Exhaust solutions, mickey mouse or snowman?
In a strange twist of events, fans have actually managed to create a little extra area for freedom of design in Formula One cars. The repeated calls for increased engine noise have made the FIA to request an investigation into what could be done to enhance the noise output of the new V6 Hybrid engines. The result of Magnetti Marelli's investigation, during which the company's engineers repeatedly visited F1's engine supplier dynos was that an additional exhaust pipe could resolve a bit of the problems.
The new regulations stipulate that either one or two seperate waste gate exhaust pipes must be added on the car, with the rules making clear that all pipes must be in promity to each other to avoid another attempt for designers to exploit the gases to their aerodynamic benefit.
Mercedes' engine chief, Andy Cowell, explained this week at Barcelona that the wastegate pipe could work as a silencer on the main exhaust. In particular when the wastegate is closed, its pipe is actually a dead end, making it a dampening chamber on the main exhaust. By removing that dead end, and creating a seperate exhaust pipe for the wastegate, the sound "is more pure, with less distortion".
Mercedes have measured this change on their dyno, and noticed an increase of maximum sound, up from 124dB to 128dB - whereas the V8 engines using until 2013 produced aroun 130dB. He did however also say that those are lab measurements, and should be taken with a grain of salt: "In the dyno, you don't have air passing around the exhaust pipes, which is obviously happening when the car is on track. This can have a significant effect on the sound levels. It also depends on the circuit, the accoustics with the grandstands, so essentially it comes down to perception".
On their 2016 cars, all but one team have chosen have two wastegate pipes. Mercedes put its pipes close together underneath the main exhaust, Red Bull have them a bit further apart from each other, and Williams even more. This setup is already being referred to as the "inverted mickey mouse" set-up. The resemblence is striking when looking at the Red Bull RB12 layout. Renault meanwhile have opted for a single, bigger pipe above the main exhaust. This has been nicknamed the "snowman" layout, again, no comment needed there.
The fact that most teams have chosen to have 2 wastegate exhaust pipes is interesting, especially when you consider that the Mercedes engine only has a single wastegate valve, meaning that teams need to split up the wastegate outlet into two pipes. According to Paddy Lowe, this has all to do with packaging: "It really isn't a big deal what kind of layout you are using. We have chosen two smaller pipes because of packaging reasons".
He also confirmed there is no real aerodynamic gain from the position of the pipes, except of course the packaging advantages of one layout to another, as a more streamlined or compact bodywork can of course have their impact in the car's drag or downforce generation.
It should also be noted that, while the current variety is a nice possibility in the regulations, teams and the FIA are currently still investigating an alternative route to improve engine sound.