Dual exhaust vs single exhaust

[Don Jordan]

speaking of that sort of stuff I have an extra manifold if some one is interested.

[LAKOTA169]

On my '37, I have a stock exhaust pipe to the muffler. Coming out of the muffler, is a Y pipe with dual 2 1/2 pipes. The last maybe 15", has 3" chrome echo cans. This is what was on the car when I bought off a web site. Don't know what kind of muffler it is, but has a nice sound at idle and a nice rumble when slowing down. I don't think it made it any faster (Don't have a "before" to compare), but in my mind, it sounds fast. And I'm happy with that. Enjoy going down through the business district in second gear with cars parked on both sides and see if I can set of the car alarms.

 

[55 Fargo]

Sounds like nobody has done a strict before-and-after comparison of stock exhaust versus dual exhaust for gas mileage and/or HP. That would certainly be interesting.

I seem to recall some magazine people doing fuel consumption test with V-8's in various cars showing that going from single to dual exhaust was just about easiest and most sure-fire way to increase both HP and mileage.

Anyone know of any old articles or research done on flathead sixes?

Here you go, 265 flattie powered dragster, so yes they can build HP. This engine would have a few more ponies than the average flatheads on here.

Check out the vid in this link   http://p15-d24.com/topic/36223-265-powered-dragster/

[Dan Hiebert]

I see "answered" already.  But - when considering intake and exhaust, remember than an engine is basically just an air pump.  The more efficiently the air enters, and exhaust exits, the better the engine will run.  Its the tweaking on either end (and some in the middle) that makes the power and/or efficiency, such as more fuel to the air, or more air coming in, increasing compression, more free flowing exhaust, etc.  Better exhaust = better sound, and so on.  Its that tweaking and getting the right combinations for the results we want that makes this hobby interesting and fun.        

[Don Coatney]

Very interesting reading. I would like to thank all those providing opinions.

I have been waiting to see where this thread would go before responding. So I opened the thread this morning and see where the thread starter selected his own response (seen in the above quote) as the best answer even though I do not see an answer in the best answer.

 

Anyway here is my take on a dual exhaust system on a Mopar flathead six engine.

 

Smoking tires. A set of duals is not the same as adding a modern V-8 engine and no matter how the dual system is configured your flathead 6 is still a flathead six.

 

Improved fuel economy. If you drive pretending you have an egg between your shoe and the gas pedal you will see an improvement in gas mileage. Also every time you tromp the brake pedal your fuel efficiency decreases as you have already spent the money to get up to speed and by hitting the brakes you are not going as far on the money you already spent. My point being that your driving style has a lot more to do with fuel efficiency than a dual exhaust system has. And in my opinion I did not buy my P-15 to be fuel efficient. I bought it to have fun. I have never kept a log and calculated MPG's as that is not my idea of having fun.

 

The "COOL" factor. In my opinion that is the prime reason for installing dual exhaust on a flathead 6. No matter what mufflers you use there is a distinct sound made by splitting the exhaust on any six cylinder engine. I have heard tell of many different configurations on making this split. 3X3, 4X2, 5X1, use of crossover pipes ETC. Each configuration makes it own distinctive sound. I have had folks asking to see my engine after they heard my exhaust and observed the two pipes under my rear bumper. These folks are amazed when the see a flathead 6 under the hood.

[casper50]

vids don't work for me

[Don Coatney]

vids don't work for me

For some unknown reason my Photobucket links are not working today. Try these

 

 

http://vidmg.photobucket.com/albums/v65/DonCoatney/movie/MVI_0030.mp4

 

http://vidmg.photobucket.com/albums/v65/DonCoatney/movie/MVI_3269.mp4

[casper50]

Sounds pretty nice Don.

[Plymouthy Adams]

hey I recognize that first film location...(where are my royalties)....for the record..there is a huge pecan tree off the left former of the apron ...

[Don Coatney]

This photo shows the shop door tree.

 

[Conroe Powdercoating]

For some unknown reason my Photobucket links are not working today. Try these

 

 

http://vidmg.photobucket.com/albums/v65/DonCoatney/movie/MVI_0030.mp4

 

http://vidmg.photobucket.com/albums/v65/DonCoatney/movie/MVI_3269.mp4

sounds great!

[sorensen_dk]

For the record.....it would very interesting if someone had photos or brochures showing a dual carb/exhaust Dodge truck chassis with the entire exhaust system exposed. I'm sure the Chrysler engineers had a cost effective configuration worked out.

 

Tom

[48Dodger]

I came to this thread a little late....I tried to read it all, but didn't, so I apologize if what I write has been said already.

 

The cam in any engine has overlap...the intake and the exhaust opened at the same time.

If the exhaust is to big, the gases will hang around and get sucked back in.

The tuning of the exhaust is like a straw you shoot a spit ball through. 

If the the straw is to big, you have a difficult time shooting that spitball down the pipe, and risk sucking it back down your throat. 

The engine needs an exhaust that's tuned so it can shoot spitballs made of exhaust.

Its doesn't matter if its split, dual, or single........  

 

48D

[Lumpy]

Yes, scavenging. That's why you wouldn't want a pipe bigger than the outlet of the exhaust manifold, be it split or stock. Length of the system also helps scavenging, with cars no problem, motorcycles its' hard to get the pipes long enough to scavenge, so the exhaust is tuned in other ways.

Blown or turbo engines being the exception...then it's bigger is better.

Scavenging not to be confused with back pressure. Back pressure is never good....although some argue that you have to have some.

k.

[blueskies]

 

The "COOL" factor. In my opinion that is the prime reason for installing dual exhaust on a flathead 6. No matter what mufflers you use there is a distinct sound made by splitting the exhaust on any six cylinder engine.

 

What Don said-

 

I did just about everything I could do to my flatty to get worse mileage, and it still got 19-20 on the highway at 70mph

 

Pete

 

 

[Don Coatney]

I do remember the sound of your #2 engine.

 

[Plymouthy Adams]

I am very much surprised at the fact Don did not take full advantage of the English language and such when describing this race..as it was only he and Pete..he had a prime opportunity to say that Don Placed first and Pete came in dead last....!!

[Don Coatney]

Those were fun days.

 

 

[Plymouthy Adams]

Don..hard to tell if you were mad...determined..or just passing gas...!

[Don Coatney]

Actually blueskies altered this photo in photo shop but he did a good job. He tried to make it look like I was loosing but he knows that is not the case.

 

[greg g]

or in the words of Dale Ernhart  Second is first loser.

[Mark D]

What Don said-

 

I did just about everything I could do to my flatty to get worse mileage, and it still got 19-20 on the highway at 70mph

 

Pete

 

 

Been spending alot of time on your website lately. Want to take a moment to thank you for keeping those pages alive. Of particular interest lately have been the OD pages.

 

Many thanks Pete.

Edited July 17, 2014 by Mark D

[Don Coatney]

Been spending alot of time on your website lately. Want to take a moment for keeping those pages alive. Of particular interest lately have been the OD pages.

 

Many thanks Pete.

Pete and I were going to send this dinner tab to Norms Coupe. But he shared the nuts so now we will send it to you.

 

 

 

[blueskies]

Pete and I were going to send this dinner tab to Norms Coupe. But he shared the nuts so now we will send it to you.

 

 

There's a whole lotta bull in this pic...

 

Pete

Edited July 17, 2014 by blueskies

[Mark D]

Guess I been sharing too much love today, but at least I tried....