Based on the XR3i, launched in 1985 as the Series 1 using the mk3 shell, 1986 saw the mk4 and series 2 version, which was manufactured until 1990. The RS turbo added a Garrett T3 turbo and low compression Mahle pistons to the 1.6 CVH engine. Featuring a small front mounted intercooler, the engine management was updated from Bosch K Jet to KE, to give additional electrical functions such as on boost enrichment and overrun fuel cut. Power was 132bhp at 0.5 bar boost. The gearbox featured a viscous coupled LSD (4.2 diff ratio in series 1, 3.8 in series 2), whilst the cars featured various styling modifications (alloys, arches and spoilers).
It is now worth mentioning that the CVH engine has been around for over 30 years, and while it can still be the basis for a very reliable power unit, most original engines are now at the end of their life, meaning that very little can be done to tune high mileage units unless the engine has been rebuilt. Likewise whilst the following tuning guide gives appropriate power for each stage, very few cars survive that actually have fully functioning Bosch KE Jetronic, so in nearly all cases, we now replace the engine management with OMEX 600 regardless of power level to give new life to the vehicle! (See engine management section)