99 RON - Page 5 - Porsche General - PistonHeads UK

I know this topic has been done to death, but with E10 now mainstream, I thought it was worth revisiting I’ve had cars remapped to run on 99 RON with fantastic results, I’ve also had cars mapped from the factory to run on 95 RON, that drove significantly better when running on 99 RON. Given that Porsches are mapped to take advantage of 98 Octane, it’s ironic then that I’ve done over 100,000 miles across numerous models, and I’ve never been able to tell the difference between regular or V-power fuel. That’s everything from Caymans to Macans to Panamera Turbos, as such, I just stick with the regular stuff. If I’m doing a track day I’ll use V Power as a matter of course, but even if I use one or two tanks before the track day, then four tanks on the track day and a tank or two back home, I still can’t tell the difference. So I wonder, am I the only one?

Rightly or wrongly I use V-Power to try and avoid carbon build up. My 911 is a keeper so I want to look after it.

I hope you guys have an understanding of what octane does and why you would use it. It's not for more power.

I only put Esso supreme +99 in my special cars which has 0% ethanol in my area.

Mr Spoon said: I hope you guys have an understanding of what octane does and why you would use it. It's not for more power. If you read my post carefully, you’ll see I never mentioned anything about power

Grantstown said: Rightly or wrongly I use V-Power to try and avoid carbon build up. My 911 is a keeper so I want to look after it. Using a 99 Ron fuel in your Porsche allows the ECU mapping to advance the ignition timing for a more efficient and cleaner burn. This is particularly relevant on DFI engines where lower Ron fuels can cause a build-up of carbon deposits on exhaust valve stems which can ultimately lead to more serious problems.

Mr Spoon said: I hope you guys have an understanding of what octane does and why you would use it. It's not for more power. An engine operates at its most efficient on the edge of detonation (knock). The higher the octane, the higher the fuel's resistance to knock, which means efficiency can rise slightly, by for (one) example advancing the ignition a few more degrees. Higher octane can permit higher compression ratios, which again increase efficiency (up to a point).

Lexington59 said: Grantstown said: Rightly or wrongly I use V-Power to try and avoid carbon build up. My 911 is a keeper so I want to look after it. Using a 99 Ron fuel in your Porsche allows the ECU mapping to advance the ignition timing for a more efficient and cleaner burn. This is particularly relevant on DFI engines where lower Ron fuels can cause a build-up of carbon deposits on exhaust valve stems which can ultimately lead to more serious problems. Good explanation of the concept I was thinking of. I hear Taffy as well with the ethanol issue. I’m not sure if the V Power is 0% ethanol in my area (Cheshire).

V Power isn’t O% anywhere AFAIK it is 5%. Only Esso sells 0% Ethanol and not everywhere in the UK.

I use Tesco Momentum wherever possible now. Much cheaper than the others too. My 993 revs to the redline with noticeably more enthusiasm than V-power which I religiously used beforehand. Also I filled up my Ferrari 308 with Momentum for the first time last Autumn and the difference was amazing. Again revving to the redline with real gusto. Even my 16 year old niece noticed the difference! Haven't tried it in my 991.2 GT3 yet but I can't see that engine needing help with revs!

browngt3 said: I use Tesco Momentum wherever possible now. Much cheaper than the others too. My 993 revs to the redline with noticeably more enthusiasm than V-power which I religiously used beforehand. Also I filled up my Ferrari 308 with Momentum for the first time last Autumn and the difference was amazing. Again revving to the redline with real gusto. Even my 16 year old niece noticed the difference! Haven't tried it in my 991.2 GT3 yet but I can't see that engine needing help with revs! you might think this, but it doesn't happen like you describe. Its the placebo effect.

SkinnyPete said: Mr Spoon said: I hope you guys have an understanding of what octane does and why you would use it. It's not for more power. If you read my post carefully, you’ll see I never mentioned anything about power you did not. I apologise for making the statement.

Mr Spoon said: I hope you guys have an understanding of what octane does and why you would use it. It's not for more power. I understood that the car was able to change the spark timing to allow ignition at a higher piston compression point and that this leads to increased power. Higher octane fuels allow higher compression ratios in cars to start with, meaning more power. Of course the compression ratio is fixed, but the timing can be changed.

