It is always useful to have a car checked from time to time on the rolling road, as it can show up potential running issues.
We had this Astra H VXR Nürburgring brought in for a health check on the rolling road this week, due to it feeling ‘down on power’ after a manifold swap by the owner, so running it up and datalogging it should highlight any issues.
We carried out an initial check over of the vacuum pipes, recirculation valve and actuator just to make sure nothing physical was at fault which could cause a problem. The ecu was also checked for any stored trouble codes, again to see if there was anything that could cause a running issue.
Running the car up on the rolling road whilst datalogging found the turbo to be down on boost, making less bosst pressure than expected and resulting in 255bhp and 290 lb ft torque down on what is expected from a Nurburgring with a remap.
Additional checks were carried out to the boost hoses and intercooler fittings, which showed no leaks or issues.
After further runs, the turbo was shown only to be capable of making a maximum of 20psi overboost, and unable to make the required boost at peak power (around 5,700rpm), so identifying the root cause of the problem to be a failing turbocharger.