Header Fab (LARGE PICS- 56K dialup users are hereby warned)

1BADRAM said:
Brushpuller: How does "to much flow hurt spoolup"? Please explain.
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I was about to ask the same question. The only time ive had that make sense is when my truck was stock and i put the 5inch exhaust on it. Since then its been more flow=faster spool up
 
Forrest Nearing said:
why would it be backed up in the header? :confused:

a straight 6 with equal length primaries and a divided collector will have equally timed exhaust pulses contacting the turbine wheel
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Exactly.

This is the only manifold I have seen with equal length and divided merge collector. The only downfall to the manifold is the size.
The ones like comp461 has are a good design as well because of the merge collector. Although they aren't equal length the merge collector is the biggest restriction. I am not a scientist but temperature reduction and flow is made with merge collectors not log style manifolds.

But everyone is entitled to their opinion and all of this information is useless without a back to back dyno shootout. Comp461, bodie, stock manifold, ats should all donate a manifold to somebody with the resources for some unbiased dyno/temperature testing.

cummins1.jpg
 
So at what point is the increased diameter too much? So with let's say 500-600hp, is the 2" pipe used in this manifold to large? I've been thinking about building one after seeing this. I'm in the process of building an intake horn, this may be the next project.
 
Each side of a T4 divided port is 1.375x2.000 which is 2.75 in2.

Each side of a T6 divided port is 1.64x2.4 which is 3.936 in2.

A 2.07 ID pipe has a cross section of 3.36 in2.

If you're only running a non-wastegated T4, then it probably wouldn't be worth it. If you're running an external wastegate, then it's definately worth it to be 2.07" instead of 1.75" or 1.50" ID.
 
Forrest Nearing said:
why would it be backed up in the header? :confused:

a straight 6 with equal length primaries and a divided collector will have equally timed exhaust pulses contacting the turbine wheel
Click to expand...

Drive psi... that is exh. backed up in the header. Mine has about 1 1/4 pounds of back psi to 1 pound of boost. Think of it like your air compressor, it pumps in air like a pulse but doesnt come out the hose in a pulse!!!
 
sdubfid said:
Exactly.

This is the only manifold I have seen with equal length and divided merge collector. The only downfall to the manifold is the size.
The ones like comp461 has are a good design as well because of the merge collector. Although they aren't equal length the merge collector is the biggest restriction. I am not a scientist but temperature reduction and flow is made with merge collectors not log style manifolds.

But everyone is entitled to their opinion and all of this information is useless without a back to back dyno shootout. Comp461, bodie, stock manifold, ats should all donate a manifold to somebody with the resources for some unbiased dyno/temperature testing.

cummins1.jpg
Click to expand...

I did a back to back dyno runs...stock to header..i made 26hp and 36tq their is power to be made with the right air speed!!!
 
Muddin_dude06 said:
Increased diameter of the manifold past a certain point would cause the gasses inside to loose velocity, and thus hurt spoolup.
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This is true!!! Mine was super laggy but realy came on in the upper mid range and up in the RPM range. To get mine to spool with a tight auto i put a venturi in the collector to speed the exh. gas up to spool the turbo. With a stick you can get by with a little more then an auto. Also with a bigger turbo i would think it would amplfy the lag. Mine is a hx 40/ 14 cm and it was undrivable with just the free flowing 2 inch piping!
 
brushpuller said:
Drive psi... that is exh. backed up in the header. Mine has about 1 1/4 pounds of back psi to 1 pound of boost. Think of it like your air compressor, it pumps in air like a pulse but doesnt come out the hose in a pulse!!!
Click to expand...


Sorry, i just looked through my notes and the drive psi #'s i posted here is wrong..:bang .I have 42lbs of back psi at 40lbs of boost. that sounds more like it!! :charger:
 
brushpuller said:
Drive psi... that is exh. backed up in the header. Mine has about 1 1/4 pounds of back psi to 1 pound of boost. Think of it like your air compressor, it pumps in air like a pulse but doesnt come out the hose in a pulse!!!
Click to expand...

