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Lark Parker
03-13-2006, 11:07 PM
I have a NOS muffler for the President, straight 8. The round body is 30" long by 5" diameter with 1.75" inlet and exhaust. The skin shows four ribs of internal chamber(?) construction.

Does anyone know how these mufflers are constructed internally?

I have been advised that the original exhaust system is inadequate for the 250 cube engine and I want to inprove the flow.

It seems to me that there is no point in increasing the exhaust pipe (1.75") size if the muffler is still the constriction point.

I do not want to modify the car by putting on some oval shape or "performance" muffler. The goal is to keep the nice quiet sound and have an original appearance. I am reluctant to cut into the muffler if nothing can be modified because of the construction. ( My first thought was to simply cut larger holes in the chamber walls but the centered inlet pipe makes a sharp dive towards the wall so I have no idea as to how it is constructed inside.) I could cut up the old muffler but it was a wrong smaller size of only 5" diameter and 23" long. Anything learned from it is questionable.

I looked around the internet but the construction info there is mostly about the new performance offerings. If someone else is better at researching old muffler construction their help is welcomed. It looks like even a 2" system size would be a significant improvement in cfm capacity.

BobPalma
03-14-2006, 08:27 AM
:) Dale: Why not ask Don Simmons? Not only will he probably understand the original construction, but he can find or custom-make you a muffler to your specifications. [:I] BP

Lark Parker
03-14-2006, 10:08 AM
quote:Originally posted by BobPalma

:) Dale: Why not ask Don Simmons? Not only will he probably understand the original construction, but he can find or custom-make you a muffler to your specifications. [:I] BP


I bought this "bigger" NOS muffler in an effort to correct and improve, so now its become a matter of honor to use it and save face.

Like a lot of Studebaker guys I need to try it myself -- :) -- gain the learning experience -- [:0]-- realize the difference between expectations and outcome -- [V] -- before I hire a pro. -- :D

studegary
03-14-2006, 02:58 PM
It has been 15 years since I last had an NOS muffler for my '40 President in my hands. It was a long, fairly slim, tubular affair. I remember it as being basically a straight through design. I wouldn't think that it would be much of a restriction for 250 cubic inches of displacement at relatively low rpms.

Lark Parker
03-14-2006, 11:33 PM
quote:Originally posted by studegary

It has been 15 years since I last had an NOS muffler for my '40 President in my hands. It was a long, fairly slim, tubular affair. I remember it as being basically a straight through design. I wouldn't think that it would be much of a restriction for 250 cubic inches of displacement at relatively low rpms.


This may depend on what we consider relatively low rpms.

I (also) thought the muffler would be a straight through design until I had it in front of me. I dion't think so now. The original plan was to substitute a larger center tube and orifices. That's why I was seeking information on the muffler's internal construction.

The engine is rated at 110hp @3600rpm and the exhaust sizing rule of thumb is 2.2cfm/hp to give a resultant of 242cfm to be handled.

I don't know how to get from 242cfm to the exhaust sizing and I was sure some engineering type would pistol whip me with his slide rule/keyboard and call me a dumbass as he gleefully calculated and posted the optimum sizing.[^]

I did find examples where 2.25" diameter system was good for 490 cfm and 2.50" was good for 557cfm. The cfm/diameter relationship is probably non-linear so the extrapolation to 1.75" cannot be made on this sparse data.

No disrespect -- but your opinion is just another opinion that is directly opposite of the two other opinions that started me on this quest. ( They were also from President 8 owners.) Based on their opinion I thought an increase to a 2" diameter would probably help.
That doesn't mean I think you are wrong or right --- It just means I am a hardhead that sometimes likes numbers.

Maybe someone else will venture a formula.[?]