Premium unleaded - worth it?

Lum

For non-performance cars, there is also the question of efficiency gained vs paying 5p/litre more for the fuel; and this is assuming you can resist the temptation to boot it more because of the slight performance increase.

Usually the numbers don't add up, which is annoying as more efficient fuel consumption = less CO2 so if the government is serious about reducing CO2 they should be offering tax breaks for super unleaded.

almillar

Thanks for the clarification Lum.
fivetide - the problem with saying that you ran an FTO no problem, is that you don't say for how long. If it's going to knock itself to death in 50,000 miles, that's a problem. If it runs for 100,000 miles, then we can take it that it's OK.

fivetide

Bought with 40,000 on the clock, sold with 97,000 on it.

Had a stainless exhaust fitted and a performance filter. Took it to a drag strip a few months before sale and had one of the quickest off the line times of the day. Car was sweet as a nut

I miss it a lot. Can you tell?

5t.

almillar

fivetide - thanks. Hey, you should have run it on 97RON and you'd have got a better time!
And this thread comes full circle...

Mr_Thrifty

so unless u drive a subaru impreza with 19 inch alloys and a 9-inch diameter exhaust pipe, or a mitsubishi evo with a big spoiler and blacked out windows, it's a waste of money basically?

AlexisV

If you have a turbo car with 170hp+, you will generally gain 5 - 15 horsepower using 98RON.

Otherwise, I wouldn't bother. Even modest engines from the last decade have ECU's that will adjust when 98RON is put in. But you'll only gain about 1 or 2 horsepower in a bog standard 1.6.

Lum

Mr_Thrifty wrote: »

so unless u drive a subaru impreza with 19 inch alloys and a 9-inch diameter exhaust pipe, or a mitsubishi evo with a big spoiler and blacked out windows, it's a waste of money basically?

Even a stock unmodified Impreza Turbo will need super, especially if it's a Japanese import.

Modified ones are frequently remapped and will need to run fuel that is at least as good as whatever was in the tank at the time the car was mapped, or if a generic map is being used then will need to run the fuel specified by the supplier of the new software.

But you are right that for normal cars the gains are not really worth the cost. People who buy Imprezas didn't buy them with fuel efficiency as their primary concern.

axomoxia

Mr_Thrifty wrote: »

so unless u drive a subaru impreza with 19 inch alloys and a 9-inch diameter exhaust pipe, or a mitsubishi evo with a big spoiler and blacked out windows, it's a waste of money basically?

Translating Muppet Speak into english...

If have tuned your subaru (you are looking at changes to the forced induction system rather than the passive induction system that Mr Muppet barely comprehends) or you are running one of the WRX STi models, they are designed to run on 98 RON or above octane. Knocking can occur with 95 RON petrol.

There are a couple of more informative threads on the Subaru forums, and presumably similar ones for other marques.

EdGasket

Brother-in-laws jag was wrecked by Tesco diesel. Had too much silicon in it and over a few years this built up to a level that persitently blocked the injectors; even new injectors. Fuel was analysed and that was the conclusion; that always using Tesco diesel had so contaminated the fuel system that the entire system from tank through to injectors needed replacing which was more than the car was worth. He was advised by the jag garage to avoid supermarket diesel with his next jag.

Joe_Horner

EdGasket wrote: »

Brother-in-laws jag was wrecked by Tesco diesel. Had too much silicon in it and over a few years this built up to a level that persitently blocked the injectors; even new injectors. Fuel was analysed and that was the conclusion; that always using Tesco diesel had so contaminated the fuel system that the entire system from tank through to injectors needed replacing which was more than the car was worth. He was advised by the jag garage to avoid supermarket diesel with his next jag.

P*ss poor design by Jag then if a fuel that meets the legal requirement for purity (you know, the standard that Jag handbooks say you should use) knackers its entire fuel system over time. Or do the handbooks say "Use fuel to X standard but not from a supermarket"? No, didn't think so!

Sounds more like a case for blaming Jag for using dodgy materials in their fuel systems that can't cope with BS standard fuel than blaming Tesco for supplying fuel to that standard