411 - Rear End view!
 

Hello everyone -

I am renovating a 411 S2 and I'd love any pics you'd like to send me of your 411 if you have any cool ideas I might be able to see.
I am currently very interested in looking at every 411 rear end(!), as am working my way between a new exhaust; what style, shape, angle, number of. I know that the number of pipes doubled from the S3 onward, but thats then. I'm trying to get the best possible look for my 411 now and would really appreciate your input.

Best wishes to you all.
Richard

Just finishing renovating my series 3

This is it without back boxes and bumper

Rather like the look without bumper
Reminds me of Alfa gta

Pictures series 3 back end
 

here are the pics of the series 3

it will have the standard down firing quad pipes which should arrive tomorrow

That’s beautiful! Well done.
Would love to see the exhaust when it arrives, I’m looking to place an order for one, but haven’t done so yet.

Here's my S5 (the photo outside a house). In case you are not aware, these twin tail pipes are actually blanked off and exit through downward facing apertures.

I've also included a photo of an S4 which was listed for sale in the past.

One thing to be aware of when changing where and how exhausts pipes exit is that you could inadvertently change how the exhaust gases flow around the car at different speeds.

It would be interesting to know whether the vents in the rear wings have the weighted rubber flap in place behind them in the S2-4 411s (I assume they do). Also whether they also have the round ventilation grills in the rear parcel shelf.

Thanks Kevin,
Both cars look absolutely beautiful.
Anyone got any S1 or S2’s they’d car to share???

Re the exhaust comments- thanks to this forum, I read about that very issue last night l, but wasn’t aware of it today. So conversation with our restoration mechanic today went quite well- yes he was aware of this potential issue but it meant I could discuss from a position of at least some knowledge.

He wasn’t aware specifically about the Bristols having downward facing holes in the tail pipe ends.

Thanks everyone.

Hi Richard,
I took some shots of the tailpipes - see attached - so you can see the blanking and bottom exit apertures.
Glad I did because I discovered several of my exhaust hangers had perished and need replacing!

Thanks Kevin, that is so useful.
I just wondered, does the awkward change of direct for the exhaust emission cause a loss of power? I was reading how exhaust systems can deliver more or less power depending on design and using these principles I am guessing that such a sudden change in direction would cause at least some power loss?

Anyone??

411 rear ends
 

Dear Richard

If photos of the 411 coachbuilders' Bucks rear ends are of any help to you I can send you ours - the bucks are currently stashed in the mighty Brabazon hangar near their birthplace. We managed to salvage the whole lot from the Bristol Cars Ltd bankruptcy auction at Windlesham, (regardless of cost!) and are finding suitable museum homes for them where they can be accessed - even, if at all possible, used as working exhibits.
We do have the (very heavy) resin templates for panelbeating the rear light details too, by the way.

Stefan Cembrowicz
Chair ,Bristol Owners Heritage Trust

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

411
 

Richard. I had the detail in the rear wing vents chromed. Not original i know but i think they work quite well

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.

Yes please! And this all sounds very exciting! We will have to visit someday once the car is back on the road and we’re actually allowed to travel again.

Richard, your guess is as good as mine :-)

Exhaust systems are inextricably linked to the intake systems, including valve timing and other variables. I suggest reading "Scientific Design of Exhaust and Intake Systems" by Philip H. Smith. It's an old book, first published in 1962, but still relevant, particularly to normally aspirated engines such as that in the V8 Bristols. It won't necessarily give you answers, but it will at last show how complex these matters are.

Bear in mind the engines in the S1-3 411s are different to the engines in the S4 & S5. The latter having greater swept volume but lower compression ratio. So the exhaust system on say an S4 may not be optimal for an S2.

411 rear end
 

I believe this is a factory shot of the just released 411 series 1. Note the car is not registered. Some one please correct me if I am wrong.

411
 

i also changed the front indicators. also not original but i didnt like the blocky ones!!

While not strictly on-topic, I happen to have the rear parcel shelf and seat out on my car at the moment, so I thought I would take some photos of the vents on the inside of the rear wings on my S5.

There is a weighted rubber flap which appears to be designed to prevent air coming into the cabin while allowing it out.

