Replacement of the catalytic converter - Exhaust Flexi gone

a2lover

New Member
Hello everybody.

Following a misfortune I needed to install a new non original catalytic converter. The mechanic that did the job installed aftermarket catalytic converter and I noticed that in the new exhaust pipe sections that they installed I noticed that the exhaust flexi section disappeared. As I don't have much knowledge of A2 exhaust systems, does this one looks well set up? Can someone identify if this catalytic converter is suitable for an Audi A2?
Are there any problems in eliminating the flexi exhaust section as they appear to have done?

Thanks
 
Hi you definately need a flexible connection from the frontpipe to the rest of the exhaust system to allow movement of the the engine on its mounts. To rigid and it wont take long for metal fatigue to set in and form cracks in the pipe at its most stessed location after all that is the whole purpose of a flexible fitting. Not only that as the vehicle is driven on any uneven /bumpy roads the back silencers will move around as they are mounted to the car by rubber mounts.
 

a2lover

New Member
Hi Michael. Thank you very much for the information on the purpose of the flexi.

What a nightmare :-( when i picked up the car on the garage and arrived home i noticed that the flexi was missing but as i didnt knew exactly what was its purpose so i thougth it was ok.
So as it is done the reparing will lead to cracks on the pipe that is coming from the engine to the CAT right?
Are there any other parts that can be damaged by this? For example the engine mounts can also be damaged by the way the repair its done? And the rubber mounts of the back silencers can also be damaged ?

Thank you
 
Hi the engine needs to be able to move slightly in order to have a smooth drive when pulling away and braking when vehicle is in gear the engine wil be forced back and forth thats why the dog-bone mount along with the main left and right engine monts are flexible (cushioned mounts) whilst the main system from the cat onwards are hung to the floor of the car by heavy rubber band type type effectively hung from the bottom of the car that is why a flexy is used although some vehicles utilise a spring fitting where the manifold meets the pipe thhis allows some movement however if the frontpipe is solidly fixed to the manifold not allowing any movement a flexible fitting is used to reduce the stress to the frontpipe
 

a2lover

New Member
Hi. Thanks for the information. So as it is done the frontpipe wont last long right? Is it the frontpipe the only part that will suffer from the missing of the flexi section? Or also since there is no flexi installed this could affect the correct movement of the engine and damage it? And the whole system of exahust Will suffer some stress right as it done to allow some movement which Will not be possible on the frontpipe area right?

I am trying to get as much info as possible to go back to Garage and ask to the flexi to be installed wich Will cost more money since the Will have to cut the frontpipe and put the flexi and weld and back together again. It would have been so much easier if they have just done it corretly the first time :-(

It is very expensive the flexi section part?
 

audifan

A2OC Donor
They removed the flexi pipe. They know the flexi is required. Their error. They pay to fix it. Audi worked out exactly what was required for the exhaust system, works well and lasts a long time.
 

a2lover

New Member
They removed the flexi pipe. They know the flexi is required. Their error. They pay to fix it. Audi worked out exactly what was required for the exhaust system, works well and lasts a long time.

Yes i understand what you saying i suppose they should knew that the flexi pipe was required but the they didnt removed it the CAT was stolen so i send it to the nearest Garage to be fixed and they did the repair that way. I found it strange because on the car parts sites the flexi is always represented in the CAT parts pictures and mine did not had a flexi inataled. It seems that the repair was incorrectly done :-(

Aslo i noticed that the car does a noise that seems like a whisper. Could it the from the lack of the flexi?
 

a2lover

New Member
Hi the engine needs to be able to move slightly in order to have a smooth drive when pulling away and braking when vehicle is in gear the engine wil be forced back and forth thats why the dog-bone mount along with the main left and right engine monts are flexible (cushioned mounts) whilst the main system from the cat onwards are hung to the floor of the car by heavy rubber band type type effectively hung from the bottom of the car that is why a flexy is used although some vehicles utilise a spring fitting where the manifold meets the pipe thhis allows some movement however if the frontpipe is solidly fixed to the manifold not allowing any movement a flexible fitting is used to reduce the stress to the frontpipe
@michael ashton

Hi Michael. I installed the flexi on it, but as far as i can relembre originaly it was placed further back, and now its monted right Next to the frontpipe that comes out of the engine. Is there any problem as it is monted now? Or should it be placed further back?

Thanks.
 

a2lover

New Member
Looks to be fairly ok positioned to me. Comparison with my 2001, 1.4:
https://www.a2oc.net/community/index.php?threads/the-s-h-e-car.42630/post-396525
@Joga

And about the length of the actual flexi? Does it seems ok? Yours flexi parte seems to be a bit longer ir maybe its just my impression looking at the photos?

Also i have noticed on the photos of your repair that near the CAT there is a part that does not exist on my new CAT. What is this part?

IMG_20211121_215423.jpg


Thanks
 
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Hi as long as some movement is available between the engine and the rest of the system it will be fine with the exeption you being aware of its position when driving over speed bumps and the like also the rubber block at the top of the picture attached to the underbody should also be attached to the bracket shown one each side fitting can be assisted by the application of a little washing up liquid Regards Mike
 
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