While some minor updates have been added to the Lotus car over the past few Grands Prix off the back of their off-again, on-again Double DRS system, the team unveiled their version of the Coanda-style exhaust system at the Korean Grand Prix for Kimi Raikkonen – the system then being applied to both cars for Abu Dhabi.
This type of exhaust system is now becoming very familiar, with Lotus one of the last of the leading teams to adopt it. Only Williams (not for the lack of trying and testing) have yet to develop a fully working exhaust system of this type and use it throughout an entire race weekend.
Coanda – you what?
No, that’s not a typo – it’s the name for these exhausts which comes from an aerodynamics term – the Coanda-effect – you can read more about it here
The old style exhaust system (dubbed “Plain-Jane” because of its conventional design) had the exhausts exit the bodywork on either side just above the top of the rear suspension. The exhaust gases would then produce some downforce towards the lower part of the rear wing.
The new Coanda-style exhaust system sees the exhausts exit on either side of the car very low to the floor and quite far forward. The specially designed apertures allow the exhaust gases to be channelled into the gap between the rear wheel and bodywork on either side and into the rear diffuser. This means that they are able to extract extra downforce from the rear diffuser of the car, improving overall performance.
The main downside to this is that the benefit does come at the expense of some engine power. Lotus are hoping to fix this by introducing a revised version at the US Grand Prix, after trailing it at the Young Drivers’ Test at Abu Dhabi. According to Lotus they are hoping to get an additional 6bhp from the revisions. With the racing so close at the moment, even this seemingly small improvement could be crucial in the teams battle for 3rd place in the constructors’ championship with McLaren.