Many conflicting ideas on the Internet about this. Should I be placing the probe in #1, #3 or #4 on the manifold?

 

In the collector.

If you put it in just one runner, you only get info on that one cylinder.

 

I do realize 4 is best. I'm only installing one. I was hoping to get some input on my hottest. I've read 1, 4 and 3. I'm guessing someone has just one installed and can tell me which is hottest in a miata.

 

Number four will be the hottest.

Do you have EGR still installed and or working?

 

Why is that?

 

Personal experience, lots and lots of threads in many different forums discussing the topic. The Miata coolant route issue, intake manifold design, less fuel(single feed rail) on that cylinder.

This has been gone over many times, usually with people standing on one side or the other.

Here is just one thread that covers it pretty well.

Myth "Cylinder #4 EGT is hottest": Busted! - MX-5 Miata Forum

 

I'm installing it at the same time as the egt.

 

In that thread, I specifically pointed out that #4 is in fact, NOT the hottest. In my case, #1 is. That may or may not be your case, unless you have direct evidence for it.

So, #4 is not the hottest, unless you can prove it.

 

I put mine right in the middle of the collector.

 

I put mine in the turbine housing, just after the manifold/turbo union. Same idea as collector, I just didn't want to drill and tap into the nice ceramic coated manifold.

 

What kind of numbers do you see from that location?

 

Very good info, thanks! I'll give someone a dollar for a pic of their probe in #4 on an NA. (insert your joke there)

 

Do you have a pic by chance?

 

I've got mine on #3 a couple inches after the flange.