UKH

Has anyone experienced a marked reduction in mpg using E10 petrol instead of E5?

'Official' sites say it could be 1% or so only.

I have a significant reduction due to something and filled up with E10 recently; I'm investigating!

Thanks 

Yes, I used to be able to drive from my home in Glasgow to Dad's home in south Bucks without re-filling. Using E10, I consistently need to re-fill just after Birmingham.

I don't track mpg, and probably wouldn't have noticed if I was only doing short trips, but for that long trip which I do regularly, it was very obvious.

From what I have read this is to be expected. I am assuming (perhaps optimisitically) that the reduction in CO2 emissions from using E10 take into account the fact that the mpg is reduced, meaning that we will burn more of it...

It's just got cold, you're tyre pressures will be down and the roads are wet, both eat power.

jk

thanks...quite significant I think. Not 1% or so.

Not another attempt to downgrade E10?

Wasn't there a long thread about this a couple of weeks ago ?

I can't find it.

Maybe it was in 'The Pub' & not saved ? I'm sure I remember contributing

Probably was posted in the Pub by the looks of it. It was early Sept and I commented in it and can’t find it.

no, I can't find it either.

what did you say on the thread?!

That 1% (or whatever it actually was) will have been determined under controlled conditions using a number of vehicles on a dynamometer, probably also on-road tests.

Ethanol is ~30% less energetic per unit volume than 'pure' petrol, E10 would therefore be ~3% less energetic than pure petrol but the actual change has been from E5 to E10, a ~1.5% reduction in volumetric energy density. It's just too small to notice anecdotally against a backdrop of changing use and seasons.

Modern turbocharged vehicles with fuel-composition sensors may well claw some of that loss back anyway by being able to alter their boost and ignition maps to increase efficiency. That said, I suspect such sensors are rare OEM fitments outside of the very high performance sector.

jk

Nope. been using it almost exclusively on the continent for several years and never noticed any marked difference between MPG on that side of the channel and this one. granted i could never truly compare like for like as im not doing the same journey on each side.

I have a fairly old Honda Civic mk8 1.4 and if anything I seem to be getting getter MPG on longer journeys. I was getting 49 mpg at best and now on a good run I'm seeing 51 mpg. This could just be the type of journeys I'm doing and the times I'm driving but it's certainly not a significant drop.

As JK says above, ethanol fuel can have advantages, it's more resistant to detonation so you can change the tuning. Maybe all the Honda gadgetry is finally doing something worthwhile.

Not been tracking MPG but my 2003 Skoda Fabia, which I’m told should work with E10, has had a lot more engine management type warnings  in the last couple months.

At the last fill I put in unleaded premium E5 and it seems a lot happier.

Anecdotal and probably subject to various biases, but I’m wondering if anyone else has found similar?

Can’t remember, sorry, but probably I commented on an increase in fuel consumption overall since I started using E10 which was early summer - since it first became available in my area.  However, my thoughts have changed over time as to the actual cause or more likely causes; ie multiple things interacting. 

jkarran has mentioned some of the things that can cause a change in consumption and there are many others.

To further complicate my average fuel consumption, the pandemic has changed my driving distances considerably and that alone maybe having a disproportionate effect overall. I do know my car’s computer “learns” and adapts and so changes/manages lots of things based on recent and past driving styles, etc. as to how it reacts and responds to driver inputs during the next journey which no doubt can change fuel consumption considerably.

Whilst weekly average mpg are generally lower (shorter journeys, less longer journeys to offset, more cold starts, etc. could explain it), I have found some (usually) longer journeys have returned a much higher ave mpg than I expected.  Overall, with more hindsight, I think my changes over just some six months can be explained for various reasons such that the increase in fuel usage can’t be attributed purely to the change in fuel from E5 to 10. Just my thoughts meantime.

However, I am looking to change to a BEV in the shorter term so I’m unlikely to get full year and more using E10 fuel to see what a longer term average will be using E10.

Interesting.

Thanks for that.

I have a Honda vtec Jazz and I haven't noticed any difference in economy on longer journeys but it seems more thirsty on urban driving. One difference I have noted is that it has an occasional flutter on tick over. If this happens when I am setting off it stalls, happened twice recently. Anyone else found this?

I monitored this over a ten-year period in the US, carefully calculating mpg's from the actual amount of fuel I put in the tank. I found about a 7% drop in mpg in my Toyota Prius with E10 compared with E0. I soon got to know the "gas" stations that were not putting ethanol into their petrol, and usually noticed the difference in performance just a few miles after filling up.

