One thing I do not do under any circumstance is use Supermarket fuel!

Where do you suppose Supermarkets buy their fuel? There are 12 or 13 refineries within the UK serving local supplies and none of them are owned by Tesco or Asda. The only difference between Shell, BP, Tesco, Asda, Esso etc fuels are the additives used, and nobody can really tell whether they benefit a particular engine type or not. Most Petrol Stations are simply re branding the same product.

95 for mine when it lands and an oil change when it needs it, no use in babying them too much

I`ve found forums can bring out the most anal people lol!

Oil, fuel and running in are the most discussed

Its the anal people who i like to buy 2nd hand cars from. ;-)

Despite improvements in engine /oil production etc the fundementals are unchanged.

All oil degrades over time and or use dependant on journeys undertaken and engines are metal against metal components expanding and contracting dependant upon operating conditions. All engines respond well to regular maintainence.

dsg boxes are exactly the same. Dsg oil is expensive but makes a rough changing box smooth again.

Where do you suppose Supermarkets buy their fuel? There are 12 or 13 refineries within the UK serving local supplies and none of them are owned by Tesco or Asda. The only difference between Shell, BP, Tesco, Asda, Esso etc fuels are the additives used, and nobody can really tell whether they benefit a particular engine type or not. Most Petrol Stations are simply re branding the same product.

 

+1

Also, Europe has very high quality fuel in general compared with other countries where the contamination of fuel can be high.

 

 

For a 25 year old, additives & cleaners might make a difference because the combustion quality can be poor.

For modern engines will electronically controlled injection, pressure & closed-loop sensing system the combustion quality is much improved so should run much cleaner anyway.

 

I have run every car I have owned with supermarket fuel & have never had a problem with the engine, catalyst or DPF. (touch-wood the Skoda stay the same way..... )

When the first FSI engines came out (Alfa Romeo I believe) they required 99 ron to do the stratisfication properly and that wasn't even available in the UK at the time.  Anything less and there was no improvement having this type of engine over a normal one.

 

98/99+ Ron will only benefit a forced induction engine.  The higher the starting power the more benefit.  From various magazine tests I remember 220ish+ hp was about the first time you would get any kind of difference albeit very slight.  Once past 500Hp you're looking at 5-10% difference which is noticeable.

 

Various Ford forums have dyno graphs on them proving 98 Ron in a 2.5T Mondeo engine reaches 230Hp where it is 217HP on 95 ron.

 

Some cars respond better to it than others.  Depends on a host of factors.

 

On a standard car it's up to you, there's a placebo effect spending more money so it must be better.  On a remapped car it's a must.

I've stayed away from supermarket standard fuel ever since my mums saxo did 4 o2 sensors after the tesco contamination. That was two sensors at a time twice a few months apart not 4 instances. They did pay for the repair work though.

I use a mix or vpower and tesco 99momentum when we have worked up a good saving per litre...

My understanding is that ethanol is less dense and has less calorific value per litre than petrol so you do get slightly worse fuel consumption with ethanol added.

Conversely ethanol has a higher octane rating and pure ethanol is used in many high performance race engines in formulas seeking to be seen as being 'green'.

I believe that one of the problems with ethanol is that it can adversely affect some materials used in older cars not adapted for ethanol so pipes can deteriorate. It was a problem when it was originally and secretly added by some Australian petrol merchants to boost profits and the fairly old car fleet experienced some issues (rust is not a major problem here).

I was not aware that the addition of ethanol was so common in Europe so most cars sold now are adapted for its use.

The local manufacturer Holden made a big thing of their engines being able to run e85 fuel a few years back. Toyota and Ford did not so I presume they cannot.

I think it's poor reputation here is more to do with the quality of the supplier than the fact that it has ethanol in it. That is the reason I think I had been advised to avoid it by mechanic friends and the Skoda dealer (not Skoda per se)

I think it's poor reputation here is more to do with the quality of the supplier than the fact that it has ethanol in it. That is the reason I think I had been advised to avoid it by mechanic friends and the Skoda dealer (not Skoda per se)

The main reason it's not recommended to use fuel with a high ethanol content in cars not designed to use it is that it can damage the fuel hoses etc. it the manufacturer has used alcohol soluble materials.

I have to say I am not entirely convinced of the merits of higher octane fuels in most run of the mill petrol cars.