I noticed 5% better mpg in my 2012 TTS. I'd been using standard for a while then switched to VPower. In my 981 I'd always used VPower for 40k miles but switched to standard since the "fuel shortage" as the possibly better economy doesn't now beat the 15p price difference. I've noticed no drop in performance. Too early for long term mpg comparison. On VPower I got 36mpg over 9999 miles. I will put in a tank of VPower from time to time. Don't touch Tesco since warned off it by a BMW technician. It knackered my wife's EGR valve.

DJMC said: Don't touch Tesco since warned off it by a BMW technician. It knackered my wife's EGR valve. and how exactly does the BMW grease monkey know the EGR valve failure was caused by fuel and specifically sold by Tesco? Take a trip to a local refinery or storage terminal. Count how many petrol tanks are there. Now work out how many companies there are, then do the math. PS i run a fuel company if you want my "credentials"

Mr Spoon - As you are in the industry I'd really appreciate some insight. Are we being sold snake oil (excuse the pun) with the more expensive fuels or is the extra cost justified with added detergents etc?

Grease monkey had 17 years experience with Porsche; Lamborghini; RR; and was peering into the engine bay, on my drive. Looking at the blocked EGR he asked "have you been using supermarket fuel?" "Yes, Tesco." Ah, that'll be it then." He proceeded to explain why, in detail. I knew he was a motor technician as he was wearing a BMW technician's uniform, and had a BMW emergency services van. Other's here have no proven credentials. After four years of avoiding Tesco we've had no further issues.

Gen question - What is it that is in, or missing from, TESCO fuel that damages cars?

DJMC said: Grease monkey had 17 years experience with Porsche; Lamborghini; RR; and was peering into the engine bay, on my drive. Looking at the blocked EGR he asked "have you been using supermarket fuel?" "Yes, Tesco." Ah, that'll be it then." He proceeded to explain why, in detail. I knew he was a motor technician as he was wearing a BMW technician's uniform, and had a BMW emergency services van. Other's here have no proven credentials. After four years of avoiding Tesco we've had no further issues. I don't care how long this person has been in the industry or who he has worked for. This is complete BS. Do you not realise that the majority of this rubbish about fuel is exactly that rubbish. So one of the UKs largest forecourt network and largest overall domestic volume of fuel all of a sudden is causing egr valves to block. If you believe that then please hand me some cash. I'd like some of what you are so eager to give away. Wow

smudger911 said: Mr Spoon - As you are in the industry I'd really appreciate some insight. Are we being sold snake oil (excuse the pun) with the more expensive fuels or is the extra cost justified with added detergents etc? You pay your money and you get what they advertise. The reality is the standard fuel spec in this country far exceeds all manufacturers requirements. This will end up in some know it all pub crap debate, but put it this way, either petrol or diesel, you won't have an issue regardless of the branding of the garage.

I have a Porsche/Wex fuel card which gives me 6p discount off ESSO premium fuels. Consequently I only put ESSO Supreme +99 petrol in both my RS and 812. Trouble is the nearest stockists to my home is 40 miles away but I make the effort and brim my cars fuel tank everytime I refuel. Its got 0% ethanol so is it worth my trouble or might be better to use Tesco Momentum or Shell 99 with 5% ethanol.

Morning Taffy, That fuel card sounds good. Is that through Porsche GB car club? I’ve been using the V-Power as it’s my local station. I might make the effort to go for the Esso though for the 0% ethanol. My understanding with the V Power is that 5% is the max they can put in, but normally it’s a lot less. I’m not sure at what point the level of ethanol becomes inconsequential.

Yes, its with PCGB. Bear in mind that getting 0% ethanol +99 doesn't apply if you live either North England or Cornwall/Devon as their fuel comes from a different refinery. Where I get it in South Wales is 0% ethanol so best to check with Wex or PCGB to make sure you get the right stuff nearest to where you live. Ethanol attracts moisture and can lead to corrosion issues with fuel lines, injectors etc I know a guy who is a lecturer in Oxford on Chemical engineering and specialises in fuels who advised me to get ESSO Supreme +99 with 0% ethanol so my info is coming from a very good source and not just internet folklore. He's on here sometimes so he might chime in if he sees it.

