Top Gear’s Top 9: naughty genius racing loopholes

Every McLaren road car since the MP4-12C has had a system called ‘BrakeSteer’ on it, where the car nips the inside rear brake disc as the driver turns into a corner to slow the side of the car nearer the apex, and help pivot the car onto its line. Clever stuff. It’s inspired by a system dreamt up for the 1997 McLaren F1 car, where a second brake pedal was used to slow wheels on one side of the car – and changed depending on whether there were more left or right-handers on any given circuit.

The innovation was very successful – worth a whopping half a second per lap – so McLaren wanted to keep it under wraps. It was only discovered after a photographer named Darren Heath (curious over why the McLarens rear brake glowed hot on the exit of turns) came across Mika Hakkinen’s retired car at the 1997 Luxenbourg grand prix. As the Finn had removed his steering wheel, Heath could get his camera into the footwell and take photos of the pedal, though it took months for the other teams to actually work out what was happening and get the FIA to ban it in 1998.

Mercedes has been so dominant in F1 during the hybrid turbo era they’re arguably the last team you’d want to find a clever loophole and extend their advantage. But to the horror of their rivals – particularly Red Bull – the 2020 car emerged with Dual-Axis Steering, or DAS.

By telescoping the steering column in and out by thrusting the steering wheel, the drivers could adjust the toe-in/out angle of the car, reducing drag on the straights and aiding tyre warm-up under a safety car. Rivals argued this was a moveable aerodynamic device (which the rules specifically ban), or that it constituted active suspension, but the FIA kiboshed the butthurt and allowed Mercedes to run DAS through the topsy-turvy 2020 season. 

So, moveable aero devices (besides DRS, of course) aren’t allowed in F1. But what if nothing on the car moved at all, and the driver provided the advantage? That was the genius of the 2010 McLaren F-duct. A snorkel on the car’s nose gulped airflow into a tube that ran parallel to the cockpit and toward the car’s rear wing.

On straights, the driver would move their knee to cover a hole in the cockpit side and block the duct, which stalled airflow over the rear wing when downforce wasn’t needed, reducing drag and upping top speed. Rivals howled that it was unfair, but McLaren’s loophole was upheld by the FIA and the other teams were forced to copy it instead, before it was banned in 2011.

The entire Brawn story is Hollywood-spec: from the ashes of Honda’s rubbish F1 team comes a mongrel car with a Mercedes engine driven by experienced but undecorated drivers Jenson Button and Rubens Barrichello.

The secret to the success of Ross Brawn’s last-gasp buyout was the ‘double diffuser’ design which vastly increased the surface area of the downforce-generating bodywork at the back of the car. 2009’s cars were subject to major aero rule changes, and as the likes of McLaren and Ferrari floundered, the Brawn streaked off into an early championship lead that it would hang onto all season, with Button sealing the drivers’ title.

In the late 1990s, the rules for top-flight endurance racing said that you had to build a small run of road-going homologation cars of your Le Mans GT1 racer. Toyota decided to only build one road-legal GT-One, which was the first loophole. The second was even cleverer. Part of the ‘road car’ element of the rules insisted the car has a boot big enough for a briefcase.

Toyota presented the GT-One to the ACO scrutineering body and declared the empty space in the dry fuel tank was to be counted as the boot capable of containing a briefcase. The ACO agreed that this did technically meet the rules as they were written, and the GT-One was allowed to qualify. However, the racing gods did not smile upon Toyota, and the car only raced three times, never taking an overall podium. 

When a designer gets a lawyer involved before racing the car, you know it’s going to be a juicy loophole.

Gordon Murray wanted to employ a fan to suck air out from under his Brabham BT46 F1 car, increasing its ground effect even in slow corners and allowing higher cornering speeds. The car’s wide Alfa Romeo 12-cylinder engine was impeding airflow underneath, and costing it vital downforce, y’see.

However, the rules stated any device whose ‘primary function’ was aerodynamics had to be fixed and unmoving. And that meant a motorised fan was forbidden. So, Murray designed the ducting that 55 per cent of the fan’s airflow was used for cooling, and 45 per cent did the downforce suction. A lawyer confirmed that would stand up in a court of law as ‘secondary function’, so the fancar wouldn’t trip over the rules.

The BT46B was so fast the drivers sandbagged during qualifying, won the race by 34 seconds, and provoked such a protest from Lotus boss Colin Chapman that Brabham chief Bernie Ecclestone insisted Murray withdrew the BT46B for the rest of the 1978 season. A similar idea is employed in Gordon’s new T.50 supercar, four decades later.

Want to run a lighter car than the official rules allow? Do what Williams did in 1982, and fit a large water tank in the sidepods supposedly there to hold water needed for brake-cooling. The brake never actually ran that hot, and after a few laps at top speed, the water in the tank would evaporate or be dumped, meaning the car was lighter than the 580kg limit – until the tanks were replenished prior to the post-race weigh-in.

While it was a cheeky innovation, the protests got Williams disqualified from a second-place finish, and soon after the rules were tweaked so cars were weighed in the state they finished the race, not after a pit-stop fluid top-up.

There have been multiple flexi-wing controversies in F1 over the past few decades, with Red Bull either benefitting from them, or crying to the FIA about other teams gaining an advantage.

In 2011, the-then dominant RB7 was spotted to have wings that bowed under load, sparking against the track in the pursuit of increased ground-effect. Aero whizz Adrian Newey had surmised that with clever layering of the wing carbon construction, the wing would remain firm during FIA tests but bend under the higher loads experienced in race conditions.

What made this innovation so clever was that other teams couldn’t simply copy the wing, because the wings have to work with the entire aero philosophy of the car – the floor, the diffuser and so on. And lo, Red Bull stormed to the second of four straight titles.

And finally, let’s just raise a bottle of overly fizzy champagne to the NASCAR loophole genius that was Smokey Yunick. The ex-US Army WW2 pilot turned racecar driver and team owner has an infamous string of rule-bending innovations to his name, including hiding a whole basketball in a fuel tank during scrutineering then deflating it after the inspection, so his now larger fuel tank capacity could hold more gas. Thus, his car needed fewer pit-stops. Genius. 

On another occasion he installed eleven feet of tubing between the fuel tank and the filler neck, again to increase fuel capacity without breaking tank size regulations. He even took to cooling fuel to near freezing temperatures before filling the car, so the less dense fuel would take up less space in the tank and – you guessed it – the car could hold more gas. Smokey, we salute you.