Under the skin of the Toro Rosso STR11

The unveiling of 2017-spec Formula 1 cars might be only a few weeks away, but Nicolas Carpentiers takes a final look at one of the revelations from last year’s campaign with under-the-skin pictures and explanations on the nimble and innovative Toro Rosso STR11.

BACK TO THE FUTURE

In the wake of growing tensions between Red Bull and Renault at the end of 2015, Toro Rosso secured a deal with Ferrari to use year-old power units from Maranello in 2016, for lack of a better solution.

Although the Faenza-based outfit had already run Ferrari engines between 2007 and 2013, the late agreement had an impact on how the power unit fitted into the STR11, which had been initially designed around a Renault plant.

Both power units present fundamentally different architectures. On the Italian engine, the intercooler remains lodged within the ‘Vee’ of the engine, in between the two rows of cylinders, in a quite unique installation.

In comparison, the Renault-powered Red Bull featured a split-intercooler design, with one half-intercooler placed in each sidepod. The Honda-engined McLaren MP4-31, for its part, had a big intercooler housed in the right sidepod. Finally, on the 2016 title-winning Mercedes W07, the same element sat within the monocoque itself and ahead of the engine.

Like their Mercedes counterparts, Ferrari’s engineers have gone for an air-to-water intercooler, but implemented it in the heart of the engine in a bid to declutter the sidepods and limit airflow resistance.

This compact design means shorter pipework can be used to connect the compressor to the intercooler. Theoretically, this results in a reduction in turbo lag, with the MGU-H also needing a lesser amount of the energy recovered by the ERS to feed and drive the turbine when the throttle is not engaged.

However, the package is probably not the best in terms of cooling, as the system in charge of cooling down the compressed air (the intercooler) is placed in a very hot area. Still, Maranello’s engine engineers managed to accommodate these constraints in reviewing the overall architecture of their 2016-spec unit.

Although Toro Rosso raced a 2015 engine, Ferrari still had to tweak it to be in compliance with the new exhaust regulations, which mandated a separate wastegate tailpipe. On the bottom image, one can spot the exhaust tailpipes that connect to the turbine fitted at the rear of the plant, and wrapped up with insulating material.