[Closed] E5 E10 Petrol question

Only learnt of this last night from the BBC news site. Bookmarking.

E10 will work out a bit more expensive. It is less combustible so your fuel economy will be reduced. So you'll use more petrol (£s) to go the same distance.

Also, FWIW, I can't put E10 in my motorbike as it will cause the plastic fuel tank to swell up and distort.

I think some of the premium fuels used to have no ethanol, but they all seem to have 5% now according to their websites

AFAIK before today all petrol was produced to E5 standards so super unleaded would have been e5 and still is. Not going to get drawn into the mire of carbon, fuel economy etc I'm sure there's a whopper of a thread on piston heads..

As I understand it the only E5 available for older cars / bikes will be what is classified as Super Unleaded at present. Do about 10-14p more expensive per litre.

No clue if new e10 will be the same price as current e5 thats being phased out.

E10 has less energy in it per litre as ethanol isn’t as energy dense from what I’ve read so mpg could drop a bit. What joy.

Use Super unleaded fuel if you have an older vehicle that isn't E10 compatible or for using in garden tools, mowers etc.

Think there is a drop in mpg of about 1% so don't think you'll notice it...but octane is boosted a bit so in theory performance should not be hampered. Pricing is another matter...someones got to pay for the loss of fuel duty as more people move to EV's.

Super etc stays as E5. If E10 is worse on MPG, then I'll go to Super as I get 10% better fuel efficiency on a motorway run, which covers the 10% premium.

My car is just within the manufacturers age - 2002 car, of which All Nissans past 2000 are compatible. But, the car is older etc, and sits unused a fair amount, so not sure the additional 'moisture absorbancy' of E10 is a good idea.

I suppose I better stick my head in 😉

The normal regular grade will now be max E10, that Is to say anywhere from E0 to E10 depending on economics (cost of bio Vs cost of buyout).

The Premium grades, which have historically been just been 97Ron plus, will now be the "protection grade" with a max 5% ethanol. In reality I'd be surprised if you actually see an E10 for quite some time yet.

Wrg to mileage figure difference between and E10 and E5 is not a straight forward answer if you look at it forensically, but as a broad brush statement you will not see any difference.

You could still have a low energy density fuel with less ethanol than you could with a fuel with ethanol, it's largely down to the oxygen content of different components.

Depending on vehicle type, you may benefit from the higher octane if the car is designed to advance the spark, therefore making it more efficient (much more to it but that's the basics). You will also benefit from the premium grades have get clean add packs, that will make your engine run happy.

There are remote areas that have been given exemptions to supply E0 to E5 as the only fuel type without affecting their liability to the government, this has been done for strategic reasons.

Old cars/chainsaws etc most have either already had seals and gaskets replaced, or their is oil added to the fuel mitigating the solvency.

There will always be some vehicles that suffer, but that unfortunately is tuff, you will need to go to experts 😎 to get stuff that your pride and joy can run..

I have a 1974 VW camper and even with the E5 fuel I have to replace all my fuel lines and have my carbs rebuilt regularly if I don’t want fuel leaks and a potential fire! I try and fill up with super where I can, but it’s not available everywhere.

You shouldn't need to rebuild carbs unless the fuel has leeched plasticisers and left deposits, and or the carbs are old with incompatible seals/gaskets. If you're going to run classics, you either have to get specialist fuel, or systematically go through the fuel system and change lines, gaskets etc to something more suitable, they are available as aftermarkets.

It's been available here in France for a while. It makes no difference I can detect over most of the rev/load range. At very low revs the engine seems a tad smoother with E10, it can be put into top gear without protest just a fraction earlier.

@Sui
Any idea on potential effects of ethanol on steel fuel lines?
My 80s banger always runs on premium being a reasonably high compression turbocharged engine. However the steel fuel lines will probably need replacing soon, as will the feed and return rubber hoses which are crimped to the steel pipes and route over the exhaust manifold.
I'm undecided whether to run flexible lines front to back or stay stock with the steel hard pipes.

Steel will be fine (pipeline networks are a carbon steel) you could go stainless but hardly worth it, the only thing that will attack them is water, but it's unlikely. It will be the rubbers that have potential to go brittle, or with some the opposite and they go soapy especially buna . Viton or PTFE are more than upto the job.