I have attached photos of the vent from the inside of the rear wing on both sides of the car. The flap is present on one side but not on the other. You can see a horizontal slit of daylight in the photo where the flap is not present. Also included a pic of the flap itself, which had fallen off on the passenger side of my 411.


These vents and the operation (and existence) of the flaps will make a difference regarding exhaust gases entering the cabin.

This is Exactly the sort of think I need to learn about!! Thank you so much.
In the last 2 days I have gone from planning to put speakers hidden under the vents to recognising what the vents are for, to now thinking more about whether the vents are working properly! My father in law had a crash in an MG in the 70’s as a result of smoke ingress in the car- so we need to get this right!

All of this is very welcome content, thank you.

Not a 411, but for my 410 Series 6, we used round donwpipes to both address the downdraft issue and keep the period look. Round downpipes were used for the 410 and possibly for early 411.

The second photo is the recreation of Sir White’s personal 410 which is claimed to be 100% per factory specs.

Wow! Don’t they look amazing! I’m seriously admiring the paintwork. Our brief is to get the mechanicals first class and the car driving perfectly , only then we will see how much is left in the pot for a paint job.

Re the exhausts- were the quad pipes original on the 410 or is that a later enhancement?
They certainly look good and the overall look is very in keeping with the 60’s era.
Thankyou for sharing.

The original pipes for the 410 (and earlier) were two single pipes. But because of the larger engine on the Series 6, we needed two sets of twin pipes. Here’s a picture of the exhaust - the diameter is such that we needed twin pipes at the end

That is a serious exhaust system!

George

I was thinking the same!
Thanks to Zorglub for sharing. its a serious bit of kit, and whilst i am planning on an upgrade, this wasn't even on my "known" spectrum... time for a re-think!

Came across this old post (re the Dennis Sevier lecture) while looking for something else exhuast related... http://www.bristolcars.info/forums/8....html#post1970

In considering everything relating to the V8 cars it is as well to bear in mind Tony Crooks eccentricities which were coupled with a great deal of common sense and remarkable marketing skills. It is my understanding that he decided that a gentleman’s express really shouldn’t leave dirty black marks on the owners trousers if left idling while the boot is filled or emptied and introduced the downward facing exhaust trims on the 410 (or it might have been earlier) to alleviate the problem. Altogether a much easier solution than trying to clean up Chrysler’s dirty engine.

Artistic licence came into play on the 411 when it was decided that four exhaust ports would better look the part (the actual exhaust pipes running back from the engine are actually no larger than those on the 410) and, a touch of genius this, they could also be blanked off at the ends to further prevent anything at all getting on to the trousers whilst preventing wicked small boys from stuffing potatoes down them. Tony Crooks escapades suggest that he was very familiar with small boys minds. The actual discharge slots ahead of the blanking plates are of larger cross section than the main pipes back from the engine, so they hardly affect the discharge which is in any case already seriously handicapped by the crudity of the Chrysler manifold at the front end. On which point I can commend SL-J’s swept tubular manifolds which do markedly improve the breathing, at a price.

I too was impressed by the neatness of the 410s rear end on an occasion when the bumper was off, I thought it reminiscent of an AC Ace.

Just in case, these are the 411 exhausts

Thanks Zorglub, looks great. I have mine on order now, but know production won’t start for another 2 weeks- I’m sharing all these imagines with the company, so it’s all very useful.
Thanks again.

I absolutely love learning these little bits of history that just don’t seem to be officially recorded but give such an insight to the reasons why things are the way they are.
Thank you taking the time to write this.

It looks okay without the bumper; it also looks very different, like a smaller car.

Just as well if anyone doesn't have a bumper, because they are probably impossible to buy now. Last time I asked at BCL (prob 20 years ago), they only had secondhand bumpers for sale, at about £900!

There’s a company in Vietnam making stainless steel ones identical. I was quoted £1400 for a new one (single, not pair of) for my 411, probably better quality than original chrome. I recently saw a Gordon Keeble with one fitted and it looked really good. I could probably reference several imports to the UK from this company. And have the contact details.
I ended up choosing a company local to me to refurb my chrome, but that was £650 per bumper.