What difference will off throttle diffuser ban make?

The FIA Technical Working Group met at the end of the week to rubber stamp the FIA's ban of off-throttle blown diffusers. They also discussed how the ban can be policed. They also accepted that from next season the whole concept of blown diffusers goes out of the window.

From Silverstone this year onwards engine makers will be limited to using just 10% of engine over-run when the driver is off the accelerator.

This will kill of the current practice of blowing high pressure exhaust gas through the diffuser when the driver lifts off the throttle - ie in corners - creating downforce but at the cost of 15% increased fuel consumption.

The key question is, will this change the order at the front in F1?

At a rather gloomy post-race press briefing in a rainy Montreal paddock we sat with Ferrari team principal Stefano Domenicali who posed this question himself,

"We need to see in Silverstone, what is the real effect of this change in the regulations with regard to the effect of the exhaust," he said. "Then, we will see really where is the second championship in terms of the level of performance above all in higher downforce tracks."

This is probably wishful thinking for Ferrari, whose lead driver Fernando Alonso, lies fifth in the championship almost 100 points behind Red Bull's Sebastian Vettel.

Off throttle blowing is a technology that was pioneered and perfected by Renault for Red Bull Racing and from early last season was part of the reason why they step up in performance in the final part of qualifying and whenever they need the extra performance.

Of course most top teams have copied the technology. McLaren and Mercedes were active in this field at Singapore last year, as we discussed it there with McLaren's Jonathan Neale. So all the teams will lose something.

But Red Bull have the best system and so will lose more of their performance advantage. But how much, is the key question?

Engineers I have spoken to suggest that the real differentiator for Red Bull in qualifying is its very powerful DRS rear wing, which can be used on qualifying laps in corners where other teams simply cannot use it, as the car would become unstable.

Of course, the superior blown diffuser created some of the downforce and stability which allowed them to use the DRS in this way, but to be clear, it's not likely that with this cut to 10% of its current level they will suddenly lose their ability to exploit the DRS.

Red Bull has owned Silverstone in the last two seasons and is likely to still enjoy a performance advantage in qualifying thanks to the DRS, but we've seen them under pressure in race conditions in the last four races. not least with the dodgy KERS, compared to the strong units on the Mercedes and Ferrari powered cars.

It looks like the chasing pack of McLaren and Ferrari are closing on them and the race at Silverstone could well be very tight, maybe even tipping the balance away from Red Bull in races. But I still expect them to be quick in qualifying.