Exhaust tubes

Ricosan

Ricosan

Senior Member
Hey Guys,

I’ve been thinking about exhaust lately.
I’ve had 2 different dual exhaust systems on my ‘34 with original cast iron manifolds.
The first set of pipes were 1-3/4 tubing and glass packs. The sound sucked and it was ugly to look at under the car.
After about a year, I had another set of exhaust tubes installed, this time with steel packs. It was a much nicer job from front to back and the sound was better but still not that beautiful melodious sound that comes from few flatheads I’ve heard over the years. You know the sound I’m talking about.
My limited experience leads me to believe that a smoother run of tube from front to back yields a better quality sound regardless of muffler.
My ‘33 has Reds headers and regular smash tubing (smithy’s mufflers) and I can at times almost hear that sweet sound when pushing hard but at normal driving speed, which is the majority of the time, it just sounds loud.
From the headers back at every bend it is smashed, resulting in multiple restrictions that effect the sound at the rear.
My question, how do you get that tuned sound? Mandrel bends?
I would love to hear your thoughts.
Richard
 
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YouTube has many recordings of Flathead engines running. Some give specifics on what parts the exhaust is made up of. Some of that sound you’re looking for may come from motors that aren’t completely stock.........Mark
 
Ol' Ron said:
camshaft & compression, makes a difference, but not every ear is the same.
G
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Agreed. Can't go wrong with straight pipes right to the back. With a relatively stock motor, it will get you the sound you are looking for without being too obnoxious.

Plus, if you find it too loud, easy enough to add a steel pack in these. Harder to length an existing system than shorten it.
 
Hey Guys,
Thanks for all the comments.
I’ve listened to a lot of the exhaust clips on YouTube but I’ve rarely seen the much info other than type and brand of muffler. I’ll dig deeper.
My motor is a stock 1933 dressed up with aftermarket aluminum heads, 2 carbs, and a slightly lopey cam and with smithys.
I may be wrong but it seems like a system of pipes without restrictions (mandrel bends”) would have a recognizable effect on the sound. Better or worse I don’t know.
Anyone tried both on a flathead?
Richard
 
Did you see the episode of "Engine Masters" where they took a BFH and started bashing in a set of tube headers between dyno runs? There had to be very noticeable damage before it made any significant difference.
 
Ricosan said:
Hey Guys,
Thanks for all the comments.
I’ve listened to a lot of the exhaust clips on YouTube but I’ve rarely seen the much info other than type and brand of muffler. I’ll dig deeper.
My motor is a stock 1933 dressed up with aftermarket aluminum heads, 2 carbs, and a slightly lopey cam and with smithys.
I may be wrong but it seems like a system of pipes without restrictions (mandrel bends”) would have a recognizable effect on the sound. Better or worse I don’t know.
Anyone tried both on a flathead?
Richard
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If you want mufflers, steel packs vs. glass packs gets you a nice braaapppp sound. The shorter the muffler, the more pronounced.

A lot of guys like to use those cheapie steel packs you find on Ebay or swap meets.
 
Which motor do you have in your 34?
What size tube are you running now?
What length mufflers?
If you are interested send me your email. I have a couple of short clips of two engines w/ 1-3/4 tubes & 12” & 18” Brockman steel pack mufflers, same cam, with similar engine configuration(s) to yours.
I agree with Ron- my perception of both of these engines: one is louder with 12” mufflers but they have different tones.........
IMO......Find one you like & copy it!
 
If you are speaking of the center port, with a divider. It has been reported to sound more like a Chevrolet.:(
 
I quit worrying about stock flathead V8 exhaust restrictions when I read JWL's description of running an 8BA with all the exhaust from the left side of the engine flowing through the tiny crossover passage in the intake with no loss of power (back to back dyno measured).
Mandrel bends will not add performance to a stock flathead.

Edit: my 38 phaeton has dual exhaust with old (at least 35 year old) "cherry bomb" mufflers that I was prepared to hate and replace (I don't like loud exhaust). Surprisingly it is not objectionable and has that flathead dual exhaust "sound". Stock 38 manifolds, shop bent pipes, and a bit crudely installed.
 
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Hey guys. Thanks for the comments.
I’m not looking for a power increase in removing the restrictions in the exhaust pipes.. I’m more interested in the difference in the sound between a smash bent system and a mandrel bent system. Anyone tried both?
Richard
 
Albert Drake's first book about Rods in Portland, Or, mentioned BRASS tubing from rear diff out [rearward]. Sound? Newc
 
Hey Newc, I haven’t had the opportunity to read Drakes book, it does sound interesting. Dual polished brass pipes out the back would look awesome but I doubt that exhaust from the differential back would have a noticeable effect on the sound.
Richard
 
The difference you are looking for can be very precisely calculated but in this case it is hardly worth it because of the relatively stock engine.
You put all of the numbers into Cholmondeleys annual grillage coefficient and then differentiate and call the sum into a Besel function. In this case the difference comes out .0021 which is not worth worrying about.
 
Pete said:
The difference you are looking for can be very precisely calculated but in this case it is hardly worth it because of the relatively stock engine.
You put all of the numbers into Cholmondeleys annual grillage coefficient and then differentiate and call the sum into a Besel function. In this case the difference comes out .0021 which is not worth worrying about.
Click to expand...

At first, I thought Pete was pulling our legs, then I found this. Wowza. Pete is one smart cookie.

https://en.wikipedia.org/wiki/Bessel_function
 
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