411 (Series 3-5) Exhaust Tailpipes

[Kevin H]

John,
I meant to say that I have seen numerous earlier V8 Bristols with exhaust tail pipes that angle downwards at the end, often with what I suspect is an aftermarket chrome tailpipe extension.

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.

And as rubbond said, exhaust smells can also be down to a leak into the cabin from the engine bay. Check the rubber belows on the accelerator pedal rod that runs through the firewall (it's basically a flexible seal).

Kevin

[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

[Rubbond]

I think it more likely that (if the tail pipes dip down and then back up),
the holes and blanked off pipes are to prevent condensed water remaining
in the exhaust.

[Nick Challacombe]

I only have two black marks having a 407 and on this the exhaust exit via
a curved stainless steel pointing
downwards at about 60 degrees for the same reason. To stop the gases bing
sucked inside the car by
the vacuum created by forward movment of the car.

Nick.

[Rubbond]

Thanks Kevin for your mention.
I would however challenge any engineer to devize a car design that would be
able to suck exhaust fumes back into the vehicle from behind the rear
bumper!
As an anecdote I was recently in the Science Museum in London with my son
(and was actually able to park in my old spot next door when a student at
Imperial!).
In the museum were of course fantastic steam engines and aeroplanes,
including the Rover JET 1, but when I saw as an addition what they claimed
to be a capsule that had actually landed on and returned from the moon, I
thought, no, that couldn't be possible in the 1970's.
I mean, consider the faulty door seals, and leaky exhausts!
Where were Bristol then?
With best regards,
Andrew Knox.

[UK6]

Bent Exhaust Tips (Tips for the unwary!)
As an aside, you will recall that the original XJ6 tail pipes had a curious
'S' bend. As you elaborated, the airflow helped direct the fumes away from
the car. My father in the 80's didn't like the look of his old XJ6's tail
pipes, so, you guessed it, he replaced them with some straight stainless
sections. After only a few miles, it became apparent that the fumes were
being reingested into the rear of the cockpit and indeed, stained the rear
hood lining. The message - the factory knew what they were doing!

Brett

Ps Downward tips more than likely make a quieter car.

[Bellerophon]

Aero Dynes were designed for the rear window to be left open when
travelling in order that a through flow of air through the car be established, and
would allow the heating to work properly.
Tony Crook was always insistent that the rear window be left open as anyone
who rode with him would know.
One word of warning regarding the exhaust protruding beyond the rear bumper
on the V8's. It can be very costly if you reverse into anything as it is
very easy to break one of the exhaust manifolds, which are not easy to
replace.
My regards,
Bellerophon