Pyrometer

What we did:

• Welded a bung (just past the turbo) on the turbine outlet for the thermocouple of the pyrometer
• Pyrometer by Hewitt Gauges (We are not thrilled with the cosmetic look of the pyrometer, but functions as it should. Hewitt is working with us to match it to the Turbo Boost gauge.)
• Installed the temperature gauge on the dash **Still need to make a permanent home for this gauge as we don’t really love the housing you see pictured. 

Why we did it:

If you hear one common complaint about the mighty Delica, it’s that they are prone to overheating.  This engine modification is so important to be able to monitor the exhaust gas temperature (EGT) in real time as we cannot risk the consequences of overheating.  We researched online and contacted a few Delica mechanics to figure out the best placement of the probe. Some suggest placement after the turbocharger and some suggest before the turbocharger. Ultimately, we chose to mount it immediately after the turbine outlet of the turbocharger. 

There is a lot of talk back and forth about the best place to install the thermocouple for the pyrometer in the Delica.  You may get a more accurate (real time) reading of the EGT if you place it in the EGR, but is doesn’t provide a reading of all four of the cylinders. This could be problematic because the internal temperatures could fluctuate on a malfunctioning cylinder and the pyrometer may not detect it in time.

Installing it just past the turbo (or in the exhaust manifold) is more reliable in terms of monitoring the running state of all four of the cylinders collectively. However, being placed after the turbocharger we need to add a couple hundred (150-200) degrees Fahrenheit (F) to the temperature read out because as the exhaust enters the turbo the temperature lowers. This happens because some of the heat energy in the exhaust is transferred to drive the turbocharger.  It’s important to note too that the temperature drop can also be related to the total flow and speed of the exhaust flow through the turbo. For us, this placement allows us to monitor the combustion process in all four of the cylinders rather than just a few of them.