[qwksti]

i didnt see anyone posting pics of this so i figured i would. lots of info on this and its easy, but some of us like pics to be sure. so here i welded a egt bung for my defi temp sensor on the runner on my GT Spec gen II headers. Good spot is about 2 inchs down from the flange.
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my thoughts on the "right" cylinder or exhaust runner to put the bung in

i dont really tune with the egt temps so im not sure its that critical. I look at it sometimes at the track but not much. Im not really sure what warning temp reading i would need to look for, for it to be in the "danger zone". Any feedback on this?

I guess you would want the gauge to read from the hottest possible point in the system, but as long as you know what the temp limit of that runner is you can figure what the rest are. ive talked to a few different people on this and from what i understand the temp difference between cylinders is real close or should be. If you have one piston thats so much hotter than the rest you got problems.

really this is a trivial gauge at best, you are only monitoring one runner, so if you have the gauge in the #3 and the #1 is going bad you wont know. kind of pointless really probly the best place to mount this is some place on the system that all the exhaust from all 4 go into one, that way you get an over all reading. even in the defi manual it does not suggest a # cylinder. Now if you have a problem with the #3 going bad time after time and want to monitor that clyinder then cool the gauge has a purpose.

Even the OEM O2 sensor is at the base of the header at the spot all 4 come together, this way the ECU gets an overall reading of all 4. Leads me to think that lots of $ in testing came to this conclusion. So maybe the best place to mount the bung is in the same area the factory O2 is. dont you think?

So in the end i just mounted it in the spot best for me. it was out of the way of my oil cooler lines and away from other stuff i had going on. works perfect.

Here is the DEFI link manual and from what i can tell they suggest mounting it at the bottom of a runner, not near the top as "they" say to. But still its not clear no reasons given. Something tells me not a lot of testing went into this.
http://qwksti.com/egt_sensor_install.pdf

in this pic you can see the small bung on the right.


Here it is close up.

[FORCFED]

Good job. Thanks for posting. I see this question asked somehwat frequently.

[stimulation]

would that be the number 3 or 4th cylinder, it matters for unequal lenght. Mine can be anywhere being equal length but I installed mine on 4th closest to the footwell opening. Nice welding job but they say to weld from the inside to reduce cracking but egt bungs are not stress points of the header.

[qwksti]

i put mine in the #2 , i think. not sure about EL, mine are UE. ive read the #4 is the best place, due to it being the hottest clyinder if thats true??? "they" are not always right about stuff like this. but im not sure how critical it is. Really all the clyinders are so close in temps, or should be. i did mine there for easy install and ease of placing sensor.

[stimulation]

for UL you get the most accurate EGT readings farthest from the turbo as it takes relatively longer travel and keeps hot gases it longer. It may not be very big difference between 3 and 4 but 3 is more exposed to debris when on dirt surface. I tune my EGT'S close to tolerance so a few degrees difference is significant.

[Evan]

If I recall correctly, most instructions for EGT thermocouples say to place them 3-4 inches away from your cylinder head, also, its a good idea to place the thermocouple in your leanest cylinder i.e. #4 runner.

Like about here

[qwksti]

good pic and info, thanks for posting!

someone from NASIOC posted this on my thread there and from this test it looks liek the #2 is not far off the #4.