411 (Series 3-5) Exhaust Tailpipes

[Richard]

Originally Posted by Kevin Howard

I should also mention that the Series 3-5 411s have a vent in the rear wings through to the cabin (beneath the rear parcel shelf) which could also have a bearing on why they had an exhaust ingestion problem in certain conditions.
A dodgy boot seal can be the culprit if there is any airway, regardless of how small, between the boot and the cabin.
Kevin

The explanation is that all cars have a smaller or larger region of separated or stagnant air at their rear-end depending on the design. If the exhaust exits into this area the fumes will be dragged along with the car and enter any cavity where there is a region of lower pressure ie. leaky boot seals or open rear windows etc.
If the exhaust gases are vented downwards they will enter a region of turbulent air and thus be dissipated.
Richard