Blog for my Saab
Having done a little research I think I now understand the working of the wastegate and APC. Wastegates allow exhaust gas to bypass the turbo. Without a wastegate opening a positive feedback loop is formed which should be able to destroy an engine. Wastegates are opened by an actuator. This is connected by some vacuum … Read more
Another chat with John at WMSS leads me to believe that the replacement APC solenoid may be faulty and causing the problems. As the wastegate functions for the base boost setting, the APC solenoid seems the most likely solution – I can’t think of anything else, but I don’t know all the intricacies of the … Read more
Having left the battery disconnected for 2 days to reset the ECU I had Friday afternoon off to fix the boost issues. So I reconnected the battery and went out for a drive – car still only boosted to the start of the end of the broken yellow/red section. To check that the car could … Read more
The car has stopped producing huge amounts of boost. It boosts smoothly to the broken yellow/red section of the gauge and that’s it. All hoses have been checked and were fine. The car had no problems on Wednesday when I last drove it hard. What could have gone wrong this time ? *sigh*
I now know the function of the one-way valve that was replaced yesterday, so shall share the information here. Nasty gasses build up in the crankcase. Instead of venting to the atmosphere these are fed into the inlet manifold where they can be burnt. I guess this is more environmentally friendly. In a normally aspirated … Read more
I have just returned from WMSS and my car sports a shiny new DI cassette. Upon arrival a number of tests were performed on various bits of the vacuum system. The one-way walve on the crankcase breather hose was found to be faulty. Apparently this is bad although and they explained why but I am … Read more
Having spoken to one of the guys who tested my car I have more information to add. It seems that analysing these plots is more complex than I had thought. 1) The Dyno The performance figures were definitely measured at the wheels – they didn’t do a deceleration run. Their rolling road is one of … Read more
The car is now booked in at WMSS towards the end of January. Hopefully they will be able to diagnose the problem and fix it. I have recieved a suggestion of removing the DI casette, stretching the springs and giving it a clean before reassembling with some silicon grease around the boots and springs. Might … Read more
Following debate on Saabscene, it seems likely that my car isn’t producing as much power as I thought it was. The thread here contains more info. It looks like the dyno figures may well have been adjusted to flywheel rather than being wheel measurements. This matches my peak torque at 1.4 bar boost to similar … Read more