[BiturboS4] Turbo failure modes
Sherowsky Family
SHEROWSKY at NETVA.COM
Thu Oct 10 17:07:06 EDT 2002
I don't know that idling your car to warm it up is necessarily bad for it.
It isn't suggested because of increased emissions and wasted gas. For my
everyday day cars (allroad and RAV4), I really have to let them idle to warm
up. I live 4 miles from work and driving cold from start doesn't let the
coolant reach operating temperature let alone the oil. Also I immediately
turn onto a 55 mph highway after leaving my house. I think in that
situation, running up to speed on a cold engine would be worse than idling
it for a few minutes before driving away.
Ron
----- Original Message -----
From: "Philip Pace" <pjpace at yahoo.com>
To: <biturbos4 at audifans.com>
Sent: Thursday, October 10, 2002 1:21 PM
Subject: Re: [BiturboS4] Turbo failure modes
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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