I was out with a mate driving around the other day and he needed to get some fuel, We stoped in at a BP and he only got a few dollars worth and then drove on untill he could find a shell.

He says BP Ultimate is a better fuel for a naturally aspirated engine and Shell V Power is better for a forced induction engine. This got me thinking... is there a fuel that the A Series engines run better on?

So which fuel do you run your A Series on? will any fuel do or is one better suited to the A Series.

I use bp ultimate but it really comes down to what sort of compression ratio you have. The new e85 ethanol blend fuel is a real treat for boosted engines, I wouldn't mind giving it a go on a high comp A-series.

There is alot of talk that it attacks the rubber lines and some alloy(?). Which is bullshit if you've got quality fuel specific line in place.

Being hygroscopic, and being a risk (because of that attirbute) are two pretty different things. Most of the moisture issues are asscoiated with marine environments seeing as their tanks are typically of large capacity and they work in a wet environment you tend to see alot more water around the place.

In the instance of cars, if you're having your fuel sitting for months on end in a large capacity tank then sure, you run a risk of developing moisture content which can develop into corrosive issues. But running it in a standard car which doesn't sit for ages and uses a tank fairly regularly won't be an issue (good to have seals and everything up to scratch).

My last A-series daily was a bomber a12 with reasonably high compression.
 
I honeslty couldnt find any difference in fuels even standard 91 octane upt to BP ultimate (98 octane).
 
Its quite likely that on paper it should have made some difference, but it was not measurable.
Economy was the same, it certainly didnt go any faster. For me  its a moot point.
 
The only time that I got more power and top end speed that seemed noticable enough was on an icy cold night on a flat straight run. (At 85 mile there is NO steering feel!!)
 
If youthink about ratio of power gain.
An a10 standard makes 62hp. A 10" gain takes it to about 68hp. Thats not a huge jump. Unless you are getting 30%+ gains, i reckon you struggle to feel the difference in the real world, where it counts.
 
Sure a dyno result "can" show differences, but there are too many uncontolled variables to anyone to make a certain determination. We all know each dyno reads differetnly, so what does that tell you about their realibility.
 
With all than in mind, I used to run premimum (95 octane)in Daisy, just cause I could,  and it only cost an extra $1-2 filling her up.