This weekend’s European Grand Prix at Valencia is a significant event in the story of the season from a technical point of view as it was the race where many teams unveiled a device which copies the Red Bull’s “blown diffuser”.
Last year three teams started the season with a double diffuser and, after establishing the legality of it, the rest of the field was forced to follow suit, including Red Bull. This year’s “must haves” so far have been the McLaren F Duct wing and now the blown diffuser. Red Bull is the pioneer and Mercedes, Ferrari and Renault have followed them this weekend. McLaren and Force India are due to follow at Silverstone.
On the grid this season the Red Bull mechanics have been carefully masking the diffuser from view. Although they do have something interesting to hide, in F1 this is often a bluff, indicating that the most interesting part of the car is somewhere else, but they want you to focus on the diffuser!
A blown diffuser is basically a way of using the exhaust gases to interact with the diffuser, which sits at the back of the car at the end of the floor. There are two main purposes for this;
* to try to move the wake from the rear wheels outwards where it will cause less disturbance
* to re-energise the low pressure air at the very back of the diffuser to create more rear downforce.
Rear downforce is important for driver confidence, if the driver feels good rear end stability he will push harder, so the gain on the stopwatch from this kind of development is often not what a simulator tells you it will be, but what the driver actually delivers from it.
The irony is that blown diffuser is not a new concept, unlike F Duct wings or double diffusers. Renault had one in the early 1980s, Frank Dernie put one on the Williams of Nigel Mansell in the mid 1980s and they were common from 1985 onwards. Adrian Newey’s team at Red Bull didn’t invent it, they revived it. The early ones were crude in that the rear of the car often became less stable when the driver lifted off the throttle. Everyone knows a but more about the science now.
They went out of the sport in the mid 1990s due to a change of wording in the rules, but Newey felt that the current rules would make it worth trying again.
The blown element operates independently of the “double” element of the diffuser and whereas double diffusers are banned from next season, the blown diffuser is here to stay.
The Ferrari’s exhaust exits have been moved from the high exit in the top bodywork, which they pioneered in the early 2000s, to the low exit near the floor to feed the diffuser. They stop slightly shorter than the Red Bull ones.
Low exhausts heat everything up in the area behind them and there is a risk here. Less widely reported, there was a new Ferrari gearbox this weekend, only on Felipe Massa’s car, designed to raise the pick-up points of the lower wishbone, in order to keep it away from the hot gases from the low exhausts.
Keeping temperatures under control is important and it was intersting to see a series of red stripes on the rear side section of the Ferrari diffuser. These stripes are of a special paint, which changes its colour in relation to the different temperature of the surface where its applied. In this way the Ferrari engineers could see which part of the diffuser reaches too high a temperature due to the hot gases directly blowing on them.
Ferrari’s update also includes new cooling ideas in the radiators and bodywork for the series of warm weather races coming up in the summer, as they have had problems with the engines in hot countries earlier this season.
This is an important update for Ferrari, who started the season as the pace setters but then lost ground as they got bogged down with developing the F Duct rear wing at the cost of other avenues. Meanwhile McLaren, Mercedes and Renault all stole a march on them.
Renault also had significant upgrades, including the blown diffuser. In this illustration by our technical artist Paolo Filisetti, you can see the old style high exhausts at the top and the new low style ones at the bottom.
Renault continue to push hard, they brought the 22nd iteration of their front wing to Valencia, the ninth race of the season.
And finally Lotus had a good qualifying session in Valencia, with Jarno Trulli the fastest of the new teams, increasing the margin over the other new teams to 1.4 seconds. That said the gap to the slowest of the established teams, ironically Kobayashi’s Sauber, had also grown to over a second.
One key update for Lotus this weekend was a new front wing solution, which owes a lot to design ideas on last year’s Toyota. Many of the engineers at Lotus came from Toyota so this is not altogether surprising.