The premium fuel chestnut.

[anchorman]

Somebody on here not so long ago said “how dare you when considering all the people struggling to make ends meet” after suggesting there are tangible benefits in using premium fuel.  The answer to that might sound cruel but I don’t and furthermore if E6 engines are available we shouldn’t be using anything less and everything else should be scrapped.  We either have a climate crisis or we don’t and taking sympathy on low income families at the cost of future generations isn’t acceptable.   Catch a bus or walk (where’s my flack jacket).   
Now for another hard pill to swallow is whether this fuel thing is true.  I’ve worked on engines that have run on both and I say there is.  I don’t care that people have been using supermarket fuel for years, they haven’t on E6 engines because they haven’t been around for more than about ten years or less depending on the maker.   This video talks about new tech measuring wear on moving engines and the relationship between upper cylinder wear and fuel and fuel and oil deterioration.  We were actually measuring wear on moving engines via umbilical wires at our technology centre in Cawston when I was there in the late nineties although I’m sure they’ve improved on it.   
 

 

[SinglePointSafety]

As a professional STEM person, I found this extremely informative and I'm quite impressed by the attempts at rigorous experimental validation. Thanks for posting this anchorman, much appreciated

[jthspace]

Very interesting.

I have an E5 only MX5 due to age and use an ethanol reducing additive if E5 isn't available on a run and top up with Redex as well if I fill with E10.

My other MX5 gets E5 when available, and it definitely runs better, acceleration and performance.

I will have to consider E5 for the Yaris Cross now I've seen this; lots of high mileage Toyota engines out there, presumably having run on petrol prior to the ethanol increase. Will we see more high mileage engine issues start to occur if they are being run on E10????

[Mooly]

Having one of the problematic 1.33L INRFE engines in an Auris I can say with certainty that using E5 (and always ESSO) results in zero audible picking and pre ignition under all conditions whereas with E10 the pinking was actually horrendous at times and I'm also sure very damaging and destructive and was without doubt a contributory factor to the cat failure. 

[anchorman]

35 minutes ago, jthspace said:

Very interesting.

I have an E5 only MX5 due to age and use an ethanol reducing additive if E5 isn't available on a run and top up with Redex as well if I fill with E10.

My other MX5 gets E5 when available, and it definitely runs better, acceleration and performance.

I will have to consider E5 for the Yaris Cross now I've seen this; lots of high mileage Toyota engines out there, presumably having run on petrol prior to the ethanol increase. Will we see more high mileage engine issues start to occur if they are being run on E10????

I’ve always said that you won’t get enough improved mpg to cover the cost of the high grade fuel but the things you can’t see are more important.  Interestingly though, when I ran my Yaris/Cross on high grade fuel, they did seem to run smoother and give noticeable improvements in economy.  I’m wary of placebo effects and I didn’t measure anything noise wise and I didn’t have them long enough to be sure about how much the economy was improved.  

[anchorman]

2 minutes ago, Mooly said:

Having one of the problematic 1.33L INRFE engines in an Auris I can say with certainty that using E5 (and always ESSO) results in zero audible picking and pre ignition under all conditions whereas with E10 the pinking was actually horrendous at times and I'm also sure very damaging and destructive and was without doubt a contributory factor to the cat failure. 

You’ve hit another nail on the head there.  The engine management computer uses a knock sensor to advance the timing just short of pinking (detonation) and it has much more scope with higher octane fuel.   You can test the effects of that by turning the distributor on an older engine and it makes a big difference.  If everything is working right, you shouldn’t hear any pinking other than an odd occasion when the engine is shock loaded but high grade fuel will definitely reduce the liability.  

[Primus1]

I wonder how many owners will be keeping their cars long enough to worry about using different grades of fuel..?

[Yaris_Cross]

25 minutes ago, anchorman said:

I’ve always said that you won’t get enough improved mpg to cover the cost of the high grade fuel but the things you can’t see are more important.

I use Tesco Momentum 99 (E5) its only 2 pence a litre more than my local garages E10 so in my view worth the extra.

 

Tesco Momentum 99
Published 28 February, 2024

Our Momentum 99 petrol contains a special blend of additives to help keep a car's fuel system clean and working at its best.

Additionally, the higher octane level (99 compared to 95 for regular unleaded petrol) gives improved overall engine performance for cars that are able to take advantage of this (generally, sportier models).

Most Tesco Petrol Filling Stations across England, Scotland and Wales stock Momentum 99. We don’t currently have a supply terminal that is able to produce our high octane base fuel to blend with our exclusive additives in Northern Ireland.

 

[skidlid]

Been using the cheapest Supermarket fuel since the mid 80's and never had an issue. Both our main cars (Yaris and Superb) are fine on E10 so that is what we use.

But our 3rd car (from the 80s) has some fuel system components in it that may not be compatible with E10 so its E5 in that one. The engine would be fine (its 20 years newer than the car) but it would be a nightmare finding out if pumps and seals (all less than 20 years old and mainly form the USA) were OK, the UK importer has no idea.

