[BiturboS4] Turbos & Warm-up

[Edwards, Dave]

Phil,

The turbos are "spooled" i.e. turning, ALL THE TIME. They only stop when the
engine is off. Whilst your boost gauge is 0 or negative, the diverter valves
are open, so all the air flowing out of the intercoolers is immediately
sucked back into the turbo inlet.

Positive boost occurs when you open the throttle, the diverter valves close,
so that pressure can build up in the inlet manifold.

Yes, using a boost gauge will help you be gentle on the turbos during
warm-up, but only as a guide, not a rule. It is engine revs which really
count, as the rotational speed of the turbos is pretty much related to
engine speed for most of the range.

I have no firm rule for warm-up, but I generally avoid revving above about
4000, and try to keep the boost below about 0.5 bar until warmed up. I admit
that I sometimes use boost above 0.5 bar for short bursts whilst the engine
is still 'cold', but only sparingly.

Cheers,
Dave

_--__--__--

Message: 8
Date: Tue, 27 Aug 2002 07:45:37 -0700 (PDT)
From: Philip Pace <pjpace at yahoo.com>
Subject: RE: [BiturboS4] 10k service - OK
To: Biturbo <biturbos4 at audifans.com>

Well this is a nice time to ask, since had been wondering about this for a
while. So I got a boost gauge and while I'm in the warm up period, I keep it
at 0 or below. BUT, when it's at 0 (which it does a lot), that means that
the turbos are spooled, just not creating boost? If so, is this an ok
situation or should I stay with as little pressure as possible? TIA
     -Phil P.