Has anyone tried to use different octane fuel for his petrol engines?

I was reading an article that turbo charged engines are better with higher octane!!!!!!!!!!

Any clues??

I tried in Swiss green fuel Shell called "Superplus" with 98 octane.

In Italy there is Shell V-Power with 99 octane.

I had already tried on other petrol machines and I found a small benefit, even in consumption. These special fuels also should take cleaner combustion chamber and more.

I converted to Diesel several years back, and hence do not use Petrol. anyway, the comments relate to both Petrol and Diesel.

I seriously doubt that there is any economical benefit in using the more expensive "superfuels". For both Diesel and Petrol, if the fuel meets the engine manud´facturer's specifications, the higher octane or cetane numbers are just wasted - they provide no engine benefits. They certainly do not save týou money or save the engine.

My opinion - worth what you paid for it.

My 2 litre TFSi used to (without any doubt) be more responsive running 98 or 99 octane petrol. If driven steadily it used to get slightly better mpg also.

Same really with my little run around 1.6 TDCi fiesta - this, having been remappped may make any differences more obvious but both myself and SWMBO can tell if it has had to have the standard diesel put in it (which has probably only been 15 times in 20,000 miles! With BP Ultimate it gets between 20-40 miles extra from the tank compared to the standard stuff. The drive is vastly better on the higher cetane stuff also. It pulls better low down and then revs smoother and pulls harder all the way through the revs.

These better quality fuels also have additional cleaning additives for the engine, supposedly keeping it cleaner inside and therefore running cleaner on the outside.

EDIT - in fact thinking back to previous cars, the only one that didnt seem to be 'better' on the posh stuff was my first Fiesta - a 1.25l petrol. Then again that engine didnt have a knock sensor so maybe the lack of internal adjustment meant it was wasted on the little petrol engine.

Edited 25 March, 201016 yr by FocusZtec

FocuzTech,

I agree with one of your premises: if you run an engine with lower octane than required AND it has knock sensing, it will run more economically on the right Octane, as the knock sensor would retrd the ignition timing. I fail to understand why there would be a benefit if the Octane is high enough, so there is no retardation of the ignition. There is no more energy in the fuel. If there are additives that keep the engine cleaner (meaning what? - less ash build up or ?) the effect will definitely not be felt immediately.

It does not necessarily apply to you, but there is a strong tendency for people to rationalize a benefit if they have paid for it. There may be a psycologically induced behaviour modification on driving style if you just forked out more for the better fuel.

What really gets me is that I heve never seen any scientific or technically reasonable explanaton from the fuel companies as to the function of the "super" components in their fuel. All of the tests I have ever seen - from independent authorities - have never found the advertized benefits. Most vehicle manufacturers come out quite strongly in their manuals, saying: "Do not use either oil or fuel additives". Clean fuel and oil to spec is all you need.

Anyway, if people are pleased with the super fuel products and it makes them more satisfied, well enough. We will never settle these diffeent opinions here unless there are some very objective data somewhere.

BTW, just because it happened that way - difficulty in reading the diffeence between the various names for diesl along the highway stations - I happened to alternate between the Superior and very superior diesel on the 4200 km trip from Malaga to Denmark a few weeks ago. never felt any difference in any vehicle behavior or fuel economy - and did not expect to either.

My impression on my previous car (a 1.3 Subaru) was that with higher octane petrol I used fewer revs for the same result and got a noticeable increase in mpg as a result, something around 10% better. This seemed consistent over a lengthy period and given it only had a small tank, if I was doing a long journey I'd use higher octane so I didn't have to stop so soon.

As some will no doubt spot, simply making less use of the accelerator pedal will correspond to better fuel economy; however my impression was that I wasn't driving any slower but rather using less throttle to do the same thing.

With the Yeti I started with normal unleaded, but as many have noted, getting away in first is not particularly swift and I thought that going super might help here (it had done in my previous car). So I put in a tank full of higher octane.

As far as I could tell, within the way I drive, it made very little difference to anything so I haven't done it again.

FocuzTech,

I agree with one of your premises: if you run an engine with lower octane than required AND it has knock sensing, it will run more economically on the right Octane, as the knock sensor would retrd the ignition timing. I fail to understand why there would be a benefit if the Octane is high enough, so there is no retardation of the ignition. There is no more energy in the fuel. If there are additives that keep the engine cleaner (meaning what? - less ash build up or ?) the effect will definitely not be felt immediately.

It does not necessarily apply to you, but there is a strong tendency for people to rationalize a benefit if they have paid for it. There may be a psycologically induced behaviour modification on driving style if you just forked out more for the better fuel.

