As mentioned earlier, the 2010 gotta-have performance trend that survived ’til 2011 was the exhaust-blown diffuser. Briefly, EBDs route some or all of the engine’s (hot, high-energy) exhaust into the diffuser to increase airflow under the car, and thus downforce. This presents the problem that downforce varies with engine use — so teams have re-mapped their throttles to ensure a smooth flow of hot, high-energy exhaust to the underfloor, even under braking when the driver isn’t on the gas pedal.
Now the FIA wants to ban aggressive throttle maps:
- FIA: Ban on aggressive off-throttle engine maps (ScarbsF1′s blog)
Unusually for a proposed FIA ban on engrossing technological development in F1, I think this might be a good idea:
[T]he problem with EBDs is that they create downforce dependant on throttle position, so as the driver lifts off the throttle pedal going into a turn, the exhaust flow slows down and reduced the downforce effect, just at the point the driver needs it for cornering.
As the engine suppliers have become increasingly comfortable with the heating effect of these off throttle mappings, teams have been able to use more of this effect in the race. One of Red Bulls advantages this year according to McLaren is their use of aggressive engine maps for downforce. At the Turkish GP several people pointed out the engine note on the overrun on Alonso’s Ferrari during FP2. Teams have clearly started to drive the engine quite hard when off throttle, to keep the diffuser fed with a constant exhaust flow.
What is now required is that the engines throttles (at the inlet manifold) must be closed to 10% of their maximum opening when the driver lifts off the throttle pedal. [...] What happens with [current] EBD mappings is that the throttles remain open, fuel continues to flow, then the delayed spark from the plugs sends the burning charge down the exhaust pipe.
Now with the throttle closed to 10%, the amount of fuel that can be burnt will be limited and thus the blown effect will be reduced. So drivers see will a bigger variation in downforce as they modulate the throttle pedal, making the car less predictable to drive.
This should lead to cars that are a bit more oversteery in braking and turn-in. If that sounds to you like the two phases of cornering where aggressive drivers like Kamui Kobayashi like to take advantage of small opportunities and mistakes to pass the guy in front, give yourself a gold star. I expect the top tier of drivers to master the extra oversteer pretty quickly and up to, say, 98% consistency. If an arbitrary F1 race has 60 laps on a 15-corner track, that means 900 corner entries in a race, of which 18 might be bobbled. If the guy behind is close enough in one of those 18 little errors to take advantage, that could lead to an honest pass without DRS shenanigans.
(I hasten to add that I pulled all the numbers in the paragraph above straight out of my ass.)
Of course, even if the FIA’s ban does produce the kind of behaviour I expect, it’s a given that Adrian Newey et al. will try — or, more realistically, are already trying — to claw back as much downforce and driveability as they can possibly manage under the new regulations. The engine-map regulation is scheduled to take effect after the Canadian GP in the middle of June. I’d expect solutions by the Singaporean GP in the middle of September, and I expect them to be awesome.