Which Exhaust Manifold?
08-29-2008, 06:53 PM
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Which Exhaust Manifold?
I am going to be purchasing a BD Super B Single turbo shortly, and also want to install a new manifold.
What brand should I get and why?
ATS, BD, etc?
I heard PDI has started making them for 03-7 Cummins, but nothing appears on their website...
ATS Pulse Flow: ATS Multi-Piece Pulse Manifolds for the Dodge Cummins application have pulse exhaust flow design, helping to spool up the turbocharger sooner with less exhaust backpressure and increase fuel efficiency. This pulse manifold design eliminates the problems with shrinking and breaking, as well as cracking and gasket issues.
All Manifolds come Pre-Assembled with Black High Temperature Coating and Pre-Tapped for Pyrometer Probe.
ATS Exhaust Manifolds are available for the new Common Rail Cummins as well as both the 12 and 24 Valve Cummins.When looking for a performance exhaust manifold go with the leader, ATS is the original designer/manufacturer holding the patent on the ball flange construction, beware of other cheap copies being produced in other countries.
http://www.atsdiesel.com/ATSWebsite/...ExManifold.asp
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BD Pulse:
Stop exhaust manifold cracks in their tracks with BD’s new Pulse exhaust manifold for the Dodge-Cummins. Cast from high silicon ductile iron, the Pulse features expansion joints that allow the manifold to expand and contract without cracking or exhaust leaks. As the name would imply, these manifolds are “pulse tuned” to assist in combustion chamber evacuation and increased exhaust flow.
The result is quicker turbo spool-up, reduced backpressure, increased power and better fuel economy. Some kits include stainless steel fasteners and washers to prevent lost or loose manifold bolts - gaskets are available separately.
http://www.dieselperformance.com/ind...duct/index/17P
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Other than these two, what other manifolds are out there?
I figure both will do a great job....but was not sure if one was better than the other.....
I thought that maybe since I was buying a BD turbo that I should get a BD manifold?
What brand should I get and why?
ATS, BD, etc?
I heard PDI has started making them for 03-7 Cummins, but nothing appears on their website...
ATS Pulse Flow: ATS Multi-Piece Pulse Manifolds for the Dodge Cummins application have pulse exhaust flow design, helping to spool up the turbocharger sooner with less exhaust backpressure and increase fuel efficiency. This pulse manifold design eliminates the problems with shrinking and breaking, as well as cracking and gasket issues.
All Manifolds come Pre-Assembled with Black High Temperature Coating and Pre-Tapped for Pyrometer Probe.
ATS Exhaust Manifolds are available for the new Common Rail Cummins as well as both the 12 and 24 Valve Cummins.When looking for a performance exhaust manifold go with the leader, ATS is the original designer/manufacturer holding the patent on the ball flange construction, beware of other cheap copies being produced in other countries.
http://www.atsdiesel.com/ATSWebsite/...ExManifold.asp
----------------------------------------------------------
BD Pulse:
Stop exhaust manifold cracks in their tracks with BD’s new Pulse exhaust manifold for the Dodge-Cummins. Cast from high silicon ductile iron, the Pulse features expansion joints that allow the manifold to expand and contract without cracking or exhaust leaks. As the name would imply, these manifolds are “pulse tuned” to assist in combustion chamber evacuation and increased exhaust flow.
The result is quicker turbo spool-up, reduced backpressure, increased power and better fuel economy. Some kits include stainless steel fasteners and washers to prevent lost or loose manifold bolts - gaskets are available separately.
http://www.dieselperformance.com/ind...duct/index/17P
--------------------------------------------------------------
Other than these two, what other manifolds are out there?
I figure both will do a great job....but was not sure if one was better than the other.....
I thought that maybe since I was buying a BD turbo that I should get a BD manifold?
