2 – EXHAUSTS
2015 F1 cars only had one exhaust tailpipe but their 2016 successors will have to be fitted with at least one extra pipe for the wastegate, with up to two additional pipes allowed. The exhaust-mounted wastegate is a control device that allows excess gas to by-pass the turbine in order to avoid high pressure in the turbo.
Article 5.8.2 of the technical regulations reads: “engine exhaust systems must have only a single turbine tailpipe exit and either one or two wastegate tailpipe exits, which must all be rearward facing and through which all exhaust gases must pass.”
In concrete terms, this means the new design could have up to three tailpipe exits instead of the single one that had been in use since the start of the latest turbo era. The rationale behind the change is to make the hybrid units louder in the light of complaints from disgruntled fans. The sound of the turbine, a distinctive feature on any turbocharged engine, will no longer be muted by the wastegate pipe, which acted a bit like a suppressor.
In a move to prevent the return of blown diffusers, the rules make it very clear where the exhaust pipes must be located, “no more than 100mm from the car centre line” for instance. In these conditions, exhaust-blowing effects could only occur below the ‘monkey seat’ and would be very limited. What’s more, the new wastegate tailpipes should only vent gas sporadically, for the MGU-H already slows down the turbine by feeding off its energy before channelling it towards the battery of straight to the MGU-K.
Finally, renowned technical expert Craig Scarborough just revealed that the FIA has sent a Technical Directive to all teams this winter in order to clarify the new exhaust rules. According to the document, the wastegate gas cannot be used to create a “fluidic switch” to reduce drag or add downforce.
Several teams planned to use the wastegate flow to develop and optimise a system drawing inspiration from the Drag Reduction Duct (DRD), tested notably by Lotus in 2012-13 but never actually raced. Scarborough explains that one team asked the FIA whether it would be legal under the revised regulations.
Head of technical department Charlie Whiting eventually ruled against it, on the grounds that the system would have featured moveable aero parts, which would contravene Article 3.15 of the technical regulations. Indeed, the latter reads: “Any specific part of the car influencing its aerodynamic performance must remain immobile in relation to the sprung part of the car.”
