eGT: Electric GT the new all-electric series with race prepared Teslas
A new series yet to kick off, but in its final testing phase. Electric GT with its Tesla racecar is an interesting addition to the world of electric racing
eGT in a nutshell
Electric GT is a fledgling all-electric racing series, the intention is to race identical Tesla Model S P100’s at classic racetracks. In this format the cars will have 4WD 800hp powertrains from the standard Tesla, but the cars will be much lightened and augmented with a reasonable amount of downforce. Plus the obligatory safety set up, with a full cage, seats and harnesses etc. Further aiding performance there will be larger wheels and tyres allied to race bred suspension and brakes.
The teams will buy the cars, that are converted by the series via partner Campos racing. Given the performance and range of the standard Tesla, the races will be full 30 minutes nonstop, with no need for mid race car or battery swaps.
At the moment the series has completed testing with the 450hp P85 based car, that is rear wheel drive only, has had the requisite safety equipment fitted and the lightweight composite panels fitted, but still runs with largely standard running gear.
Pau Media day
In the build up to the series launching, there was a media day at the Pau Arnos circuit, a short drive from the French town that hosts its own street race. Pau Arnos is worth a mention, not only is it the headquarters for the eGT series, but also has become an electric-only racetrack. Fitted with the electrical infrastructure to charge cars in each garage, it aims to be a hub of electric motorsport, for both track and track-day drivers.
The prototype car that has been used for testing to date was available, for drivers and passenger rides. This car has already tested extensively at Pau Arnos, Calafat and Vallelunga. I got to have a close look at the car, talk to the engineers and partners and even have a few laps in the passenger seat.
This is not an official Tesla race series, although Tesla have given tacit approval. But the electric powertrain will remain standard, as Tesla will not permit any changes to the high voltage side of the car. Thus, the car runs with the standard 450hp (P85) rear wheel drive set up and battery.
So, the basic Tesla layout is retained, that is a transverse motor driving the differential via reduction gears with the inverter package housed on the other side of the diff. Being an electric car there is no multispeed gearbox, as the motor has the torque to pull from a standstill to top speed. Equally, there is no clutch, with there being no gearbox and no need to idle the motor. The battery sits under the floor and without the front motor package, the front ‘engine’ bay is effectively empty aside from the steering mechanism and cooler package.
Even the two large cockpit screens are retained and feature the standard road car displays and menus, the racecar showing it is playing FM radio on the dash!
With the constraints on the high voltage side, modifications to the powertrain are largely to the cooling system. This system is needed to keep the battery cool, as the cycling of charging in the pits and discharging around the lap generates a lot of heat. On the standard Tesla the Battery Management System (BMS) is used to maintain the cell temperatures, making sure overheating doesn’t prematurely degrade them, to ensure the longest life for the battery pack. On the racecar this means that full power laps will soon lead to hot cells from the rapid discharging, it is then that the BMS cuts in to protect the battery pack, by limiting the battery output and therefore limiting power through the motor to the wheels. This process is known as ‘derating’ and the output will be derated until the temperature moves back into the normal operating window. So, on the racecar the standard radiator is flanked by two more radiators fitted behind the side grilles on the front bumper. Heat from the radiators vents out into the wheel wells and through the outlets cut into the wider wheel arches.
Resolving the cooling issue will be the toughest challenge to the series, ensuring the motor can deliver enough power to last the full race. Especially with the P100 specification racecar, having the double motor set up and an output of 800hp. At Pau the P85 spec car derated after a couple of fast laps.
Part of the process of getting the Tesla to become a pukka racecar is stripping weight, to this end the P85 car lost some 500kg, racing at around 1700kg, making it close to the Audi R8 V10 power to weight ratio. This test car has been prepared by Campos racing, who are the technical partner for the series. They have also designed the full racecar, with the parts already drawn, but awaiting the first P100 to be delivered before manufacturing starts.
Inside the car is fully stripped as you would expect, with an added roll cage, OMP race seat (two in the test car for customer passenger rides), harness and extinguisher system. The driver has just two pedals and a carbon butterfly-style steering wheel, as well as the two displays mentioned above. As the car’s throttle pedal is fly-wire, due to the very nature of the fact it’s an electric car, the pedal feel and return is provided by the series partner R53’s own design throttle damper. This mounts to the pedal and telescopes with pedal movement, it provides the resistance and damped feel as the pedal is depressed and the return effect, with both a spring and oil damper. To allow different brake bias set ups the car is equipped with a tilton adjustable brake pedal. In the final spec racecar, the screens will display more pertinent info for the driver, as well as info to be picked up by the in-car cameras to inform fans of what’s going on in the car.
Again, the effect of the electric drivetrain is that despite the sound deadening being stripped out there is little noise inside the cockpit whilst lapping the track. This allows the driver to hear as well as feel things like tyre squeal, brake noise and kerbing, useful driving pointers that are lost to the driver with a noisy internal combustion engine.
Again, the core of the car is the standard Tesla bodyshell. Then, the outer panels are modified for reduce weight, improve cooling, add more downforce and to allow the wider Pirelli tyres.