Thanks, that's very useful.

I read that on some turbo petrol cars you could run much more boost when running on E85 because it was less susceptible to knocking, and you could extract much more power. If we are on E10 would a modern turbo petrol advance the timing a bit more than with E5 for the same reason?

In reality I’d be surprised if you actually see an E10 for quite some time yet.

It’s at the pumps around me already - saw it when I filled up my diesel 🙄 car…

@Sui we've talked before so I hoped you'd chip in. I checked last week and Esso are still claiming synergy 99+ is ethanol free. While they do, the mower and chainsaws will get that (+ star-tron stabilizer). The vrs will got a tank of synergy last instead of the usual v-power, it seemed to give better mpg by about 10%. I was stunned at that and suspect it must be just conditions/fluke, but I'll try synergy again. Any views on Esso Vs shell?

Big daddy, you saw the stickers as it's law now (from 1st). Think Sui means it'll be a while belt the actual fuel changes

It’s at the pumps around me already – saw it when I filled up my diesel 🙄 car…

Just because it's labelled as E10 (which it has to be now) doesn't mean that there will actually be 10% ethanol in there.

@bigdaddy All Tesco’s standard unleaded pumps have said E10 for a bit, but as @sui has said above it just means max E10

I read that on some turbo petrol cars you could run much more boost when running on E85 because it was less susceptible to knocking, and you could extract much more power. If we are on E10 would a modern turbo petrol advance the timing a bit more than with E5 for the same reason?

I guess so, I know the Aussie car guys love E85 and use flex fuel ECUs to maximise power from it, they also fit larger fuel pumps or additional pumps because you use a LOT of it. It would ruin your day commuting on it I think.

Fair enough, I stand corrected!

Thanks all,

It’s at the pumps around me already – saw it when I filled up my diesel 🙄 car…

As others have said, it just means max allowable. Economics will dictate what actually ends up in there.

Ref E85 use, because the energy density is 1/3rd less of non oxygenated components, it means you need to pump a boat load more fuel through, but if you can burn it quick enough (which the timing will do) then you can/will get better performance. Think of top fule methanol cars, similar energy density, but my they drink fuel like crazy..

Oh also the Esso 99ron, to the best of my knowledge there is no ethanol free fuel with Esso, they will be using it to boost the Ron, they certainly changed the labelling round my way..

Ref mpg gains Vs vpower possibly a fluke, and or you were still running an older batch of non ethanol 99ron plus add pack differences, time of year, tyre condition etc really hard to know.

In reality I’d be surprised if you actually see an E10 for quite some time yet.

Been at the garages around here for a couple of months? Are you saying the label may not reflect what’s in the tanks.

Don’t think it will cause too many car issues but I hear the E10 could cause issues with lawnmowers etc if they are left in the shed with fuel in the tank and that they should be drained over winter

Sorry I don't understand the max allowable point for labelled E10...

If more %ethanol is 'better' so it is being phased in, what is the need for a maximum.?

what is the need for a maximum.?

Engine (and other component) compatibility

Been at the garages around here for a couple of months? Are you saying the label may not reflect what’s in the tanks.

Yes.

As a few have said it's a maximum amount. Most vehicle manufacturers have signed of on E10 for quite some time, not least because so many platforms are used globally, some are happy with E20, but you do notice mileage drop at this point.

The key parameters within a fuel spec are normal physical characteristics, but there are also some compositional too as these can have a detrimental effect on components and emissions. The reason we speak about ethanol so much and not other oxygenates, is down to cost making it the preferred option for octane boosting (next to lead nma, and manganese additives), but as they've for the most part been ruled out of bounds, you go with Ethanol, but as said above it comes with some downside, so hence the labelling.

There is an ongoing debate if we further increase ethanol content to 20 or even 25% (very large studies done recently) as there are benefits with potential octane increase in efficiency, but also using less fossil derived fuels despite the lack of energy density of oxygenates. There is a balancing act. There are also plenty of trials that have been carried out now using ethanol converted to a typical petrol (dehydrate and drop the oxygen molecule) which can service legacy fleets or stranded assets. Other tech terms you'll hear is e-fuels or carbon capture.. they're all being developed to replace fossil.

