Ok, so first off, I bought the pipe used. The seller says it was off a 98 A4 with Quattro (it looks kinda like a b6 pipe to me, but whatever) but his reputation has declined for me. Regardless, I have the pipe now.








This final pic serves no purpose but to amuse you. Enjoy Elephant Dog.

Three inch diameter both sides. My question is, will this mate with my stock exhaust? I know my DP is 2.25" and the turbo is 2.85" or something. I got gaskets, but they're for the cat, and thus will restrict the flow. Should I try to get three inch diameter gaskets, or will the 2.25" work fine? I want to do this right, not find out it makes all sorts of f-ing backpressure and resistance.

The other question concerns the spark plug non-fouler trick. Now I know the basics, and I know everyone says to use the HELP! ones, but no one around sells them and I'm NOT buying them online and paying for shipping on a $6 part. So Napa sells some, they're 14 mm thread and about as long as the helps. Here's a pic:


Now 14mm translates to 0.55 inches, I don't wanna drill through the non foulers trying to get the O2 sensor to fit. Anyone have any luck with the Napa or Autozone brand non foulers? Need some help on this one. Thanks!

 

i got my non-foulers from autozone and stacked 2 together. they bolted right on to my test pipe and the sensor threaded right into it without drilling. no check engine light!

 

Just to clarify, it's just the downstream O2 sensor that needs the anitfoulers, right?

 

right

 

any idea of the part numbers or size of these non foulers? This is great news!

 

not sure on the size or part number. when there screwed into the TP there like 2 or so inches tall. only thing i can think of is take the TP to autozone and find the ones that thread in to it and if they do im sure the sensor will thread in. from what i remember i think there was only like 2 different size non-foulers and it wasnt hard to tell at all wich ones you need and they came in boxs of 2 haha
sorry about not knowing size and part number its been over a year.

 

Its ok. Apparently my Autozone sells Help! ones. They need a tiny bit of drilling so the O2 sensor screws in, but its a good fit.

 

Ok cool, just checked the writeup on audiworld. They say to use the 42009 non foulers, but they also say the 42002 will work. I got the latter so I think I'm set.

Now for gaskets. I'm thinking since my downpipe and the gasket are the same size, I should stick with that gasket, rather than going to a three inch one as it wont seal well on the downpipe. Correct?

 

Okay, I'm gonna install that testpipe today. Though I dont have a o2 wrench/socket. So I was just gonna pull the sensors out with a deep socket 22mm and then drive it over to a buddies house who has the o2 sensor. Is there anything bad (besides a CEL) with driving up to 10 miles without sensors?

 

Probably just the obvious exhaust leak out the hole lol I dont think you could damage anything real bad because I think the exhaust will just hit the firewall when it comes out