in those even if it was recommended.
My N/A BRZ required 98 Ron.
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Definitely more torque from Tesco Momentum in my 2003 Forester X
There will be if its a Turbo because as if I remember correctly Subaru specified high octane fuel for the turbo models. Not sure about the N/A models but i doubt it would make much (if any) difference in those even if it was recommended.
My N/A BRZ required 98 Ron.
But the BRZ is not a 2003 off roader.
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Definitely more torque from Tesco Momentum in my 2003 Forester X
There will be if its a Turbo because as if I remember correctly Subaru specified high octane fuel for the turbo models. Not sure about the N/A models but i doubt it would make much (if any) difference in those even if it was recommended.
My N/A BRZ required 98 Ron.
But the BRZ is not a 2003 off roader.
Yes funny that, isn't it.
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Yes funny that, isn't it.
Sorry TB, that was meant to be a witty retort.
Upon seeing it again today it looks sarcastic and sharp.
I apologise.
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Yes funny that, isn't it.
Sorry TB, that was meant to be a witty retort.
Upon seeing it again today it looks sarcastic and sharp.
I apologise.
Perhaps I should expand on my original comment.
The BRZ/GT86 produce 200 bhp from a N/A 2 litre engine. In relation to roadcars that is a pretty high state of tune. The original BMW M3 produced about that from a N/A 2.3 (the Evo's produced a bit more), at the same time a Sierra Cosworth needed a turbo to get 200 bhp from a 2 litre (a rubbish figure by todays standards).
Go back to the 60's and 100 bhp per litre was accepted as an excellent figure from a racing engine, the all conquering Cosworth only produced 400 bhp form its N/A 3 litre which increased to 500 bhp over its 20 years of use in F1 cars. The Cosworth BDA used in fords rallying Escorts produced about 240 bhp from a N/A 2 litre after a decade of development and that needed to rev to 12,000 before you had all that power. And those cars used an evil brew of petrol to get less bhp/litre than the BRZ/GT86 get today using pump fuel.
So I think its pretty fair to say that its only to be expected that the BRZ/GT86 need 98 RON to get max power but what is just as incredible, they will still run safely (but a bit down on power) on 95 RON wheras the monsters of 50 to 30 years ago would melt pistons without the special brews.
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So I think its pretty fair to say that its only to be expected that the BRZ/GT86 need 98 RON to get max power but what is just as incredible, they will still run safely (but a bit down on power) on 95 RON wheras the monsters of 50 to 30 years ago would melt pistons without the special brews.
That's the benefit of modern electronics
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So I think its pretty fair to say that its only to be expected that the BRZ/GT86 need 98 RON to get max power but what is just as incredible, they will still run safely (but a bit down on power) on 95 RON wheras the monsters of 50 to 30 years ago would melt pistons without the special brews.
That's the benefit of modern electronics
I think I read somewhere that the 2.0 litre engine in the BRZ is the block off a pre-existing motor with a new head and that they took a gearbox that had its roots in a truck originally.
What I did learn is that Subaru's NA engines are not very good at producing torque.
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Definitely more torque from Tesco Momentum in my 2003 Forester X
There will be if its a Turbo because as if I remember correctly Subaru specified high octane fuel for the turbo models. Not sure about the N/A models but i doubt it would make much (if any) difference in those even if it was recommended.
My N/A BRZ required 98 Ron.
But the BRZ is not a 2003 off roader.
But both are boxer engines, I believe, even if one is turbocharged. Maybe that type needs or significantly benefits from the higher octane fuels. No surprise for the high performance cars though.
Edited by Engineer Andy on 13/07/2020 at 14:11
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Definitely more torque from Tesco Momentum in my 2003 Forester X
Going up the A3 Hogs back I can do it in 4th gear on Momentum at 50mph but need to peg it down to 3rd on 95 octane.
I normally use Momentum or BP 95 but years ago put a tankful of Jet in. I thought my car was due a service or something was going wrong as the car felt awful. The next tank of BP sorted it out and back to normal. It's a low performance, non-turbo engine but fuel makes a huge difference for some reason.
Incidentally, I own a S2 Etype that seems to run as well on 95 as 99, though I usually use Momentum.
It might be for the Jet fuel (pardon the pun) that it was from a less-used filling station, and so the fuel may have been degraded a bit. Still, it's probably nowehere near as likely as just using lower grade fuel generally, and or the Jet stuff may not have the larger amount of cleaning agents as those in the 'top' branded ones like BP, Texaco, ESSO and Shell.
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