RON 95 or 98

[Tooraphil]

Should I be using 98 octane petrol or is 95 alright in tsi110 

[Ootohere]

Welcome.

Up to you, try both at different times and see what you think, brim to brim,

is it smoother on Super Unleaded, is the tank range a bit more so covering the extra expense.

[shyVRS245]

Not sure whether you get the 3 cylinder 1.0 turbo or the 4 cylinder 1.2 turbo but both will be fine on the 95 octane unless you plan to remap it when the warranty expires then I would recommend the higher octane.

[TheWanderer]

For a smaller less potent engine I'd be using bog standard 95 Octane, it's not really worth it unless you have a larger engined car or RS, as I wouldn't expect you to gain many more miles out of it against the extra cost.

 

An alternative to it would be to try something like Millers Eco Max (Petrol) for a few tanks against 98/99 Octane and then do a few tanks without anything in except 95 Octane.

 

You'll soon find out what the best option is.

Edited 14 September, 2019 by TheWanderer

[Ootohere]

@Tooraphil

What is the difference in price in Australia between 95 and 98 octane?

[Tooraphil]

About 10 cents per litre

[Kenny R]

Does it not have a recommended octane sticker on the rear of the fuel flap.

[Tooraphil]

It says min 95 octane but always used BP Ultimate in the Alfa

[TheWanderer]

13 minutes ago, Tooraphil said:

About 10 cents per litre 

 

So unless it's really necessary, use the bog standard stuff and save yourself some money. Don't give it to the taxman.

[Ootohere]

An Ex Tech has posted in the Mk3 Fabia section about being in on tests with fuel and 1.0TSI producing less power on Super Unleaded than on 95 ron.

 

I have driven 1.0TSI DSG's with 115 ps and for me it would always be 99 ron i use.

It is only 5 pence a litre more than supermarket 95 ron, and cheaper than BP / Shell / Esso / Gulf etc 95 ron, 

and lots less than crazy priced 97 ron the BP have in the UK.

Also less than Shell V-Power Nitro + which i never use, not to save money just Bore Wash maybe with crappy long life oils and 'Secret Detergents'.

Same secret ones as the Tesco Momentum 99, Esso Super. BP etc.

 

Since the debate will go on for ever it is great that all a driver needs to do is see what they think when they use different octanes.

They have it day by day, week by week, and on and on. 

 

If a 110ps or a 95ps 1.0TSI produces less max power or Nm torque on higher octanes and that is a proven fact then that is a strange one, 

but then VW Group Engine Management / Software from Bosch can be strange to get WLTP / RDE & RDE2 results....

 

 

Edited 14 September, 2019 by Roottootemoot

[Kenai]

I use M99, at a 5p per litre premium, I'm happy enough with the £10 a month or so extra it costs me, to put a better fuel in (assuming no economy improvements).

 

I haven't bothered doing much in the way of comparisons but for the fuel to pay for itself over a year, it only needs to deliver me roughly a 1.5mpg improvement.

[Ootohere]

@Kenai  and maybe £15 a month less than the Shell 99, or BP, Esso, Gulf, Texaco 97 ron.

[Kenai]

Indeed. The only thing tempting me away now is the local Costco has just added a fuel station, though their super offering is only 97 these days, not the 99 it used to be. It is 9p cheaper than M99 near me though 🤔

[Ootohere]

Only once did i get bad Sainsburys 97 ron SuperUnleaded.  Sainsbury Bridge of Dee Aberdeen,

luckily the car had a switchable remap.

unluckily i was booting it about 8 miles after filling up in an outside lane with an Audi up my jacksy when it went into limp mode.

After changing the map to 95 and my pants when i got home, i phoned but they denied that the tanker put 95 ron in the 97 ron tank.

 

2nd time.

Tesco Blackpool and i had a few days in the and Dales while going south and all was well, stayed the night at Preston and was heading to Santa Pod.

Happy as a sandboy as i set off from the hotel and on the busy road having fun and same thing again.

A tank full of 95 ron and into Limp Mode, went to hard shoulder, switched map to 95 ron, headed down the road and then topped up with 102 ron i had in the boot a couple of times untill i got a full tank of 99 ron.

