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Discussion Starter #1 (Edited)
so I've read what little is on here in the way of egt probe location. Sounds like 1-2" from the head and I've read #1 cyl and #3 so which one? Any pics of one installed on a 3.4 (not interested in seeing one on a supra :rolleyes: )If mounted 2" away safe temps are 1600?? Someone mentioned that there was some info on Gadgets site - couldn't find the link.

Thanks,
TBob
 

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Well it probably won't be like yours but here's where mine is:


I choose that spot because the 2001 factory manifold is double wall and I wasn't sure how to weld up double walled tubing. It seems to run up to 1400 pretty easy, but it hasn't gone past that. From what I've heard 1500-1550 is where valves can start melting.
 

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The center jugs run a tad hotter so I would monitior one of those. At least the center jugs are where both of my heads developed cracks and it stands to reason they run a tad warmer than the end cylinders.
 

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Discussion Starter #5
You have an egt set-up on yours? If so I'll check it out at azrocks...mine came in last night and I'm not sure where a good location would be the down pipe from the header looks like it might be double walled. Is the header itself double walled? I'm guessing pass side is the side to put it on?
 

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Nope.
It depends on where you want to monitor but the down pipe would be kinda late to get any useful info from a pyro. I'd pick a center cylinder and put it as close to an exhaust port as I could get it while not introducing any mechanical problems. Like I said before, when my heads cracked the center jugs on both heads cracked necessitating replacement of both of them, fucking TRD. So the center ones appear to run a tad hotter.

I have one on the SB in the FJ though. Fortunately for me, for a refreshing change, the rams horn exhaust manifold I have has 1/4 NPT plugs for each cylinder making it super easy to mount the probe right at the exhaust port for any cylinder I choose. No drilling, tapping or welding was required. I picked a middle one, cylinder 5 I think it was. If I decide to move it to another cylinder, I can in a matter of minutes. Since there is a plug for each cylinder there is some tempation to put a thermocouple in all of them but I'm not building an engineering test bed and I can make better use of the money.

As far as dealing with the heat shield on a stock exhaust manifold, I'd probably start with a small center hole drilled though the heat shield and the manifold, then go at the sheet metal with a hole saw making a generous sized hole taking into account wrench access. There is not enough depth to use a step bit on the sheet metal heat shield so the next best thing for sheet metal is a fine toothed hole saw. Followed that by drilling and tapping the manifold for the probe itself as the casting thickness for stock exhaust manifolds is typically thick enough to allow tapping. You might want to double check that before you go making a big hole though.

If you have headers, then there is no heat shield to deal with so all you have to do is drill staying far enough away from the flange so not to introduce a cracking problem. Then I'd weld in a threaded bung for the probe if your probe is the threaded type as the wall thickness in the header tubing typically isn't thick enought to allow tapping. If it's a strap on type probe you can get by with just a simple hole keeping the size of it down to just enough to allow the probe tip to get in there and still not tough the probe itself. Remember, you want to measure exhaust gas temp not the temp of the header tube.
 

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97 V6, Cyl # 3, Passenger side....it looks like the heat shield touches it, but it doesn't, so I didn't change it.
 
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