I suppose the difference in fuel consumption depends to some degree on the specific engine.

The only times I have noticed a drop in performance in my diesel car in the UK, it has been very marked with engine stuttering etc. and I have put that down to something like water getting into the storage tanks rather than a bad batch of fuel from the refinery.

But which "Gas" were you putting in in the US? Their regular is 87 RON and the cars are tuned to use it so maybe the benefits of ethanol in fuel aren't seen, only the disadvantages.

I was putting in the petrol recommended for the Prius, which was a higher octane than 87 RON, usually called Premium, I think. Generally there was no indication on the pumps whether the fuel contained ethanol or not. (Usually the pumps had stickers on them saying "may contain up to 10% ethanol", or something like that). The ethanol was added at the "gas" station, not the refinery.

They don't even need to know that - any modern engine will adjust boost and ignition timing as far as they can go without knocking.

That sounds like a recipe for disaster.

Failed Moonshine batch? 

I assure you that that was the way it was being done in western Houston for years. 

Ethanol is hydroscopic so absorbs water so long term damage could be water damage. classic car and bike owners are worried but for now can fill up with super. 
Ive a 2 stroke vespa for work commuting and using super so no problems so far. The fear seems to be carburettor problems. old carbs will have a brass float inside, soldered together to make it air tight. Water will corrode the solder over time and once the float starts to take on water, fueling problems will follow.

It was me that started the other thread because My wife's 1.2 Skoda Rapid went into limp mode  100 miles after I'd first ever used E10. Did the same 100 miles later. An expensive dealer diagnosis showed nothing ( although to be fair an interim mechanic had cleared the memory)

Since I was on holiday I filled up with  the pricey stuff for the 400 mile journey home  but I've been running around with E10 since and no glitches.  

Not done any mpg comparisons, but I do think I can feel a difference in acceleration and generally how the car feels to drive. I know it's very subjective and might well all be in my head, but personally I think it 's made a difference.

I never really used to notice much of a difference between premium unleaded and the bog standard stuff, but after noticing the car feeling a bit different and slightly sluggish after a couple of E10 fill-ups I did fill it up with premium petrol, and it feels much better to me. Since then I've been using premium petrol. I should probably try E10 again to see if I can tell the difference and properly decide whether it's worth spending extra on a fill-up (or better yet get the gf to fill my car up and not tell me which one, so I can run a proper experiment without bias!).

My car is a 9 year old 1.3l Yaris (so obviously not turbocharged as more modern small-engined cars seem to be, if that makes a difference), for reference.

Well, that's how it started with me, thinking this was just a subjective impression. That's why I started calculating mpg's carefully (for about ten years over nearly 100,000 miles of driving) and soon discovered that it was not subjective. One thing I have wondered is whether with the high humidity in Texas, the ethanol in the fuel in ones tank can absorb some of the atmospheric humidity, making the problem worse than it might be (but I think that's unlikely).

This is why I am now so "cool" on E10.

So I thought I would pass on my experience to UKC, and what to I get?: a dislike!

ps. I calculate the mpg by filling up the tank to the cut-off point at the pump, and then refilling it at the same pump to the same cut-off point and recording the exact mileage in between. The only time this goes wrong is when the garage is cheating on their volumes. They are meant to be strictly calibrated by law in TX (and here), but on several occasions I have came across places that were way off, i.e., when one is expecting to be able to put about 8 1/2 gallons into a 10 gallon tank, finding I was able to put in something like "11" gallons! But most of the time the volumes are pretty consistent. Invariably, the mpg's calculated in this way are not as good as those estimated by the car's computer, which plays the error bars the other way.

Surely solder and brass are resistant to water. Just looking around at all the brass taps in the house. Maybe it's galvanic corrosion between the aluminium carburettor shell and other metals.

This E10 fuss has been a real boost to the sales of fuel treatments and stabilisers. The trend on YouTube is videos of people separating out the ethanol by adding water with food colouring and then separating off the coloured aqueous layer. The issue you then have is you lose the good fuel additives that retard detonation and you have loads of idiots storing relatively large volumes of fuel in inappropriate containers in their garages.

I follow James Pearson on Instagram, and he says it's E12.

That’s the info being given out but thinking on, that’s just the bit that’ll affect me as my vespa fuel tank is plastic. Corrosion in steel tanks is a worry too.

