Date: Thu, 04 Sep 2003 19:54:48 +0100 From: Johannes H Andersen <johsnopsamfitter.com> Subject: Re: How much boost?
Paul Halliday wrote: > > in article Xns93EC66512BFC6fritzfriicomnopsam17.128.40, Gary Fritz at > fritzxxxnopsamrii.com wrote on 04/09/2003 17:03: > > > Paul Halliday <pjghnopsamyonder.co.uk> wrote: > >> Turbos take a very long time to cool down :) At least 30 seconds > >> should do the trick - > >> What you're doing here is allowing the turbo to spin down while oil is > >> still being pumped by the idling engine. Turbo-chargers can still be > >> spinning at pretty high speed even when the car is at rest and you > >> can't hear it whistling. > > > > Is that assuming you were hot-rodding it into your parking spot? What if > > you drive reasonably sedately into the garage or parking spot -- has the > > turbo already had a chance to spin down? Or does it have to be *idling*? > > I always drive the last couple of hundred yards reasonably sedately and let > the car idle for about 30 seconds when I've parked up. I think it sensible > to take that approach on all turbo cars. It's not actually a hassle - just > get into the routine and do all the stuff you would've done after turning > the car off before you turn it off. > > Also when starting up, do not sit there revving the car to warm it up. Drive > straight off don't rag the proverbial out of it until it's warmed up. > > I've heard a ragged turbo (and it doesn't sound pretty) on a car I looked at > to buy. Basically, the guy fired up the car in the morning and top revved it > up a steep drive onto a steep hill and then first geared about 50 yards to > the junction. He showed me a receipt for a brand new turbo within the last 6 > months. The car sounded like a helicopter taking off. So, if a turbo can > sound that bad through improper fire up and turn off procedures within six > months, think on - 30 seconds :) > > Paul I quite agree with all that. When the engine is switched off, the oil supply to the turbo is also cut, so there is only so much oil left. A hot and fast spinning turbo may run dry. When the engine is started up again oil will not immediately flow into the turbo; it relies for a short while on the leftover oil.
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