Hi,

completely standard UK WRX bugeye - guess its mapped for 95RON but after reading some posts yesterday warning against running it lower than a quarter tank etc and about the quality of fuel that's put in:

Is it worth me putting in V-power or something with 97RON? Will I see the benefit - and if so, after how long as there will always be some 95RON in the tank (at least until I've done a few fillup cycles?)

The consumption figures I'm getting are quite low so wondered if there is any justification paying more, especially if it gives me more MPG?

Thanks

 

You'll always get better results out of a higher octane and will make everything run just that bit smoother regardless of what is was mapped for. I'd say just try it out, it should feel better and the Tesco99 gets me more mpg too.

 

Also, I'm not convinced about the 1/4 of a tank thing - I suppose the argument is that there is all sorts of crap that gathers in the bottom of the tank.

However if you think about it - when you fill up at the pumps, the pump itself is basically a high pressure hose (given how much petrol it puts in in such a small time). That volume of fluid going in so quickly is going to stir up anything that is in the tank and as such would be pulled through the fuel filter as it would be in suspension in the fuel.

Thoughts?

 

I'm not sure it's the cr4p in the tank issue ben...

I thought the lower fuel level causes fuel pressure issues in the injection rail....that combined with hard cornering results in lean fueling to 1 or 2 pistons

 

Really! well you learn sometihng new every day

Surely that's a bit of a design flaw? Doesn't the fuel pump keep a standard pressure throughout - it's not like it's being starved!

 

I'll give the Tesco one a try and yes - the issues with running less than a quarter tank is something to do with the lean fuelling or something? One of the engine tuners on here has written about it briefly somewhere

 

Yep, I seem to get better mileage on Tesco-99 as well. It's cheaper than V-Max too.

Avoid BP-Ultimate like the plague, and not sure about Total-Excellium

Not sure if Sainsburys/Asda/Morisons do "premium" fuel - never heard about them if they do. though I believe that Sainsburys use BP for their fuel