Only one example, but my Uncle was getting terrible mpg in his car (older car, can't remember what) and he switched to super unleaded and it's much better now. He does a good mix of local trips and longer motorway journeys. He's in his 80s and drives pretty sedately.

It also appears that, according to info I've been getting - book on the subject of fuel plus info from the Vintage Motorcycle Club, Royal Enfield Owners Club and BSA Owners Clubs - that fuel pipes can rot, plus gaskets and grommets, and worse still some actual fuel tanks, can perish due to the presence of Ethanol. Obviously E10 has twice the Ethanol of E5, so the effect is much more drastic.

You have to remember that fuel systems were designed when there was no Ethanol in fuel.

On a side question - the source of the Ethanol is as a by-product of the sugar industry. I was under the impression that the government was trying to reduce sugar intake. So if they succeed in reducing sugar consumption, then where is all this Ethanol going to come from in future ?

One of the main ways of making ethanol is from sugar - by fermentation! (BTW, this reaction produces not just ethanol but also CO2.) So the sugar industry can and does produce ethanol from sugar.

I recently picked up some plant that was running crap and was in getting serviced. It was small plant such as Belle cement mixer, power pack and hydraulic pack. It was at one of those places that mainly did  petrol lawnmowers. The old guy inside said "stop using that crap, cheap, petrol." He told me it absorbed moisture too much and was obviously bad for the engine. Stick with premium.

And the reason we are putting more Ethanol in petrol is to reduce CO2 emissions. So presumably this means we're actually producing MORE carbon dioxide due to this change, just at the factory rather than the exhaust pipe. 

It should be bioethanol and thus made by drawing CO2 from the atmosphere (using sunlight) so thus a nett zero contributor of CO2. Sounds great doesn't it...

However I read that 80% of the energy gain can be consumed by harvesting, manufacture and distribution so a rather poor return. Worse still is the use of valuable food production capacity to provide the feedstock

I read a report in America about five years ago that suggested that by the time the energy consumption and CO2 generation during production were factored in, there was little or no benefit to E10 in the US, except as a subsidy for farmers. Another negative factor of ethanol production from corn is that it pushes up the price of corn.

The standard feed stock in places like south America where ethanol is a popular fuel is sugar cane bagasse, the waste left over after the majority of the useful/easily extractable sugar has been extracted. For years the aim has been to use cellulosic biomass to produce biofuel and with this aim people have been engineering microorganisms to either produce enzyme mixes that can be added to feedstock which break down the cellulose and liberate the sugar or otherwise the produce yeasts that can directly use the alternative feed stock.

Often some of the fuel produced is used directly to produce more fuel by heating the fermenters but there is a substantial net gain and any CO2 output comparison needs to include the equivalent used in fossil fuel extraction and purification.

If you are old enough you'd remember when National (National Benzole) and Discol (Cleveland Discol) were common brands in the UK and they had loads of ethanol in the fuel. Previously benzole was used as an anti-knock (pre-detonation additive) but after the war it was more important to the chemical industry so replaced by methyl or ethyl alchohol. In fact the first Benz ran on alchohol as did Model T Fords and most cars of the early days, in fact up to WW2 petrol was cursed by performance car owners. To cure the knocking compression ratios were reduced until lead tetraethyl was introduced. Where modern cars fall down is the compression ratio is far too low to burn alchohol effectively, the cars for countries like Brazil which have E85 have different engines. The USA have been running on E25 for decades.

As long as the various seals and gaskets are appropriate the only identified problem in Germany (we have had E10 for over ten years) is the carbon filters in the fuel tank breathers stop working effectively, the premium manufacturers know this and fit better ones (there was a move to have this included in the MOT).

I thought you were announcing a new very hard route with a rather boring name

Quite, the OP missed a trick there, should have had a clickbaity thread title like

Can you go from E5 to E10 overnight?

Just watched a very good youtube vid where the guy tested both under fairly controlled conditions including measuring the ethanol content prior to the test.  He found there was no significant difference in carbon build up but about a 4% difference in fuel economy.  He was planning to do a longer test and this was only in a petrol generator powering a couple of loads.

Cheers

Toby

Agreed, the whole idea of solder is to make a watertight seal.

Not watertight, ethanol tight, a known corrosive chemical

Water is more corrosive to metal than ethanol. Metal corrosion is a  redox reaction but ethanol doesn't conduct and salts do not dissolve in it. 

