E-racing365 can exclusively reveal details of the directive given to teams before last weekend’s Santiago E-Prix which caused Lucas di Grassi to lose pole position.
The Brazilian was sent to the back of the grid for not complying with a request from Spark Racing Technology to adhere to specific braking parameters during qualifying.
Di Grassi was then judged to have not respected the instruction manual of the FIA supplier, Spark.
“The driver used more brakes in the “inlap” during qualifying than in the flying lap without any reason,” stated the official FIA bulletin issued an hour prior to the race.
SRT Directive Details Uncovered
It is common in racing for teams to get maximum temperature into their brakes to assist with tire temperature management.
However, in Formula E, the grooved Michelin tires run to recommended ‘hot pressures’ and it is alleged that drivers have previously done their qualifying laps below the specified pressure.
A technique of then using the brakes to increase the temperature and pressure in their tires is used on their in-laps.
This can result in what is known as a significant ‘heat soak’ within the Brembo calipers if the car then sits idle in the pits as they do after qualifying while waiting for turns to be parked in Parc Ferme.
E-racing365 understands that this contributed to the incident in Marrakesh where NIO’s Tom Dillmann suffered what is believed to have been a ‘leaking caliper piston seal’ on his brakes and was unable to stop his car effectively.
This resulted in damage to three cars after he caused a chain-reaction incident which included the two Envision Virgin Racing cars of Robin Frijns and Sam Bird.
After this incident SRT issued safety guidelines to teams ahead of the next round in Santiago.
E-racing365 was given a copy of the official communication to teams on Saturday evening. This has not been seen in the public domain until now.
It states, via a letter from SRT technical director Theophile Gouzin, as follows:
***After a 250 kW quali lap or quali lap training, during the qualification, and after the checkered flag during the race, it is forbidden to intentionally use the brake to increase the brake temperature (then raise the tire pressure as example):
***The rear axle braking must be performed using the MGU regeneration mode, going up to the maximum regeneration power allowed by the battery (PMaxCharge broadcasted by the battery BMS).
***There is no reason to use the rear friction brake disks, and it is a safety requirement to not overheat the rear calipers.
***It is also strictly forbidden to overlap brake pedal and throttle pedal intentionally.
***The braking points must be comparable to a normal flying lap.
Spark Racing Technologies would not comment to e-racing365 on the matter when approached in Santiago on Saturday.
Directives Triggered by Tire and Brake Protocols
The issues relating to the SRT directive sent to teams last week has its roots in Michelin stipulations on minimum hot and cold pressures which are run at races.
A leading engineer with significant Formula E experience told e-racing365 that the complex scenarios relate back to how the tires are managed.
“The teams aim to run the tire pressures as low as possible, and then put as much energy in to the tires as they can on the in lap to get them up to the minimum hot pressure,” said the engineer, who wished not to be named.
“This is believed to be why some cars immediately do their 250 kW lap in the group stage of qualifying – so that the tire pressure is still relatively low.”
Unsubstantiated paddock rumours abound that teams must be starting below the legal minimum, which is believed to rarely get measured before qualifying itself, with the driver then driving the car ‘against the brakes’ on the in lap in order to get them suitably hot.
“This would have the effect of radiating heat in to the wheels and tyres when the car is in line for post-run pressure measurement,” the engineer said.
“But to be fair to [SRT] they have to react to the brake failure on safety grounds in the pit lane and di Grassi could also have avoided a penalty by actually complying, like everyone else did.”
It is currently not known why the cold tire pressures, when the cars are in parc ferme immediately before qualifying, are not regularly measured or why the minimum cold pressure is not raised so that the cars cannot fail to reach the minimum hot pressure.