The Astra J VXR runs a whole new engine compared to its predecessor. It now

has a A20NFT engine (or LHU as it is also known by).


This engine has a duplex timing chain system, balance shafts and a high pressure fuel pump with direct injection. The engine offers 280PS (276HP) and 400Nm (295lbft) torque as Standard.


Running a Square bore / stroke at 86mm the DI engine runs a compression of 9.3:1 from the factory, while also boasting VVT (Variable Valve Timing) and a twin scroll Turbo charger



GCAP's bespoke custom ECU remaps will tweak the fuelling, boost, ignition timing etc to boost the power to around 300-310bhp with up to 360-380lbft of torque without any hardware modifications.


We advise at this stage the addition of a panel filter to allow the vehicle to breath better.



We now address the somewhat restrictive induction system. We swap out the airbox and induction plastic piping for a cone filter with a high grade silicone pipe. This allows the turbo to suck in air more efficiently. Aided by a remap we tend to see around 308-315bhp and 380lbft torque.



At this stage we now address the exhaust system. By removing the restrictive cats and fit a larger bored free flowing exhaust system, we again open up room for more power. We remove the 1st cat completely, then offer either a sports cat or decat for the secondary cat. Joined again by a remap we tend to see around 320-335bhp and 380-400lbft torque.


As the standard set up runs a 2.75" exhaust, a cat back system is optional. We find that by only replacing the catalytic converters with a more free flowing option, the power is opened up. However there are no negatives to adding a complete system, and will of course aid the performance when going up through the levels of tune, with the added bonus of a more deeper exhaust note.



At this stage we focus on cooling the intake temperatures. At stage 2 the car will be struggling to keep the air cool via the standard intercooler, therefore after prolonged use the car's bhp will begin to fall. To ensure a consistent performance figure, we swap the standard intercooler for an uprated front mounted cooler. Combined with a map tweak we see figures in the 340-355bhp range and up to 390-420lbft torque.


We offer full engine forging the A20NFT engine.


On the A20NFT engines found in theAstra J VXR, we offer a full strip down and rebuild service using ZRP or PEC conrods. The pistons we swap out for some low compression forged Wossners. Over the last 3 years we have seen a number of the Astra J VXRs fail due to ringland failure on pistons. By forging, we eradicate this plus allow the ability to safely run up to 600bhp / 600lbft.

Included in the rebuild are all new gaskets top and bottom end, plus a full head rebuild including valve lapping, new stem seals, full degrease and skim. Customers have the option of upgrading the valve springs and stem seals whilst this is done.


We can offer a variety of suspension and handling upgrades spec'd to your exact needs, whether it be fast road or a full on track set up.


We can offer lowering springs, coil over kits, uprated engine mounts and bushes.


We also offer a variety of clutch and flywheel set ups ranging from stage 1 - stage 3. Single mass flywheel conversion, uprated clutches, 4 and 6 paddle clutches and uprated covers. To help aid put the power dowe we also recommend the addition of a limited slip differential at any level of tune.



GCAP Performance

6 Powis Mews

Notting Hill


W11 1JN