The CO2 problem is turning carbon that's been locked away underground for millenia into CO2.  This has a drastic affect on volumes of CO2 in the atmosphere. CO2 from bio-ethanol production has only been locked away for a matter of months and thus just tickles the atmospheric levels - it's essentially a short-term cycle.

Sorry I thought you said water damage!

Being cold will help, the air is more dense,better suck squeeze bang blow

It doesn't matter how long the CO2 has been locked away, the critical factor is how much of it is unlocked.

Do it blind - get someone else to fill it up for you a few times, change around what they put in, and not tell you which.

Have to disagree with that statement.

I’ve been burning pallets for the last 6 or 7 years for house heating, yes, I’m still pumping out CO2, but that’s probably several tonnes of fossilised carbon that I haven’t used, let alone what would have happened to said pallets.

Plus it was free

The carbon isn’t “locked away” in this instance, it would be released when the sugar cane rots or gets eaten by an organism that then emits CO2. It’s just temporarily held as part of a short term cycle. Short-term cycles of CO2 and O2 are essential to life on Earth as we know it. CO2 isn’t “bad” in itself; disrupting long term stores of carbon in ways that change the equilibrium of the atmosphere is the problem. 

I tend to think that we are willingly reversing the atmospheric changes that made diluted-oxygen breathing organisms possible on this planet in the first place. 

Perhaps it is the "eternal" cycle in some creation myths taking effect, to give rise to a new evolution ab initio

Not sure how you're working the percentages, did you factor in the way that ethanol combusts in a progressive and power transfering piston-friendly way and why some US racers actually choose very high ethanol/methanol contents. "Gas is for cleaning the windshield but methanol is for racing". I don't think it's as simple as counting the carbons etc.

I'd be astonished if anyone can actually obserbe a real world performance difference, assuming of course their fuel system is compatible). Super, which now means E5, being better for everyday usage is 99% marketing scams (the 1% is the slightly additional cleaning agents added to try to differentiate product)

Engines that are optimally designed for methanol are not identical to those that are optimised for petrol.

I suggest that you make careful measurements over many tank-loads with the different fuels to see how the ethanol additives affect your mpg and car performance. I noticed pronounced changes to both, but could only measure the mpg (over a ten-year period in the US). Maybe you will be one of the lucky ones whose car is not very noticeably affected. Otherwise, be prepared to be astonished. I was.

I wasn't suggesting something like you can get an old Vauxhall Cavalier and shove 100% methanol in it and expect it to run well. I understand that cars e.g. like those running on E85 are modified for that. I was just pointing out that it's not as easy to compare power yields of differing fuel types as just looking at the theoretical chemical energy.

I'm still surprised to hear that someone's car would have noticeably different fuel consumption between E5 and E10. E10 can cause some people problems with o rings and lines but I wasn't expecting economy as an issue. Sorry to hear that, if you don't mind me asking, what car do you have?

I'm all for it as it's the only E10 I can cope with.

Methanol isn't ethanol. Flex-fuel engines that run on E85 are common as muck, ones that run on M85 are only experimental.

VS wetter roads and a seasonal change to the underlying hydrocarbon blend in 'petrol'.

Jk

Not quite experimental, a friend has a car  that runs on methanol, but it has 1500 bhp does a quarter mile in around 8 seconds has a terrible drinking problem and wouldn't get through the door of a MOT station.

I just compared the volumetric energy densities then applied them crudely to the changing fuel mix. I did mention the greater knock resistance of alcohol as a possible benefit in limited applications but no, it's not 'accounted for'. 

Methanol isn't ethanol. I think it's mainly used in performance engines as a chemical charge-cooler and octane booster (both getting less important as direct injection grows in that sector).  

Super is necessary if your engine knocks (or worse) on regular which is very unusual for production vehicles. Mostly it's pointless.

Jk

Methanol is used in some fuels as the principal ingredient and not just an additive, e.g., drag-racing fuels and model glow-plug engine fuels, usually supplemented with nitromethane. It was also the principal ingredient in the fuel for the Rolls-Royce R engine in the Supermarine S6b that broke the world airspeed record in 1931.

Spent years driving around with a 45 gallon drum of it in my van, fuel for speedway and grasstrack bikes. Never took off as a fuel for road cars though but it might in the future.

Keith

apologies for breaking into this thread but I noted a post from you in 2108 whilst looking for  Nigel C Rayner. He’s is an ex colleague of mine and I wondered if you had managed to track him down.

Kind Regards