Date: Fri, 30 Jan 2004 12:36:47 PST From: mojavegnopsamveg.iwvisp.com (Everett M. Greene) Subject: Re: Service rating of turbos
Grunff <grunffnopsam.com> writes: > Everett M. Greene wrote: > > > It is my understanding that light-duty turbos as used in > > passenger automobiles and pickups are not rated for > > continuous use at anything near full capacity unlike > > those used in heavy trucks, airplanes, etc. Is this > > true? > > Service ratings don't really work in the same way in cars. The vast > majority of cars are built with a certain life (mileage) expectancy. Say > the engine is expected to last x00,000 miles - where x is anything > between 1 and 5. Any other major non-wear components are engineered to > last about the same amount of time - given average driving conditions. > > Interesting you should mention turbos, because they are an exception. > The simplicity of a car turbo means that it has only two failure modes - > eroded turbine/compressor blades and worn shaft bearing. This means that > as long as the incoming air stream is clean (good quality, clean air > filter with no air leaks anywhere else) and the supply of oil through > the bearing is of adequate quality, flow rate and temperature, the turbo > will last almost indefinitely! Sure it will eventually fail due to metal > fatigue, but this will be after millions of miles, not hundreds of > thousands. I wasn't thinking expressly about Saab turbos. I've read that some light pickups come with a warning about the turbo not be rated for extended use such as towing a heavy trailer up long grades.