>> What does the boost curve look like on this car?
> Factory boost on the SVO, ... is ~15 psi max ... All the boost
> is in by ~3000 rpm or so, and tends to creep *up* at WOT and max > rpm, not
down (the gauge reads to 21 psi).
Is this a stock gauge, or an aftermarket gauge? Electric or manual?
The reason I ask is because the Talon's factory boost gauge reports pure
fiction. According to it, I make boost at steady cruise, and I make full boost
from about 2000 all the way to redline.
I got the biggest suprise of my life when I put an aftermarket (AutoMeter, good
enough for NASCAR, good enough for me) mechanical boost gauge on the car. Full
boost *only* at full throttle; rise time from 0->full boost of about a second or
two, depending on which gear I'm in at the time. Occasional partial boost
(~5PSI) under part-throttle acceleration (like pulling away from a stop sign)
that quickly drops to zero as speed stabilizes. Nothing at all like what the
stock gauge reports.
>> A stock T25 Talon makes about 14-15 PSI at 3500, falling to 8-9 >> PSI at
7400 -the tiny turbine can't move any more air.
> The *compressor* and its housing might, if it's
> falling into very low efficiencies, but I'd suspect something in > the factory
engine management system instead.
Once the turbo reaches its airflow limit, it supplies a fixed volume of air. The
engine, however, by virtue of continuing to accelerate, consumes progressively
more air as RPM increases - so the amount of overpressure drops.
Is it the turbine or the compressor maxing out? I don't know, and it doesn't
matter - the turbo as a system maxes out, and I don't have or want the freedom
to exchange parts of the turbo at will.
The 14b doesn't have this problem,it maintains 15PSI to redline, but you pay for
it with more lag. Under extreme conditions (rolling forward at idle in second
gear, stomp on it) it can take upwards of 3 seconds to make full boost.
Under race conditions it's not nearly this bad 'cause I downshift to spool up
the turbo, but the lag is most definately there, and its unquestionably longer
than the T25 was.
TNSTAAFL
DG
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