Our Stage 4 Conversion for Astra & Zafira VXR (Z20LEH) builds on the Stage 3 hardware components that are:

. Full Exhaust System, preferably 3” (76mm) throughout
. Large Intercooler

To this we add the following:

. K06 Hybrid Turbo
. Klasen High Flow Inlet Manifold
. Stage 4 Software

With our Stage 4 we have addressed the main issue and negative comments we have read & heard regarding other versions of the Stage 4; that is the lack of torque when compared to a Stage 3 or Stage 3+ (with a KO6 turbo).

We have laboured with this for some time before being fully satisfied and ready to fully release this as a package.

You can see from the graphs that we have not lost any mid range torque what so ever. This is due in part to the Klasen High Flow Inlet Manifold with its longer runners which treads a fine balance between good top end gains but not all at the expense of mid range torque.

The turbo utilises parts selected from the KO6 KKK parts bin alongside a vastly uprated bearing pack, which when combined with some carefully developed software means that torque does not have to be dropped to combat the surge and related throttle closing issue often reported.

The result is an increase in power of 35-45 BHP with no loss of torque.

The graph shows the comparison between a Stage 3+ and Stage 4.