Got it.
So presumably E5 might be anything from zero to 5%?

Got it.
So presumably E5 might be anything from zero to 5%?

Yep, same for E10.

It's only the flexfuel grades that have a min amount, think it's 65% for the E85 due to winter cold start issues...

@Sui here's the quote

'Although our pumps have E5 labels on them, our Synergy Supreme+ 99 is actually ethanol free (except, due to technical supply reasons, in Devon, Cornwall, North Wales, North England and Scotland). Legislation requires us to place these E5 labels on pumps that dispense unleaded petrol with ‘up to 5% ethanol’, including those that contain no ethanol, which is why we display them on our Synergy Supreme+ 99 pumps.

There’s currently no requirement for renewable fuel, like ethanol, to be present in super unleaded petrol although this could change in the future, in which case we would comply with any new legislation.'

from here
https://www.esso.co.uk/en-gb/fuels/petrol

the page has been updated again since i last looked as it now says right up top 'All regular fuel is now E10'. So they are claiming the synergy supreme 99+ to be ethanol free. The tank I had, and it was a tank...I was on fumes, was back in late July and up in Liverpool. My local Esso (Brixton) is being refurbished so I'm yet to see what they will have. my usual Shell (crystal palace) is E10 for regular now, but the Vpower remains E5. I emailed Shell back when we last talked about this and Shell confirmed they no longer guaranteed v-power to be ethanol free. I'm happy enough with v-power in the car but will try more tanks of synergy, and will use that for the chainsaws.

I wish I'd known all this before I rebuilt a friend's petrol strimmer that'd been laid up full of fuel for 11 months and was donald ducked because ethanol had rotted all the rubber bits.

Interesting reading, thanks.

@neil thanks for that, I'll have to go have a look into it, it's been a little while since I spoke to anyone there!

Use Super unleaded fuel if you have an older vehicle that isn’t E10 compatible or for using in garden tools, mowers etc.

Thanks for making that point, hadn't thought about the mower. Checked car was okay on gov.uk checker but forgot about mower.

As a few have said it’s a maximum amount.

Interesting. So, it’s just like “May contain nuts” on some food packaging.

Heathrow - labels all say E10. My car seems to be using a bit more fuel, but that could be down to increased traffic.

Drac
Full Member
As a few have said it’s a maximum amount.

Interesting. So, it’s just like “May contain nuts” on some food packaging

Yep.

My Mk4 Golf petrol engine isn't E10 compatible, so it looks like Premium for me.

Will I need to do anything different with my 2 yr old petrol lawnmower?

At the moment I just fill it up with unleaded Perry and try not to leave any in it over the winter

If you only need smaller amounts of Ethanol free petrol for an old garden tool or a classic motorbike say, then removing the stuff seems pretty straightforward (if a little bit of a pain for larger amounts)

Removing the ethanol will dramatically lower the Ron too.

If you want ethenol free buy Esso synergy supreme 99+. The other makes of premium may have some ethanol but are better then the regular. If Esso changes, then Aspen or Stihl motomix alkalyte fuel is very good, but expensive.

For those that might struggle with the official government checker, you can also use this https://www.zemo.org.uk/work-with-us/fuels/projects/e10-checker.htm

Removing the ethanol will dramatically lower the Ron too.

At 5% it's not too bad, a 95 will drop to 93.5 give or take. 10% will drop maybe 3 numbers. Most cars have a protection map/knock limiter that will mitigate against it but you'll see a drop in performance.

then Aspen or Stihl motomix alkalyte fuel is very good, but expensive.

They will certainly work and are nice and clean at the tailpipe as they don't contain aromatics (though if you did do this in an engine the fuel wasn't designed for, there are potentially long term issues with gaskets going brittle), but would t fill my car up at £4 a litre.

Oh also, I wouldn't recommend doing what that bloke up there is doing, you'll end up with excessive amounts of water in your fuel which will cause rust. Of you only need a small amount, then Stihl or aspen is a good bet.

Yeah running a car on aspen would cost a lot!

