Paul,

I believe this turbo, the Garrett GT-2860R with the 76 trim and optional
0.86 A/R  housing might be just what we are looking for in our aviation
uses.   I`m considering it as the turbine for the turbocompound test
engine use but perhaps it might be a good choice for Dave`s plane as
well.
The bigger A/R will slow the wheel down but provide more torque at higher
rpms.

The high content Ni body and Inconel turbine wheel will handle the heat
better than the standard IHI turbochargers from Mazda which are, lets
face it, 20 year old technology.  The Garrett in addition has ball
bearings, is compact, has a built in waste gate and has both water and
oil cooled jackets.  Whats not to love?  Beside the price we will have
to drill the threads out of the holes.  I don`t know if the lack of a
split turbine mouth will an issue  I imagine it depends on the exhaust
manifold design.

No info on weight unfortunately.

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2860R_707160_5.htm

Doug in Japan

I'll study it Doug. And get back to everybody on it. .86 A/R is not all that big.
Could be bigger. I have seen them with over one. If it is a automotive turbo
there is excess HP built in to accelerate. We are going to need an unusual
combination. Might be OK for turbo compound as the engine will slow the turbine.
-----------------------------------------------------------------------------

A quick thought.

Lets separate turbo compounding from turbo charger for the moment.

For turbo charger the diverted valve manifold and turbo tach is the way to go as
you can use any turbo charger. You set a turbo RPM redline  and the diverter
takes care of holding that. Manual or automatic. Boost is whatever you get
at that turbo RPM. If you are feeling rich you can up the turbo RPM red line
and risk a turbine failure.

Apparently what we have gathered so far is there is so much kinetic energy in the
rotary exhaust it tends to ignore more or less built in waste gates.

Got to run. Be back later today.