Having made no significant changes to its car since the season began, BMW Sauber has prepared a significant upgrade for this weekend's Spanish GP.
The changes are far ranging, but the car retains the F1.09 title and has not gained a "B" spec suffix. As a result, the car has appeared in the Barcelona pit lane with a new nose and front wing, revised sidepods and rear wing.
The chassis has also seen a weight reduction program to aid weight distribution for the re-sited KERS system. However, the car has yet to appear with a double-deck diffuser, whose introduction has been delayed for two races.
Through 2008, the BMW Sauber team was the most aggressive both in its early season development and in the design of the solutions it produced. But despite an early start to the 2009 car program, the F1.09 brought to the opening four races was far too conservative.
In detail, the Barcelona specification is a quite a radical overhaul and innovative in several areas. Starting at the front, the nose has been raised to create more space between it and the front wing for the extra turning vanes mounted to the nose cone.
Then the sidepods have had a complete reworking, the bulky sidepods complete with the wedge-shaped KERS cooling inlet have gone, replaced by a more contemporary solution.
Pictures of the cars stripped in the garage show that the KERS hardware has been relocated to other areas. This has allowed the radiators to be brought inwards and the inlets have been reshaped to create a larger undercut. To the side of this, the pod wings have been made much larger and complex.
Lastly and grabbing a lot of attention has been the revised rear wing, with the revised mounting struts and a supplementary winglet. This winglet sits in the 15cm free zone in the middle of the rear wing and sitting to high up in the airflow would be capable of creating efficient downforce.
Lastly, the diffuser does not yet have the double decker format, such as Brawn use. However, the new diffuser looks less obstructed by the rear crash structure than before and does follow Brawn's solution of having a flap to close the starter hole to help maintain the low pressure within the diffuser.
The sum of these bodywork changes, as well as the lightening work on the chassis, means BMW Sauber has made a large step to catch up the rest of the field in design terms.
But only when the double-decker set-up arrives in Turkey will the team be on a par with them, but by then it will already be round seven in a 18-race season. Catching up on pace might be possible, but to catch up on points for the championship may already be too late.Related stories:Willy Rampf: new package a step forwardKubica warns upgrade not enough