• GP Week

Blown diffusers explained

Paulo Filisetti
June 30, 2010
Ferrari's blown diffuser with heat-sensitive red stripes on the bodywork © Sutton Images
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Valencia was the race where a number of teams debuted their Red Bull-style blown diffusers, as GP Week Technical Editor Paulo Filisetti explains ...

The race in Valencia was particularly interesting from a technical point of view, and probably saw the most changes at a single race to date in 2010, as many teams introduced broad changes in their aero packages.

The most talked about update in the paddock were the low-exhaust layouts, pioneered by Red Bull, but now adopted by Ferrari, Renault and Mercedes. After Red Bull's success early in the season, most engineers now see the blown diffuser as a necessity but it has taken them some time to get it to work.

Ferrari had been planning to debut its version in Valencia for several months, and the adoption of the new exhaust system was finally cleared at a filming day at Fiorano, so as not to breach the in-season testing ban.

The solution dramatically increases the efficiency of the rear under-body aerodynamics. The diffuser is directly 'blown' by the exhaust gases, accelerating the airflow passing through it and improving the extraction of air from underneath the car. This also increases the overall quantity of air feeding the diffuser and sucks the car to the track at high speeds.

Ferrari has also made minor adjustments to the F10's sidepod bodywork in order to better accommodate a slightly revised radiator layout and cope with the increased heat within the sidepods due to the narrower section.

Furthermore a new gearbox, only on Felipe Massa's car in Valencia, was adopted to raise the pick-up points of the lower wishbone, in order to keep it clear of the hot exhaust gas flow.

Very sharp eyed viewers may have seen a series of red stripes degrading towards the rear side section of the diffuser. These stripes are put on with a special paint, which changes its colour in relation to the different temperature of the surface where it is applied. This allows the Ferrari engineers to monitor how hot the diffuser is getting with all that exhaust gases blowing on it and make adjustments if necessary.

Renault's blown diffuser paid dividends in Valencia © Sutton Images
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Renault was another team that introduced a low-exhaust configuration. In this case the exhaust is not visible, as there is a sinuous cover thermally insulated on its top side. Mercedes has also made big changes to the rear of its car in order to get the same effect.

Another aero change worth mentioning from Valencia - although not exactly a new idea - was the front wing on the Lotus, introduced to cater for the medium-downforce configuration at this circuit. The wing was new to the T127 but its roots are based in Mike Gascoyne's past employment at Toyota. Two years ago, the Toyotas sported a very similar solution, specifically designed for medium-downforce tracks including Valencia.

Looking ahead to the British Grand Prix, keep an eye out for McLaren's blown diffuser that the team hopes will close the gap to Red Bull in high-speed corners.

"We will have a bigger package for Silverstone [compared to Valencia]," said McLaren's engineer director Paddy Lowe. "The rest of the teams are playing catch-up with the blown diffuser. It's quite a significant performance step. That's something we're aiming to bring to the British Grand Prix and to try and make it work from the outset."

McLaren will perform some straight-line testing with the updated car ahead of Silverstone to make sure there are no overheating issues.

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