Renault confident in radical exhaust

The Enstone-based outfit has caused a stir in the pitlane at the first official pre-season Formula 1 test with its unique exhaust concept - which sees the exhausts exit at the leading edge of the sidepods.

The aim of this layout is to blow the exhaust gases out as far forward on the floor as possible - so the blown diffuser effect works on a greater portion of the underbody than if it were just exiting at the rear.

Although the design is not without its complications - which include overheating issues and difficulties that come from controlling tricky exhaust flow - Renault is in no doubt that the benefits outweigh the risks.

And despite Vitaly Petrov having a troublesome first day of testing with the R31 - where a number of reliability niggles meant it completed just 28 laps to end the day more than 2.5 seconds adrift of pacesetter Sebastian Vettel - the team is not wavering from its belief in the idea.

Renault team principal Eric Boullier told AUTOSPORT that he was sure getting the exhaust working perfectly was not the work of the moment - but he thinks it will be vindicated in time.

"It's always risky," he explained. "I'm happy that we had some creative designs on the car. We clearly back our team and definitely our technical team because we want to be fast, we want to be at the front.

"We know it takes time. You have to be creative. You have to find different ways of creating downforce or performance points. We have been taking this path because we believed, quite early in 2010, that we could find more gains going this way.

"In the wind tunnel, or on paper shall we say, the car already has more performance than 12 months ago. If it's on the car it's because we believe it works. But we will see on the track."

Renault's engine chief Rob White said that the team had worked on the exhaust idea for several months - after realising the advantages of the blown diffuser last year.

"Clearly it was very clear one of the hot subjects to emerge last year was blown floors and for most of last year our chassis partners became very interested in making use of the exhaust energy to make the best aerodynamically performing racing car," White told AUTOSPORT.

"For me the key thing, if the chassis guys want to do something different with the exhausts, then we have to work with them to fit that within our constraints. Clearly there's a multi-dimensional balancing act to perform in terms of the engine requirements, which are relatively straightforward - there are design criteria for the exhausts which we give to the chassis team which determine the kind of acoustic and pressure-drop behaviour of the exhaust.

"We have some packaging requirements - they need to not bump into a few bits of engine - but the external envelope is often determined by the car and its internal aerodynamics."

Although Renault is the only team that is running the exhaust configuration in Valencia, a number of other outfits are believed to already have the concept under development and are set to introduce it before the start of the season.