I had a Fabia vRS for a good long while and can say having religiously filled it with BP ultimate for about 6 months from new; a forced change to regular unleaded (started running it as my company vehicle and wasnt allowed to buy super) I noticed no difference in performance or fuel economy....didnt run any differently either. And it was recommended to run that on 98 Octane (95 being fine with "possible torque output reduction").

I think I hard tuned vehicle...something like a high revving E46 or E90 M3 would absolutely benefit from it but not likely a 2.0 TSI.

Im pretty sure in most cases even the high output 2.0 TSI's recommended fuel is 95 RON (unless Ive misread the S3 and Golf R brochures).

This is not scientific, and some fuels only have just a few tanks for measurement, but here is the League Table for Fuel Consumption from above table (my car).

 

1. Shell Premium (x2 fills) 30.72 mpg - 112.2%

2. BP Premium (x2 fills) 28.35 mpg - 103.5%

3. Esso Premium (x5 fills) 27.54 mpg - 100.1%

4. Tesco Premium (x10 fills) 27.1 mpg - 98.9%

5. Tesco Momentum 99 (x6 fills) 27.09 mpg - 98.9%

6. Shell V-Power Nitro+ (x4 fills) 26.01 mpg - 94.96%

 

*Percentage figures are returns vs my overall mpg of 27.39 mpg over 8K miles.

 

Obviously, the highest accuracy will be the fuels with the most tank-fills. The two most commonly used are Tesco Premium and Tesco Momentum 99, both of which return pretty much identical results. Rather surprisingly Shell V-Power (the most expensive fuel) returns the worst results over 4 tanks and >1000 miles of driving, yet Shell Premium was the winner (although only two tanks were measured).

 

My conclusion is:- Higher Octane and additives are worthless within a new TSI engine. They are a waste of money and provide zero gains during normal driving conditions.

 

I will also try a few more tanks of Shell Premium, just in case it is the amber-nectar for Octy VRS's.

 

*Note: Results based upon real-world tests and recorded results rather than supposition and what mates say in the pub :beer:.

Edited 10 March, 201511 yr by Orville

http://www.briskoda.net/forums/topic/339011-whats-the-best-fuel-that-can-be-used-to-run-a-octy-vrs/

 

a comprehensive test has been conducted on this posting, worth a read.

As for the difference between running lpg and petrol that's a useless comparison due to the wildly different energy content between the fuels

 

Wildly different???

 

RON value of LPG - typically 100 to 110 depending on the mix of butane and propane which varies between winter and summer

Calorific value is typically 20% lower than 95 RON - hence why you get approx 20% lower mpg on LPG

 

Hardly wildly different - all it means is that you can run more advance and a higher compression ratio with LPG before knock occurs due to the higher octane rating - hence my observations regarding ignition advance and how on some ECUs it can take quite some time for the ignition to advance to the optimum - it doesn't do it in a matter of minutes. It will instantly retard the ignition when it detects knock, but doesn't instantly advance to the maximum, approaching the limits it gets very conservative in terms of further advance.

 

Plus, these values have to be learned across the rev range at varying loads.

 

The advantage of running 98RON (other than the detergents) is the higher octane rating, which with the same compression ratio means you can run more advance, which on part throttle will aid economy. But, at the end of the day you are going to gain 2 or 3% if you are lucky, so it is hardly worth it if you are paying more for the fuel.

 

The difference in calorific value will affect the fuel trims, hence why you overlay a LPG map on the petrol map to extend the injector period. If you get this wrong, and see long term fuel trims drifting to + or -10% or more, when you switch back to petrol it takes some time for those long term trims to re-adjust. The closed feedback loop of the lambda sensors will of course correct this with the short term fuel trims. Open the throttle a bit or the engine isn't up to temperature and there isn't a closed feedback loop anymore and you are relying on the underlying map and learned values.

 

What I am saying is don't expect instant results, give it a couple of tankfuls to settle down, and at best expect a couple of percent better mpg, if you can even measure that small a difference.

 

No it doesn't , if the fuel grade isn't suitable the ecu picks it immediately

Op how have you measured the difference in performance?

you are correct that it "senses" the fuel isn't up to spec and pulls timing or injects more fuel but if it is suitable then the ECU takes a while to get itself back to optimum. I've proven this on my TSI whenever I've run ethanol blend fuels (economy goes to pot). It takes about 1 tank of "pure" fuel to get back to normal.

OP: why is your economy so terrible? Do you do lots of short trips around the suburbs?

