The unexpected technical upgrades at Sepang

Formula 1's return to Malaysia now comes late in the season, moving it closer to the track's original position on the calendar when it first opened.

However, the change of date does not alter the weather significantly, with the tropical heat and humidity being a key factor and requiring improved cooling both for car and driver.

But aside from Sepang-specific parts to tackle those challenges, there were a surprising number of upgrades on show, which will form the aero packages for the remaining races.

It is impressive that, even at this late stage of the season there is ongoing development on some of these cars, despite the need to divert resources onto preparing for the rule changes in 2017.

It was widely believed that development would ease off once the European season ended, but this doesn't appear to be the case.

This suggests that although the 2017 rules will bring very different cars, some of the development in front wing, brake duct and turning vane design is at least partly applicable to next season.

FERRARI FINALLY GETS COMPLEX

This time last year, Ferrari was building up the aero complexity of the SF15-T. Part of that package was the introduction of complex turning vanes and an under-nose bat wing.

It was surprising that this complexity was lost when the SF16-H was launched, and it has taken 15 races for the car to deploy similar details in this area.

So once again Ferrari matches it rivals, with three-part turning vanes under the front suspension, and a distinctly Mercedes-style bat wing hanging from below the raised chassis.

Along with these two parts the vertical vanes mounted atop the T-tray splitter have been extended, all these parts adding to airflow along the flanks of the raised chassis.

This directs airflow around the car, separating the turbulent front tyre wake from the clean airflow passing over the car.

MERCEDES ADDS DETAIL

The Mercedes philosophy of breaking up aero surfaces with slots and serrations appears to be continuing.

For Sepang the W07 was fitted with a new front wing endplate mounting. Outwardly the parts look the same, but the vertical vane that usually sits on the horizontal footplate has now been separated for part of its length.

This allows the high-pressure building up above the wing to bleed underneath and add to the strength of the outwash vortex being created by the outer section of the front wing.

This open section requires a couple of metal supports to keep the structure strong enough to support the loads from the airflow.

This part didn't appear to run long enough to be part of the Malaysian GP weekend plan, so it may have been tested so it can reappear at the more aerodynamically demanding Suzuka circuit.

McLAREN TWEAKS ENGINE AND FRONT WING

As in Singapore, McLaren brought the revised front wing and brake ducts, as well as the rear wing endplate with the Toro Rosso-style open fronted louvres.

Some small changes were made to the front wing specification, but only in the detail of the gurney flaps fitted to the curved outer section of flap.

More important was the new power unit fitted to Fernando Alonso's car, which has had two development tokens used on what have been described as reliability updates, including a stronger block and revised exhaust.

This was merely tested in free practice in order take a grid penalty at this race, allowing the full benefit of the new V6 at Honda's home race in Japan next weekend.

TORO ROSSO IS ALL ABOUT DRAG REDUCTION

The STR11's weak point, its year-old Ferrari engine, continues to drive aero development aimed at running the car with less drag.

With its power deficit to its rivals with 2016 engines, STR cannot run the same level of downforce, as it cannot afford the drag penalty that comes with it.

So the team is working hard to develop rear wings that suit the track conditions, being efficient in creating downforce for less drag.

In Malaysia, this led to a new rear wing with a distinct crescent profile.

The centre of the wing is much flatter in angle of attack to the outer sections, so the wing's downforce is largely created near the wing tips. The rear wing endplate slots help to reduce the drag these steeper sections produce.

WILLIAMS ADOPTS SERRATIONS

Overt development has ended on the FW38, but the car did gain a new detail in Singapore, with the front wing slot being serrated for the first time.

Following Mercedes and other teams, where the airflow under the wing is stretched to the point where separation can occur, a serrated slot gap helps reattach the airflow without forcing a larger redesign of the wing itself.

For Williams, this detailing is applied only to the narrow rearmost slot on the front wing flap.

This appeared in Singapore and remains on the car in Malaysia.

HOW THE RENAULT FIRE TOOK HOLD

While sky-high ambient temperatures are always a major Sepang talking point, it was heat of a different kind that grabbed the headlines in Friday practice, as Renault suffered a rare flash fire when Kevin Magnussen returned to the pits.

Renault's technical director, Nick Chester explained: "There was a problem with a valve on a fuel breather pipe which meant fuel escaped from the vent".

The fuel tank needs vents both to allow for the fuel level to go down when on track, plus the fuel load to expand with heat.

As the fuel tanks are lightly pressurised with air, rather than being at ambient pressure, the breather valve needs to be set at a pressure slightly higher than in the tank to work effectively.

Any failure of the breather valve could send fuel or vapour through into the airbox, where it can easily be ignited by the hot surfaces of the engine.

This valve failing is likely to be the cause of this weekend's fire.

According to Renault these were new specification parts, and it reverted to the original spec for the second practice session.

Almost unnoticed in Singapore were revised sidepods on the Renault.

These are more sloped as they pass over the radiators, slimming much earlier than the old bodywork.

This update was unexpected, as Renault was believed to have finished development on the RS16 for the year.