One of our recent jobs was this Astra H VXR, brought in to have a K06 turbocharger fitted (complete with an uprated recirculation valve), along with our CSRacing Full Height Front Mounted Intercooler. Whilst in our workshop it was also converted to Evans Power Cool 180 Waterless Coolant.

Already fitted with a 70mm exhaust system it was onto the rolling road for mapping and full set up. During mapping the mid range and top end boost was reduced slightly due to the 70mm exhaust system giving more back pressure than a 76mm system and also because the engine did not have steel rods or uprated valve springs. Once the ignition timing and fuel were optimised we saw results of 304 point something bhp (so nearly 305bhp!) and 341 lb ft torque. With a 76mm system estimated gains are 305-310bhp so this particular car is making good power on a 70mm system.

There is still some in reserve to come for this car once it has a 76mm exhaust system to help with back pressure reduction as 310bhp+ is more than possible, with potentially even more should an inlet manifold, steel rods and uprated valve springs/shims be fitted.