VXR Engine Transplant Following on from last month, Griffin Autos complete a VXR engine transplant and fit the Z20LEH into an Astra Coupe.
In last month’s tech section we followed Griffin Autos as they made a start on the VXR engine and M32 gearbox transplant into an Astra Coupe which previously had a Z20LET. In the last issue Griffin removed the old engine in less than a couple of hours and serviced the VXR engine in preparation for fitting it to the Coupe.
This month, there’s more work involved, including swapping over various components to ensure the VXR engine and gearbox can be fitted and will run properly. Luckily, there are no bodywork modifications required to fit the engine and gearbox and in this respect it’s a fairly easy swap.
One of the major differences between the Z20LET and VXR’s Z20LEH concerns engine management and the engine wiring loom. The later VXR uses a CANbus system that isn’t compatible with the older Astra Coupe. Griffin Autos has found a solution to this problem by fitting the Coupe’s Z20LET loom to the VXR engine, including the crank, cam and knock sensors. They’ve also discovered that the VXR’s injectors and airflow meter aren’t compatible unless the ECU is remapped, so the Coupe’s components have to be used instead. The Coupe has a mappable ECU so larger injectors and the airflow meter from the Z20LEH can be fitted along with a remap.
Fitting the larger six-speed M32 gearbox into the Coupe is relatively easy. The gearbox mounts have to be swapped over, but luckily they all fit in the same locations as the Coupe’s original F23 ’box and line up inside the engine bay. The gear linkage and gear lever from the M32 housing need to be used, and will be fitted to the Coupe.
Set aside a full day to swap over components and install a VXR engine and M32 ’box into an Astra Mk4. The following pages cover step-by-step guides for swapping over the ancillaries between the engines, making the necessary gearbox modifications and finally fitting the engine and ’box. Difficult y rat ing: 5/5 Time ta ken: One day Screwdrivers, pry bars, spanners, sockets, pliers Two-post ramp or large trolley jack and substantial axle stands Two transmission jacks, two trolley jacks or two large bottle jacks Breaker bar Cable ties Impact driver Penetrating fluid Various hammers Containers to drain oils and coolant