Mine was 1/4" NPT...and it sure wasn't fun tapping it.

 

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Ahhhhh.... The Qzilla instructions say 1/8" though in this case..

1/4"NPT is a pretty big hole to be drilling in a manifold..

 

I did my recon xzt gauge friday night. You drill the manifold with a 21/64 drill bit. The pyrometer probe bushing is 1/8"-28 npt or 1/8"-27. They say you can use either one. Now the manifold is actually at least 3/8" if not a 1/2" thick. They tell you not to run the tap in too far, but your gonna need to sink it in at least 3/4 of the way to get enough threads for the egt probe bushing to safely be installed, seal, and stay in the hole. Make sure you use cutting oil on the tap, and work it in, then back out a little, and then go in forward some more, do this constantly. I ran my engine when I tapped it and when I drilled it so the shavings just blew back out of the hole.

I like my recon gauge alot, it works good.

 

I should have specified that my gauge/probe is not from Quad. Thought we were talking about probes in general.

Definitely a big hole. I wasn't happy when it showed up and I realized it was 1/4". It does make it easier to get the shavings out though. Funny thing is the probe is actually MUCH thinner than my last Autometer pyro which was 1/8".

 

I am guessing the manifold gets too hot for teflon tape. What type of compound do you use to seal the fitting?

 

Anti-seize compound...

 

As I recall, I drilled and tapped with the engine running and a rag stuffed in the tail pipe to maintain positive pressure. Wear safety glasses...those chips come your way surprisingly fast. -- Bill

 

Its pipe thread so you dont need to use a sealing compund on the exhaust manifold. The fitting is stainless steel, so you shouldn't need anti seize either.

 

Well I didn't get it done today,got busy in town but thanks to the guys that offered to walk me thru it, I will hit you up this week when I get ready but with all the good info I think I can get it done.

Glad I waited, now I know about the rag in the exhaust and the threads not needing any sealer.

 

Ok, the chip got here today and the Commander will be later this week or next. So if I install the XZT now and the wire harness (harness is from race box) now, will I have to start over and use a harness that comes with the commander or can I use this harness?

 

I am pretty sure You tap into the xzt harness. It should say that in the destructions for the commander. You can go to Quadzillas website and download the instructions on the commander page.

 

I have done that many times and it looks like there are alot more things to connect to but it doesn't show more wires or the ones that come with a chip.