It's hardly a secret, pmsl!

 

And where would this need to take place? I'm located in Gloucestershire be looking to have it done sometime before Christmas.

 

Sorry but there are numerous things that can be done to improve mpg and I dont see giving away stuff I have learned over years of tuning subaru engines on an open forum where competitors read. Sorry if thats a problem.

 

Either on the road from your house or on a localish dyno like subaru4you in newbury for example.

Simon

 

it's no problem my question was retorical, you hardly make a car do 50 mpg now do you lol! Of course you can lean off mixtures and add a bit more advance in, but as you said earlier your cars actually do more like 26 mpg rather than the op's 30, so you clearly can't work miracles!
It's simple physics and it's as simple as that

 

people seem to forget the standard map is rather ****e and can lead to engine failure, especially in the 2.5l . Iam at a loss why you wont want max safe map available for the sake of a couple of quid. If it seems expensive weight it up against the cost of a rebuild which is quite possible

 

No miracles no.

Currently getting around 28mpg from a 600bhp build on cruise

I was referring more to the specifics than the overall picture.

Simon :d