Unleaded petrol - can i skimp?

[Grendel]

Would running the car on half half make a diference for example half super and half normal?

[kevin..in]

Would running the car on half half make a diference for example half super and half normal?

make you unpopular at the pumps

[Grendel]

No what i mean is when the tank is half full of super put half tank of normal in rather than topping back up with super would it make a differnce?

[Chris \'aka rustboy\' Amm]

Would running the car on half half make a diference for example half super and half normal?

make you unpopular at the pumps

LOL! yeah and grab some diesel to that should really rattle some cages oh and LPG if they have it

[BenF]

hmmmm strange!

i thought higher octane fuel was only really important on forced induction cars such as turbo'd and superchargered engines.

Normally forced induction engines are much more sensitive - usually as the air being fed into the intake of the engine is hotter than atmospheric air, as it has just been compressed.

But if you wind the timing forwards on a NA engine you'll also reach the point where you get pinking which costs torque and power at high revs - you'll hear it as tapping on a part throttle cruise.

i run my MR2 turbo on super all the time since i've had it out or paranoir mainly hehe. my old MK1a used to run like a dog on super, it really didn't like it but it was fine on 95ron weird!

That is odd. If you normally run the car on unleaded, you shouldn't notice any difference at all on SU - unless you got it from a garage where they didn't sell much SU and (eg) its been contaminated by water ..?

i've been on the MX5 forum lately and they have a different view on this and some posts on there say the UK has a higher rated fuel!

i know the US run a lower rated fuel but i've also read they meassure ron differently, could this mean the japs do too?

In the Europe, we use RON - in the USA they use Octane rating, which is actually the average of two measures - RON and MON.

Effectively, it means 92-93 US Octane fuel is roughly equivalent to 97RON fuel here.

(see http://en.wikipedia.org/wiki/Octane_rating )

i really don't understand why different parts of the world run such different fuel types!

Its just really different ways of measuring and expressing the qualities of the fuels.

Japanese 100RON fuel though would be great to get here - in Germany Shell do 100RON V-Power fuel, with branding similar to Optimax over here .

I'm off to fill my Turbo'd Roadster with 99RON at my Tescos now