kenny (dremel)

John or Mike, more formally ;-P

I'm planning on drilling into my cat (as pictured below) to mount my EGT probe - the white spot is where I'm attempting to drill, and I've got the car running - can you foresee any problems with this? I tried emailing Ed Morfe who had also done this, but it came back undeliverable. Then I saw that John had done it, but you had drilled into one of the exhaust manifold runners with the car running - how did you do this without injuring the turbo?

Since I'm drilling post-turbo, should I be fine just drilling while the car is running? Sorry for all the questions on one stupid gauge, but I just don't want anything shredding the turbo. While it would be a good excuse to upgrade, I need the cash for other things ;-) Any advice? Thanks in advance fellas.

<img src="http://1.8t.org/~kjgarreau/drilling-into-cat.JPG">

ModifiedA4

i would think its bad. could creat hot spots in the cat and burn it out.

kenny (dremel)

<a href="https://forums.audiworld.com/performance/msgs/50513.phtml">https://forums.audiworld.com/performance/msgs/50513.phtml</a>

I would think if anyone would've noticed a problem, it'd be John, and he ran his shavings *through* the turbo, which I think would cause more problems than running through the cat.

But of course that's why I'm asking questions. ;-)

ModifiedA4

yikes....drilling while running through the turbo? that sounds like a gamble.

Audi2ptzero

You should be fine drilling in that spot with the car at idle.

AZBBoy

why not just turn the car off? you probably (maybe?) have a good reason but I can't think of one

DAP@EPL

so what you'll be seeing there isn't exactly engine EGTs. Furthermore, you can (I think, I know the S4s can do this) log O2 sensor temperatures there via VAG-COM... not as easy as a gauge, but no install mess.

Personally, if it were my car, I'd prefer to have the probe in the manifold. Also, I would drill it with the car off and use a small vaccum attachment to suck out as much of the metal shavings as I could before starting it up.

Just my $.02.

-Dave Pramanik

kenny (dremel)

to blow the little shavings that are created by drilling out of the catalyst.

xr4tic

I started with a very fine drill bit, and what you'll find, is that with the car running, the exhause will be blowing out the hole, so a lot of the shavings will be blown out, assuming that you slowly work up in drill bit size (for smaller shavings)

The only problem I see, is that the cat could catch the shavings if the shavings are too large, the honeycomb material in there is pretty small.

If you absolutely want to put it in the DP, then pull the cat off, then drill it, just to be on the safe side. It's a lot easier pulling the cat then it is the exhaust manifold.

If you put in the exhaust manifold, I'd still pull the cat so it doesn't catch any shavings.

xr4tic

I think maybe it was SCC, one of thier project cars was being worked on, and the shop that did the work said they drill it with the engine running all the time.

Besides, if the turbo blew, I'd get to upgrade