Shanghai tech: Ferrari's engine worries, Friday scares explained

China's Shanghai circuit is the first event on the 2016 Formula 1 calendar where the cars' front end - and in particular the front left - is pushed hardest.

This means, after two races on stop/start tracks where drivers were limited by rear-tyre performance, tyre management is critical to keep the front left working while preventing the other more lightly-loaded tyres from graining.

Two very long straights and two big braking events means this track stresses the powertrain and brake set-up too.

As was the case at the first two grands prix, technical developments are more simple add-ons rather than major new parts, the development rate this year being notably slower than the previous two years under these regulations.

This is a result of the cars maturing under these rules combined with the need to focus on producing designs for new technical regulations in 2017.

FERRARI - ENGINE WEAKNESS SUSPECTED

Oddly there are still no visible changes to the SF16-H, the car remaining largely in the same specification as it finished testing.

It may be that Ferrari's attention is focused on its power unit. The updated 2016 PU is yet another step closer to Mercedes, but it appears to be carrying a handicap with its turbo.

With failures both in testing and for Kimi Raikkonen in Australia, it seems the turbo is overstressed and prone to problems when running at full speed.

So Ferrari has detuned the performance, reducing the load on the turbo at top speed.

Rather than running the turbo at high RPM towards the end of the straight, the MGU-H is used to reduce the turbine's speed by unloading it as it charges the energy store.

This tactic helps the turbo at some cost to power at the end of the straight, but at least provides more energy for the ERS elsewhere around the lap.

In qualifying this tactic isn't necessary for one lap, but it does leave Ferrari with a power loss through the race, when repeated stressing of the turbo could cause unreliability.

At least the pre-race failure that affected Sebastian Vettel in Bahrain wasn't attributed to the turbo.

But the electronics and warm-up lap procedure have been revised to prevent a reoccurrence of the exhaust valve failure Vettel suffered at Sakhir.

MERCEDES - REACTING TO BRAKE SCARE?

The subtle changes made to the W07 in China are revised brake ducts front and rear, plus alterations to the complex bargeboards.

Nico Rosberg's car ran a front brake duct with an extra flick added above the meshed air inlet.

This inlet area has been the focus of much attention since the Australian Grand Prix, when a foam earplug got stuck to the mesh and reduced cooling to the front brake.

It's not clear if the new fin is related to the same issue, but the team is now running the entire outer brake duct sprayed with a non-stick coating for all sessions.

Further back along the car the already complex multi-part bargeboards introduced during testing have been revised.

Formed from six upper vanes and nine floor level fingers, it's the fingers that have been changed and are now longer, projecting forward into the airstream by several extra centimetres.

This greater length probably increases their effect in directing air under the floor, which along with the altered rear brake ducts makes for better flow and therefore downforce from the diffuser.

RED BULL - FLOW-VIS SHOWS MERCEDES-INSPIRED TWEAKS

Red Bull conducted a series of aero tests during free practice, with both sensors and flow-vis paint used.

It was not immediately clear what parts were new, but the focus on the front wing flaps and their wake eventually leads to the identification of Mercedes-like serrations in the slot gap between the two rear wing flaps.

Similar to Mercedes, the serrations appear to be located at the wing's undersurface and in a small span of about 20cm near the wing tip.

These serrations create turbulent flow, breaking up the otherwise laminar airflow.

This is more effective at keeping the airflow attached to the steeply angled wing profile in this area.

WILLIAMS - TYRE SCARES EXPLAINED

There were several technical items of note on the Williams, from the new nose and front wing assembly being tested again, to the rear brake/wheel issues suffered by Felipe Massa.

It was Valtteri Bottas's turn to test the new nose and wing, which was soon discarded during free practice.

It's not clear if the set-up requires other aero parts to be fitted in unison or the brake duct issues forced the team away from its intended schedule.

Massa's car suffered two similar rear tyre failures in first practice. The second failure was later traced to the inner brake duct drum rubbing the wheel and causing the wheel to fail.

Williams has been running new complex inner brake drums this season.

