Astra VXR - Stage 4 Conversion

By Thorney Motorsport

Dyno Charts:

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After nearly 2 years of testing and development we are ready to release our Astra VXR Stage 4 conversion. As with all power upgrades each stage of tuning simply exposes the next weakest link in the chain. With stage 1 we upgrade the ECU but cant go any further as the exhaust restricts power, with stage 2 we go further but heat is the limiter so we upgrade the intercooler etc. With stage 4 we finally replace everything on the engine that needs upgrading to run much higher power. However, with the LEH bottom end (pistons, rods) really being unable to cope long term with more than 340bhp we limit the power from the stage 4 to under this level, but it does mean if you replace the bottom end (stage 5) then 380bhp is yours for the taking. In other words this is a stage 5 conversion but power limited to 345bhp to protect the standard bottom end.

The Thorney Motorsport Stage 4 Conversion comprises:

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• Garrett GT28 Turbo
  Specified solely for our Stage 4 Conversion, it features Roller Bearings, Uprated Seals and Shafts.
• TMS Equal Length Manifold
• TMS Large Bore Downpipe (Fits to TMS Exhaust by Milltek)
• TMS Oil Feed & Breather Pipes
• TMS Stage 4 Remap (Available via. TMS Bluefin Device)
  (FOC Upgrade to existing TMS customers.)
• TMS Front Mount Intercooler
• Thorney Motorsport Race Exhaust System
  
• 1.9 CDTi Astra H Airbox Conversion
• Uprated Manifold Studs
• Extra Heat Shielding
• All New Silicon Hosing
• New Boost Sensor
• All New Gaskets
  
• 345BHP & 380Ft/lbs

At the heart of this conversion is the custom turbo and equal length manifold design. The manifold is built by the same company that supplied Red Bull Racings F1 manifolds so the quality of construction is exemplary, it is a true equal length which is crucial in maximising airflow from the larger turbo, no point creating power via boost if its wasted in blocked airflow. The turbo itself is a Garrett GT28 unit with a variety of changes made to TMS specifications, the turbo is rated to 450bhp maximum so we have designed the unit to generate maximum power and torque but well inside its limits.

We recommend that your car have an LSD fitted as well as a big brake upgrade (either our own Alcon kit of AP Racing) as a minimum but it's not compulsory. The standard TMS/Vauxhall warranty applies, however there is only a 12 months warranty on the turbo which is standard Garrett terms. The conversion can only be undertaken at our Milton Keynes HQ as extensive dyno time is needed during installation.

The price differs on the options you choose, but the starting guide prices are:

Std. Car -> Stage 4 - £8,995
Stage 1 -> Stage 4 - £7,995
Stage 2 -> Stage 4 - £5,995
Stage 3 -> Stage 4 - £4,495