Omega thermocouples

[jpearl at qsihome0.qsi.com]

           Currently I'm using a dual sweep EGT from AutoAvionics. I can't
          say that the meter is the fastest in the world but it does
          provide a decent  measurement to compare against and was key in
          my spotting a bad injector (too cold?!). The sensors have
          withstood several thousand miles of use and I believe the package
          was right around $200 for a dual sweep - with pyrometers!.

           Where I'm most interested in the Omega box is for looking at
          intercooler efficiency and MAT. (smile) Is it possible to data
          log from that meter by any chance? What other sources has
          everyone found for good instruments? An aircraft company has sent
          me several catalogs (something Spruce..?) and they've got dual
          sweep EGTs rated for flight use that are competitively priced
          against AutoAvionics auto gauges. FWIW - the AA senders only
          required a small hole in my manifold and are held in place via
          band clamps. I've had zero trouble removing them from the
          manifolds on several occasions. If anyone is interested in
          looking at these gauges I'll dig up the phone number for them.
          they make quite a few interesting gauges ($$)...

           jvp at qsi.com



           >>>I have had some experience with pyrometers a.k.a. exhaust gas
          temperature meters.
           I bought the gauge from AutoMeter for about $75 (comes with the
          amplifier module) and then discovered they wanted another $100 for a
          thermocouple! So I called Omega, and tried an open-junction 1/16"
          K-type. It lasted about 10 minutes. I should have known that the
          vibration would break the little weld ball off where the wires meet
          (the actual thermocouple).
           Then I tried a 1/16" enclosed end, 321 stainless. This responds a
          little slower, but will last for about 3 months or so (not so good at
$31 each). The end just burns right off, especially when doing lots of
full-boost blasts at 1600 F temperature.
           321 is not supposed to do this. Omega thinks it's a combination
          of corrosive gas, extreme temperature, and vibration. They suggest
          going to a 1/8" (but this will slow the response). Also the stainless
          compression fitting is irreversibly bonded to my exhaust manifold
          despite the use of copper anti-seize paste...
          -Charles
          '81 745i
          p.s. I usually saw about 1050 F at idle (retards to 1 BTDC for lower
          idle emissions). About 1250 F at part throttle cruise, and up to 1600
          F at 15 psi boost. It's interesting to observe the effect of changing
          the AF meter flap tension on exhaust temps...