I'm getting ready to install my 4" CAI. I'm using ABS tubing that is 1/4" thick. The fitting I bought for my PCV system is a 3/8" barb x 1/4" NPT. I have the hole drilled into the pipe already. Do I have to run a tap through the hole or will I be able to twist it in..?

Home depot doesn't have a 1/4" NPT tap so I would have to order it online. What do you guys think?

 

Make a cut into the first couple of threads in a v shape it will cut its own threads then and put some siliconon it to seal it up

 

You don't need to tap it. It'll seal up just fine.

 

If you wanted to tap it, I am sure a local machine shop would let you use one if you brought the piece in. Any shop should have one, repair shop, machine shop etc. If you didnt want to purchase one, like Roger said it will seal fine. You could even heat the ABS plastic with an industrial hair dryer to soften it a little.

 

Just screw it in, it's tapered so it'll make it's own threads, just keep some pressure on it until it grabs.

 

exactly what he said, it's better to let it cut it's own threads into plastic because there's a big chance using a tap the hole will be too loose and then not seal.

Just put some pressure on it and turn the fitting in there, then pull it back out, and seal it with your sealant of choice.

 

I tried letting it thread itself but couldn't get enough pressure on it to start. It is hard to hold on to. I'm going to my universities machine shop tomorrow to borrow one. Thanks guys

I ended up going out of town last minute so I wasn't able to work on the CAI anyway