All of the pyros I have put in and seen had a 1/4 " NPT or 1/4" - 18 NPT. The boost fittings are 1/8" NPT. On the pyros, the coupling slid in the 1/4" fitting and then clamped down. I have not seen a 1/8 fitting on a pyro.
Chris

 

The Westach pyro/boost combo gauge uses 1/8 NPT for both.

I used the socket/rachet method too. Use lots of bearing grease to tap both but especially the intake. It's aluminum doesn't like to be tapped.

 

Geno's Garage gave me both a 1/8 and 1/4 NPT fitting for my pyro probe. I tapped for the 1/8 figuring if I screwed that up somehow I could redrill for the 1/4. I used a T style tap handle I bought from Sears.

 

Sounds like you guys are putting the thermocouple in before the turbo?
Why is that?
I thought the whole idea was to measure the temp so you don't have a meltdown on the turbo, should'nt you measure exit temp?
That way you know what temp the turbo is.
Hasn't anyone read the directions the auto meter ones for instance??
In the trucking industry they all measuure after the turbo.
25c worth.
GB

 

Run the tap in about half way and then check the fit. Don't go all the way to the bottom of the tap threads without checking as you go. Could end up a little loose if you are not careful due to doing by hand.

 

EGT measuring is for two reasons.
1- the reason you mentioned, shut down at 300 degrees to prevent oil coking on the turbo shaft.

2- piston meltdown. Our pistons are aluminum topped, aluminum melts at sustained temps of over 1,350 degrees.
This is why we measure the temps as close to the pistons as possible.

Engines cost considerably more than turbos.


phox

 

Actually...the accepted practice is 5-6 exposed threads on the tap. As said above...stop a little short and test fit.

 

I did it the same way and used grease on the tap to keep the crumbs out of the manifold...

 

I was concerned about the location of my pyro guage and E-mailed U.S. Gear tech who told me to tap the probe in the exhaust pipe as close as possible to the turbo housing.

 

That's the standard response,
if they told you to put it pre-turbo, they are afraid you could hold them liable if the probe broke off and took out your turbo.

Pre is the only way to be.


phox

 

I went with PRE TURBO here...



So far no problems... Also I DID NOT pull the turbo to install it. I did it very carefully to keep the chips out of the manifold and cleaned up carefully too...

 

Just did mine last night. Used a very strong magnet tool to keep shavings out of hole when drilling. Also when using a tap. If you do not have room for the handle like I did. Use a 1/4 rachet extension. The rachet side of the extension will go over the tap. The socket side of the extenstion will go throught the tap handle. Works like a charm......

Dave