Hey folks -
I wanted to take a few moments to make a strong recommendation for a specific pyrometer thermocouple probe I have just completed testing on.
Result: Can you imagine an EGT gauge reacting nearly as quickly as the boost gauge??? VERY QUICK REACTION!!! That's what I am seeing with this probe... I highly recommend it.
It's a model sold at a dirt-cheap price by aircraft spruce:
part number 10-01478
Here is the link to their website with it:
http://www.aircraftspruce.com/catalog/inpages/micro8egt.phpAircraft spruce is very pleasant to work with and can ship small orders no problem by parcel post. I opted for the 1/8" NPT version... which is a little less material to drill and tap into the exhaust manifold and a little easier to position than 1/4" NPT.
This unit is fully shielded (not an exposed junction) but yet very thin barreled, and with a skinny tapered tip, making it in theory quite quick reacting, only slower than an exposed junction type. The fully shielded should make it long lasting and reliable in a sooty diesel exhaust environment (unlike an exposed junction type probe I'd imagine.)
As for an installation location, here is where I opted to install my thermocouple this time around:
Although I have previously gone straight into the turbocharger's turbine housing, I wanted a location that was preturbine and balanced across all four cylinders, but also allow me to swap between two different turbos without swapping the thermocouple or buying two of them.
I'd like to give fatmobile some credit for inspiring this location (via his excellent post with pics
here), although I did change the location a little bit to avoid the downpipe support bracket bolt (to make it a little easier to maintain.)
After the drilling and tapping...
Can't forget the anti-seize (this fitting is very high quality stainless by the way.) Copper-based is a good idea for any fasteners that touch the turbine housing or exhaust manifold.
And the final installed position of the probe. I wanted it preturbine, and so all four cylinders supplied heat:
The hole had to be angled to be well centered in the exhaust port and also clear downpipe support bracket underneath:
Oh yeah - another thing I wanted to share: I have had problems in the past with my EGT gauge going out because of the thermocouple electrical connections in the passenger compartment becoming corroded. My solution this time was replacing the connectors with some weatherpak connectors.
These very slick little guys are quick-disconnectable and completely shield the conductors from the outside atmosphere/moisture.