WOW! Exhaust Leak!!! check this thread out
 

Today, after buyin' a few Bud Ice's (didnt drink any beer yet), I pulled out of a driveway, and stepped on the pedal because there were cars comin', and the next thing you know, I here what sounds like a loud pop. I let off the gas, and when I stepped on it again I realized I have a "Phat" exhaust leak. Initially I figured that I blew an exhaust gasket because I was on the accelerator so much. Pulled over to check and make sure before any more damage was caused, and the pipe/flange that bolts to the turbo was disconnected. I laughed! It was easy to see because I have a cone filter installed and the air box has been removed. I will get my welder out and remove the flange and exhaust pipe and weld it together.
The whistling sound the turbo made was awesome! I have always loved that sound. This whole situation has motivated me to think about an aftermarket exhaust system. I definitely dont want anything loud, although I do love Flowmaster's, but I do want to enhance the whistle sound. As far as the muffler sound, I would like something subtle like the Infiniti G35's. Let me know what you guys think. I will update when I fix the issue. Check out the pictures.

By the way, it happened to my Silver A4 in my Signature.

Attachment 46360
Attachment 46361

I repaired the pipe/flange today. I will post pictures tomorrow.

Here are the pictures.

First I had to mark where the flange and catalytic converter meet when fixed, so that way I didnt weld it on and it wouldnt fit.
Attachment 46223
Then once I removed everything, I had to grind the edge of the pipe so it would slide into the flange.

Once I did that, I pounded it on tight.
Attachment 46224
Then I was ready to weld it.
Attachment 46225
These are the pictures of my welds. I am still learning how to weld, but this will work good enough.
Attachment 46226
Attachment 46227

I took a picture of my wifes 2001 Audi's flange because they decided to weld it from the factory. My Audi is a 1997. You will be able to tell a difference between my weld and the factories weld.
Attachment 46228

Here are the pictures.

First I had to mark where the flange and catalytic converter meet when fixed, so that way I didnt weld it on and it wouldnt fit.
Attachment 46218
Then once I removed everything, I had to grind the edge of the pipe so it would slide into the flange.

Once I did that, I pounded it on tight.
Attachment 46219
Then I was ready to weld it.
Attachment 46220
These are the pictures of my welds. I am still learning how to weld, but this will work good enough.
Attachment 46221


I took a picture of my wifes 2001 Audi's flange because they decided to weld it from the factory. My Audi is a 1997. You will be able to tell a difference between my weld and the factories weld.
Attachment 46222

looking good. Nice job man

Great man. I wish I could weld some things out too. I am also looking forward to get that whistling sound on my car.

http://upload.wikimedia.org/wikipedi...azda-B2000.jpg

Friend of mine in college had a Old Mazda truck, the muffler had come clean off from the engine, I swear to god it sounded like a Formula 1 Race Car.

This happend to me also only it seperated after the cat but befor the cat flange. it sounds mean.

But my question is shouldnt i be worried about cold air hiting my exhaust valve and burning them up? Because i was considering leaving it that way. but ive been debating with other techs and i keep getting back and forth answers.

Exhaust valve? I dont know of any exhuast valve other than whats in the cylinder head.

That is what am talking about. the backpressure sucking cold air back through the exhaust on deceleration.

I havent heard of anything like that creating a problem.

even when decelerating there is no air being sucked back in from the exhaust. when decelerating the pistons go through the same motion there for the intake and exhaust valves do the same. when the intake valve opens the piston intakes the air the the exhaust opens and lets the very small combustion out.

Holy Crap! This same exhaust leak just happen to me today. I started my 99 1.8T Wagon after work and it just sounds awful. I popped the hood felt by the turbo with the engine reving and I could feel the exhaust coming out. Unfortunately I do not have a welder and I have to find another way of fixing it. I may look into an after market exhaust or a muffler shop. Any suggestions. Freaking Audi-such a love hate relationship.

Where do you live? I may be able to help.

I'm up in washington, so probably not. But I will check the exhaus shop and let you know.

Good Luck. Maybe you can remove the exhaust and catalytic converter, and have a shop weld it for you. It would be a lot cheaper. Just make sure to mark the two before you remove it so it will all fit and bolt back together properly. I did, thats what the two white marks are for in the above picture.

All done. $20 for a weld and a couple hours of work-- it's fixed. Thanks.

Did you have the exhaust and catalytic converter removed? $20 is affordable.