Andreas Mikkelsen (NOR)/Ola Floene(NOR)-Volkswagen Polo WRC

We analyze and understand  deeply the system that makes the cars roar in the WRC.

The turbocharger has lasted a couple of decades in the world of rallys. Years of experience and research in the delicate art of recycling gases and air expelled to redirect back to the motor. For what purpose? As for winning performance clear: this has crystallized in engines today howl in the WRC, authentic marvels of sophistication.

Let’s start with the basics

Basically, a turbocharger is a system that reuses exhaust gas ejecting motor. Such gases are routed to a turbine, turbo housed inside, which rotates at approximately 150 000 revolutions per minute (rpm). In places like Mexico, even turns a little faster, because the air is warm and oxygen is scarce. Elsewhere, as in Sweden, it operates at a speed slightly lower, because the air is cold and dense _courius, right? _. This turbine is connected to a compressor, which compresses the air to achieve greater momentum. In turn, this results in higher torque and more power.

Okay, then, what is the additional strength provided by this system to cars World? According to experts, if we compare with a Super 2000 car, which works naturally aspirated engine, the advantage in the pair would be about 100 newtons meter, and this is amazing!

More equality

During the era of Group B, back in the 80s, teams were free to propose and implement innovative tricks to improve performance cars such as Lancia, which used both a turbocharger and a supercharger in his famous Delta S4 . But now in the World much higher standards prevail.

All teams are required to use the same turbo model, US brand manufactured by Garrett, with the same board reduction of 33 mm, which is responsible for air volume control which supports the system. M-Sport had a chance to spin the turbo faster, but it does the effect known as “drowning”, since the air flow passing through the choke plate is already full, you can not beat that volume . So, if we did turn the turbo faster, suffer no harm and would gain additional power.

The similarities between the technical specifications of the current cars cause differences in times for each leg of a rally derived almost exclusively on the skill of the pilots.

No delays

The pilots of the first utilities and cars equipped with turbo (like the Saab 99, for example) will remember that feeling when treading thoroughly noticed: the car hit a kick, shot out with you and you quedabas back to the well pegadita seat back for seconds. That happened just when the turbo accelerated and gave her extra power boost. This is known as delayed response of the turbo, but today WRC drivers no longer have to worry about it.

When loose the throttle valve that releases air into the exhaust system before the turbocharger position, describing the ‘anti-delay system “opens. So you delay the ignition at the same time and inject the fuel. Then explodes right in the turbo, which continues to rotate even without acceleration. Basically, the delay is eliminated in the same response.

So, the response of the engine when the driver steps on the accelerator is more fast, immediately can feel the increase of the speed. But ensure that the system is correctly set is one of the key tasks of engineers in both the test and during the competition. If the setting is too aggressive, the rear axle of the car tends to slide, slowing and hindering the correct exit of corners.

The future of turbos

Turbochargers WRC cars would be able to still control much more power (the same engines, with a larger choke plate, generating about 70 additional horsepower on the WTCC WTCC); why teams like M-Sport have reached a point where their systems can no longer evolve more. The only additional benefit that could be obtained would be reducing friction.

Maybe, probably they could refine bearings and stuff _Finally, they are the parts more damaged from turbo_ too the turbine wheel is the most damaged parts with bearings_, but now turbos are used with ball bearings and friction is very low, so the losses are minimal in this area. It is a very efficient unit.

Thanks for reading,