You may know about the ongoing boost issue that I've had since getting CS3. It wasn't a major problem, but I like things to run perfectly.
Anyway, I went down to Courtenays today to see if they could fix it. They started by upgrading my base map to an Astra GSi one and re-did CS3 on that. This did not fix the problem, but did improve drivability and by the look of it, economy too.
We then put the car on the rollers. Mark watched the actuator while Jon drove the car on the rollers. Mark could see the actuator spiking when the boost was dropping. The theory is that the back pressure is causing the weekend actuator to open up under initial full load, then the ECU reacts to put it back again.
So the problem was found. In my attempts to correct the problem myself I had tightened the actuator. This gave slightly better peek boost figures and results in much better power than I had before - despite the small drops caused buy the actuator.
I now have 257bhp @ 5628 and 269.3 @ 2864 lb/ft torque. Even so, there is a major dip at 2800rpm due to the actuator.
Instead of ordering a new actuator, I have ordered a VXR turbo unit which will be fitted with an uprated actuator and CS4. Not sure when the turbo will come in - fingers crossed soon.
So anyone who has the boost issue I previously described, it is likely to be the actuator.