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Exhaust boxes?

Technical issues not related to a DLOC car marque, eg tyres, ethanol, other car makes, etc. and legal, political and insurance
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Sydsmith
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Exhaust boxes?

Post by Sydsmith »

I have a 1937 light 15 requiring an exhaust system (I know of two other members also in the market) and need some help in deciding exactly what I should be looking out for. I know that I can ask a specialist supplier but the quotes I have had would build the HS2 rail link, so before I raise a mortgage, bite the bullet and order a system I am looking at the prospect of custom building a system from stock items.

I intend to use mild steel, I have a V8 250 with a 10 year old mild steel system and it is as solid as a rock and I do like the sound that mild steel makes compared with stainless.

I have more or less sorted the pipework and measurements are no problem. Though it is impossible to know the original measurements but where the pipework has to run and the boxes have to fit there is not a lot of room for variation. My problem is I have no knowledge of exhaust boxes, I know one when I see one but apart from size and shape they all look the same from the outside and I don't no hay from a bulls foot when it comes to buying the correct boxes. (I appreciate that's what I am paying a specialist supplier for).

I know there are expansion boxes, back boxes and silencers also that back pressure is a matter for consideration.

The original system used two boxes, one just after the down pipe which was a strange diamond shape, and one standard cylindrical box by the rear axle, it is all made up on one and half inch pipework.

The old boxes are clearly not original completely shot and no help, so what I need to know is what type of box, silencer, expansion or back box do I need in the front and rear positions?

The original diamond shape box is no more and a standard cylinder was used last, I doubt a box of the original design would be available and would be very expensive to have built, beside we don't have one to copy.

What effect does the type of box have on the back pressure and the silencing ability of the system?

I know others have used available boxes from modern vehicles with success and there are suppliers who can supply boxes of the size I think I might be able to use at quite reasonable prices, but it's not a matter of penny pinching just what to buy for the best.

I am sure some one out there will know a thing or two about exhaust system design and can help me chose suitable boxes.

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theoldman
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Re: Exhaust boxes?

Post by theoldman »

Syd,

I can only speak about my own past experience, but i found Earlpart at Heanor extremely helpful and they provided an excellent system.

They can make one up if you have the vestiges of the old one, or do one from a (rough) drawing.

Neil
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theoldman
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Re: Exhaust boxes?

Post by theoldman »

ps - there's no such thing as a Daimler Light 15!
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Sydsmith
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Re: Exhaust boxes?

Post by Sydsmith »

Hi Neil thanks for the suggestion, I am away tomorrow but will try them on Tuesday when I get back.

The car is a 1937 Daimler Mulliner light 15 sports saloon, similar to Dave Captain Bobo's car, I posted pictures recently if you look at my posts.

Syd

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theoldman
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Re: Exhaust boxes?

Post by theoldman »

There is no such thing as a Daimler Light 15...............................
There is no such thing as a Daimler Light 15...............................
There is no such thing as a Daimler Light 15...............................
There is no such thing as a Daimler Light 15...............................
There is no such thing as a Daimler Light 15...............................
There is no such thing as a Daimler Light 15...............................
There is no such thing as a Daimler Light 15...............................

I believe some French firm made one, however.

N.
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Simon Hyslop

Re: Exhaust boxes?

Post by Simon Hyslop »

Hello Syd,

I don't - really I don't, mean this to prolong the subject but this is meant to be helpful.

Back in the mists of time, Austin made a car they called the 12. Some years later, they made a different car that they also called a 12, but they still made the original 12 as well. To differentiate between the two, they called the "old" 12 the "Heavy 12" and they called the new 12 the "Light 12" because it was, simply, lighter.

There was also a general sort of idea that cars of 10hp and below were "light" cars, the sort of car the average person might buy, as opposed to "real" cars which were , well , for lack of a better term - Heavy !

About the same time - 1933/34 ish, the concept of differentiating between two types of saloon arose. The first was a saloon with three windows (i.e. three lights ) on each side. If it was a cheaper car, it might be the sort of thing that a family man might have or maybe a salesman, or a taxi - plenty of room for two or three adults and a couple of children or luggage. If it was something from the carriage trade, it might have a division and the first window was for the driver, the second for the passenger door (and/or jump seats) and the third window enabled the Owner in the Back to look out on the Other People.Both were termed a "six light saloon".

Makers had the need to make their products a bit more exciting and appeal to the aspiring middle class and also those who used to be able to be able to afford a chauffeur and so appeared the "four light" saloon. This also went by the name of the Close Coupled saloon - because the back and front seats were usually closer together, or a "Sports Saloon" or , if it was something that otherwise would have been from the carriage trade, an "owner/driver" saloon.

Just to confuse things a bit more, BSA/Lanchester/Daimler did call the Lanchester 12 the "Light 6", probably because the engine was small (under 1400cc) in comparison with the (Heavy?) 6 they put in your Daimler.

In more recent times, various adverts have appeared mixing all these terms, and others too, until it's pretty hard to work out exactly what is being meant. Usually it's because they have a rather boring car to sell and they're trying to make it sound better but in your case, for my money anyway, it's the other way round. It sounds like you've got a really nice car going under the name Citroen gave to one of their models and calling it a Light 15 is very much a misnomer because of all the points above. It sounds like it's a Four Light saloon, maybe better called , as the company did, a 15 Sports Saloon, and very nice to have it must be too.

I mean no offence in this, just to explain why the term "Light" usually brings forth a response...

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Re: Exhaust boxes?

Post by ranald »

Sorry for going off the subject........but, this brings to mind some magazines I have have in the loft from the 1930s called "The Light Car & Cycle Car". Syd, I hope you get your exhaust problem sorted soon. Best wishes, Ranald

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Re: Exhaust boxes?

Post by Petelang »

My Daimler Fifteen is a "six light". Nothing to do with weight but all about the windows.
So the correct term is a " Daimler Fifteen Six Light Saloon"
Peter
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Sydsmith
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Re: Exhaust boxes?

Post by Sydsmith »

Thanks every one for all of that, very informative indeed. I accept I have made a mistake and wrongly thought that the correct term for the Mulliner 15 sports saloon was a "light 15 sports saloon". My apologies I will make sure it never happens again.

viewtopic.php?f=4&t=759&p=3715#p3715

I would much appreciate it it we could now get back to my question about exhaust boxes I still have the problem with the exhaust system.

Does any one know what the difference is between expansion boxes and silencers and is the term back box the same as one or other of these?

How do I deal with back pressure and what is it's effect on the car if it is to high or to low?

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Re: Exhaust boxes?

Post by theoldman »

Syd,

Sorry for the sarcasm!!!

Anyway, down to business.

When Earlpart made the system for the E20,(which actually was a "Light 20" ha ha!!) they asked me what the original was and I quoted them 1 x "Full Silence" and 1 x "expansion", which they made for me.. The car ran much better as it was discovered that someone had fitted 2 x "Full Silence" in the past which was preventing the gas's movement and applying a slight back pressure to the engine.

Have a word with them - they are very helpful with older cars.

Cheers

Neil
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