Taffy66 said: Yes, its with PCGB. Bear in mind that getting 0% ethanol +99 doesn't apply if you live either North England or Cornwall/Devon as their fuel comes from a different refinery. Where I get it in South Wales is 0% ethanol so best to check with Wex or PCGB to make sure you get the right stuff nearest to where you live. Ethanol attracts moisture and can lead to corrosion issues with fuel lines, injectors etc I know a guy who is a lecturer in Oxford on Chemical engineering and specialises in fuels who advised me to get ESSO Supreme +99 with 0% ethanol so my info is coming from a very good source and not just internet folklore. He's on here sometimes so he might chime in if he sees it. Ok thank you, I’ll check. I’m not sure if Cheshire is ‘North’ so hopefully I’m close to a 0% supply.

dsgrnmcm said: Gen question - What is it that is in, or missing from, TESCO fuel that damages cars? Nothing - as Mr Spoon says.... it's BS from someone who does not know what they are talking about. More importantly, Tesco don't make fuel, and they get their RON99 from Greenergy, the same people who supply ESSO with the 0% ethanol RON99

Orangecurry said: Nothing - as Mr Spoon says.... it's BS from someone who does not know what they are talking about. More importantly, Tesco don't make fuel, and they get their RON99 from Greenergy, the same people who supply ESSO with the 0% ethanol RON99 Mostly correct however some important differences. At each refinery every fuel truck gets the same fuel apart after filling with petrol different retailers add various additives to their own spec preferences. This can be ethanol or any other additive to boost octane or some form of detergent.

...wasn't suggesting Tesco RON99 was 0% - simply that it is the exact same base product.

Taffy66 said: I know a guy who is a lecturer in Oxford on Chemical engineering and specialises in fuels who advised me to get ESSO Supreme +99 with 0% ethanol so my info is coming from a very good source and not just internet folklore. He's on here sometimes so he might chime in if he sees it. And this is the problem, "i know a guy". I dont care what university he is a lecturer at, or what you claim his qualifications are, as the simple fact is, if this guy is who you say he is, he wouldnt spout such b ks.

There's a lot of misunderstanding in this thread about octane and how differing octanes result in differing performance (or not!) in a Porsche (or any similar car). Essentially most petrol cars (from around the early 2000s to 2010s at least) have their ignition timing and fueling controlled by a computer, which (when not idling) looks up the current engine load and rpm on two tables table, one tells it the correct amount of fuel to inject, the other the correct amount of ignition timing advance/delay to use on the spark. When you want to adjust them using separate software, they look like this: These are the "maps" that people talk about adjusting when they "remap" a car. Now, sometimes conditions (poor fuel, blocked filters, etc) will mean that the pre-set ideal fueling and timing actually are no longer ideal and cause issues with the engine (knock, pre-detonation, inefficient burn, etc). The engine has sensors to tell the ECU this is occurring. The sensors can't tell the ECU the cause of the sub-optimal running, only that sub-optimal running is occurring. When it does occur, the ECU starts to amend the fueling and ignition (typically by gradually adding more fuel and retarding the timing until the issue resolves itself) to run the engine on a "safer" setting. This is obviously less fuel efficient, more pollutant and drops power, similar to limp mode. So, running 95 RON fuel in a car that is pre-set to run on 98 RON fuel will probably cause a loss of power in some conditions. However, adding 98 RON fuel to a car mapped to run on 95 RON fuel won't add any power and likely won't add any fuel efficiency either. Similarly, adding 99 RON fuel to a car mapped for 98 RON won't make the engine produce any more power or efficiency UNDER NORMAL OPERATING CONDITIONS. What running a higher octane fuel can do is add a bigger safety margin before the car starts to pull timing or add fuel due to adverse conditions. Hope this explains what is an incredibly complex subject in simple terms. Edited by youngsyr on Thursday 3rd February 13:47

youngsyr said: Hope this explains what is an incredibly complex subject in simple terms. Thanks for this interesting post. I have a related question to your last few paragraphs: I recall a while back a PHer did back to back dyno tests on his completely stock 335i, one with 95RON and then with 99RON. The results were something like 300bhp on 95RON and 320bhp on 99RON. Whilst the engine would've been mapped for 95RON and it was hitting its listed outputs with 95RON, was the ECU taking advantage of the tighter timing available and power increased as a result? Similarly does this apply to all modern cars?

david-j8694 said: Thanks for this interesting post. I have a related question to your last few paragraphs: I recall a while back a PHer did back to back dyno tests on his completely stock 335i, one with 95RON and then with 99RON. The results were something like 300bhp on 95RON and 320bhp on 99RON. Whilst the engine would've been mapped for 95RON and it was hitting its listed outputs with 95RON, was the ECU taking advantage of the tighter timing available and power increased as a result? Similarly does this apply to all modern cars? No it doesn't apply to all modern ECUs - some can take advantage of higher grade petrol, others cannot... Just to confuse you further - all things being equal, 99 ron with 0% ethanol will produce more power than 99 ron with 5% ethanol in the same car and more likey than not will also give slighly better fuel economy... As Mr Spoon says - UK base fuel spec is so good anyway, that our cars will happily run on supermarket/branded fuel without causing damage, as long as you are adhering to the manufacturers min requirement.

