Please bear with me on this as I am total noob about cars.

I've got a '98 V70 XC 2.5 Turbo Petrol Automatic, and due to the ridiculous gallons-to-the-mile type fuel economy, got it converted to LPG (although due to LPG being ****e, totally inefficient and very sluggish, I now tend to alternate depending on the situation).

I found the LPG very bad at first on the poor efficiency / poor performance double whammy so I took it back for some tweaks. The LPG guy showed me the engine map set-up, a two axis graph with RPMs along the top and gas pedal / throttle usage (or something like that) down the side. He'd set it up badly in the first place with all of the numbers being around 170, the effect being it was using too much gas at low revs and cruising speed and too little gas at high revs and during acceleration. He tweaked it so most numbers were at 140, except high gas pedal / throttle - mid revs at 180-ish, and high gas pedal / throttle - high revs at 210. Thus meaning I now have better performance when I put my foot down.

I'm due to take it back for another tweak and want to know more about getting it set-up for the optimum efficiency / performance balance.

Basically I now have a car with 4 performance options:

LPG + Economy Mode = fairly slow, reasonably efficient (due to LPG prices outweighing lower MPG)
LPG + Sport Mode = mildly powerful, mildly efficient (useful for overtaking runs)
Petrol + Economy Mode = mildly powerful, not so efficient (generally smoother)
Petrol + Sport Mode = fairly powerful, not at all efficient (but good fun)

My current line of thinking is to tweak the mapping for the LPG so it is less powerful and more efficient and rely on the sport mode or petrol for when I need more power. Since I have those options available it seems wasteful to have LPG running more powerful as around town or on motorways it's fine if it's sluggish.

BUT. I need to know more about how this works....

1. How does the turbo work?? The LPG guy said it was kicking in at 3000 RPM (although with LPG it took longer to get there and wasn't as powerful overall). Will it always kick in at 3000 RPM? Or does it correlate more to gas pedal usage?

2. How does the sport mode work?? It seems to kick the revs up pretty quickly towards the 5500 mark at most speeds - is this just overrevving it (by dropping a gear??) or getting the turbo to kick in sooner??

3. Does the mapping set-up sound sensible?? Any advice for it??

Thanks in advance.