Current car likes shell VPower 99Ron - runs smoother, tad more power, pops and bangs more on the overrun to annoy the locals (modern turbo so adjusts to either, and yes its noticeable) Are you saying that this will now become 95Ron E5? Hope not.

With my 1960 bsa ( that has never been converted to unleaded even) what do you think any issues might be. Its got modernish fuel lines so they should be OK. float in the carb is plastic and the needle rubber tipped. Might that be an issue?

The octane levels in the "protection grades" will remain as they are marketed, so don't worry about that, premium grades have a min req of 97ron, those marketed with higher will be higher!

The BSA bike, im assuming the tank is metal, some bikes have old plastic tanks and they can get very thin after a while. Again it's the rubbers you need to look at, if your lines are relatively new you're likely to be ok, just check what they are made from.

just going back to whether there's actual legislation on the fuel or labelling or whatever, apologies if this has been stated above, but what legislation / guidance is actually in place forcing any changeover?
is the only forced change that petrol stations now cannot supply old style 'E5' cooking petrol, it has to be super/premium grade E5?
in which case, given the E5 and E10 are both maximum standards, wouldn't whatever be supplied in E10 now just be whatever is cheapest, regardless of how much ethanol is present.
where is the economic encouragement to use more ethanol being driven from?
producers? other governments?
Say I believed that for environmental reasons I should be using fuel with more like 10% ethanol in, where would I be able to know I am buying this from at the pump? it could just be like the old E5 regular no?
I guess electric cars aren't mandatory but provision is being made and choice is there. at least you know its running on electricity and not "up to 10% electricity"
am I being a bit thick here?

I was complaining on another thread that my ancient lawnmower refuses to die and I therefore cannot justify getting an electric one. This is despite me never servicing it, never topping up or changing the oil and leaving it outside all year round. Maybe if I chuck in some of the new fuel and leave it I'll finally have a reason to get a new mower

@tjagain - you just may have to rebuild the carb more regularly, change fuel lines and get in the habit of not leaving any fuel in the system for long periods of it sitting idle.
There's quite a bit of chat in the whole classic world about all of this and the general consensus seems to be to use Super fuels where you can, check carb and fuel tank seals regularly and to run the system dry before storage. A few places have said they are looking to formulate a fuel specifically formulated for leaving in a system over winter, basically a litre or so that you put in. Some fuel systems don't like being sat dry as the fuel makes the gaskets swell slightly (my Mini's carb is like this) and if it goes dry it will go hard, crack and need replacing.

It will go the same way as when leaded fuel went, people will come up with solutions.

Another motorcyclist with plastic tanks here, one swelled enough for it to hit the forks on full lock (actually an mot failure but got it through) on another the paint has bubbled & the third one just gets touched by the handlebar mount & left two little marks in the tank paint. All due to ethanol in petrol & that was on E5, have now been using the super unleaded when I can. E10 definitely not getting anywhere near them ☹️

@dendennis

Regular grade fuels will be as they always were, but with a maximum allowable amount of Ethanol at 10%

Premium, has never been quite straight forward depending on the supplier. Premium grade was always about higher octane and better additive packages. This is still the case, but what is happening now is that the Premium grade will have a cap of 5% ethanol so that older vehicles can use it.

in both cases, its the economics of is the Ethanol cheaper, than the buyout clause of now have ethanol. For this, you need to read up on the RTFO guidance. This is basically what incentivises/penalises fuel producers to include more "bio" / sustainable components in their fuel. This has always been done on what's called a "mass balance" system, where if you could have 2 products, 1 @ 100% sustainable, the other at 0% sustainable (for this argument the ethanol is the sustainable product). You could, at the pump claim that the fuel is 50%sustainable on a mass balance, as long as you only accounted for 50% of the ethanol to sustainable elsewhere – i.e. you were not claiming credits for 100% of it, whilst claiming 50% on the actual fuel used. You can play around with the percentages all you like. But for every litre of fuel that you DO NOT have as sustainable, within the mandate* there is a penalty of 50pence per litre. Some components can be double or triple accounting – such as 2nd gen ethanol – this could be worth 2 credit points – on the open market this could be worth £1 (for arguments sake), but the material only costs you 60ppl – so you’re quids in.. There are also some development fuels (these are ones my place has helped develop), that are 100% sustainable and triple accounting, but as they are expensive the effective £1.50/L trade doesn’t quite cover the cost of the manufacturing – but it’s getting there.