david-j8694 said: youngsyr said: Hope this explains what is an incredibly complex subject in simple terms. Thanks for this interesting post. I have a related question to your last few paragraphs: I recall a while back a PHer did back to back dyno tests on his completely stock 335i, one with 95RON and then with 99RON. The results were something like 300bhp on 95RON and 320bhp on 99RON. Whilst the engine would've been mapped for 95RON and it was hitting its listed outputs with 95RON, was the ECU taking advantage of the tighter timing available and power increased as a result? Similarly does this apply to all modern cars? I don't know about very modern cars (from about 2015 onwards), but certainly from late 90s to early 2010s models, the typical ECU would not take advantage of higher octane fuel (by advancing timing and/or reducing fuel) beyond the standard set up. It would only reduce how aggressively the engine is tuned if poor running (primarily det and knock) are detected. This is why many cars from that time (Forced Infuction engines in particular) can gain noticeable power by being remapped on higher octane fuel.

Orangecurry said: ...wasn't suggesting Tesco RON99 was 0% - simply that it is the exact same base product. I thought Tesco 99 is 0 ethanol ?

ds666 said: Orangecurry said: ...wasn't suggesting Tesco RON99 was 0% - simply that it is the exact same base product. I thought Tesco 99 is 0 ethanol ? 'Fraid not. Only Esso 99 is 0% ethanol. (and then only in part of the country.)

ds666 said: I thought Tesco 99 is 0 ethanol ? It was always 5% ethanol - from the day they introduced it to the market…

Cheburator mk2 said: ds666 said: I thought Tesco 99 is 0 ethanol ? It was always 5% ethanol - from the day they introduced it to the market… Again, second hand information from someone who claimed to have industry knowledge - even a specialist fuel like V-Power is not consistent throughout the country or even from one season to another. He mentioned that any particular station's V-Power may have a different composition from summer to winter, for example. So, to say that one fuel definitely always has X, Y or Z, beyond meeting the minimum standards and advertising claims, can be misleading.

As I understand it, the interesting thing about ethanol in performance terms is that it burns cooler than gasoline. This means that you can run more boost pressure and/or timing in a forced induction car before experience det or knock caused by high engine temps. This can mean even more power being released from a remap on these cars than using a similarly high octane gasoline.

youngsyr said: As I understand it, the interesting thing about ethanol in performance terms is that it burns cooler than gasoline. This means that you can run more boost pressure and/or timing in a forced induction car before experience det or knock caused by high engine temps. This can mean even more power being released from a remap on these cars than using a similarly high octane gasoline. That’s very true. But as it has less calorific value than “pure” petrol you would need more of it. Hence the engine would need to be mapped for fuel containing higher ethanol % to take advantage of higher knock tolerance. No such thing as a free lunch

Cheburator mk2 said: youngsyr said: As I understand it, the interesting thing about ethanol in performance terms is that it burns cooler than gasoline. This means that you can run more boost pressure and/or timing in a forced induction car before experience det or knock caused by high engine temps. This can mean even more power being released from a remap on these cars than using a similarly high octane gasoline. That’s very true. But as it has less calorific value than “pure” petrol you would need more of it. Hence the engine would need to be mapped for fuel containing higher ethanol % to take advantage of higher knock tolerance. No such thing as a free lunch That's exactly what I said, wasn't it - FI engines mapped on high ethanol fuels can achieve higher power outputs than those mapped on similar octane rated gasoline?

Cheburator mk2 said: ds666 said: I thought Tesco 99 is 0 ethanol ? It was always 5% ethanol - from the day they introduced it to the market… Point me in the direction of that “fact “ pls

ds666 said: Point me in the direction of that “fact “ pls Err, like press releases at the time of launch. Tesco’s own website even now. Industry tests? Or you think it’s “pure” petrol?

There are very few 'facts' published on the exact composition of the mixtures - trade secrets, and competition between all the big boys - it's in their interest to keep it all vague. Our detergent is better than yours... and so on. As far as facts go, the rules are that the fuel can contain up to 5%, or up to 10%. So ESSO want to provide 0% ethanol to appeal to a certain demographic of driver - Tesco's marketing department apparently do not. Go to Tesco and look on a pump. And even though IIRC Tesco own 35% of Greenergy, Greenergy make very little on their website of the fact that they supply Tesco.

