411 - Rear End view!

[Richardmulcaster]

Originally Posted by jalli

Richard. There are others that know more than me out there. I was originally told that the down facing pipes were to stop marking the garage wall, which i think is nonsense.

I believe that there was an issue with exhaust gas being circulated into the cabin which was solved with the down facing pipe exhaust

Yes, thanks for that- I did find a piece about this on the forum that seemed to get to the bottom of it, can’t find it now, but basically it seems accepted that there was a backdraft of exhaust emissions into the car if the vents were not present because exhaust smoke exited into the vortex behind the car, whereas it needs to vent into turbulent air below the car. Speaking with my mechanic last night he said that Jaguars and Aston Martins of the same era had the same problem- they solved it by making their pipes a bit longer. It seems Bristol had a more novel solution to the problem.

While the presence of downward facing slits is now a fact, what isn’t conclusive in my mind is the need to blank off the straight through route to the end of the pipes; I have read conflicting reports on whether they are needed or not if the slits are present.