Cylinder Pressure Measurement

[RABBITT_Andrew at mv8.orbeng.com.au]

>piezo transducer was mounted in the combustion chamber, I suspect in 
>the head somewhere. I have an aircooled motorcycle, that I could
>bore a hole in the head, without worry of leaks.

Yup! this is the normal location, although Kistler (who make these 
things) also supply a version installed in the spark-plug)

>Pressure info would be as good, or better than a dyno, to tune
>and check mods to an EFI, as well as the motor, wouldn't it?

Sure, but you have to load the engine somehow, and control it

>Are the transducers prohibitively expense, short lived, weird
>calibration. What are the problems in dealing with these, or
>are like lambda sensors, for us DIY'ers?

They are expensive (usually upwards of $A2000 each I think) and 
require a charge amplifier to convert the signal to a voltage.  They 
are generally difficult and time consuming to calibrate and maintain 
and you need to sample them at least on a 360_CA basis to get 
meaningful data.   Calculations performed using these sensors in the 
test envrionment include, IMEP, Coefficient of Variance (Combustion 
stability), burn rate, pressure rise rate, indicated torque and 
probably lots else, however you also need to know your TDC accurately 
to do this.

I think that they are used in World Sports Car (ie Le Mans) class 
racing in real time, and some of the Japanese manufacturers (at least) 
have been attempting to develop production versions of the same thing. 
(there are some papers on this out there somewhere)