<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ernest:<BR><B> cal,<P> how could you say this? intercooling only refers to slightly cooling off the air charge *after* it's compressed and before it goes into the engine; there's no relation to the temperature of the turbo or the oil that flows thorugh it.<BR> seeing as how there is no change in the amount of heat energy within a volume of air as it's compressed, compressing air increases the temperature of the air becuase you still have the same amount of heat energy, only now in a smaller volume. factor in that the turbo impeller is in fact driven by exhuast gases, and it only stands to reason that turbos are going to get hot. (and as previously mentioned, these impellers can get up to some pretty extreme RPMs when being driven under load, even when not being driven fast or at high RPMs; it only seems reasonable that you would want to let them spin-down before shutting off the flow of oil that lubricates and cools them.)<P> FWIW, even the owners manuals for the light pressure turbos like the S40 recommend allowing a minute or 2 for the impeller to slow down and for the oil to cool it down before shutting off. (using a synthetic oil that has better heat transfer characteristics and is more resistant to heat breakdown can only help.)<P> in summary, i'd think that you may be able to get through the warranty period without any turbo-spindown without failure, but is that all you want to get out of your vehicle? a minute at idle to allow it to spin down and cool down seems like a small investment in performance and longevity.<P><BR>cheers!<BR>e</B><HR></BLOCKQUOTE><P><BR>I am just going to "butt in" here, in this interesting discussion and give you my opinion which has been arrived to by talking to many reps, both in the US and Sweden. As I mentioned, previosuly, unless you have been driving the car aggressively, you should not have to sit there and wait for 1-2 minutes for the turbo to slow down. Since these turbos have become WATER cooled (that means that the main shaft of the turbocharger has a "vein" in which antifreeze runs through, therby increasing the heat tolerance) the "cooling down" period has been diminished in importance. It is a good and a preventative measure to allow yourself, anytime, a few seconds before you shut off the engine anyway...such as gather your belongings, turn off the radio, raise windows, close sunroof and then shut it off. Do you have to? Most likely not. But it is the same as when the oil and filter change intervals are every 7,500 miles but you have not too much to lose by investing $25 extra every 3,750 miles and do an extra lube job!<P><BR>Yannis<BR><P>