Date: Thu, 27 May 1999 22:52:25 +0200 From: Robert Brown <rjbnopsamnet.se> Subject: Re: when can i take a road trip?
Hi, comments below . . . Regards, Robert Pierrick Brenot wrote: > I almost always respect the 5-10 seconds idle before shut down, and more > when I have driven fast using a lot of full boost. Must admit that I also wait after driving hard, regardless of what the Saab people say, no offence intended them ;-) > > Do you mean that I could ignore this simple rule after a normal ride ? > My 900 is a 16VTurbo MY1991. As I write this, I'm hoping that someone (such as a mechanic with knowledge of materials wear in exhaust-driven turbines) will magically pop up and help out in the discussion. The line of reasoning I received was that the water cooling will suffice to hold surface temperatures sufficiently low - and ensure that the oil maintains its lubricating properties - while the turbine winds down. Both the water and oil have stopped once the ignition is off. For the _older_ turbos, shutting off the engine without prior idling meant that the oil stopped, some evaporated due to high temperature, and a quickly-spinning turbo would spin on a relatively dry bearing for too long. After a couple of years or so, you got the chance drive down the street with lots of nice white smoke pouring out (just as they did back in the old turbo Formula 1 days). I nonetheless have doubts concerning whether the water cooling is sufficient to prevent premature wear, in the cases where the turbine is spinning quickly immediately prior to shutdown. My advice, for what it's worth, is that you can park and pull out the key straight away if you've taken it easy during the last 1/2 - 1 minute or so. But I don't know from what year Saab compressors got water cooling. Let's hope that someone else reading this knows more than I do ... // Robert (1999 9-3 200) > > > thanks in advance > ck > 1991 900T > > Robert Brown <rjbnopsamnet.se> wrote in message > news:374C5BFA.6171EAA7nopsamnet.se... > > > > Another tip - the turbo bearings are now watercooled which means that the > > instructions on earlier models - "idle 15 seconds before shutting down" > can be > > ignored to a certain degree, though you may like to exercise due care. Any > > comments from turbo owners out there? > > > > Robert B in Gothenburg (drives an '83 900 and sometimes gets the keys to > his > > girlfriend's 9-3 200T. Aren't girfriends fun) > >