Like all teams, the clearance between the drum and wheel is reduced to a minimum, with the drums often featuring low-friction tape in bands around the inner and outer edges to help keep the drum from contacting the wheel.

Any further misalignment or movement in the drum will lead to abrasion and heat on the wheel rim and cause it to fail.

It appears that this was the cause of Massa's problems.

During pre-season testing there were at least two other similar wheel failures for other teams.

The practice of running such tight clearances inside the wheel, though often unproblematic, clearly creates extra risk.

TORO ROSSO - POWER ADVANTAGE SMALLER THAN EXPECTED

While the 2015 Ferrari power unit run by Toro Rosso is more powerful than the Renault engine run last year, the new Renault and Honda units have each shown increased performance over last season's. So although STR does enjoy a power advantage over some of its rivals, it's not as great as perhaps expected.

With this in mind the team arrived in China with two new rear wings, both of a low-drag nature to aid it on the long straights.

The two wings take two different approaches to cutting drag. The first is a revision of the team's usual rear wing, featuring a relatively large main plane and flap, mated to the unique slotted Toro Rosso endplate.

To reduce downforce and therefore drag, the flap's shape is trimmed, making it much shorter in chord length near the wing tips.

This reduces the drag induced by the pressure difference at the wing tip.

The second wing is a dedicated low-drag piece. Both the main plane and flap are shallower, reducing the angle of attack to produce a more efficient wing.

The endplate is of the same open louvered design of the other wing, but with the wing angle being much flatter just two louvers are used in the endplate.

McLAREN - NOSE CHANGES

McLaren has mated the two different front wings it has used so far this season to a revised nose design.

When viewed from below the shape of the nose's thumb tip merges into the main nose shape.

This reduces the tip's ability to guide airflow under the car, which can be a very powerful effect.

So a long flat vane trailing the nose tip is used to guide the airflow back along the car.

Marussia used a similar solution when it introduced its 'finger' nose back in 2014. That nose soon gained a fairing merging the nose into more of a vane shape underneath.

RENAULT - DRAMA LIMITS DEVELOPMENTS' MILEAGE

The novelty for Renault was a new front wing cascade element, though issues with Kevin Magnussen's rear suspension limited running in practice.

The new front wing design mates a small winglet to the inner cascade element, replacing the inner flag vane on the older specification wing.

The winglet's appearance suggests it's made from rapid prototype material. Making such a small, complex part from machined metal or moulded carbon fibre would be a tricky manufacturing challenge.

This suggests the winglet is not heavily loaded, and used not for downforce but for airflow manipulation.

This is another way for the cascades to offset the wheel's turbulence and drag.

Magnussen's dramatic rear end failure in free practice transpired to be a failure of the rear suspension.

It's suggested that one of the carbon fibre rear suspension elements failed, leading to the collapse of the suspension and the wheel/tyre dragging along the track.

Checks were completed on both cars and modifications have been made to the parts for the rest of the weekend.

HAAS - BREAKING NEW GROUND

Like Renault, Haas brought new parts and suffered technical issues in China.

For Esteban Gutierrez it was a brake problem in practice two, the rear brakes binding leading to overheating and eventually fire.

The car returned to the pits where the flames were expelled.

The heat from the fire caused the resin in the carbon fibre outer brake drums to melt and the composite returned to its natural state of threads of carbon, these being littered all over the garage floor (pictured below).

As the problem affected both rear brakes it was traced to issues with the brake by wire system, the software putting on the rear brakes when the driver wasn't pressing the pedal.

This compounded the misery for Gutierrez, who had also lost running to a gearbox sensor problem in Friday morning practice.

On the positive side, the team brought front wing revisions in the shape of a new 'R' winglet and vane fitted to the cascade set-up.

Rather than the 'R' vane being just another reworking of the usual cascade set-up, it is instead genuinely a new idea.

The vane's inner tip is as close inboard as the rules allow, so this vane works with the Y250 vortex to direct airflow around the front wheel.

This pushes the front wheel wake further from the car to improve the aerodynamics at the back of the car.

It's possible other teams may look at this design as a new opportunity to work the front end aero.