petrol.

Rhinoman wrote:

Stu stu wrote: All I can say is jap import cars run better on high octaine fuel because that's what there mapped on

The Suzukis and Mazdas that I've looked at have had exactly the same mapping. I've just been looking at an MX5, I was told that the Jap model had different mapping and a higher rev limit but that wasn't the case - the same mapping for Japan, the EU and the US.

Depends on the car. Generally models only available in the home market are mapped accordingly eg skylines are usually mapped for the better jap fuel.

Having owned several mx5's can confirm all jap/us/uk models are mapped the same regardless of where it was going after production. The only exceptions being ones going to California and the odd Jap special editions that ran more power although these generally are just as happy as on 95 as my previous and current jap import.

Back on topic Ive never found any difference when buying from fuel from different places. Although there was a spate a few years ago in my local town where there was a sudden influx of cars of all ages suffering from o2 sensor and cat failures. Mechanics started putting 1 and 1 together and in nearly all of the cases the customers had been using the local tesco's for fuel. After testing it was found the fuel was high in silicone. No other local petrol station had this problem.

Low octane,high octane,10% ethanol,super,supermarket,branded,my sz4 runs exactly the same and returns the same mpg.

i have been working on Japanese vehicles since early 1978 they have always been lean burn engines and the 660cc ones go very well

I think we all agree and disagree with some of the the comments, so i'll put in my wodden spoon and stir!
I've run scooby imports and as said they would run crap on super market standard fuel but ok on Tesco super 99 ron. In japan their fuel is/was 101 ron i believe, My Jim defo run's better on the 'better' fuels and 97 plus ron fuels ect. son hench i always put in 'super unleaded'. Decent plugs as well makes a difference but at £60 a set for the jim is excessive. BTW i'm running an 06 DOHC Jim.

Mart

The only tests I've done did give me a slight MPG increase using premium fuels (Shell V Power) but not enough to counter the extra cost.

I will say though, none of my vehicles will ever have supermarket fuel in them unless it's my only option and a last resort.

Jimnyash wrote: The only tests I've done did give me a slight MPG increase using premium fuels (Shell V Power) but not enough to counter the extra cost.

I will say though, none of my vehicles will ever have supermarket fuel in them unless it's my only option and a last resort.

I avoid supermarket fuels ...............because the damn queues at Morrisons etc. drive me mad. Drive straight to a pump at Mobil etc. Worth paying the extra to avoid the frustration BUT I'd use any fuel and do use Asda etc. fuels regardless. I detect no difference at all. :whistle: