Bahrain Grand Prix technical insight

For the teams at the Bahrain Grand Prix this weekend, finally reaching the last of the early flyaway races will be a relief.

Soon the cars can be returned to their factories and greater developments can be added.

Most of the updates in Bahrain will be track specific, with greater cooling allowed for the engines and brakes, while further details of the Chinese GP updates have also emerged.

McLaren

McLaren continues to push hard in bringing new parts to its MP4-30, and now there are different diffuser and rear wing specs available to the drivers.

Although seen in China, the diffuser change is still being trialled and tends to be fitted to one car. The underfloor remains one of the most important aero development areas, but the restricted space available for the diffuser means the differences between the specifications are difficult to spot.

The new set-up, usually seen on Fernando Alonso's car, follows a common philosophy up and down the pitlane where the diffuser expands outwards as well as upwards.

This expansion of the airflow accelerates more air under the car for lower air pressure and thus more downforce. Such is the lateral divergence of the diffuser that the outer walls forming the diffuser's sides stop short of the maximum length allowed and point sideways behind the rear tyres.

What looks to be quite a conventional new rear wing was tried in free practice. For any other team this would not be newsworthy, but as McLaren has run the wavy-edged wing since mid-2014, this represents a distinct change in philosophy.

McLaren's new wing features simple straight edges to the wing's surfaces, whereas previously the slot gap forming the leading and trailing edges featured an organic wavy edge. This was understood to improve the reattachment of the airflow after DRS closes the flap.

With new aero staff in the team, it's possible a more conventional geometry has been found that also achieves a quick return to downforce production after DRS is closed.

Red Bull

After Red Bull's big change in front wing philosophy (to a more 'outwashed' wing) in China, this new version gained a small addition in Bahrain. The new wing's endplate vane had a small flick added to its outer surface.

This tiny detail will add a little more control to the front wing's effect on managing the front tyre wake.

Elsewhere on the Red Bull, the brakes received detail upgrades, increasing the amount of bypass airflow through the wheel. Now more airflow is collected by the brake ducts and passed directly through and out of the wheel, without cooling any parts.

This bypass airflow works with the front wing endplate and blown front axle in pushing the tyre wake away from the car, rather than aiding cooling of the brakes, which remains a weak point of the 2015 package.

Lotus

Still to receive the major upgrade that was expected over the first races, the E23 has detail changes evident this weekend, these being cooling, diffuser and front wing-related.

As is quite typical for Lotus, the cooling outlets at the back of the car were sized differently to reflect the different heat requirement of the sidepods here. Although the sidepods are externally identical, inside them the radiators are packaged differently left to right.

For Lotus, the left sidepod is largely to house the air intercooler for the Mercedes engine, leaving the right sidepod to house the engine's oil and water coolers. Thus in the heat of Bahrain, the right sidepod has more work to do and the coke bottle exit is commensurately larger, creating asymmetry at the back of the car.

Behind the car, the small flap that runs along the top trailing edge of the diffuser was shortened slightly - a small change but one that might point to other less visible changes around the diffuser and rear brake ducts. Similar detail changes were evident on the front wing in China. The inner tips of the front wing flaps were cut down to a squared-off shape.

Toro Rosso

Continuing to enjoy a competitive season on pace, if not reliability, the STR10 has gained an enlarged cooling outlet for Bahrain.

The STR10 has a unique cooling layout. Each sidepod carries an air intercooler for the turbo, while the remaining space is taken up with oil and water coolers for the combustion engine and ERS.

But the Renault power unit installation still needs a large oil cooler, so STR has mounted a very large chevron shaped oil cooler between the chassis and engine. The cooler's arrow-headed shape points upwards and is fed by the bottom half of the rollhoop inlet.

All of the heat rejected by these coolers is ducted backwards and out of the flanks of the sidepods. For hot conditions, the panels forming the coke bottle exit are enlarged.

But rather than simply making it wider, the shape is kept narrow with the panels being deeper vertically and keeping flat sides. This maintains a better airflow to the rear wing endplates and rear brake ducts.

Sauber

Sauber is still experimenting with the new front wing Felipe Nasr trialled in China. More detail changes have been added to the car for Bahrain, with more parts waiting to be added once the cars can be returned to the factory in Hinwil.

It also transpires that gearbox changes have allowed both cars to be brought up to the same rear updated suspension geometry specification from China onwards. Marcus Ericsson first ran the current specification in Malaysia.