2020 vs 2019 https://i.imgur.com/jkXJTC2.jpg
These 2020 sidepod changes reflect Renault's philosophy/doctrine and situation perfectly.
Renault clearly opted for RB-inspired sidepods/engine cover for 2020, like RP during the 2019 season, https://pbs.twimg.com/media/EAU_fpIWsAA ... ame=medium
an engine cover that merges the top airflow and the side air flow more upstream of the diffuser...
But since this is the Renault team, one of the most conservative and thrifty teams*, they chose the easiest and cheapest way to implement that change. They kept the internal parts unchanged (the electronic and mechanic elements below the radiator ducts, the radiators and their ducts and the exhausts) and they 'simply' made the bodywork go wider around the exhausts and made it circumvent those pipes viewtopic.php?p=888270#p888270
and they added the RB-style overcut...
A more ambitious/less tight-fisted team would have reworked the internal parts of the car (the electronic and mechanic elements below the radiator ducts, the radiators and their ducts, the exhausts etc) to improve the undercut too. That's what each team does every year... Actually, Racing point did exactly that during the 2019 season when they moved to this type of aero https://i.imgur.com/Gszfa0c.jpg
*the offcial reason is to spare money and ressources for 2021... It makes sense**... or will make sense in 2021 if they do invest all of these spared efforts and ressources and build an ultra optimized and compromise-less car in 2021.
**they've gone too far in that route recently IMO and that cost them the 4th place in 2019 for example.
Needless to say, this team has a huge room for improvements design-wise. The sidepod is just an example among many others. Just look at the airbox design and the centerline cooling system that remained unchanged since 2018, or the 2020-nose/2019-tub transition https://i.imgur.com/5I7hErj.jpg