In August
1985 the seventh-generation Skyline "Nissan
Skyline R31 2000 GTSR" was launched and was the
first to reintroduce the 6-cylinder DOHC engine. Only 800 units
were built to allow homologation for Group A Touring Car racing.
The ultimate version of the R31 was the RB20DET-R powered HR31
GTS-R Coupe, claimed 210 ps (154 kW), with racing versions making
over 430 hp (321 kW) in Group A trim. The R31 GTS-R had a reworked
version of the normal RB20DET with a much larger turbocharger
on a tubular steel exhaust manifold, as well as a much larger
front mounted intercooler boosting power.