Exhaust smell inside cabin with windows down

[Wahlstrom]

As topic reads, after I have put on S4 rear and a B7 exhaust, everytime I open the windows or sunroof the cabin smells of exhaust.

I wonder if the connector at the turbo is leaking..
I've had the engine running, while feeling with my hands if there should be a leak.. but didn't feel a thing..
Felt around this part

 

[DrStrange]

Wish I could be more help with this Wahlstrom but ive been told on numerous occasions that this is 'expected' and 'fine'.

2 of my mates, 1 with an A4 and 1 with an A3 have also said the above.

Ive had this smell with the windows up since owning the car (3 years now) and on some days the smell is more prominent than others.

Will let you know if the smell disappears as a result of my mechnic fitting a few things. (Then you'll know it was an issue)

 

[Wahlstrom]

Im thinking of two causes..

1: when removing the old exhaust I used some force hitting the exhaust clamps from the front to the rear.. thinking the connection pictured above could have moved..
But I felt with my hands around it afterwards with engine running and couldn't feel any leaks..

2:
When fitting the S4 rear bumper, I found the cause for noises when playing music loud..
it was some rubber flaps on a vent under the bumper. I yanked them off.
Come to think of it now, this means it could draw exhaust in from this vent now that I've removed the flaps, when opening a window..

 

[Wahlstrom]

This is the vent I'm talking about.. there was some rubbery flaps in each section making it valve like, so air could go out, but not in..
but it vibrated like crazy because the bass sits above, so I pulled them off..

It could be the reason

But, the exhaust tips ends outside the car.. when driving the exhaust should be blown away..
perhaps it creates a powerful suction through the cabin ??

 

[Wahlstrom]

Yesterday the boot was semi locked as I had some larger things in the back..
When accelerating while cold engine I had to stop because I though something was on fire..
The smoke was coming through..

So my idea of that vent sucking in exhaust when sunroof or window opened might be right

 

[aragorn]

Those flaps are there for a reason. IE to stop stuff being sucked in.

Aerodynamics creates a low pressure area and lots of turbulence behind the car. Its very common for exhasut to enter the cabin if you drive with the tailgate open.

 

[Wahlstrom]

Yeah but those flaps made an annoying sound when music was playing.
My plan is to put a plate of sound deadening material on it to close it

 

[Wahlstrom]

Done