08-29-2008, 07:04 PM
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08-29-2008, 07:19 PM
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Well here is an opinion. I own my own racing engine shop and have an understanding of how AIR makes an engine make power. My head porter and I looked at BD and ATS manifolds at Indy on display and both agreed the ATS had much better design for airflow. If you compare the two side-by-side look at the turbo flange area where it transitions into the "main cavity". Pay attention to the radius. My head porter even had me weld up material or the outside of his stock manifold so he could make his stocker flow better. Keep in mind that air starts to tumble if you bend it sharply 7 degrees or more and the smoother the radius with no "casting imperfections" will flow more air, thus making more power. Engines make power by pumping air, the more in and out the more you can fuel it to make more power. The ATS also had better "short side" turns out of each port. The BD has a distinct sharp corner to bend the air around. They are about the same price but even if the ATS was more that is the one I'd buy. And a little help with a die grinder will help out as well. The shape of a port is as much as if not more important than the size. This creates more "air speed" rather than "air volume".
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08-29-2008, 11:02 PM
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Well here is an opinion. I own my own racing engine shop and have an understanding of how AIR makes an engine make power. My head porter and I looked at BD and ATS manifolds at Indy on display and both agreed the ATS had much better design for airflow. If you compare the two side-by-side look at the turbo flange area where it transitions into the "main cavity". Pay attention to the radius. My head porter even had me weld up material or the outside of his stock manifold so he could make his stocker flow better. Keep in mind that air starts to tumble if you bend it sharply 7 degrees or more and the smoother the radius with no "casting imperfections" will flow more air, thus making more power. Engines make power by pumping air, the more in and out the more you can fuel it to make more power. The ATS also had better "short side" turns out of each port. The BD has a distinct sharp corner to bend the air around. They are about the same price but even if the ATS was more that is the one I'd buy. And a little help with a die grinder will help out as well. The shape of a port is as much as if not more important than the size. This creates more "air speed" rather than "air volume".
Your statements about the nature of airflow need a little correction/clarification/context.
I'm no expert on fluid dynamics, but I *do* know that there's nothing magical about that 7 degree number you quote. The ability of air to flow in a laminar manner is a function of air velocity, pressure, humidity, etc. Think in terms of air viscosity and inertia and you'll get my meaning.
If the air flow is travelling slowly, it can stay laminar at even 60 degree bend (assuming a tight, but rounded radius).
At higher speeds, flow separation (and internal shearing, which creates drag due to internal pressure variance) happens a lot easier, and changing air direction while preserving laminarity is quite the challenge indeed.
Keep in mind that air is both elastic and compressible, which makes its flow qualities somewhat unique.
Finally, the ideal flow conduit for intake and exhaust are slightly different, a result of the fact that air naturally flows more orderly when expanding from higher pressure to low than it does when being sucked in and compressed from low pressure to high.
h
08-30-2008, 07:02 AM
#9
I'd favor the ATS, too from what I've seen.
Your statements about the nature of airflow need a little correction/clarification/context.
I'm no expert on fluid dynamics, but I *do* know that there's nothing magical about that 7 degree number you quote. The ability of air to flow in a laminar manner is a function of air velocity, pressure, humidity, etc. Think in terms of air viscosity and inertia and you'll get my meaning.
If the air flow is travelling slowly, it can stay laminar at even 60 degree bend (assuming a tight, but rounded radius).
At higher speeds, flow separation (and internal shearing, which creates drag due to internal pressure variance) happens a lot easier, and changing air direction while preserving laminarity is quite the challenge indeed.
Keep in mind that air is both elastic and compressible, which makes its flow qualities somewhat unique.
Finally, the ideal flow conduit for intake and exhaust are slightly different, a result of the fact that air naturally flows more orderly when expanding from higher pressure to low than it does when being sucked in and compressed from low pressure to high.
h
Your statements about the nature of airflow need a little correction/clarification/context.
I'm no expert on fluid dynamics, but I *do* know that there's nothing magical about that 7 degree number you quote. The ability of air to flow in a laminar manner is a function of air velocity, pressure, humidity, etc. Think in terms of air viscosity and inertia and you'll get my meaning.
If the air flow is travelling slowly, it can stay laminar at even 60 degree bend (assuming a tight, but rounded radius).
At higher speeds, flow separation (and internal shearing, which creates drag due to internal pressure variance) happens a lot easier, and changing air direction while preserving laminarity is quite the challenge indeed.
Keep in mind that air is both elastic and compressible, which makes its flow qualities somewhat unique.
