03-01-2023, 10:18 PM | #1 |
Senior Member
Join Date: May 2018
Location: Tallahassee
Posts: 375
|
Exhaust tubes
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 Last edited by Ricosan; 03-03-2023 at 07:03 AM. Reason: Wrong info |
03-01-2023, 11:19 PM | #2 |
Senior Member
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,322
|
Re: Exhaust tubes
Straight pipes.
|
Sponsored Links (Register now to hide all advertisements) |
|
03-02-2023, 05:03 AM | #3 |
Senior Member
Join Date: Jan 2012
Location: Lyman,ME.
Posts: 2,631
|
Re: Exhaust tubes
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
__________________
I'm thinkin' about crankin' My ragged ol' truck up and haulin' myself into town. Billy Joe Shaver |
03-02-2023, 07:49 AM | #4 |
Senior Member
Join Date: May 2010
Location: Chester Vt
Posts: 8,864
|
Re: Exhaust tubes
camshaft & compression, makes a difference, but not every ear is the same.
G |
03-02-2023, 08:49 AM | #5 |
Senior Member
Join Date: Feb 2013
Location: Pittsford NY. USA
Posts: 1,096
|
Re: Exhaust tubes
MagnaFlow glasspacks!
__________________
1952 Ford F1 1965 Ford Falcon Sprint 2007 Ford Mustang GT |
03-02-2023, 09:00 AM | #6 | |
Senior Member
Join Date: May 2010
Location: NJ
Posts: 6,186
|
Re: Exhaust tubes
Sponsored Links (Register now to hide all advertisements)
Quote:
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. |
|
03-02-2023, 11:25 AM | #7 |
Senior Member
Join Date: May 2018
Location: Tallahassee
Posts: 375
|
Re: Exhaust tubes
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 |
03-02-2023, 11:42 AM | #8 |
Senior Member
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,322
|
Re: Exhaust tubes
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.
|
03-02-2023, 11:42 AM | #9 | |
Senior Member
Join Date: May 2010
Location: NJ
Posts: 6,186
|
Re: Exhaust tubes
Quote:
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. |
|
03-02-2023, 11:51 AM | #10 |
Senior Member
Join Date: Feb 2011
Posts: 2,114
|
Re: Exhaust tubes
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!
__________________
Tim Downtown, Ca |
03-03-2023, 06:50 AM | #11 |
Senior Member
Join Date: Sep 2016
Location: Melbourne Australia
Posts: 541
|
Re: Exhaust tubes
Another variable (as I understand it) is how close the mufflers are to the engine.
|
03-03-2023, 07:44 PM | #12 |
Senior Member
Join Date: Jun 2022
Posts: 283
|
Re: Exhaust tubes
|
03-04-2023, 10:12 AM | #13 |
Senior Member
Join Date: Oct 2014
Location: NE Iowa
Posts: 1,665
|
Re: Exhaust tubes
Does blocking the cross over change the sound?
|
03-04-2023, 10:39 AM | #14 |
Senior Member
Join Date: May 2010
Location: CLAYTON DE
Posts: 1,283
|
Re: Exhaust tubes
If you are speaking of the center port, with a divider. It has been reported to sound more like a Chevrolet.
__________________
Enjoy yer day. Tom Hate can't fix what it started. |
03-04-2023, 04:45 PM | #15 |
Senior Member
Join Date: May 2010
Location: South Texas
Posts: 1,631
|
Re: Exhaust tubes
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. Last edited by 38 coupe; 03-04-2023 at 04:52 PM. |
03-07-2023, 08:23 AM | #16 |
Senior Member
Join Date: May 2018
Location: Tallahassee
Posts: 375
|
Re: Exhaust tubes
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 |
03-07-2023, 07:47 PM | #17 |
Senior Member
Join Date: May 2010
Posts: 2,489
|
Re: Exhaust tubes
Albert Drake's first book about Rods in Portland, Or, mentioned BRASS tubing from rear diff out [rearward]. Sound? Newc
|
03-08-2023, 07:49 AM | #18 |
Senior Member
Join Date: May 2018
Location: Tallahassee
Posts: 375
|
Re: Exhaust tubes
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 |
03-08-2023, 11:02 PM | #19 |
Senior Member
Join Date: May 2010
Location: Wa.
Posts: 5,409
|
Re: Exhaust tubes
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. |
03-09-2023, 08:36 AM | #20 | |
Senior Member
Join Date: May 2010
Location: NJ
Posts: 6,186
|
Re: Exhaust tubes
Quote:
https://en.wikipedia.org/wiki/Bessel_function |
|
|
|
Sponsored Links (Register now to hide all advertisements) |
|