ASTRA J VXR TUNING
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.
SUSPENSION & TRANSMISSION
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.