Last weekend put some E5 in at the nearest Shell and it was £1.65 a litre. Yesterday at Tesco E10 was £1.34 a litre. That is £1.41 a gallon extra for no benefit whatsoever on new cars.

[jthspace]

28 minutes ago, anchorman said:

I’ve always said that you won’t get enough improved mpg to cover the cost of the high grade fuel.....

My MX5 ND (2018) will return between 5 and 8 MPG better with E5. Recent tour of Lake District (4 car group) resulted in an average of 50 MPG on the run up.

As you say, not enough to cover the 12p to 15p average difference at the main petrol stations

[Ralph H]

10 minutes ago, Primus1 said:

I wonder how many owners will be keeping their cars long enough to worry about using different grades of fuel..?

I’m one of those people who changes my car regularly so I’m not overly worried about engine wear. I tried a couple of tanks of premium fuel in my last car after reading comments on here but I personally couldn’t tell any difference.

I wonder whether it’s worth paying more in the long run as with modern engines which wears out first the engine or all the other parts of the car?

[Flatcoat]

I always use Vpower type fuels and have done so for about 20 years. Whether petrol or diesel I tended to run remapped engines and convinced the higher cetane or octane plus other additives had noticeable benefits WHEN USED REGULARLY! My nephew is a a senior race engineer with United Racing (half owned by McLaren) and former owner of his own team racing Minis and Chevrolet. He is senior engineer for one of United’s LMP teams. He drives an M2 Beemer and always uses Vpower type petrol, he wouldn’t use anything else whatever the car. 

[MikeSh]

1 hour ago, Yaris_Cross said:

I use Tesco Momentum 99 (E5) its only 2 pence a litre more than my local garages E10

That's a daft comparison. How much more is it than the Tesco E10? (Usually from the same pump.)

[Cyker]

It'd be very unusual to get better mpg from E5 as, per litre, it has less "fuel" in it than E10.

Where it would benefit is if you have a high-compression engine which is designed to run on it at a higher compression ratio but would knock with normal fuel, but most cars are designed to run on, and be most efficient with, 95RON so they can't really take advantage of the higher octane rating of E5.

Where current E5 benefits normal cars is the additive packages they put in it - They usually* have a higher % of lubricity enhancers, octane boosters and especially detergents and dispersants etc. per litre compared to E10, which will help clean off any crud building up on anything the fuel touches, mainly the injectors.

I still throw a tank in now and then as a habit from when I had a diesel Yaris, where it made a very noticeable difference.

I have to say with the hybrid, presumably because petrol burns much cleaner to begin with and this not being a 15 year old car  , I notice very little difference between the two in terms of performance, fuel economy or even engine note. I have noticed changes in engine note with specific brands more than I have between E5 and E10 (Mine sounds rougher with Shell anything, but smoother with BP E5 and Jet E10! )

 

*Shell Fuelsave was an exception, as that was E10 with a similar high additive package, but that seems to have been discontinued...?

[jthspace]

I have used Miller Oil's petrol additive in my 1993 MX5 and it's . . . . WOW!

• Octane enhancement of up to 2 octane numbers ( 20 points ) dependent on fuel quality.
   
• Prevents valve seat recession when used with unhardened valve seats.
   
• Prevents detonation, hot spots & over run.
   
• Prevents fuel system corrosion and helps protect components.
   
• Combats the adverse effects of ethanol in fuel up to E10.
   
• Carburettor anti-icing formula.
   
• Contains anti oxidant to improve fuel life

This product is an ‘all in one’, multi-shot, petrol fuel treatment providing ethanol protection, lead replacement and an octane improver dependent on selected fuel quality.

Recommended for all classic engines previously requiring leaded fuel and now running on unleaded fuel. One bottle treats 10 tanks, based on 50L tank size.

VSPe 500ml (Part Code: 7917)

Dosage Rate

One 500ml bottle treats:

500 Litres (10 x 50L tanks) of unleaded fuel

1ml/1 Litre of unleaded fuel

£33 is not cheap - but then again, neither is my restored MX5, currently on 145,000 kms

Just don't read the health warnings.

[anchorman]

2 hours ago, skidlid said:

Been using the cheapest Supermarket fuel since the mid 80's and never had an issue. Both our main cars (Yaris and Superb) are fine on E10 so that is what we use.

But our 3rd car (from the 80s) has some fuel system components in it that may not be compatible with E10 so its E5 in that one. The engine would be fine (its 20 years newer than the car) but it would be a nightmare finding out if pumps and seals (all less than 20 years old and mainly form the USA) were OK, the UK importer has no idea.

Last weekend put some E5 in at the nearest Shell and it was £1.65 a litre. Yesterday at Tesco E10 was £1.34 a litre. That is £1.41 a gallon extra for no benefit whatsoever on new cars.

Not in an E6 engine you haven’t and whether it is no benefit is simply untrue.  If you worked in a garage with a healthy throughput of cars, you’d soon be delving into engines with gummed up injectors and blocked GPFs.  I’d go so far to say using high grade fuel is essential in modern diesels.  Browse any forum for the horror stories.  

