The technology of IndyCar – a rich heritage

As IndyCar sets off for the 2026 season at St. Petersburg, the cars racing have an incredible heritage.

Not simply the longstanding history of IndyCar racing itself, but the car used this weekend has its roots all the way back to 2012.

In this time, the car has, of course, had updates and has proven incredibly adaptable.

When motorsport.tech last gave an overview of IndyCar technology in 2019, the car had already then been augmented with the aero screen.

More recently, it’s been the powertrain that has seen a plug-in update, with a hybrid system being neatly incorporated in between the engine and gearbox.

Indy powertrains

In the current era, IndyCar runs a 2.2l V6 twin turbo engine, supplied by either Honda or Chevrolet.

With tuning, allowing power between 550hp and 750hp, depending on the type of circuit be it super speedway, speedway or road course.

With these engine specifications being tightly regulated and the cars having fixed aero, i.e. no DRS, passing another car can be problematic.

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Therefore, IndyCar introduced a push to pass system. This gives the driver an extra boost of power with strict limits on individual duration and total use during a race.

It’s all controlled by the driver with a button on their steering wheel. As the push to pass is a boost in Turbo pressure.

This gives the driver a rush of top end speed, allowing them to pull clear on the straights or at least draw level into the braking area.

Hybrid system

For IndyCar, the next step was to introduce a hybrid system. This would reflect well on the series and the roadcars being produced in the USA.

It would also provide a complimentary effect to push to pass, as it gives the drivers a boost of torque when exiting corners.

Such a system could provide up to an extra 100hp, in short bursts with the energy store being recharged under braking in a KERS-like fashion.

As with push to pass, this is under the driver’s direct control from the steering wheel.

The challenge for the series and its technical partners was, how do you introduce an MGU, power electronics and energy store into an already tightly packaged race car?

Typically, a hybrid package on a race car would involve the energy store being mounted inside the survival cell.

Then the power electronics and MGU somewhere close to the engine or gearbox.

Already 10 years old at this stage, the Dallara built DW12 chassis had no accommodation in the fuel cell area for the energy store, while the space around in the engine and gearbox had no space provided for the MGU and its electronics.

As either it was in an aerodynamically sensitive area or butting up against the DW12 chassis.

Where there was room though, was in the bell housing that spaces the gearbox from the back of the engine.

This housed an oil tank but was otherwise largely empty and provided the opportunity to package the entire hybrid system.

The hybrid system itself was originally going to be supplied as a turnkey unit by an outside manufacturer, but part way through this project, it was agreed it would be taken on equally by Honda and Chevrolet.

Quite a unique partnership, given the rivalry between the two manufacturers.

What resulted was an innovative and compact hybrid system that simply slotted into the existing bellhousing position.

Despite weighing 45 kg, the net result in the car’s overall weight was expected to be neutral, as there were other weight savings, including the removal of the starter motor and alternator, which were effectively replaced directly by the hybrid system.

Its layout is quite simple from the clutch on the back of the V6 engine. A shaft passes into the motor generator unit, then onwards into the gearbox.

In this position, the MGU can both restart the engine and drive the car on electric only should the need arise.

Above the motor generator sits another unique feature. The energy store is not a battery in the same sense of a collection of Lithium-Ion cells, but instead Super Capacitors.

Supercaps, as they’re typically called, are able to rapidly charge and discharge a large amount of power, the flip side is that they do not retain energy for longer periods very well.

Given the use case in Indycar, these fit perfectly with the system’s design.

Then, above these are all the power electronics that transfer the electrical power from the supercaps to the MGU.

A small cooling system is incorporated with exits for the cooling fluid to pass out the side of the bellhousing to a radiator. The supercaps themselves do not need cooling.

Through the power electronics, the car can be provided with not just the voltage to the MGU, but also lower voltages for the car’s 12v and higher voltage ignition/injection systems, as well as the aforementioned engine starting mode.

Summary

In use, the hybrid system can recover and therefore discharge as much energy as can be found under braking.

Being an electric motor it provides instant torque, giving the driver a boost at low speeds.

While this system met its requirements, it has not been without criticism from teams and drivers.

The neutral weight balance was not entirely met and it came a rearward weight bias that the teams and in particular, the drivers had to handle.

This was an inevitable consequence of trying to package some kind of hybrid system into a chassis that simply wasn’t designed for it.

But not to be deterred, Indycar have kept the hybrid package on the car and are now working on an all new full-car package for 2028.

That will finally end the DW12 car’s racing life at sixteen years old! Not a bad innings.