(Motorsport-Total.com) – During the qualifying sessions for the two Formula 1 races this weekend in Silverstone (Sprint and main race), a curious detail stood out: Both Mercedes drivers completely lifted off the throttle just a few meters before the finish line during qualifying.
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This is unusual, because normally drivers try to cross the line with the throttle fully pressed to gain the last few hundredths.
As paradoxical as it may sound: There are situations in Formula 1 where it can actually be advantageous to lift off the throttle before the finish line by exploiting certain nuances of the regulations. After qualifying, Kimi Antonelli spoke about the counterintuitive nature of what he had to do.
“It wasn’t easy,” he said, explaining: “In Q3 I also had to lift off the throttle, and with these power units it’s always a bit complicated because sometimes you have to drive in a way that doesn’t feel quite natural.”
What Antonelli describes is a principle that applies to all teams. Ferrari, for example, already instructed Lewis Hamilton on Friday to carry more speed through the Becketts complex so that he could only get back on the throttle later before the Hangar Straight.
This means sacrificing some power on corner exit. However, the crucial point is that the MGU-K can then deliver power longer on the straight, where the performance gain is greater.
The clever trick from Mercedes, however, is based on a slightly different principle – and is particularly interesting because it shows how complex the current rules are.
Why a power ramp exists
To understand this, you need to know: When the MGU-K is switched off, the FIA requires a gradual power reduction for safety reasons. Imagine a long straight.
If a car suddenly switched off its electric motor and power dropped immediately from 350 kilowatts (kW) to zero, a safety issue would arise because the driver would suddenly lose about 500 horsepower.
Therefore, the rules on fast tracks like Silverstone prescribe a linear reduction, with a maximum drop of 50 kW per second. This rule primarily serves safety, especially in the race, where a non-linear power drop could lead to large speed differences.
In qualifying, however, the situation is different. On a flying lap, teams want to use every joule of energy. Earlier this season, some teams, including Mercedes and Red Bull, found a way to circumvent this rule by activating an emergency procedure that switched off the MGU-K.
However, since this increased the risk of dangerous situations – because the MGU-K remained deactivated for about a minute – the FIA banned this method for performance purposes in qualifying.
Mercedes has now found a clever way to achieve the same effect through a careful (and fully legal) interpretation of the regulations, so that the MGU-K power can be reduced much faster, even if one could argue that the rule was never intended this way.
Lifting off the throttle to cut power
The crucial question Mercedes asked itself was: Under what circumstances can this power ramp be bypassed? The regulations specify several situations in which the MGU-K power may be reduced faster.
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One of these occurs when the driver completely lifts off the throttle: The combustion engine then requires no power but actually decelerates – and the MGU-K must respond accordingly.
If the electric motor continued to deliver power even though the driver was completely off the throttle, the car would not decelerate as intended. Mercedes exploited exactly this principle.
Silverstone: Driver ratings by Marc Surer and the editorial team
The team programmed the control electronics to recognize based on the distance traveled on the track when it should not follow the normal power ramp. Instead, the MGU-K continues to deliver maximum power.
The drivers then only have to lift off the throttle a few meters before the finish line. Before the battery is fully depleted, the MGU-K can immediately switch off its power instead of following the gradual reduction – and remains compliant with the rules.
It is an exceptionally clever solution, even though it feels completely unnatural from the driver’s perspective, which is why it must be intensively trained in the simulator and other teams have not adopted it so far.
Even Mercedes customer McLaren surprised by the trick
In Silverstone, this trick was particularly effective for two reasons. First, the section from the last corner (Club) to the timing line is relatively short, so the driver can easily lift off the throttle just before the line.
Second, both the last chicane (Vale) and its exit offer several possibilities according to FIA regulations to reduce power quickly and save energy for the final acceleration impulse on the straight.
Such a system must of course be extremely precisely tuned, both on the driver side and in the software. The software must not only know when the battery is nearly empty but also exactly where the car is on the track to instruct the MGU-K to continue delivering maximum power instead of entering the normal reduction phase.
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After qualifying on Saturday, McLaren team principal Andrea Stella said: “When we saw it for the first time yesterday in the sprint qualifying, when Antonelli did it, it surprised us a bit because we hadn’t discussed something like that.”
“I’m not even sure if it’s available to us [as a customer team], because probably additional elements are needed to use the power unit in this way,” said Stella.
“As I said, there are ongoing technical discussions with HPP to ensure we get everything out of this power unit because it is an extraordinary piece of engineering. There is a lot of performance in it, and much depends on how you use it.”
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