The Lancia Delta S4 was one of the fastest and most advanced Group B rally cars ever developed, it would also directly lead to the entire Group B class being shut down by the FIA. In some ways the Delta S4 was the quintessential Group B machine – it was a lighting fast, fire-breathing rally car that proved both successful and lethal.
What is Group B?
For the uninitiated, Group B was founded in 1982 by the FIA alongside Group A and Group C. Group A was for production-derived vehicles with a minimum homologation production numbers of 5000 vehicles per year, and there were strict rules governing power, weight, and technology. Group C had far fewer restrictions but there were limits placed on fuel load and minimum vehicle weight.
Group B was the Goldilocks class that had very few restrictions on technology and power, and the minimum homologation production number was just