McLaren did a fantastic job adjusting their chassis to completely different Renault power unit architecture over a very limited period of time and they believe that they would be in trouble if they made their decision latter than they did.
After three years with Honda, McLaren switched to Renault as they hope that additional engine power and better reliability will help them return to the regular fight for the podium places for the first time since 2012.
McLaren didn’t have their driver on the podium since 2014 Australian GP and havent’ won and started from pole since 2012 Brazilian GP.
Two fundamental arhitectures
Technical director Tim Goss praised his team for the work they have done to customize the chassis for Renault’s power unit.
“Renault’s architecture is very different,” Goss told Autosport.
“You have two basic architectures, Mercedes/Honda and Ferrari/Renault. The difference is in the position of a turbo charger.”
“The Mercedes/Honda approach [which Honda adopted in 2017 and initially had big vibration problems] includes the compressor in the front of the engine and the turbine at the rear while the MGU-H sits inside the V of the V6 engine.”
“Ferrari/Renault has a compressor behind the engine, MGU-H behind it, and the turbine behind the MGU-H. This requires a different approach to chassis and transmission design and as we now have a fresh experience with both approaches, we can see the advantages and disadvantages . ”
“There are things I like in Renault’s approach and some of them frustrate me, but in the end, we were lucky enough to make the decision to change the engine on time. We could not bring it later.”
Renault engine sits more at the front

Renault’s positioning of the compressor and the MGU-H behind the engine influenced the design of the rear end.
“We had to reconfigure the chassis, change the cooling system, and reconfigure the gearbox to fit everything, but we managed to do it without significant compromise on the chassis, even though it was a big change.”
“With Renault, the front end of the engine is much simpler, the engine can be moved forward and the aerodynamic impact of the engine and the exhaust system is much smaller, but you have a turbo near the rear suspension so you have to adjust it and extend the transmission [the rear suspension pick up points are moved to the rear]. ”
“But we did a fantastic job, really a fantastic job.”