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Need help with installing downpipe

22 May 2020, 02:51

Hey all, so I took on the task of putting a catless downpipe onto my 225 AMU. I thought that the hard part would be removing the old downpipe, but now I'm having trouble getting the new one on. Unfortunately, unlike the 42DD, my downpipe doesn't break into 2 sections near the turbo area. I spent all night trying to shove it in and couldn't.

Now I'd prefer not to drop the subframe. The only other option I'm seeing is removing the center driveshaft that goes to the back of the car. Anyone have any other ideas? If not, when removing the center driveshaft, there are 3, 12 point bolts. I can only get access to 2 of them, how would I rotate the shaft to get access to the third?

Thanks in advance!

Re: Need help with installing downpipe

22 May 2020, 06:24

I'm doing the same job next weekend and the subframe will need to be dropped. It's simple enough to do.

Re: Need help with installing downpipe

22 May 2020, 07:24

Is there a write up on doing this? Will I need new bolts?

Re: Need help with installing downpipe

22 May 2020, 08:14

How to courtesy of Waks site, it's how to change the ARB but involves dropping the subframe and yes the bolts should be replaced. https://wak-tt.com/tt_farb/tt_farb.htm

Re: Need help with installing downpipe

22 May 2020, 17:23

I take it you cut the old downpipe off or it had already blown apart at the flexi joint like my S3 did.

I changed the downpipe on my S3 whilst the head was off as the old downpipe to turbo bolts had rusted and rounded, it was impossible to get them undone + I had been losing coolant and assumed a head gasket failure + it was due a timing belt so all at once.

I also fitted that same ebay downpipe on my TT whilst the head was being rebuilt and forged rods fitted after a happy accident.

Doing it this way meant the support bracket needed removing but in both cases it worked out okay. but the Subframe is a relatively painless approach.

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YES you need bolts they are about £36 from SEAT, SKODA, VW, AUDI dealers and a 27mm socket and a 3-4' breaker bar and a big torque wrench

but after I reversed over raised ironworks I broke my ebay downpipe up by the turbo, so bought a posh pipewerx version (just exactly the same as the ebay version apart from I bought it with a sports cat then fitted a decat pipe, to save the sports cat for sunday best (eg MOT)

if you are not in a hurry have a think about what else you might do.

1. If fitting a 3inch downpipe you need to uprate the main bush in the dogbone engine mount to a powerflex bush (yellow?, some people use the diesel red one, and I think black is just soft like your worn out stock one). if you dont do this, the engine torque will make the downpipe hit the tunnel, propshaft etc and put extra stress on the flexipipe etc too

You remove the dog bone mount first and fit it last - this is so you can sort of tip / rock the engine to help inch the downpipe up past the prop shaft and tunnel

2. the car needs to be aligned after moving the subframe. <- I left the steering rack connected and you can fit the 3inch downpipe by carefully moving this out the way but must be cautious you dont damage, crimp etc any of the pipes etc. you also need to get it back as close as you can as the subframe is connected to the entire front end alignment components.

3. do you need new drive shafts - or cv joints or boots? - I have bought both drive shafts for my S3 (when one CV joint was clunking off when reversing and then properly worn out after showing off to my kids on the way back from Thorpe Park shark hotel stay - coming off roundabouts #fireUptheQuattro
I also changed both on my TT when one inner boot had been split for a few months and the outer boot had also split, and I was fitting the downpipe as the driveshaft outers need removing (may as well remove both)

These were £89 for the pair in both cases from J&R and have been problem free in both cars (not everyone agrees, but it is usually people who paid £400 a pair said they would never waste £90 on a pair again ;) ) it is much cleaner and easier than taking apart drive shafts fitting boots etc. and as one was split for months that joint would surely need changing.

4. do you need track rod ends? they are £8 each and you will probably want to remove them anyway so you are not yanking the steering rack etc

5. do you need lower arm joints? the bolts need to be replaced in any case, they may need cutting off anyway and you will probably break the boot trying to remove it - and if you are replacing them you dont need to be super careful when removing them. about £30 a pair (not sure I quite remember but not bank killing)

6. are your steering rack boots okay ? that is another £12 a pair

(Some rich people totally remove the sub frame and service that, change those bushes and also replace the wishbones.)


Remember you are under a car and it weighs a lot, use the correct support stands tools etc, and if you wear glasses put an old pair on to protect your eyes from falling debris and tools.


good luck, update us with your progress.

Re: Need help with installing downpipe

23 May 2020, 06:06

So I decided to go a different route. First there is a heat shield covering what looks like the power steering line where it goes into the tie rod area. Kind of below the center driveshaft. I removed this by removing 1, 13mm nut, and 3, 13mm bolts. This was somewhat of a hassle but it helps a lot.

Another thing I did was cut the hanger off of the down pipe. Not ideal but I have access to a welder. And then finally I had to trim the two studs coming out of the firewall that are used to mount the upper o2 sensor bracket and also a mounting point for the strut tower brace. I haven't checked but if I don't have enough threads to remount, I will probably end up using a stud welder. Pretty awesome tool.

Obviously this wasn't ideal. I wasn't able to get subframe bolts in the mail for about a week or more. This is my only car so I didn't feel safe re using the stretch bolts until then. This was more of a hassle but definitely less intimidating.

Re: Need help with installing downpipe

23 May 2020, 07:34

I don't understand, did you fit it from below still?

Is this a 3inch downpipe or stock.

Re: Need help with installing downpipe

23 May 2020, 23:55

It is a 3in downpipe and I fit it from above.

Re: Need help with installing downpipe

24 May 2020, 01:19

Say what... that's amazing... do you have a any photos?

Re: Need help with installing downpipe

24 May 2020, 02:08

I will get some tomorrow haha, it was an interesting experience.

Re: Need help with installing downpipe

24 May 2020, 10:43

idonthaveklutch wrote:I will get some tomorrow haha, it was an interesting experience.

Is it left or right hand drive?

Re: Need help with installing downpipe

24 May 2020, 13:23

I mean photos of the route.

I was wondering whether removing all the engine mounts and try to float that out the way might make some room to get in through the wheel arch..

I suppose a left hand drive TT would have the brake servo on the other side? I know some 3in downpipes can be bigger on LHD as there is more room, but then there's less space on the TIP side. for a B5 oversized TIP.

Re: Need help with installing downpipe

24 May 2020, 19:47

These are the best images I could get for now. So basically to get it in from the top all I had to do was shave some threads off of the studs that serve as a mounting location for the strut tower brace

Edit: Also, it is left hand drive
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Re: Need help with installing downpipe

24 May 2020, 20:14

There's no chance of getting it down there on a RHD. I was thinking about cutting the pipe and adding a V clamp joint but i still don't think it would go in from the top.

Re: Need help with installing downpipe

24 May 2020, 20:52

That was a thought I had too. The legit 42DD downpipe has a flange in the location you're referring to. Just like the oem one. I believe that cut is the determining factor for how easy of a job it will be.
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