This was a lot harder than it looks.
There were no specific dimensions from Garrett on exactly
how to install this in an Hitachi compressor AKA 2nd gen Mazda
turbo. They merely say take this to a machinist. Yea sure.

The learning curve was rather steep. The sensor has
a 6 mm .5 mm pitch extremely fine thread.
We at first tried to tig weld the mounting tube in. That
proved to be unworkable as it distorted the threads.
We had to start over with a new threaded tube.
JB Weld is the only practical solution. One must treat
the aluminum with a preparation kit or the epoxy
in JB Weld will not adhere to aluminum that has had a chance
to oxidize or weather in other words.

The rational for this tachometer kit is the centrifugal loads
on the turbine blades are extremely high at over 100,000 RPM.
The loads are in fact proportional to the SQUARE of the RPM.
If the loads are 100% of failure at 100,000 RPM they
will only be 72% at 85,000 RPM. Since we don't have
any real numbers of how long the blades will last at any
given RPM I have decided to limit the RPM to 85,000 for now.
Later on, after we get some real world numbers on what continuous RPM
the blades fail, than maybe we can up the turbo red line.

Many people have failed Mazda 2nd gen turbo turbines and Mistral had
gone through three all by themselves. Unfortunately they did not
record turbo RPM numbers. Nor did anybody else for that matter.

The rotary exhaust temperature being several hundred degrees F higher
than a piston engine does not help. That drastically weakens the metal.
The metal tensile strength goes from 60,000 psi at 1200 F
down to 5,000 psi at 1600 F. BTW That is the root cause of exhaust valve
failure in piston engines. An exhaust valve dropping its head is a
catastrophic failure. That alone makes the rotary ten times more reliable.
No exhaust valve!!!

If a turbo charger turbine fails it is more like an annoyance as the
parts go out the exhaust. The engine still runs while still
generating considerable HP. No crashes have been attributed to turbo
charger failure.

In a car the turbo never runs flat out for long. Usually just
a few seconds in an all out drag race. The opposite is true for
cruising at high altitude in an aircraft engine hour after hour.
The higher the altitude the lower the back pressure on the turbo
and the higher the turbo RPM.

Paul Lamar

Paul,

Have you seen information on the new Borg Warner EFR series turbos. Looks like
they are set up for race cars. They use a gamma Titanium Aluminide turbine.
Article in the March Super Street magazine.

Dale Davies