Tapping for pyro gauge

[Thornbird]

Getting ready to drill and tap for my autometer egt and boost gauge. Have a couple simple questions for someone who has installed the autometer probe. I'll be drilling the air horn for the boost and the exhaust manifold for the egt. My question is, what size taps do i need for these? I've read where people have been using a 1/8-27 tap, so that's what i bought. Is that what i need for the autometer kits? I bought the more expensive probe if it matters any. Should i drill a pilot hole with an 1/8 bit and then go up to a 7/16 and then tap? I just don't want to drill and tap everything only to find out i used the wrong size. I originally planned to drill and tap some piece of junk metal to make sure it works. Any info would be greatly appreciated. Thanks

[prostock]

Which motor do you have?

If it's a 12 Valve, I don't think you need to drill for the boost gauge.

[Thornbird]

I've got a 2001.5 { as they say} with the 24v engine. So after i looked at a 7/16 drill bit, i knew it was too big. 5/16 and i tapped the air horn, fairly simple to do. So now the boost gauge is working and i'm only getting 15psi running it up to around 2k in each gear. Cruising down the highway, it reads 0 psi, gas it a bit and it'll jump. Does this sound normal? Trying to get a baseline for a box stock truck.

[SFriend]

I run about 15 and up depending on the hill. But cruising i am running about 3-10. 0 is only if I am on a coast. Might want to check and see if there isn't a leak somewhere. This was a way easy install by just removing that one large plug and installing an adapter.

About the pyrometer. I used a 1/4" tap. That is what I needed with the kit I got. You need to remove the turbo and stuff some rags into the engine side and tape off the turbo side of the inlet. Use an 1/8" drill first and then the right tap drill for your pipe tap. If you use a 1/4 it is 7/16, 1/8" is about 5/16 or a Q drill.

[Rattlebox]

Hey Steve-
This is off topic but I was curious if you got any MPG improvement from cleaning your IAT?

[SFriend]

You have way too good of a memory. I have been working too many hours to get at it. I did stop by to buy one at the autoparts store, but they did not know what an IAT was.

I will tackle it this weekend, I hope and then we will see.

[SFriend]

I went out and found a sensor that is located on the drivers side, near the rear of the engine like you suggested. It had a molex connector on it. I removed it and it looks brand new. I called around, but will have to visit the dealer for a replacement. Looks like next week now.