I think your method is slightly flawed as a single tank isn't a decent test - you need to run at least 3 tanks through.

Your spreadsheet is a thing of beauty but it's missing the all important cents per km figure.

Also, does the seat-o-the-pants meter detect any difference in torque? My 1st gen TSI gains a lot of sub2500rpm torque with higher octane fuels (105ron e85 ethanol blend is unbelievably torquey & powerful - and throws a CEL after 300km).

Good reading here

http://www.autocar.co.uk/car-news/motoring/high-octane-equals-better-mpg

And here

http://www.pistonheads.com/gassing/topic.asp?t=302977

 

OP: why is your economy so terrible? Do you do lots of short trips around the suburbs?

I think your method is slightly flawed as a single tank isn't a decent test - you need to run at least 3 tanks through.

Also, does the seat-o-the-pants meter detect any difference in torque? My 1st gen TSI gains a lot of sub2500rpm torque with higher octane fuels (105ron e85 ethanol blend is unbelievably torquey & powerful - and throws a CEL after 300km).

Economy is terrible because the car is used mostly within Central London, rarely getting above 40mph. I have listed two runs with 3 consecutive tanks of Super, but there is no improvement for me. Also, seat of my pants is more important to me than anything a Dyno would say.

Interesting that a lab that can prove the extra power (which you would expect from a higher octane rating) couldn't scientifically prove the difference in economy in one highly scientific test, but in a 'seat of the pants' test could prove 14% gain!

My mk3 tsi has now covered almost 20k. Almost all of this mileage has been on 98 RON however my last two tank fills have been tesco 95 RON. I can feel the difference in throttle response up to circa 3k rpm. Car feels slightly heavier/sluggish in response however no real difference In mileage returns.

An easy way to describe the difference in throttle response would be the difference between standard and sport driving modes for the engine. Very noticeable to me but maybe not so to others. Worth an extra £3 per fill? Yes to me for the improved throttle reponse where the car is driven the most.

My mk3 tsi has now covered almost 20k. Almost all of this mileage has been on 98 RON however my last two tank fills have been tesco 95 RON. I can feel the difference in throttle response up to circa 3k rpm. Car feels slightly heavier/sluggish in response however no real difference In mileage returns.

An easy way to describe the difference in throttle response would be the difference between standard and sport driving modes for the engine. Very noticeable to me but maybe not so to others. Worth an extra £3 per fill? Yes to me for the improved throttle reponse where the car is driven the most.

Parsey83's comments mirror my own. MPG variations seem minimal, but my last 3 cars felt 'sweeter' running on premium Shell fuel, latterly v-power. They also ran consistently a few degrees cooler. The difference in price was less than the costs of a decoke/EGR replacement, which I have never had to have (Jetta GTI had done 152k miles when sold, Bora 178k and now being used by my son, engine still sweet as a nut). Interestingly, I filled the Jetta with BP's superjuice once, when I was unable to find a Shell station and the engine hated it - throttle response was markedly inferior, starting ditto. When Shell first started marketing a premium grade petrol, Shell Advanced, back in the early eighties, Vauxhall engines hated it so much they broke, so I guess it's horses for courses. Bit like beer, isn't it, one man's mead is another man's poisson!

You can't just blame central London congestion for your low mpg figures Orville. I occasionally drive through the worst congested areas too and get better figures.  The one exception... You do loops of Fulham, Hammersmith, Kensington earls court.... Of that is the case you are doing quite well!

Interesting that a lab that can prove the extra power (which you would expect from a higher octane rating) couldn't scientifically prove the difference in economy in one highly scientific test, but in a 'seat of the pants' test could prove 14% gain!

Ahh, but my ass feels real world performance and not artificial Dyno runs where turbo spool times are not measured, boost is held for FAR longer than on normal roads, and heat build up is much more excessive due to lack of airflow/cooling.

I am sorry, but how it feels on the road is much more important than how a car measures under wholly unrealistic load situations. On the road a car will not hold full boost at high rpm for several minutes. This is why Dyno's show unrealistic gains from high RON fuels - the engines are stressed beyond normal road and even track conditions. Push any engine towards its heat and pressure thresholds and it will be more likely to induce knock, the point where higher RON fuel is beneficial. All I am saying is that on the road such thresholds are rarely met within our (majority UK) temperate climate, so above spec RON is not needed. Dyno runs only prove how a car performs on a Dyno.

