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Exhaust temp gauge...where to mount sensor?

Posted: Mon May 01, 2017 12:59 am
by WRXish
Where is the best place to mount an egt sensor?

Re: Exhaust temp gauge...where to mount sensor?

Posted: Mon May 01, 2017 3:17 am
by mike-tracy
Newer cars have it in the up pipe, right before the turbo. I don't know if that's literally the best place, but it's where smart engineers placed it.

Re: Exhaust temp gauge...where to mount sensor?

Posted: Mon May 01, 2017 5:16 pm
by Legacy777

Re: Exhaust temp gauge...where to mount sensor?

Posted: Tue May 02, 2017 6:38 pm
by Alphius
You want to see EGT at the exhaust port, so most people put it in the cast elbow that bolts to the head.

Newer Subarus have an EGT sensor in the uppipe in order to monitor the catalytic converter temperature to prevent it from melting and going through the turbo. You don't care about that really, so monitoring EGT at the uppipe is far less useful.

Re: Exhaust temp gauge...where to mount sensor?

Posted: Wed May 03, 2017 6:04 am
by jamal
Yeah, drilling and tapping one of the cast collectors works, I've done it a whole bunch of times. Driver's side tends to be easiest.

Re: Exhaust temp gauge...where to mount sensor?

Posted: Wed May 03, 2017 7:34 pm
by carfreak85
Literally, the best place is inside the combustion chamber, but in most applications that's not possible. The next best place is as close a physically possible to the exhaust port in the cylinder head, because you want the true temperature of the combustion in the cylinder, not what the temp is six feet downstream and two cats later.

In my opinion, cylinder number 3 is the most suspect based on proximity to the turbo and the associated radiant heat, but if one cylinder gets less airflow or fuel, that would be the one to target. (Ideally you'd run one probe per cylinder, but that's not really practical)

On my WRX, I drilled and tapped the cast iron manifold about 2 inches downstream of the #3 exhaust port, drilled a hole in the heat shield and reinstalled the shield.

Re: Exhaust temp gauge...where to mount sensor?

Posted: Tue May 09, 2017 1:40 pm
by WRXish
I was thinking that what I really want with my setup, at least until I get things sorted a bit better is to have a bung installed in the collector on the headers, since I have no turbo and I want an aggregate of all four cylinders to see overall temperatures. But from what you guys are saying I need to pick one cylinder and monitor that. or weld in bungs in all four cylinders and test all four to see which one is the leanest of the bunch and keep the monitor there. I need to know if I am running dangerously lean or not and cant think of a better way to look at all 4 cylinders at once. Or maybe install a wideband O2 sensor and a gauge to read that just downstream of the collector. Any thoughts? What say ye?

Re: Exhaust temp gauge...where to mount sensor?

Posted: Wed May 10, 2017 3:21 pm
by Alphius
If I had to choose one or the other, AFR all day, especially on an N/A engine.
Sensor needs to be pre-cat but should be after any exhaust system merges.