Cheburator mk2 said: ds666 said: Point me in the direction of that “fact “ pls Err, like press releases at the time of launch. Tesco’s own website even now. Industry tests? Or you think it’s “pure” petrol? Do you have a copy ? Tescos own info suggests “up to 5% “ ( in line with e5) and tests I can find suggest 2.5%. What’s confused me is that my local petrol station is a tescos express within an esso petrol station … Edited by ds666 on Friday 4th February 07:27 Unfortunately your shouty and condescending reply adds nothing to the facts … Edited by ds666 on Friday 4th February 07:30

The only way you will ever know what is in your local outlet is by camping out there, and pouncing on the tanker driver when he arrives, and ask him. Every delivery of course. If you choose this new lifestyle, you could start an internet 'blog', and get famous and influence people, all in a non-shouty and non-condescending way of course.

Will the tanker driver know?

The only petrol in the UK guaranteed to be 0% ethanol is Esso +99 supplied directly from their own refineries. Due to logistical reasons Esso fuel station based in North Wales, North England and Cornwall are supplied through licence from other third parties refineries and consequently have 5% ethanol added. This has developed into a very interesting thread indeed

Taffy66 said: The only petrol in the UK guaranteed to be 0% ethanol is Esso +99 supplied directly from their own refineries. Due to logistical reasons Esso fuel station based in North Wales, North England and Cornwall are supplied through licence from other third parties refineries and consequently have 5% ethanol added. No it isn't - ESSO branded petrol stations get their fuel from their nearest distribution points - if that's in 'the South' it is supplied by Greenergy. Greenergy supply the 0% Ethanol (to be double-clear) Edited by Orangecurry on Friday 4th February 08:48

I don't think ESSO has a refinery in the UK anymore. This is probably out of date, but shows the actual refineries.

I am told he presses the buttons... when the tanker is filled at the distribution points (I hope that is less unclear) Edited by Orangecurry on Friday 4th February 09:13

Orangecurry said: I don't think ESSO has a refinery in the UK anymore. This is probably out of date, but shows the actual refineries. You need to go back to school. Esso is a subsidiary of US based ExxonMobil. https://en.wikipedia.org/wiki/Fawley_Refinery https://www.exxonmobil.co.uk/Company/Overview/Abou... https://www.exxonmobil.co.uk/Community-engagement/... https://wholesalefuels.esso.co.uk/en-gb/ https://www.nsenergybusiness.com/projects/fawley-o... https://www.ogj.com/refining-processing/refining/o...

regardless, it's Greenergy that supply ESSO branded petrol stations, including the 0% ethanol. https://www.greenergy.com/greenergy-becomes-fuel-s... https://www.greenergy.com/esso I'll trawl through the old threads where I thought you'd also posted such things....

A bunch of car blokes trading insults regarding second hand knowledge / press releases concerning petrol chemical compositions. There are indeed some weird corners of the internet. But don't mind me... carry on: it's quite funny.

XMA Simon said: A bunch of (insert anything here) blokes trading insults regarding second hand knowledge / press releases concerning (insert anything here). There are indeed some weird corners of the internet. But don't mind me... carry on: it's quite funny. So you've never been to a pub with your friends? You should get out more rather than looking at weird corners of the internet.

Orangecurry said: The only way you will ever know what is in your local outlet is by camping out there, and pouncing on the tanker driver when he arrives, and ask him. Every delivery of course. If you choose this new lifestyle, you could start an internet 'blog', and get famous and influence people, all in a non-shouty and non-condescending way of course. You can of course, buy some of the petrol in a clean container, take it home and put some in a clear measuring jar/tube. Over time any ethanol will separate, giving you an answer.

I use 99 RON to purely flaunt how wealthy I am.... ......as I weep looking at the £s go up and the Ltrs barely move.

XMA Simon said: A bunch of car blokes trading insults regarding second hand knowledge / press releases concerning petrol chemical compositions. There are indeed some weird corners of the internet. But don't mind me... carry on: it's quite funny. Quite - no point letting the facts get in the way of a good argument ...

ds666 said: XMA Simon said: A bunch of car blokes trading insults regarding second hand knowledge / press releases concerning petrol chemical compositions. There are indeed some weird corners of the internet. But don't mind me... carry on: it's quite funny. Quite - no point letting the facts get in the way of a good argument ... Well, you know what they say - the best way to get the right answer quickly on the internet is to post up the wrong answer.