Edited 11 March, 201511 yr by Orville

I have to say I am not entirely convinced of the merits of higher octane fuels in most run of the mill petrol cars.

I had a Fabia vRS for a good long while and can say having religiously filled it with BP ultimate for about 6 months from new; a forced change to regular unleaded (started running it as my company vehicle and wasnt allowed to buy super) I noticed no difference in performance or fuel economy....didnt run any differently either. And it was recommended to run that on 98 Octane (95 being fine with "possible torque output reduction").

I think I hard tuned vehicle...something like a high revving E46 or E90 M3 would absolutely benefit from it but not likely a 2.0 TSI.

Im pretty sure in most cases even the high output 2.0 TSI's recommended fuel is 95 RON (unless Ive misread the S3 and Golf R brochures).

The Golf 7R is recommended to run on Super unleaded

You can't just blame central London congestion for your low mpg figures Orville. I occasionally drive through the worst congested areas too and get better figures.  The one exception... You do loops of Fulham, Hammersmith, Kensington earls court.... Of that is the case you are doing quite well!

I have no complaints about fuel economy given the environment I drive within. My earlier post was merely explaining why my mpg is terrible compared to others who commented. 27mpg from a car with 220+ PS, driven mostly in town is pretty good compared to my old Subaru's which struggled to break 20mpg (and which did benefit from higher RON fuels on the road).

Ahh, but my ass feels real world performance and not artificial Dyno runs where turbo spool times are not measured, boost is held for FAR longer than on normal roads, and heat build up is much more excessive due to lack of airflow/cooling.

I am sorry, but how it feels on the road is much more important than how a car measures under wholly unrealistic load situations. On the road a car will not hold full boost at high rpm for several minutes. This is why Dyno's show unrealistic gains from high RON fuels - the engines are stressed beyond normal road and even track conditions. Push any engine towards its heat and pressure thresholds and it will be more likely to induce knock, the point where higher RON fuel is beneficial. All I am saying is that on the road such thresholds are rarely met within our (majority UK) temperate climate, so above spec RON is not needed. Dyno runs only prove how a car performs on a Dyno.

I think you misunderstood me, I was pointing out that the same company claim wildly different results depending how they run the tests.

As others have said, if you can feel a difference for the sake of a few quid a tank then why not.

I tried the shell premium diesel in my PD140 and it gave worse economy but felt a little more powerful. Went back to the standard diesel after a couple of tanks.

Sent from my HTC One_M8 using Tapatalk

I think you misunderstood me, I was pointing out that the same company claim wildly different results depending how they run the tests.

As others have said, if you can feel a difference for the sake of a few quid a tank then why not.

I tried the shell premium diesel in my PD140 and it gave worse economy but felt a little more powerful. Went back to the standard diesel after a couple of tanks.

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Sorry I misread your original post. Apologies.

My mk3 tsi has now covered almost 20k. Almost all of this mileage has been on 98 RON however my last two tank fills have been tesco 95 RON. I can feel the difference in throttle response up to circa 3k rpm. Car feels slightly heavier/sluggish in response however no real difference In mileage returns.

An easy way to describe the difference in throttle response would be the difference between standard and sport driving modes for the engine. Very noticeable to me but maybe not so to others. Worth an extra £3 per fill? Yes to me for the improved throttle reponse where the car is driven the most.

 

I have the same result as parsey - with 27k under the belt running on 99 for 90% of fill ups, it does seem to be more sluggish when running 95.

Ahh, but my ass feels real world performance

I know the Octavia is roomy but how do you fit a donkey (or similar) in there without scratching the plastic or paint?

That conundrum aside, in some cars I reckon I have felt more performance variation from differing environmental conditions (temperature, humidity), my mood, or road conditions than from the type (or brand) of fuel I have used.

There is always the 'placebo' affect as well, if you put in more expensive petrol expecting more performance or economy then do you unconsciously drive to achieve the expectation.

To do it more scientifically you would need to do a sort of double-blind test where you fill it up blindfolded so you don't know what you put in (could be dangerous) OR get someone to do it for you and not tell you what was put in until the tank is empty

I am not knocking what others have said because their experiences are different from mine and take into account more factors.

But, when I eliminate as many variables as possible then in a steady state cruise there is no discernable consumption difference between 95 and 98 Octane fuel in my car.

Edited 11 March, 201511 yr by Gerrycan