Hi, my friend has a 5 pot st 225, completely standard. And it is wank on fuel as to be expected. Obviously it will run stoich off boost so the cat works correctly.
My question is, are there any remaps out there that offer better fuel economy in light throttle situations? ie lean it off/advance timing here. Obviously the added power will be advantageous also .
thanks in advance

 

Running a leaner mixture on light throttle will not be possible. The mixture is controlled by the oxygen sensor so that the cat can do it's work. Leaning this mixture will result in fault codes on at least the after-cat oxygen sensor and problems with the MOT.
The only possibility is to advance the ignition timing, which should be done very, very carefully, otherwise the engine may start to knock.