Want To See Some Terrifying Turbo Lag? Watch This Group B Test Video

In the 1980s, Lancia developed a supercharged and turbocharged (aka twincharged) engine for their midengine/AWD Delta S4 Group B rally car. The idea was the two compressors would eliminate any kind of lag in boost. It doesn’t look like it worked out that way.

The system worked with a supercharger starting to feed boost to the engine at low revs while the turbocharger was busy spooling up and lagging. Once the turbo was up to speed, a clutch would disengage the supercharger. Nissan later used this system on their awesome March Super Turbo, but Lancia did the whole twincharged thing first.

Supposedly the whole system worked, but watch this video (particularly the onboard at 5:55) and it doesn’t exactly look like things are perfect. There’s a moment when the engine picks up like crazy, the whole frame goes blurry, and the car rockets forward. The driver barely has time to grab the next gear.


But hey, what do I know? This was a test session after all, and it’s possible the twincharging system got tuned to be much smoother and progressive into the car’s career.

I don’t imagine that would have been easy, since this engine produced well over 500 horsepower out of 1.75 liters, but it’s possible.

Contact the author at raphael@jalopnik.com.

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No, it never got smoother than that. The first time I saw one in action was actually frightening. Car exits corner, there is an explosion, car is elsewhere.