Any ideas on getting a bit of downpipe / prop shaft clearance

Stuart B

Registered User
Joined
Oct 2, 2015
Messages
3,565
Reaction score
770
Points
113
This downpipe fitted my s3 perfectly. I have undone the downpipe to ensure it is rotated as much as possible 1mm movement.
Are the engine mounts different? Eg length of dog bone? (As I fitted my S3 dogbone mount with its yellow power flex upgrades) I think if the dog bone was 5mm longer that would bring the downpipe down to clear. Or I remove downpipe and lengthen the holes?

Thanks :)

Screenshot 20181208 150711 Gallery
 
What about?

1. I changed the thiming belt the engine mounts have a tiny bit of movement - could this be the difference?
Or
2. Chinese hotside incorrectly located studs?
 
I wouldn't be surprised if the Chinese hotside wasn't helping matters. You seem to have a lot of balance weights on that prop. I have a small one that caused me some issues. The downpipes for the S3 and TT are made to be the same. I am not sure if the dogbone mount length is the same on the TT and S3. They have different part numbers. The bushes may be interchangeable but possibly the overall length is different.
 
Did you check the height of the hot side was the same as oem? I.e. from CHRA side to the downpipe flange face?
If it was thicker it would move your downpipe over to the drivers side and contact the prop like that.
There might be very minimal movement left-right on the mounts so try that.
 
Made a bad assumption in the hot side. Its the manifold which determines the position of the downpipe via the hot side so not sure where the CHRA is involved?

I will have a look at the mounts I maybe able to slightly twist the engine, moving the engine towards the bulk head tilt it enough.

Aftermarket dogbones are for S3 and TT but I will give it a check. Just in case it is a tiny difference.
 
Made a bad assumption in the hot side. Its the manifold which determines the position of the downpipe via the hot side so not sure where the CHRA is involved?

I will have a look at the mounts I maybe able to slightly twist the engine, moving the engine towards the bulk head tilt it enough.

Aftermarket dogbones are for S3 and TT but I will give it a check. Just in case it is a tiny difference.
The CHRA isn’t involved. You have a Chinese hot side in there. Is the thickness of the hot side the same as OEM, from CHRA side to the flange side? If the flange is thicker for example, this will move the downpipe drivers side like I say.

Equally it could be the manifold. Although I don’t recall any Ill fitting downpipes because of Chinafolds, but it shouldn’t be ruled out

I’m just speculating here
 
The pipe is too high, moving across the drivers side will hit the other side of the channel. It needs to move down like rotate to 7:30pm instead of 8pm ( if you know what I mean,) although I could rip off the heat sheild if need be.


To try and manipulate the engine a tiny bit.
1. I've soaked the passengers mounts with wd40 and will continue all week, these are famous for snapping as never being touched unlike timing belt side,

2. my neighbour is making me a 4mm spacer / shim for the dog bone it helps a tiny bit but the prop shaft moves with it too, so there's a sweet spot

3. I am taking the downpipe off the turbo and going too try to slot the holes whilst still floating around in the wheel arch to position it perfectly. Rather annoyingly the locking nuts simply undid the studs from the turbo.

What I did notice in the red charge pipe tiny silver flecks? Too small to pick up I should have tried to photo them. But I would like to know where they came from. Obviously, I've only driven 4 miles up to ~3k rpm just when the turbo started coming in. The compressor span freely so pretty unsure of the source of these.

One thing s3 versus tt regarding engine fitment which may impact this is, it's really difficult to fit the top thinking cover on the TT without breaking it on the s3 you just wiggled it down the TT doesn't have the same amount of space, and that's not just me.
 
Same here, chinafold.

Although nothing near as bad as yours
 
thanks well we will see how it can be improved - thats the problem with changing so many things in one go.

now I just need to grow the balls to redo up the timing engine mounts. I think the slotting of the downpipe and the spacer will do the trick and will post up the pics.

I couldn't leave it, it will either knock off the balance or go through the flexi-pipe.
 
Fitted this and adjusted the engine mounts to twist the engine, apparently ttshop regularly fits a dog bone spacer with 3 inch downpipe. This is 4mm but I reckon 6mm might be better, I used 60mm bolts.

20181214 180808


Screenshot 20181216 164044 Gallery
 
This downpipe fitted my s3 perfectly. I have undone the downpipe to ensure it is rotated as much as possible 1mm movement.
Are the engine mounts different? Eg length of dog bone? (As I fitted my S3 dogbone mount with its yellow power flex upgrades) I think if the dog bone was 5mm longer that would bring the downpipe down to clear. Or I remove downpipe and lengthen the holes?

Thanks :)

View attachment 171395
chinafold syndrome.
sometimes between slack in downpipe flange studs/holes and turbo/mani + Big Lever bar, you can make it move to clear.
sometimes not. then spacer flanges get used to move turbo/mani down And/Or downpipe

joys of chinese things and their inability to make things consistent.
Some clear some dont.. but also on after market downpipes, if they just chose to mount the damned flexi lower down the pipe it would never be close to the prop. Again, some are different to others.. Add it all up it will sometimes cause a rub.
 
Thanks Bill, well it's not rubbing at the moment.
At MOT place for today and tomorrow.
I'm hoping they pass it, these Mark 1 TTs are such a lovely car, i want to start driving it soon.
 
  • Like
Reactions: S3AMJ

Similar threads