What really gets me is that I heve never seen any scientific or technically reasonable explanaton from the fuel companies as to the function of the "super" components in their fuel. All of the tests I have ever seen - from independent authorities - have never found the advertized benefits. Most vehicle manufacturers come out quite strongly in their manuals, saying: "Do not use either oil or fuel additives". Clean fuel and oil to spec is all you need.

Anyway, if people are pleased with the super fuel products and it makes them more satisfied, well enough. We will never settle these diffeent opinions here unless there are some very objective data somewhere.

BTW, just because it happened that way - difficulty in reading the difference between the various names for diesl along the highway stations - I happened to alternate between the Superior and very superior diesel on the 4200 km trip from Malaga to Denmark a few weeks ago. never felt any difference in any vehicle behavior or fuel economy - and did not expect to either.

Are numbers "scientific"? I get 620-640 km per full tank with Shell V-power (98 octanes in Greece) and around 570 with 95 oct. on my 1.2. Same driving conditions and roads. Not mentioning the bigger torque with 98 oct. and, more important, the quieter functioning. But the latter is just my personal feeling.

Are numbers "scientific"? I get 620-640 km per full tank with Shell V-power (98 octanes in Greece) and around 570 with 95 oct. on my 1.2. Same driving conditions and roads. Not mentioning the bigger torque with 98 oct. and, more important, the quieter functioning. But the latter is just my personal feeling.

Not scientific but I just know that every non premium tank I do I get around 30 miles less and Im driving it in the same driving pattern in the same way every day.

I also agree that my common rail 1,6 unit is smoother and quieter - more noticeable when cold - on the more expensive stuff.

No way is it a phsycological thing either. Ive driven the cars after SWMBO has filled then up and Ive phoned her 15 mins into the journey and said - 'youve put the cheap stuff in havent you'? Every time Ive been right and she has done it as there was no premuim stuff available when she needed to fill it.

She notices it too. Ive been around cars and car tuning in general long enough to realise that the 'better' fuels do make a difference.

I seem to remember Evo Magazine testing a number of different petrol grades/brands to see if there were any real differences.

IIRC they tested a Golf GTI and a BMW M5 - the Golf showed no benefit from running on the higher octane petrol, but the BMW engine produced more power as it was able to adjust. So I guess it depends on engine technology.

I've always been told that you should buy fuel from a busy petrol station as it goes 'stale', and that has more of an effect on performance than anything else? That could of course just be an urban myth.

Fuel definately goes 'stale' but I doubt that any garage would have fuel in the tanks long enough for it to happen unless it is an exceptionally quiet garage.

I've no idea whether the better fuels are worth it. I've used them occassionally but not noticed any difference.

Has anyone tried to use different octane fuel for his petrol engines?

I was reading an article that turbo charged engines are better with higher octane!!!!!!!!!!

Any clues??

My vRS octavia was recomended a high octane -98 and certainly ran better for it. Snowmonster's recomended octane is 95 which equates to standard UK unleaded ( I think ) so I've been sticking to this, he will also run on lower octane fuels, so to spend money on the really high octane fuels seems a pointless expence.

My vRS octavia was recomended a high octane -98 and certainly ran better for it. Snowmonster's recomended octane is 95 which equates to standard UK unleaded ( I think ) so I've been sticking to this, he will also run on lower octane fuels, so to spend money on the really high octane fuels seems a pointless expence.

But surely if 95 ron is the lowest recomended rating, the ECU will advance the timing to improve performance if you feed it the higher rated stuff still?

We recently had a meeting at work about aviation fuels with some high up people from BP - one had been much involved with BP Ultimate 102 for racing cars. I asked them about whether BP Ultimate was worth it in my car (they didn't know what I drove apart from it was a Skoda). Their view was that it was a cleaner burning fuel and because of the higher cetane rating it would be quieter. As to more performance or MPG they were hesitant. They did say if you swop from one to another after a period of time though you would notice the difference. It does take a little bit of time, I understand, for the engine monitoring systems to adapt to a fuel spec.

My personal experience and thoughts having run Shell Optimax in various cars and then BP Ultimate diesel in my Fabia vRS and now the YETI (YETI to be now stated in upper case to ensure visble forum compliance ) is that cars do run better on the more expensive fuels. I once put Asda stuff in the Fabia vRS due to a last minute unexpected motorway trip and it ran like a pile of pooh...

But surely if 95 ron is the lowest recomended rating, the ECU will advance the timing to improve performance if you feed it the higher rated stuff still?

No, 95 ron is highest recomended, 91 is lowest. :no: