[BiturboS4] Turbo failure modes

[Philip Pace]

No. Your car idling without moving isn't good for it. I think driving carefully
for the first 5-10 minutes is the best way to go (though I do let me car 'warm
up' until it drops to the typical idle RPM, and then I start driving...
carefully). Plus, it takes really really long to warm up the car when it's
idling. Driving does it quicker.

--- daniel chisholm <dbc112 at yahoo.com> wrote:
> Would it make sense to let the engine idle and heat up?  The turbo will
not
> move and oil will circulate faster when you first drive..
>
>
>  Philip Pace
> wrote:Awwwww man... per your last paragraph, I didn't know about them
still
> spinning
> fast as the RPMs go north. My problem is that I try to build _no_ boost
> before
> I hit 175 (the second tick). I set my own max RPM at around 3500.
>
> Your explanation is excellent, Dave. Thanks for the input and I'll throw
this
> at my girlfriend and see what she has to say about it NOW.
> philpace
>
> --- "Edwards, Dave" <Dave_Edwards at iOra.com> wrote:
> > Phil,
> >
> > I'm no expert, but I do talk to experts whenever I get the
opportunity.
> All
> > have told me so far that the warm-up is more important than the
cool-down.
> >
> > I think you're right that turbo failure is most likely to actually
occur
> > when the turbo is hot, especially when it's spinning fast. But wear
is
> most
> > likely to occur when its cold, because the oil is not lubricating
> properly.
> > As long as the turbine is not spinning much that's OK. However
spinning
> the
> > turbine fast whilst the oil is not lubricating properly is bad news.
> >
> > AFAIK there are the following main failure modes:
> > 1) Turbine 'seizes' up. Mainly due to lack of oil, probably from
coking.
> > Reason is use of semi-synth or mineral oil, and/or not cooling down
> > properly.
> > 2) Turbine bearing wear. Mainly due to improper lubrication. Reason
as
> > above, but also due to not warming up properly.
> > 3) Turbine blade stretch. Due to overspin. Reason chipping to far too
high
> > boost (for given air flow).
> >
> > The main point is that turbos often fail for a combination of
reasons, not
> > just one. If you want your turbos to live long then you need to
address
> all
> > the causes.
> >
> > Regarding the 2500, yes I did not make myself clear. What I meant was
that
> I
> > keep the boost AND the engine revs low. Yes I do have a boost gauge,
but I
> > don't need it during warm-up: As you know, trying to drive the car at
for
> > example no more than 0.5 bar boost is not easy as once the turbos are
> > producing such a boost, it's too easy to go higher. No, much better
to
> just
> > be gentle on the gas and you know that there's probably no boost at
all
> > without even looking at the gauge.
> >
> > However my main point about the 2500 rpm is that if you gently
accelerate
> > the car but don't change gear, you can get the revs well above 2500
> without
> > registering much if any boost. As a result you might think that
you're
> being
> > easy on the turbos, but you're not: The rate at which the turbos spin
is
> > related to engine revs. They are still forcing air into the
intercoolers,
> > however most of it is being recirculated by the DVs. Yes they are
under
> less
> > stress because of the recirculation (lower pressure differential),
but
> > nevertheless spinning the turbines fast whilst the oil is cold is
still
> not
> > advisable.
> >
> > As I said, I'm no expert and am ready to be corrected if I'm wrong.
> >
> > Cheers,
> > Dave
> >
> > --__--__--
> >
> > Message: 15
> > From: Philip Pace <pjpace at yahoo.com>
> >
> > I agree, but was told recently that the warm up doesn't matter that
much.
> H=
> > ow many turbo failures happen during the winter months in cold areas?
> > Warming = up the oil takes forever under those circumstances. If
there IS
> > stress on the turbos when they're cold, wouldn't you think that more
would
> > fail when it's cold out? All I could say was that cold causes them to
> wear,
> > but heat ultimately destroys them. She didn't buy that. Can you
address
> > this?
> >
> > Also, you say that you keep the RPMs below 2500? That's when you're
likely
> =
> > to get the most boost! Do you have a boost gage? I was surprised at
where
> > and = how boost is on the car. Maybe you already know. I've been
leaving
> it
> > in a lower gear longer and overall boost is a lot lower during warm
up
> time.
> > My 2¢
> > -Phil
>
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