EGT probe size. What size do you use?

[ROLLGUY]

I am going to start offering the disc for the EGR block off kit with a bung for an EGT probe. I need to know what size most of you are using. The ones I have seen are either 5/16, 3/8, or 7/16. I don't want to have all 3 sizes in stock. I think all EGT probes have a flare type fitting (AN?) on the end. If some or all gauges come with adapters for pipe thread, then I would need to know the size as well, because it might be easier to just weld in a bung with pipe thread. Thanks in advance, Rich

[mach4]

1/8 NPT

[mach4]

One thing you could do is weld on a 1/4" thick "pad" and have two versions - drilled/tapped and undrilled. If someone had a non-npt pyrometer for some reason, they could order the undrilled one and drill and tap their own. That would also be the non-pyro version for anyone that doesn't plan on installing a gauge at least right away. Works for inventory too - if you run out of NPT product, just drill and tap some.

[Dan Stokes]

Mach4's idea is a winner! I got mine from Auber but I don't recall the size off the top of my head. You could look it up easily enough on their website. Mine looks exactly like the one that came with my Edge tuner for the big truck so I'd guess it's pretty common.

BTW - there's a lot of discussion about where to measure EGT. Mine is in the turbo out elbow, some folks claim it needs to be in the turbo housing and lord knows where others think it ought to be. I'm not sure that the EGT spot is ideal but my theory is that any measurement is better than no measurement and you'll get to know "normal" for your engine.

Dan

[ROLLGUY]

Originally Posted by mach4

One thing you could do is weld on a 1/4" thick "pad" and have two versions - drilled/tapped and undrilled. If someone had a non-npt pyrometer for some reason, they could order the undrilled one and drill and tap their own. That would also be the non-pyro version for anyone that doesn't plan on installing a gauge at least right away. Works for inventory too - if you run out of NPT product, just drill and tap some.

That sounds like a great idea. The pad will be stainless steel, so it might not be the easiest to drill through for the average user. However, I could drill them out to order if need be. I do think that this will be more costly than just welding in a 1/4 NPT bung. I will talk with my welder and see what he thinks about it. He has a lathe, so parting off the pads from a piece of round bar should be no big deal for him....Rich

[SirNik84]

I think the one I installed in my moms car was 1/4npt and the one I installed in Justins Duramax was 1/8npt. I say drill and tap for the larger size and if someone has the smaller size sell them a SS reducer.

[Diesel911]

Originally Posted by Dan Stokes

Mach4's idea is a winner! I got mine from Auber but I don't recall the size off the top of my head. You could look it up easily enough on their website. Mine looks exactly like the one that came with my Edge tuner for the big truck so I'd guess it's pretty common.

BTW - there's a lot of discussion about where to measure EGT. Mine is in the turbo out elbow, some folks claim it needs to be in the turbo housing and lord knows where others think it ought to be. I'm not sure that the EGT spot is ideal but my theory is that any measurement is better than no measurement and you'll get to know "normal" for your engine.

Dan

On Engines that come stock with them and only one they are installed on the Exhaust Manifold where exhaust gasses from all Cylinders come together right before the Turbo Charger.

On Engines that have one per Cylinder they are installed in the Exhaust Manifold near the Exhaust Port on the Cylinder Head. Since you are trying to monitor the Exhaust Gasses coming out of a particular Cylinder you don't want the Probe out in the common Manifold area.

I have only seen that type of set up on large Stationary Engines.

If you are adding and the Engine was not made for one you are sort of stuck having to put it wherever you can.

I wonder what the typical Tem drop is pre and post Turbo?

[Waste_Gate]

I used Auber's 1/4 inch NPT fitting drilled and tapped on the bottom of the turbine inlet.

[Simpler=Better]

To answer, 1/4-20 straight because I'm cheap and that's the one that comes with an Auber kit. I always install them pre-turbo, directly in the gas flow.

Unless I misread, this is a bad idea-the EGR port is way back from the exhaust flow and won't give you anywhere near an accurate measurement, nor a fast response. If you're talking about adding a bung to your test pipes, add a 1/4-NPT and people can select a plug or adapter locally as needed.

Another good use for that port is exhaust pressure monitoring (1/8" NPT or 1/4" NPT)