Super Unleaded

fivetide

Strider590 wrote: »

Well... Yes but no. Higher RON fuel doesn't give greater performance, it's purely that high performance cars need it to run at designed capacity.

This is probably the nub of it.

Using super unleaded will not give your car more performance than the manufacturer said it would. What it will do, if your car can utilise it properly as almillar said, is allow it to use all that performance.

Subaru, the example given, will allow the car to run on 95, as said, they couldn't sell it if it didn't. However, it will retard the timing and you will get slightly less performance. How much difference it makes and whether you'd notice it in day to day driving is probably negligible though.

I've owned a number of Japanese import cars, including ones never officially imported here and all have been fine on either fuel.

Lum

Been done to death on these forums in the past. I vaguely remember the conclusion being:

99% of people, including the "typical" MSEer, if such a thing exists:
Don't bother, use standard. Possibly run some form of super through every 3 or 4 tanks if you believe the engine cleaning additives are worth it, probably more use if you use cheap+nasty supermarket fuel the rest of the time.

People who own a car that explicitly states it needs a certain octane rating:
Go with fuel that is of that octane rating or higher (V-Power & Tesco = 99, all others = 97)

People who own a modern car with fuel injection that is capable of taking advantage of the fuel and care more about performance than economy:
- If your car is European (e.g. BMW 3-series): BP Ultimate
- If your car is Japanese (e.g. Mitsubishi Evo X): Shell V-Power

People who own Japanese imports:
- Performance cars (e.g. Nissan Skyline): Shell V-Power
- Non-performance cars (e.g. Toyota Estima): Whichever is cheaper. Might be able to get away with regular but check the owners forums to be sure.
The reason for this is that "standard" in Japan is 98 and "super" is 100. Japanese cars that require super will sometimes have an orange sticker in the fuel flap, or possibly a sticker recommending a specific brand e.g. Shell Pura (Japanese V-Power)

londonTiger

on the fuel flap on my naturally aspirated 1.6 modest car, it asks to fill with at least 98 octane which IMO is really for performance cars.

Most standard petrol in the UK in 95 octane. So will it be much of a difference in the golf from putting 95 and 99 (shell v power).

DUTR

londonTiger wrote: »

on the fuel flap on my naturally aspirated 1.6 modest car, it asks to fill with at least 98 octane which IMO is really for performance cars.

Most standard petrol in the UK in 95 octane. So will it be much of a difference in the golf from putting 95 and 99 (shell v power).

As you know I have a Golf (no pics in this thread lol) anyways on the filler cover it shows (98) 95 RON, but it is as others have mentioned, ideally 98 RON is what to use but it can use 95.
There is a difference but not night and day. So it's up to the user whether the extra cost is worth it or the extra saving is worth the loss in driveability.
I must add that for a time I was using Tesco super and occasionally the light would come on, so I only use Shell or Sainsburys for super now.

Ultrasonic

I've just discovered there is a surprisingly detailed test report produced by Millbrook and provided via the Tesco website. It gives both fuel economy and cleaning data for its standard and Momentum 99 unleaded fuels compared to competitor's 95 and 99 RON unleaded, across a range of eight different cars.

Report here: http://www.tescopfs.com/content/downloads/mbk_12_0311_2.pdf
Tesco page here: http://www.tescopfs.com/momentum99/testing_results

I've in particular never seen an attempt to quantify cleaning/deposits left before. Momentum 99 does a little worse than the others on this front actually. There are statistically significant changes in fuel economy shown too, and not just for higher performance cars.

Ultrasonic

DUTR wrote: »

I must add that for a time I was using Tesco super and occasionally the light would come on, so I only use Shell or Sainsburys for super now.

What light would that be?

DUTR

Ultrasonic wrote: »

What light would that be?

Why would what be?
Tesco and Asda sell the lowest cost fuel around here that is for sure, I like my car to diet on Super, and hence I used the Tesco Momentum as Asda only do 95 or diesel, after a time the light used to illuminate in the car, still ran fine but irritating that it was on, the VAGCOM thing didn't detect any anomilies.
Shell and BP are also nearby along with a Texaco, well Texaco charge super unleaded prices for standard, so they are out of the question, BP was closely followed, Sainsuburys is the lowest cost near me, but that is 5 miles away, so the round trip compared to using the local Shell is offset, that said the Sainsburys I noticed is 97 RON.
My post earlier isn't to say don't use supermarket fuel, as personally I think it is BS, however obviously there is some difference that my car doesn't like with Momentum.

Ultrasonic

DUTR wrote: »

Why would what be?

:huh:

In your post above you said that 'the light would come on', as I quoted, but you didn't say what light you were talking about. I still have no idea what your initial point was I'm afraid.

DUTR

Ultrasonic wrote: »

:huh:

In your post above you said that 'the light would come on', as I quoted, but you didn't say what light you were talking about. I still have no idea what your initial point was I'm afraid.

The engine light or one of them, the amber/yellow one I cannot remember exactly as it has not been on for years now, if my following post does not clarify things for you, then we will have to leave that be I'm afraid as the book for the car is in the safe and it's awkward to access to specify which light it is and it would make little difference now as I have stopped using momentum and don't intend to start again, that said I am not suggesting that users stop using it if it works for them.

It's this light under the EPC towards 9 o' clock

Ultrasonic

DUTR wrote: »

It's this light under the EPC towards 9 o' clock

It presumably has the same meaning as it does in my Skoda, which relates to exhaust gases. I guess it is triggered by a Lambda sensor reading? I'd be interested in what any mechanics thought about this...