Edited 14 September, 2019 by Roottootemoot

[Gerrycan]

5 hours ago, Tooraphil said:

Should I be using 98 octane petrol or is 95 alright in tsi110 

I have an older 2014 1.4tsi, the same engine but with slightly lower power at 103kw.

I have (almost)  always used 95 Octane and have had no problems. I did put a few successive tanks of 98 in on a mechanic's recommendation but could detect no power, smoothness or economy benefits, so switched back.

As others have said, it is not an expensive experiment to use 98 to try out for yourself.

 

I'd advise you avoid the local 91 Octane brew. Yes, it is cheaper (around 13 to 18 cents a litre in Adelaide), but it is well below the recommended octane level and the engine will not operate as efficiently to avoid pre-ignition. It also can have much higher levels of sulphur (140ppm max) compared to 95/98 (40ppm max) which might also affect an engine designed for Europe's 95 octane with sulphur at  only 10 ppm max.

Similarly it is best to avoid the E10 fuels with 10% Ethanol added to the high sulphur 91 octane base fuel. While it does raise the octane to 93 or 94 there can be issues if not stored or dispensed correctly due to Ethanol's hydroscopic properties potentially causing separation in the tank, it also has a slightly lower caloric value.

Probably less of an issue now that ethanol is added by the fuel companies compared to the early days when some petrol 'pirates' illegally shandied their products for bigger profits causing unprepared fuel lines to melt. All modern cars can cope with up to 10% ethanol content.

 

[ahenners]

7 hours ago, Kenai said:

I use M99, at a 5p per litre premium, I'm happy enough with the £10 a month or so extra it costs me, to put a better fuel in (assuming no economy improvements).

 

I haven't bothered doing much in the way of comparisons but for the fuel to pay for itself over a year, it only needs to deliver me roughly a 1.5mpg improvement.

 

It has a 7p premium at my local these days.. used to be 5p. Makes the argument for 95 and saving a few pennies even stronger for this right northerner 😎

 

Edited 14 September, 2019 by ahenners

[superchiwawa]

Well, given the octane rating is an indicator to resistance to spontaneous ignition under compression (think detonation due to high heat increase during compression stroke of the engine cycle, also known as pre-detonation, or pinking, or knock), the generic answer to this question would be it depends on the compression ratio of your engine, and if the fuel and ignition mapping were tuned to adjust to the octane change and take advantage of the higher octave.

 

My swift sport had an 11.1:1 compression ratio, which is considered very high and was tuned to run on 98. It could also run on 95 (albeit not very well as I hear could pinking), but generally the way this works is a knock sensor is fitted to detect pinking and, as I understand it, in this situation the ignition is retarded so the spark ignites the air fuel mixture later past top dead center (TDC). 

 

A later detonation past TDC means less efficiency as the effective compression ratio is lower and thus there is less time/volume or capacity for the explosion to expand/push the piston down, therefore you have a shorter power stroke.  Remember the greater the compression the more energy is stored in that tight space at TDC.

 

So in theory, 98 is better, IF the Engine Management System can detect the change and has been developed to take advantage of the high compression + high octane (ie effective compression ratio at ignition) potential.

 

In short, check the compression ratio of your engine. If it's above 10 or so, then it's possible.

 

[Gerrycan]

Things have moved on quite a bit from when compression ratio was considered the main factor for determining petrol octane although you are right in that it is a factor but what with variable valve timing, direct injection and super/turbocharging etc, it is just one of many.

The Mazda SkyActive range of engines  make a big thing of the high compression ratios they run, claiming around 14:1 for European engines running 95 Octane and 13:1 ratio for the Australian market 91 Octane and while these are very incredibly compared to traditional ratios I suspect there is a bit of marketing bumpf in there. There will be a major difference between the published figure and actual figure, the former probably based on simple cylinder volumes at bottom and top of stroke, and the actual compression ratio which starts when all valves are closed and the top of stroke.

 

Our other car is a 2003 Toyota Echo with 1.3L NA engine, it was quite advanced for its time with multi-point injection, 16 valve head and VVT. The manual says its 10.5:1 compression engine is designed to run on Australian 91 octane fuel and while you can use higher octanes there is absolutely no benefit. Almost embarrassingly blunt. This is definitely not a sporting engine although very durable with performance and economy as per original spec at 186k km.