2.0TDI twin exhaust, one pipe is a fake??

[michaelab]

I've recently driven behind a couple of 2.0TDI A4s with the twin exhaust on the left side, and I've noticed (especially when my headlights illuminate them well) that the outermost pipe doesn't appear to go anywhere as I can see a silver coloured 'wall' further up the pipe. The pipe is also completely squeaky clean inside, whereas the other (innermost) pipe is all sooty and black, as you would expect. Is the outermost pipe just a fake for looks? Would Audi really do something like that?

[Abyss]

Just had a look at mine and this is indeed true!

[kodkod.84]

Could well be- a lot of the A3 TDI back boxes I see are only single pipe.

For reference here is what the underside of the b8 looks like

[Phil K]

It's only the clean fumes that come out of the outer most one!

[theskyfox]

I'm gonna throw a curve ball here. Do you think its possible that maybe only one is used if its a lower spec (120/140ps) model and perhaps both are used if its 170ps?

My old 1.9TDi had a twin exhaust exactly the same..and used both of them..and it was an 8 valve engine!

-Andrew

[kite]

Some twin exhausts have a butterfly valve that only opens when driving with gusto....

[drmartin]

They both work, you will notice it more in the cold mornings, and its the same on all 2.0TDi Engines to.. another way is placing your hand over each exhaust with the engine running.

[NickH A4]

Mine are equally sooted.

170PS

Nick

[Sportwag]

Both of mine require regular cleaning - I try to keep the chrome tips clean and so far have not had to use any abrasive polish!

[rd1]

Mine both work and its a 143 so do the twin ones on the A3. Perhaps its for selling more of the chrome tips at £55 each!