[TonyHSD]

I am probably the member that drives one of the older cars here and the one that uses the highest amount of petrol and for me the E10 is ok to use when E5 it’s not available or way too expensive. However similar to what Toyota manual says about oil can do 5w30 but switch back to 0w20 at the next oil change I will refill with E5 from bp or esso, Shell next time. 
Also not two petrol station sell same fuel, base perjury it’s same and even may come from the same refinery but the end product in your tank is different. The cheapest garages sell cheap for a reason - those fuels lack important additives and can cause issues. 
Most people never had any problems, until one day they have and then the big headache and large repair bills has become. 
E5 - better fuel for all engines, big or small, and the real benefit is only one - no problems now and no problems in the future. 👌

[anchorman]

Just now, jthspace said:

I have used Miller Oil's petrol additive in my 1993 MX5 and it's . . . . WOW!

• Octane enhancement of up to 2 octane numbers ( 20 points ) dependent on fuel quality.
   
• Prevents valve seat recession when used with unhardened valve seats.
   
• Prevents detonation, hot spots & over run.
   
• Prevents fuel system corrosion and helps protect components.
   
• Combats the adverse effects of ethanol in fuel up to E10.
   
• Carburettor anti-icing formula.
   
• Contains anti oxidant to improve fuel life

This product is an ‘all in one’, multi-shot, petrol fuel treatment providing ethanol protection, lead replacement and an octane improver dependent on selected fuel quality.

Recommended for all classic engines previously requiring leaded fuel and now running on unleaded fuel. One bottle treats 10 tanks, based on 50L tank size.

VSPe 500ml (Part Code: 7917)

Dosage Rate

One 500ml bottle treats:

500 Litres (10 x 50L tanks) of unleaded fuel

1ml/1 Litre of unleaded fuel

£33 is not cheap - but then again, neither is my restored MX5, currently on 145,000 kms

Just don't read the health warnings.

I don’t use it in my Lexus or recent petrol engined cars as I only put high grade fuel in.  I used millers eco diesel max along with my high grade diesel in my Mazda CX-5s.  Excellent stuff.   

[anchorman]

2 hours ago, Primus1 said:

I wonder how many owners will be keeping their cars long enough to worry about using different grades of fuel..?

It’s a good point.   I certainly haven’t but the therapy on deterring me from new cars still hasn’t worked.  It’ll have to soon because I’m not working forever.  Some of my cars of my cars have gone to mates so it has maybe set them off on a good footing.   

[hind]

I'm using cheapest E10 fuel I can find and I plan to keep the car as long as possible. I will let you know when my injectors fail 🙂

[skidlid]

1 hour ago, anchorman said:

Not in an E6 engine you haven’t and whether it is no benefit is simply untrue.  If you worked in a garage with a healthy throughput of cars, you’d soon be delving into engines with gummed up injectors and blocked GPFs.  I’d go so far to say using high grade fuel is essential in modern diesels.  Browse any forum for the horror stories.  

What is an E6 engine. Only fuel round these parts is E5 and E10.

When we had modern diesels we used the cheapest supermarket fuel and like with petrols no issues. In 10 years of having cars with DPF's (Euro 4 and Euro 5) not a single issue.

[Madasafish]

4 hours ago, Primus1 said:

I wonder how many owners will be keeping their cars long enough to worry about using different grades of fuel..?

I bought my Honda Jazz in 2012. Always used the cheapest fuel except when trying to get better mpg.  I use Fuelly to produce mpg so accurate --- same results every time.. no difference..

Over 12 years and 62k miles the only variations are weather and journey length and road type. Changes of fuel make no difference..

[Mooly]

6 hours ago, anchorman said:

The engine management computer uses a knock sensor to advance the timing just short of pinking (detonation) and it has much more scope with higher octane fuel.   You can test the effects of that by turning the distributor on an older engine and it makes a big difference.

I remember those days... 1.1L Escorts and trying to get the last ounce of performance from them. The Toyota on E10 could literally sound like a bag of spanners after for example slowing to exit a motorway and then accelerating away again from say 5mph in second. It would clunk and clank and at time I felt the timing get whacked right back as the acceleration was reigned in. You then felt it advance over the next few seconds as it picked up. 

So its E5 all the way now along with the Denso plugs I think the Prius uses and for which I can't just remember the number (IXX ish equivalent to the dropped HC20 in heat range I believe) and not the Toyota recommended HC16 which were a hotter plug and a total absolute disaster in the 1.33L when used with E10 fuel.  

  

[hind]

2 hours ago, skidlid said:

What is an E6 engine

Euro 6 emissions level? 

[Neptuneblue]

6 hours ago, Primus1 said:

I wonder how many owners will be keeping their cars long enough to worry about using different grades of fuel..?

 Me. Mine is a 73 plate 2.0 excel. The right amount of technology, nippyness and economy to see me through till the electric/ hydrogen/ whatever future is sorted in 10 years. I’ll still only have 80k miles on by then.

It’s run exclusively on the good stuff for the reasons mentioned by others above. I use Costco so cheaper than ordinary virtually everywhere else where I live.

As I’ve noted before: it’s my perfect car😎