Exhaust help

ian_s3

ian_s3

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The flexi pipe on my exhaust has started to blow on my 2011 s3. Would it be possible to remove the y-piece that is straight after the cat which includes the flexi and come straight out cat into next section of exhaust. Can anyone see any issues with doing this? The only reason I'm not changing to full exhaust is that I'm not too bothered about decat or sportscat. Any help would be very much appreciated, thanks.
 
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You will restrict the flow of the exhaust too much IMO and potentially cause high EGTs and over stress the turbo. Why don't you just buy another OEM downpipe off a member? Place a wanted ad on the forum classifieds.
 
I'm struggling for time as my MOT due in 2 weeks. I was hoping to avoid replacing whole pipe right up to the turbo
 
Don't see the issue, my sportcat down pipe is one single straight piece.
 
I take it you just have cat then 1 pipe into backboxes?
 
I wouldnt have thought it would restrict it as another said ifanythingit would free it up, im going to try and get mine done on the weekend, i have a milltek catback too
 
audi upgrades
Yes, the Milltek is a single pipe from the turbo to the cat-back, BUT it is 3" whereas the OEM system is around 1 3/4" for each pipe and is known to be a restrictive item with the 2 pipes. Yes it will pass the MOT OK, but as I stated it will have an effect on back pressure as your exhaust gas flow rate will effectively be cut in half! You have an S3 right? Buy a used OEM downpipe, they are readily available on ebay or via this site and will probably cost less than the welding will to botch your current downpipe.

This will help explain what I mean.
mv_sport_downpipe.jpg
..
 
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nluk100 said:
Yes, the Milltek is a single pipe from the turbo to the cat-back, BUT it is 3" whereas the OEM system is around 1 3/4" for each pipe and is known to be a restrictive item with the 2 pipes. Yes it will pass the MOT OK, but as I stated it will have an effect on back pressure as your exhaust gas flow rate will effectively be cut in half! You have an S3 right? Buy a used OEM downpipe, they are readily available on ebay or via this site and will probably cost less than the welding will to botch your current downpipe.

This will help explain what I mean.
mv_sport_downpipe.jpg
..
Click to expand...

Ok thanks. If I was to go down changing whole pipe I would probably go for the stainless down pipe with sportscat as its the same work involved. My question now is, would it definitely pass mot with sportcat, and would it bring on engine management light? I've read before that people say it needs mapped after down pipe is fitted. Is this a requirement, or will it be fine without a remap?
 
Sometimes the dash light comes on and sometimes you are lucky. It is possible to buy spacers that hold the sensors further out from the exhaust flow and this can avoid the light too. In addition to raising the BHP and ft lbs, the stage 2 map will stop the light appearing.
I took my car for its first MOT with the APR sports cat. The chap had to warm it up quite a bit before it passed.
 
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If you're looking at a sports cat now then it could be an expensive option. £450 for the down pipe + around £200 for a basic remap and error code delete (more if you want a decent S3 remap).

There's an OEM downpipe for sale atm in the classifieds on here - I sold one for £75 last year.
 
ian_s3 said:
Ok thanks. If I was to go down changing whole pipe I would probably go for the stainless down pipe with sportscat as its the same work involved. My question now is, would it definitely pass mot with sportcat, and would it bring on engine management light? I've read before that people say it needs mapped after down pipe is fitted. Is this a requirement, or will it be fine without a remap?
Click to expand...
Just to check, did you go for this? I'm in the same position, apart from having a custom down pipe and sport cat fitted. My question is did you have to get a map after fitting to stop the engine light coming on, or any faults showing?
 
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