Finally, the ideal flow conduit for intake and exhaust are slightly different, a result of the fact that air naturally flows more orderly when expanding from higher pressure to low than it does when being sucked in and compressed from low pressure to high.
h
!Hohn, you always have some very scientific answer.What exactly do you do for a living?I enjoy your posts.Wish I understood them better!
08-30-2008, 07:35 AM
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This is more like "aerodynamics 201" so it's not something you necessarily would have had in high school. Don't sweat it!
What do I do for a living? I am a developmental engineer at Cummins.
Aerodynamics is really not that hard to understand once you kinda learn how air "thinks".
For example, think about air flowing through a round tube and making a 45 degree turn. An important element of that turn is the bend radius-- basically how long is that bend. If the has a sharp angle inside, there is essentially no bend radius-- it's a hard transition.
But you'll more commonly see something a little more gradual.
For example, look at this picture:
From left to right, the "bend radius" gets smaller, and as a result, the speed at which the air can flow smoothly through the turn is slower.
This because air has mass, and just like car taking a corner, it needs a more gradual turn at high speed.
But air won't "go off the road' in the way you may be picturing. Instead, you'll see a pocket of lower pressure on the inside of the bend, and as this becomes a partial vacuum, the flow in the tube will get chaotic as it tries to restore the pressure balance.
Think of a flag waving in the wind. Why does it wave back and forth? It's because the flag is constantly moving from high pressure to low pressure (nature always seeks equilibrium), but it overcorrects and so it ends up "chasing its own tail" so to speak.
When air is flowing chaotically, it's called "turbulence". Anyone who's flown understands what this is.
When air flows smoothly, it's said to be "laminar" because the air will tend to follow flowstreams that resemble layers in the flow. (perhaps you see the word relationships between laminar, laminate, and layer).
Anyone, feel free to ask more questions if your interested.
jh
What do I do for a living? I am a developmental engineer at Cummins.
Aerodynamics is really not that hard to understand once you kinda learn how air "thinks".
For example, think about air flowing through a round tube and making a 45 degree turn. An important element of that turn is the bend radius-- basically how long is that bend. If the has a sharp angle inside, there is essentially no bend radius-- it's a hard transition.
But you'll more commonly see something a little more gradual.
For example, look at this picture:
From left to right, the "bend radius" gets smaller, and as a result, the speed at which the air can flow smoothly through the turn is slower.
This because air has mass, and just like car taking a corner, it needs a more gradual turn at high speed.
But air won't "go off the road' in the way you may be picturing. Instead, you'll see a pocket of lower pressure on the inside of the bend, and as this becomes a partial vacuum, the flow in the tube will get chaotic as it tries to restore the pressure balance.
Think of a flag waving in the wind. Why does it wave back and forth? It's because the flag is constantly moving from high pressure to low pressure (nature always seeks equilibrium), but it overcorrects and so it ends up "chasing its own tail" so to speak.
When air is flowing chaotically, it's called "turbulence". Anyone who's flown understands what this is.
When air flows smoothly, it's said to be "laminar" because the air will tend to follow flowstreams that resemble layers in the flow. (perhaps you see the word relationships between laminar, laminate, and layer).
Anyone, feel free to ask more questions if your interested.
jh
08-30-2008, 10:21 AM
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Well I will leave all the "over everyones head" talk to you. I was trying to use a level of description that could be understood by everyone. While I understand your train of thought we would need many, many more long replys from you explaining air flow in that detail. And still some would not grasp the idea. I will not get into any kind of pissing match with you on air flow, I just tried to give a short,simple explaination. But the bottom line to this thread is which one would YOU get? The ATS has my vote. I was actually surprized when I saw the BD manifold. I am sure BD spent a lot of money to design and have a casting made, it could be so much better.
08-30-2008, 10:31 AM
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Oh, I am in Granger Indiana. Near South Bend/Elkhart area. While my engine work has been gas engines for drag and circle track cars for 20 years I have been venturing off into this diesel world too. The main warehouse I get most of my parts from is stocking more and more diesel truck performance items that I could sell and install. I just need to think of another name for my shop to include "diesel performance", and I haven't had much luck thinking of a good name.
08-30-2008, 04:59 PM
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