Alternative location for Cylinder Head Temp Sender, Considering one of the #3 Cylinder exhaust studs Options

[bobhasissues]

I have some new 914 2.0 repro heads from DRD. The new heads use a 12mm spark plug rather than the stock 14mm. I want to use a ring terminal type Cylinder Head Temperature Sender under the #3 spark plug just as I did on my stock heads. The problem is the outside diameter of the ring terminal of my 12mm CHT sender is larger than the bore of the spark plug hole so I can't put the sender under the #3 plug as designed. As many of you probably do, I had the 14mm ring terminal sender on my stock heads and that took a lot of manipulating of the terminal stem to get it to fit. This is way worse, the OD of the 12mm ring will not even fit into the plug bore.

I asked Darren at DRD what to do and he suggested to use the fuel injection CHT location out on a fin by the intake manifold. I don't like that idea because it seems too far away from the chambers to pick up any major temp fluctuations.

I'm considering changing to an 8mm ring terminal on the sender and double nutting it onto one of the #3 exhaust studs.

Anyone have a better location?

[GregAmy]

DubShop makes that thermocouple/thermister-thing for tuning warm-up on the Micro/Megasquirt. It's intended to be inserted under one of the engine tins screws (I use the one behind the #3 intake manifold). It's not intended as an accurate measurement of CHTs in the context of how we discuss them and the allowable temperatures.

One major advantage to that sensor is that it already has the pull-up built in, so all you have to do is wire it up to the MS (5V, ground, sense). It's the easy button for the purpose of managing engine warm-up and enrichment. Works great.

I also installed a standard K-Type thermocouple under the #3 plug to be used for tuning purposes, to ensure I'm not running too lean or hot. I ported that into the Microsquirt's ADC7 input via an Adafruit amplifier. It will not provide feedback to the ECU for corrections but I can log the data and later compare it to trends to see if I'm getting too hot (good so far). It can also provide warning limits if I'm using the ShadowTuner dash on an Android tablet.

So Ted, I suggest moving forward with the DubShop sensor for warm up enirchment and then work later toward adding the CHT for info.