A new version of the 2016 Formula One technical regulations has specified the details of a change that will allow cars to have up to three exhaust tailpipes, contrary to the current single exhaust pipe.
In an attempt to increase noise and a typical turbo sound, the FIA is mandating either one or two seperate exhaust tailpipes for the wastegate. In 2014 and 2015, these exhaust gases were routed into the main exhaust, somewhat muffling the noise when the wastegate opens.
For clarity, the wastegate is a valve that is meant to direct exhaust gases away from the turbine and dump them directly into the exhaust in order to protect the engine and the turbocharger
As always though, the new regulations are pretty tight on the dimensions and location of the tailpipes.
5.8.3 The cross-sectional area of the turbine tailpipe exit at the rearmost point of the turbine tailpipe must lie between 7500mm2 and 14000mm2
, and the total cross-sectional area of the wastegate tailpipe exit(s) at the rearmost point of the wastegate tailpipe(s) must lie between 1590mm2 and 2375mm2. If there are two wastegate tailpipe exits they must be equal in area.
Essentially, the regulations stipulate that each of the 2016 exhaust pipes must be located in the same area where currently the single exhaust pipe is allowed. Also, while the diameter of the turbine exhaust pipe must be between 98mm and 133.5mm , the diameter of each wastegate tailpipe must be between 45mm and 55mm.
With both required to be identical in size, the choice for a single or two wastegate tailpipes will likely be determined by engine requirements, namely how often the wastegate is used.
No matter of these requirements, if a single wastegate pipe is used, it's likely it will be positioned on the car's centreline, just above the main exhaust pipe, while with two wastegate pipes, each one will probably be positioned on each side of the main tailpipe.
With the change being influenced by noise requirements, it's interested to note that no car has yet run on track with such configuration, contrary to the earlier proposition of a conic final section of the exhaust.