You then apply that in it’s various forms, and it’s the increased buy-out that effectively forces you to use bio at the pumps. However the lower oil price goes, the less likely you will have ethanol in fuel as it trades much higher, and therefore it can be cheaper to pay the buy-out, OR buy credits to off-set the bio you haven’t used… simple hey..

*The schedule of bio is below;
Renewable Transport Fuel Obligation (RTFO) guidance: 2021 - GOV.UK (www.gov.uk)

Obligation period Specified amount, as share of
fossil fuel, by volume
Specified amount, as
share of total fuel, by
volume 13
1 Jan 2021 - 31 Dec 2021 11.235%
1 Jan 2022 - 31 Dec 2022 11.607%
1 Jan 2023 - 31 Dec 2023 11.857%
1 Jan 2024 - 31 Dec 2024 12.107%
1 Jan 2025 - 31 Dec 2025 12.360%
1 Jan 2026 - 31 Dec 2026 12.613%
1 Jan 2027 - 31 Dec 2027 12.867%
1 Jan 2028 - 31 Dec 2028 13.122%
1 Jan 2029 - 31 Dec 2029 13.378%
1 Jan 2030 - 31 Dec 2030 13.636%
1 Jan 2031 - 31 Dec 2031 13.895%
1 Jan 2032 - 14.155%

I get all that,I think, except....E10 is Max 10% yet those shares are all greater then 10% that's leaving me confused!

@sui, do you know of ul91 or ul94 is available in the UK? My understanding ( could be wrong) is aviation Ron is a different scale to UK motoring Ron (us being different again) and ul91 is roughly super unleaded

neilnevill
Free Member
I get all that, I think, except….E10 is Max 10% yet those shares are all greater then 10% that’s leaving me confused!

yes it's a little confusing -either the supplier has other grades they are "mass balancing" elsewhere to offset the liability (this is done on your total supply of all products), or they are passing the cost on in the fuel*.

take 100Litres of fuel - If as of today you only had 8% bio/renewable, then you are in deficit of 3.23%. you would look to have to pay 50ppl on that 3.23% over the 100 litres – this works out at 1.61ppl over that 100L. Do remember though, if there are double or triple accounting components in there, then there may be no excess to pay.

Also, do remember the values above is not ethanol content – its ALL renewable/bio content, it is a separate issue from labelling at the pumps which is covered by different regulations.

neilnevill
Free Member
@sui, do you know of ul91 or ul94 is available in the UK? My understanding ( could be wrong) is aviation Ron is a different scale to UK motoring Ron (us being different again) and ul91 is roughly super unleaded

You’re sort of correct.

If referring to American labelling, UL91 and UL94 is based on AKI (antiknock) which is RON+MON/2. So a typical 95RON would be ~ 95+85/2 = 90. A super would be 98+88/2=93

However this grading is also used in aviation gasoline (there are many grades). In this instance the number is referring to the MON (Motor octane number). You have 91, 94, 100 and a few more.. So the RON in this cases is significantly higher than normal super.

The number balances of Ron and Mon (sensitivity) can vary wildly depending on how fuels are made, but for road use the Ron is the over-riding factor for compliance.

I was complaining on another thread that my ancient lawnmower refuses to die and I therefore cannot justify getting an electric one. This is despite me never servicing it, never topping up or changing the oil and leaving it outside all year round.

Sounds like my lawn mower. Always surprised when it starts straight up every spring and sure I will actually get round to checking the oil for the first time ever this winter...

If referring to American labelling, UL91 and UL94 is based on AKI (antiknock) which is RON+MON/2. So a typical 95RON would be ~ 95+85/2 = 90. A super would be 98+88/2=93

im going to partially correct myself - Whilst Amercians do use AKI, they do also use the terms UL91, 94 etc as the RON rating. US fuel is genaerlaly of a lower quality than Europe.