>>We have narrowed the turbo selection down to the Garrett GT35 84 trim
0.94
 >>A/R and GT37 82mm, 52 trim, 0.54 A/R or GT37-TO4 housing 76mm, 52
trim, 0.70
 >>A/R as being the closest to the TO4e-50-P trim.

 >>The Draw of the GT35 is it is a bolt-on with a TO4 manifold footprint.
 >>The GT37 with TO4 housing is ambiguous as to whether the housing is the
 >>turbine or compressor section therefore the footprint is in question.
 >>I think the GT37 units are much closer to getting centered on the turbine
 >>maps based on what we are guessing so far about performance (Cliff
Manzke's
 >>numbers)
 >>
 >>The GT series is Garretts answer to the new performance market. They
are all
 >>ball bearing. Not sure if all turbine wheels in series are inconel or
if that
 >>is option.

 >>My thoughts are this, although Greg's "no wastegate" approach worked
for him,
 >>if instead you go the wastegate route and use an adjustable boost
controller,
 >>although more expensive and complex to install, it adds an extra
margine of
 >>safety to the system and at critical times may be one less thing to
monitor
 >>and control. Going without means settling for "best guess" and I'm
just not
 >>one who is comfortable with that ambiguity.
 >>Any thoughts, ideas, criticisms or advice?
 >>...Chrissi

What would be wrong with using manifold absolute pressure to control a
throttle governor? The power lever would then set the governor to the
desired MAP (which would have a preset limit) and the governor adjusts
the throttle. Kind of like a farm tractor, which should make aircraft
engine 'traditionalists' happy. :-)  It would automate what Greg does
manually.

A way to make the governor more fail-safe would be to let it move a
spring against the motion of the throttle. Then the governor could be
overridden by the mechanical throttle if it fails or you need 'war
emergency' power.

This would keep the complex stuff away from the high temp & pressure of
the exhaust & come closer to meeting the true definition of FADEC, which
should make Tracy happy. (second :-) ) If a micro controller is used as
Paul suggests, then Russell's idea of temperature monitoring could be
used as another limiting factor for the governor.

Charlie England

 
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