Ever since the introduction of the new rules in 2009, teams have been exploiting these rules in many areas to try and get as much downforce as possible out of their cars.
At first it was the Double-decker diffuser pioneered by Brawn, Toyota and Williams in 2009. Brawn had the most effective out of the three teams which is quite evident looking at their results at the start of the 2009 season. Other teams soon followed suit; by midseason, almost all teams had it on their cars due to its big advantage. The FIA banned the innovation for the 2010 season but that didn’t stop the teams from continued manipulation.
In 2010, there were mainly two controversies, McLaren’s F-Duct and Red Bull’s “flexi” front wing.
McLaren’s F-Duct was deemed legal. The F-Duct was a complicated innovation; it basically gave the MP4-25 a huge straight-line speed advantage – which was pretty obvious at the 2010 Turkish GP – by stalling the rear wing. At the 2010 Hungarian GP, teams questioned the RB6’s front wing legality claiming that it does not abide by the rules due its flexing tendencies. All of the controversy was soon silenced by the FIA; the F-Duct was banned for the 2011 season, and the FIA mandated stricter front wing regulations.
2011 soon arrived, and with it came yet another dispute. This time, it was the off-throttle EBD, short for Exhaust-blown diffuser.

How do EBDs work and what are their main advantages?
The novelty was first introduced by Red Bull Racing. It gave their RB6 great aerodynamic gains. All teams soon copied the design for the 2011 season after witnessing the dominance of Red Bull’s RB6 in 2010.
Exhaust-blown diffusers work by locating the car’s exhausts in front of the rear wheels so that the hot, fast flowing exhaust gases can be channeled towards the car’s rear diffuser, increasing airflow through the diffuser and in turn increasing the amount of downforce the diffuser produces.
As you all know, when a driver is no longer on the throttle, the engine does not produce exhaust gases, but teams took a further leap in that department by using off-throttle blown diffusers.
Off-throttle EBDs channel exhaust gas into the diffuser, even when the driver is not on the throttle. Teams had to modify their engine mapping so that when the driver lifts off, although fuel supply and ignition are cut, airflow through the exhaust continues. This technique is called “Cold blowing” because with no fuel or ignition, the gas coming out of the exhaust is cold. Other teams bettered that technique with “Hot blowing”. Fuel injected into the hot exhaust pipe ignites, increasing the amount, speed and temperature of the airflow exiting towards the diffuser, hence, greater amounts of downforce.

What are the 2012 Exhaust regulations, who will lose out the most, and how will teams go around these new regulations?
Off-throttle exhaust-blown diffusers are now history due to the FIA’s decision of banning the devices for the upcoming 2012 season. The FIA argues that the practice of blowing gases through the diffuser during lift off  infringes Article 3.15 of Formula One’s technical regulations, the final part of which states that ‘any car system, device or procedure which uses, or is suspected of using, driver movement as a means of altering the aerodynamic characteristics of the car is prohibited’.
The exhausts must now sit in a high and far forward position disallowing any direct exhaust-blowing towards the diffuser. The exhausts must feature just two exits; no other openings in or out are permitted. The final 10cm of the exhaust must be pointed rearwards then tilted slightly up.
The team most expected to lose out is no other than Red Bull Racing, basically because their technique was the most effective considering they’ve built their car around it.
The 4-day testing in Jerez revealed many solutions – the most extreme coming from McLaren and Ferrari – as some teams tilted their exhausts towards the vanes around the rear brake ducts, or  towards the rear wing, to produce as much downforce as possible.

McLaren’s exhaust is in some sort of slit bubble facing the area around the brake ducts.

Toro Rosso’s exhaust is pointing upwards toward the rear wing.

So who will come on top this year?
Only the 2012 season opener in Australia will tell.
I personally think that Red Bull still holds an advantage over its rivals. Their RB5 was a superior car in 2009, managing to clinch a 1-2 in China with no double-decker diffuser or any of those innovations.

By Joe Baaklini