2015 Japanese GP Tech Highlights

After the barrage of upgrades that appeared in Singapore, the Japanese GP weekend was a relatively quiet one for developments. Aside from Force India applying the finishing touches to its B-spec VJM08, the only major update came from Mercedes who had, incidently, not brought anything to Singapore a week ago.

So – not much to talk about in this week’s Tech Highlights but we can go into some detail about the Mercedes and Toro Rosso tweaks.


As Suzuka is a high-speed circuit, most teams applied a slightly lower drag approach to their car setup to improve efficiency. These changes are similar to those made at Spa so it is no surprise that Mercedes’ new bits are an evolution of their low drag specification components from a month ago.



The rear wing endplates – which were not evident in Singapore – are a higher downforce version of the ones first introduced in Belgium. They feature the three distinctive vertical slits along the bottom, and now include a very long leading edge slot similar to that used by Red Bull.

The trio of staggered slits push air upwards from one side of the endplate to the other, encouraging the overall upwash of flow at the back of the car and linking with the natural aero paths of the rear wing and diffuser.

Managing rear tyre turbulence is still a big area of development in Formula 1, as proved by Ferrari’s extreme 9-slot floor that debuted last week. The vertical slot at the front edge of the new endplate is designed to bleed off high pressure that builds up on one side of the ‘plate at speed. This has two benefits: the wingtip vortices produced are not as strong as the pressure delta between each side of the ‘plate is reduced. Secondly, there is less disruption to the outwashing air coming out of the diffuser. These two advantages improve the efficiency of the car’s rear aero.

Previously Mercedes have had two slots in the endplate – one about mid-way up and another right down near the bottom, rather than a single continuous aperture. The new slot proves that even the very top teams are still trying to find a better way of dealing with this difficult and unpredictable turbulence.


In addition, new rear bodywork was installed on the W06’s sidepods. Whilst this looped arrangement is not new (it was introduced very early in the season), the much larger diameter hoop is more prominent than before. Instead of branching out of the top of the sidepod and extending down to meet the floor, the bodywork now does a complete loop on itself and rejoins the sidepod further down.

It has always been a bit unclear as to what exactly this device does. My guess is that it streams any turbulent flow coming off the exposed lower wishbone arm and pullrod through the hoop, mixing with the hot air exiting the cooling outlet directly next to it before rising as one large mass of turbulent flow. This would be instead of a wider band of turbulence disrupting flow rising out of the top of the diffuser and affecting its performance.

Toro Rosso

Along with the front wing updates brought to Singapore, Toro Rosso continue to add to their STR10 with small refinements as they aim to close in on Lotus in the Constructors’ championship.

Following in the footsteps of the likes of Ferrari and McLaren, the Faenza-based squad introduced an additional fin alongside the main bargeboard, with half of it exposed beneath the axed-shape leading edge of the floor. It sandwiches between the base of the sidepod turning vane and the very end of the bargeboard to catch any flow that might be separating in this area, vorticising it and sending it along the sidepod undercut. Doing so will aid airflow attachment along the side of the car and work the central section of the rear diffuser harder.

There were also subtle re-profiles of the sidepods, including the central cooling outlet. This is now smaller and more oval shaped rather than a rounded triangle, raising bodywork further clear of air passing along the ‘pod’s undercut and exploiting the Gurney flaps and flick-ups that surround the rear crash structure.

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