Thus, the front bumper, bonnet, wings, roof, doors, tailgate and rear bumper are formed from composite materials. The specific material being a unique flax based composite produced by Bcomp. This being an alternative to carbon composites, the woven material effectively being grass! (see the more detailed post about this composite system).
At the front the bumper incorporates a splitter, the wheel arches are wider and vented for additional battery cooling. While at the rear there are again wider arches and rear bumper with a small diffuser underneath. The ‘look’ of these parts match the P85 base car, but the subsequent P100 racecar will follow the base car’s updated styling.
Mounted with aluminium pylons is a full width rear wing, that adds some 900N of the downforce, useful as the car is racing with slicks at full racing circuits such as Barcelona and Silverstone. The front splitter helps to aerodynamically balance the car with 500n of downforce, but understeer is still the predominant handling trait with the test car.
One interesting development with the Bcomp composite is the roof panel. LEDs have been incorporated into the net-like backing. With the composite being translucent and the LED strips being dense enough, they can be lit to light up the roof from the outside, not simply to help identify the car, but also to display details like car number, position in the race and other data to inform fans on track about what’s going on with the car.
Suspension wheels, tyres and brakes
The giveaway that the test car is not the full Campos racecar is evident when looking into the wheel wells without the tyres being fitted. There is standard Tesla suspension, the double wishbone, upright, damper and brake set up is from the base road car. While still bestowing the car with adequate handling, the car being balanced, with good initial turn in and corner exit traction, the future car will have bespoke running gear.
Whilst still being based around the standard tesla layout, there will be fabricated wishbones and uprights. Then the dampers being developed by R52, based on Penske hardware. The brakes are equally elaborate aluminium CNC Milled from Alcon, with six pistons at the front and 4 pistons at the rear. These operating on steel Alcon discs, with a grooved disc face. Five stud Braid wheels with 18” diameter are wrapped the Pirelli tyres, sized at 305 660-18. As mentioned the cars will race on slicks, with wets an option. The test car used for demonstrations at Pau, run grooved wet tyres, the cold French November temperature working, well with the soft compound, the driver reporting great grip with this set up. With this grip and the tight nature of the Pau Arnos track, the brakes were given extra cooling while in the pits with a blower.
As the test car still ran the standard suspension, the wider wheels were made with a deep offset, partly provided by an extended hub machined from aluminium.
With the nature of the track and the potential performance of the car, I felt it wiser to take a passenger ride in the car, rather than risk disaster with my lack of track driving experience. Duly I strapped on a helmet, climbed through the multipoint roll cage and buckled up the OMP six-point harness. My driver was Alex Toril, a young Spanish driver, he was experiencing his first laps of the car and track to, although he had the Finnish driver Emma Kimilainen familiarize him with track briefly beforehand. A number of young drivers were on hand to test the car through the day.
Aside from the oversize screens on the bare dashboard and the amount of light coming in through the translucent composite roof panel, from inside the car looked like any other Touring/GT car. However, there was not the rumble of an engine, the car silent aside from some cooling fans and buzzing. Setting off was equally smooth and silent, the slight whine of the motor and transmission being in the background the specks of gravel being kicked up by the tyres. Having completed 5-6 laps beforehand the tyres and brakes were warmed up, while the battery still had plenty of charge, but was already warm from the previous laps.
Pau Arnos, is a short track, with a basic kidney shape layout plenty of gradient changes amongst the hills surround it. With its shape and being surrounded by fields and trees it feels somewhat like the Brands Hatch Indy circuit.
Starting at the highest point in the pits, the pitlane exits onto an open 180 double apex bends, that dips down to a fast-left hander towards two right turns forming the far corner of the layout. Then the track drops steeply down into a gentle righthand curve to the lowest point of the track. This descent ends with a slight right bend into a sharp left turn that immediately climbs up to the final corner. Approached still climbing uphill, the final turn is a hairpin-like tight right onto the short flat straight. Missed when exiting the pitlane, the lap actually starts with a right-left switch, that drops away on entry only to climb on the exit of the left turn, this is particularly tricky and tyre marks on the track suggest not everyone has got it right in the past!
First sensations of the powertrain are plenty of torque to accelerate from the slow turns, but little evidence of power oversteer. The turn in was good giving way to mid-corner understeer, Alex doing a good impression of a young Alonso getting the car into the turn with the initial bite, sometimes getting some corner entry oversteer on the brakes into the tighter turns and then correcting mid corner to make the apex. As mentioned the sound of the brakes, kerb strikes and areas of the track strewn with gravel were obvious to the ears.
After two laps both of us felt the hot battery’s control system derate the power and the climb through the final corner onto the short straight was at somewhat diminished speed. Not to be slowed by a mere lack of power, Alex threw the car at each braking point, apex and kerb on the final lap, again the car keeping a nice balance and not fighting back at the aggressive driving. A final slow near-silent roll into the pitlane ended the lap and I was impressed how well the car went with the set-up Campos had managed to dial in with few modifications to the standard car.