Swine Enthusiast said: I use 99 RON to purely flaunt how wealthy I am.... ......as I weep looking at the £s go up and the Ltrs barely move. Pfff , I fill my I pace up with 99ron - only the good stuff mind ( that I read about in The Sun ) .

ds666 said: Do you have a copy ? Tescos own info suggests “up to 5% “ ( in line with e5) and tests I can find suggest 2.5%. What’s confused me is that my local petrol station is a tescos express within an esso petrol station … Edited by ds666 on Friday 4th February 07:27 Unfortunately your shouty and condescending reply adds nothing to the facts … Edited by ds666 on Friday 4th February 07:30 Why so triggered? Didn't get the answer you wanted?

david-j8694 said: ds666 said: Do you have a copy ? Tescos own info suggests “up to 5% “ ( in line with e5) and tests I can find suggest 2.5%. What’s confused me is that my local petrol station is a tescos express within an esso petrol station … Edited by ds666 on Friday 4th February 07:27 Unfortunately your shouty and condescending reply adds nothing to the facts … Edited by ds666 on Friday 4th February 07:30 Why so triggered? Didn't get the answer you wanted? No , just seeking facts , not strongly put “opinions “ Lots of people on here would make great politicians …

Taffy66 said: I have a Porsche/Wex fuel card which gives me 6p discount off ESSO premium fuels. Consequently I only put ESSO Supreme +99 petrol in both my RS and 812. Trouble is the nearest stockists to my home is 40 miles away but I make the effort and brim my cars fuel tank everytime I refuel. Its got 0% ethanol so is it worth my trouble or might be better to use Tesco Momentum or Shell 99 with 5% ethanol. I just got a Esso wex fuel card but don't use much fuel so only got a 1p discount from pump price on premium fuels. I've just changed over to Esso +99 for my 928 & an E280 then the premium diesel for my Cayenne. Will defo look into the PCGB thing, Do I just join and then get the porsche/wex fuel card or are there other conditions for the 6p discount? I also have a nectar card and get points if I buy things from ebay (dont really shop at Sainsbury's) and with 300 nectar points I can get an extra 5p off per litre. I'm wondering if you can also do this to make your discount 11p off per litre which makes it even better value, though your 6p off is great. How can you check if the +99 is 0% or is all the +99 Esso 0% ethanol? I use the esso store locator thing and check the +99 check box. Have a short drive but is worth it for a full tank. Also I can use my wex card in Europe to pay for fuel but don't get a 1p per litre discount in Europe. Does yours work in Europe with or without the discount? Also prices at Esso can vary a fair bit for the premium fuels, (at least near me) wondering if there is a website that I can check the prices of the premium fuels at different stations, 2 local to me are expensive so another towards the town centre is better priced so i'll use this one. I'm off to Europe soon for a few months and will be back and forth for a few years. I can use the wex card at Shell and Tesco to pay but no discount but don't want to, i've had enough of this fuel business and have decided to stick with the 0% ethanol as i have noticed problems with 2 of my cars since the introduction of 10% ethanol. I've always used 5% in the 928 but dont drive it much so dont know if it affects it but will switch it to +99 Esso as soon as the tank is empty but this will take some time. I'm not using much fuel since covid though now i'm travelling to europe a few times fairly regularly the extra cost still isn't too much. I want to experience the difference also. Even at £500 / £1000 a year more it seems well worth it. I have read that there could be upto a 3% increase in fuel economy using 0% ethanol but I haven't taken this into account. thanks tigertiger12

