Airbus hopes to have an initial customer for its higher-weight A330 programme by the end of the Farnborough air show, as it aims for entry into service in summer 2015.
The programme, raising the maximum take-off weight to 240t, will initially cover the A330-300 before being applied to the -200 and then the A330-200 freighter.
It will extend the -300's range by 400nm and the -200's by 270nm, or offer respective payload increases of 5t and 2.5t.
Airbus will achieve the increased performance through a combination of aerodynamic improvement and greater engine efficiency - each of which will contribute 1% - and use of the load-alleviation function to allow the wing to cope with higher stresses.
Rolls-Royce is to upgrade the Trent 700 engine for the type, to complement the modernisation, while General Electric says it is also "pursuing a collection of improvements" to the CF6-80E. Both manufacturers are aiming to cut fuel burn by at least 1%. Pratt & Whitney also powers the A330, with its PW4000 Advantage70.
The A330 wing's inboard slat will be reshaped, says the airframer, while the protruding flap-track fairings will be shortened - enhancements which have been derived from the A350 programme.
Load alleviation has already been applied to the A320 and Airbus will similarly capitalise on the A330's flight-control surfaces to de-stress the wing by shifting load inboard in turbulence.
"We're not changing the empty weight of the aircraft," says Airbus marketing chief Alan Pardoe. "Structural weight is the enemy of everything."
He says that, to a degree, Airbus has "piggybacked" off the design effort for the A330 freighter to "fully exploit the structure" and make the improvements.
Airbus chief operating officer for customers John Leahy says that the aircraft, at least for now, will not have the sharklet wing-tips which had been proposed as a possible option.
"I haven't given up," he says. "I think the engineers have given up."
Leahy says the sharklets might have offered a "couple of percent" greater efficiency on the A330 but preliminary analysis has indicated that the modification would involve wing twisting that would halve the gain.
"Will you want to have it for an extra percent?" he says, adding that such a modification - if it was developed - would probably be pushed out to the 2020s.
Airbus wants a quicker development schedule, and intends to conduct detailed design over 2013-14 with a view to performing flight tests in 2015 and putting the improved -300 into service in mid-2015, with the -200 following early in 2016.
The airframer is pursuing the Boeing 777-200ER market as well as the replacement market for A340-300s and early A330s.
Leahy says that Airbus is negotiating with a customer and hints that an agreement might be reached by the end of the air show.
Rolls-Royce states that the improvements on its Trent 700 will be derived from technology already proven on later powerplants including the Trent XWB and Trent 1000. The programme, it adds, will be finalised this year and the enhanced engines will be offered for retrofit as well as installation on the higher-weight A330.