Much ado over blown diffusers leaves Formula 1 fans and media baffled

This afternoon Formula 1 served up a war of words, which is hard to describe, much less explain.

It's hard for even the specialist media to understand, much less portray to F1 fans. Nor does it do great service to the sport or to the people at the centre of the argument.

F1 thrives on intrigue and hype, but this is one confrontation which would perhaps have been best left behind closed doors.

McLaren boss Martin Whitmarsh and Red Bull boss Christian Horner got worked up and battled it out in an FIA press conference over how much percentage the throttle should be allowed to be open when the driver lifts off the accelerator pedal.

As sporting narratives go "off-throttle exhaust blown diffusers" are not exactly Ali versus Frazier or a Maradona's "hand of god" goal. It's a very obscure point in a sport which is already complicated enough to explain to the public.

In a nutshell, there are two methods of blowing the diffuser to create extra downforce worth around 4/10ths of a second per lap when the driver lifts off the accelerator. One involves introducing fuel into the system, which is the Mercedes way. The other does not, this is the Renault way. The FIA tried to impose a blanket rule on all engines that the throttle could be no more than 10% open, but Renault objected that this left Mercedes' system at an advantage. The FIA then changed the ruling today to give Renault 50%, believing that this makes the relative penalty to both engines the same. This was a surprise to McLaren and Ferrari.

Renault argues that it needs to be allowed to have the throttles open 50% when the driver lifts off as it is an important part of cooling the engine and has reliability implications.

After the press conference I interviewed both men for TV and even they were having problems explaining concisely what the argument is about.

Horner was indignant, unhappy that the FIA's change of ruling is being painted by Whitmarsh and others as a performance advantage for Renault and his team.

Whitmarsh said that the ruling was a 'surprise' to him and other teams and meant that they would have to follow suit, changing the way the Mercedes engine operates to allow them the same 50% throttle opening as Renault.

In fact, talking to engineers tonight, it seems that Mercedes is allowed to operate 68% open if it does not inject fuel, which allows for the differences in throttle mechanism between engines.

And it gets worse: these engines and maps are so clever that they switch from one method of blowing depending on the corner.

Whitmarsh describes today's ruling as a "very substantial performance benefit" for Renault and compared it to asking the FIA to be allowed to run a car 100 kilos lighter because the brakes can't cope with the loads.

Horner has a different view, "Let's not make any mistake here," he said. "Firing on over-run, the thrust that that generates through the exhaust, generates a bigger effect. Let's just be absolutely clear on that."

One of the most important things in any competitive sport is that whatever the rule, it's the same for everybody. It's hideously complicated for the FIA to try to regulate two different systems.

And mid season rule changes are never a good idea because they confuse the public.

To my mind, it would have been better for the FIA to avoid mid season changes and simply say that all blown diffusers are banned at the end of 2011 (which they are) and until then teams can carry on with what they are doing. No-one was complaining before about equivalence, but they are now.

It takes away from the championship if people perceive that it wasn't achieved on a level playing field. That's why this is a loss for Red Bull and a win for McLaren.

* Saturday update - After consultations on this overnight, the FIA has reverted to the previous ruling that only 10% throttle opening is permitted, much to the annoyance of Red Bull and Christian Horner.