Can this thread be renamed, the inaccurate adventures of PH fuel knowledge users

tigertiger12 said: I just got a Esso wex fuel card but don't use much fuel so only got a 1p discount from pump price on premium fuels. I've just changed over to Esso +99 for my 928 & an E280 then the premium diesel for my Cayenne. Will defo look into the PCGB thing, Do I just join and then get the porsche/wex fuel card or are there other conditions for the 6p discount? I also have a nectar card and get points if I buy things from ebay (dont really shop at Sainsbury's) and with 300 nectar points I can get an extra 5p off per litre. I'm wondering if you can also do this to make your discount 11p off per litre which makes it even better value, though your 6p off is great. How can you check if the +99 is 0% or is all the +99 Esso 0% ethanol? I use the esso store locator thing and check the +99 check box. Have a short drive but is worth it for a full tank. Also I can use my wex card in Europe to pay for fuel but don't get a 1p per litre discount in Europe. Does yours work in Europe with or without the discount? Also prices at Esso can vary a fair bit for the premium fuels, (at least near me) wondering if there is a website that I can check the prices of the premium fuels at different stations, 2 local to me are expensive so another towards the town centre is better priced so i'll use this one. I'm off to Europe soon for a few months and will be back and forth for a few years. I can use the wex card at Shell and Tesco to pay but no discount but don't want to, i've had enough of this fuel business and have decided to stick with the 0% ethanol as i have noticed problems with 2 of my cars since the introduction of 10% ethanol. I've always used 5% in the 928 but dont drive it much so dont know if it affects it but will switch it to +99 Esso as soon as the tank is empty but this will take some time. I'm not using much fuel since covid though now i'm travelling to europe a few times fairly regularly the extra cost still isn't too much. I want to experience the difference also. Even at £500 / £1000 a year more it seems well worth it. I have read that there could be upto a 3% increase in fuel economy using 0% ethanol but I haven't taken this into account. thanks tigertiger12 You need to join PCGB first before you can apply for the Porsche/Wex fuel card. The fuel card is free and offers a 6p discount on all Esso premium fuels(both petrol and diesel) but no discount on Esso standard fuels. UK Esso fuel stations which supply 0% ethanol Supreme +99 are only the ones supplied by Esso's only UK refinery which is at Fawley Hampshire. This refinery supplies most of Southern England and South Wales. However Esso retailers in Cornwall, North Wales, Cheshire, Northern England and Scotland get their Supreme +99 from other refineries not owned by Esso and contain up to 5% ethanol. I buy my Supreme +99 from Crosshands in South Wales which gets it from Fawley but if you're on the border with the aforementioned areas then best to do your own due diligence. To recap buying Esso Supreme +99 is no guarantee of 0% ethanol just the stuff from Fawley. All Esso Standard +95 has 5% ethanol irrespective of where it is is retailed at.

Taffy, do you own a Ferrari 812 Superfast? This really is a specialist motor. I can now understand why you are so particular about fuel...

I am by my own admission overly fussy about which fuel goes into my sports cars . My dailies operate perfectly fine on whatever fuel is closest to my home. I'm also very careful what food I put in my own gut ie no heavily processed whatsoever. My cars gets treated like my body. Work hard but play harder with only the best fuel either way.

Perhaps. But where’s the fun in that?

My main motivation is 0% ethanol rightly or wrongly.

ScienceTeacher said: Taffy, do you own a Ferrari 812 Superfast? This really is a specialist motor. I can now understand why you are so particular about fuel... A motor that specialist will run on petrol from any source in the UK and Europe. Edited by anonymous-user on Sunday 6th February 07:30

Taffy66 said: My main motivation is 0% ethanol rightly or wrongly. I think the 812 will run on 2 star leaded

I’d go for that, then. Probably run fine without a service and oil change for 50K miles too.

Yellow491 said: I think the 812 will run on 2 star leaded Probably will and still have more horses under the bonnet than any Porsche.

So what fuel should I be using?

981SPYGANG said: So what fuel should I be using? quite simply, one from a forecourt. Petrol for petrol cars. Diesel for diesel cars. The rest I'm not fussed about.

Seriously, though, sitting a car half full of E10 for weeks on end may start to absorb some water which could be problematic. Everyone says that, don’t they?

ScienceTeacher said: Seriously, though, sitting a car half full of E10 for weeks on end may start to absorb some water which could be problematic. Everyone says that, don’t they? Where do you and other people get this trash from. Condensation is not an E10 problem. It is just a problem, often most don't notice it. This is no different to the "crap in the bottom of the fuel tank" comments. I've yet to see a fuel sender not at the bottom of a fuel tank.

I think the car would have to absorb a hell of a lot of moisture before any separation occurred. Not quite sure what I mean by that, but litres of the stuff, probably, which is quite improbable in a half filled tank however long it is left. This may take many months or more if it happens at all. Other evaporation may happen first.

ScienceTeacher said: I think the car would have to absorb a hell of a lot of moisture before any separation occurred. Not quite sure what I mean by that, but litres of the stuff, probably, which is quite improbable in a half filled tank however long it is left. This may take many months or more if it happens at all. Other evaporation may happen first. Out of curiosity how does the water get into a sealed petrol tank? I think it's more likely the ethanol will start to degrade after a couple of months. But on a flexfuel system it wouldn't really matter anyway. ETA, that's if you have had a flexfuel system fitted of course.

