<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by devalmyth:<BR><B>this is off the point, but y do's the oil have to be changed reguly with turbos compared to non-turbos???</B><HR></BLOCKQUOTE><P>The turbo creates a LOT of heat for the oil to take, which is why there's an oil cooler on the turbo cars. Petroleum based oil will start to break down sooner than synthetic oil as a result of the high heat. The breakdown leads to sludge, and if the turbo isn't cooled sufficiently, the oil cokes up inside. If the oil isn't changed reguarly at short intervals, it can be very bad for the long term life of the turbo, particularly if it's not watercooled.<P>The cool down period of idling the car allows oil to continue flowing through the turbo while it's not under load. When the engine is finally shut off and the oil stops flowing, the turbo should be cool enough that it won't burn up the oil inside.<P>With a watercooled turbo, there's the additional help of the water to cool the turbo, in addition to the oil. Cool down time is still very important, but it doesn't take as long.<P>Synthetic oil can be used for long change intervals in a turbo because it doesn't break down as easily as petroleum oil. In a non-turbo car, the oil doesn't get as hot, so it tends to last longer.<P>