I believe that the ethanol is hygroscopic, absorbing water vapour from the air. The air is drawn in and out of the tank due to temperature changes and the incoming moist air is dehumidified by the ethanol ... degrading this. Hence if the tank is full, there is less air to expand and contract and the quantity of dehumidification therefore substantially lower.

ChrisW. said: I believe that the ethanol is hygroscopic, absorbing water vapour from the air. I believe you are correct ChrisW. said: The air is drawn in and out of the tank due to temperature changes and the incoming moist air is dehumidified by the ethanol ... degrading this. Ah...condensation then ChrisW. said: Hence if the tank is full, there is less air to expand and contract and the quantity of dehumidification therefore substantially lower. Yes of course. Thanks. I imagine it would take a good few weeks for half a tank of E10 to noticeably degrade.

I try to put cars away with a full tank ... but I think it would never be a problem for the length of time that it takes a battery to discharge itself .... and I always use E5 ... some Esso Supreme has less than 5% ethanol ...

Up to now I've been using Shell VPower which is supposed to be E5, but isn't at all apparently. I shall be going E40-50 in the near future.

Esso - as good as they are, really need to increase the stations that stock Supreme Unleaded. I pulled into three separate Esso stations on way back from Norfolk to London and none of them had this fuel, two of them even branding Supreme on their forecourt but only seemed to stock diesel. Just went to Shell in the end.

popeyewhite said: ChrisW. said: I believe that the ethanol is hygroscopic, absorbing water vapour from the air. I believe you are correct ChrisW. said: The air is drawn in and out of the tank due to temperature changes and the incoming moist air is dehumidified by the ethanol ... degrading this. Ah...condensation then ChrisW. said: Hence if the tank is full, there is less air to expand and contract and the quantity of dehumidification therefore substantially lower. Yes of course. Thanks. I imagine it would take a good few weeks for half a tank of E10 to noticeably degrade. And yes of course, condensation on the metal inside of the fuel tank if cooler than the incoming air ...

It's cheaper to use 99RON over 95RON in my V8 Cayenne, due to the increase in mileage from the former. Comparing Tesco 95 to 99. YMMV

https://youtu.be/Pwk_u71Izpg?si=rq_egUUTvdbx6zb2 From the horses mouth, interview from JayEmm, ignore him, the interviewee makes sense!

andygo said: https://youtu.be/Pwk_u71Izpg?si=rq_egUUTvdbx6zb2 From the horses mouth, interview from JayEmm, ignore him, the interviewee makes sense! I didn't watch it because I'm afraid I can't stand JayEmm, but FWIW Shell V Power is the best. I've heard that from so many tuners now, and read that many tests, really no other fuels make sense if your engine can be/is tuned for it.

Bit of an update... I switched over to RON 99 not long after starting this thread - mainly because the PCGB Wex fuel card gives 6p discount but also because RON 95 changed from E5 to E10. At first, I thought I noticed a slight improvement, but I didn’t pay too much attention after that. Lately though, I’ve been doing a regular 500-mile round trip for work, so I decided to run a proper back-to-back comparison between RON 99 and RON 95 on the same journey. On RON 99, I get an extra 4.5 mpg over a full tank, managing 550 miles on one fill (right down to empty). On RON 95, I couldn’t quite make it - I had to stop and throw in two gallons just to get home, which left me with ~30 miles still showing on the range. For my car at least, the extra cost of RON 99 is easily justified by the noticeable boost in range and efficiency.

Agreed I get 10% better fuel economy in my truck and smart car running super unleaded

Interesting test on Tesco Momentum - https://youtu.be/cdHZsgiuXVQ?si=RWpon_KuFDKPozDL

It would be interesting to see the cost/benefit of the higher octane fuels. For the 12 p/litre premium of V Power over standard 95, it will need to be much better. That said, my Mezger gets fed Momentum, V Power or Supreme 99 if available.

brisel said: It would be interesting to see the cost/benefit of the higher octane fuels. For the 12 p/litre premium of V Power over standard 95, it will need to be much better. That said, my Mezger gets fed Momentum, V Power or Supreme 99 if available. Depends upon the engine ECU and how well it can adjust to the higher octane. My V8 Cayenne will give sufficiently more MPG on 99 than 95, that it's cheaper per mile on 99 than 95. On a performance engine, literally a 2-3mpg gain is enough to offset the price difference. Edited by TEKNOPUG on Sunday 19th October 08:34