Correct :clap:

Dale
 
brushpuller said:
Drive psi... that is exh. backed up in the header. Mine has about 1 1/4 pounds of back psi to 1 pound of boost. Think of it like your air compressor, it pumps in air like a pulse but doesnt come out the hose in a pulse!!!
Click to expand...

so what do you think is happening when you're spooling up? you know... when drive PSI is considerably lower than boost?

also, gas still travels in waves and pulses even if it's under pressure
 
I've found the header likes to be smaller than you'd think. I got our's to start to react at around 1.5" and 12" long primairies. I also found better response to collect the primaries,123, 456, about 6" before the turbo. The secondaries are 1.75". Length and diameter are critical I belive.
 
Forrest Nearing said:
so what do you think is happening when you're spooling up? you know... when drive PSI is considerably lower than boost?

also, gas still travels in waves and pulses even if it's under pressure
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Drive PSI is first... so you'll have drive PSI befor boost, Little drive PSI very little boost!


Oh im sure it does to some minuit amount, but not enough to make a differance in turning the exh. wheel!!!
 
jcj said:
I've found the header likes to be smaller than you'd think. I got our's to start to react at around 1.5" and 12" long primairies. I also found better response to collect the primaries,123, 456, about 6" before the turbo. The secondaries are 1.75". Length and diameter are critical I belive.
Click to expand...

I agree!!!!
 
I have ran numerous tubular manifolds, so big asome small so long some short... short seems to be best for spoolup, long is great for top end, dont ask me why I dont know just dyno number and track tested parts. I made 20more hp with a longtube header 321 ss, as where I made 20 less hp with a short routed header both equal length, made 34ftlbs more with the short header due to spoolup.... but also lost the tourque faster... I think it all about money and space to work in? either way you are giving something up to get something the best you can do it comprimise. I would rather have the top end for drag racing rather have the torque for sled pulling.
 
jcj said:
I've found the header likes to be smaller than you'd think. I got our's to start to react at around 1.5" and 12" long primairies. I also found better response to collect the primaries,123, 456, about 6" before the turbo. The secondaries are 1.75". Length and diameter are critical I belive.
Click to expand...

What do you mean by "start to react"? Good results, better spool, more hp, or a combination of the above?
 
outlaw99 said:
I have ran numerous tubular manifolds, so big asome small so long some short... short seems to be best for spoolup, long is great for top end, dont ask me why I dont know just dyno number and track tested parts. I made 20more hp with a longtube header 321 ss, as where I made 20 less hp with a short routed header both equal length, made 34ftlbs more with the short header due to spoolup.... but also lost the tourque faster... I think it all about money and space to work in? either way you are giving something up to get something the best you can do it comprimise. I would rather have the top end for drag racing rather have the torque for sled pulling.
Click to expand...

Can you give us an idea of what primary length was in a "short" header vs. the "long header"? Inquiring minds want to know! :Cheer:
 
outlaw99 said:
I have ran numerous tubular manifolds, so big asome small so long some short... short seems to be best for spoolup, long is great for top end, dont ask me why I dont know just dyno number and track tested parts. I made 20more hp with a longtube header 321 ss, as where I made 20 less hp with a short routed header both equal length, made 34ftlbs more with the short header due to spoolup.... but also lost the tourque faster... I think it all about money and space to work in? either way you are giving something up to get something the best you can do it comprimise. I would rather have the top end for drag racing rather have the torque for sled pulling.
Click to expand...

did you try coating/wrapping/insulating the long tube to keep the heat in it better? curious if it could end up being the best of both worlds
 
The "pulses" or waves will become one if the header is too small or to big. Too small they'll get backed up and all run to gether. Same with too large/ too long, they'll lose velocity and run to gether. The valves will create waves or pulses, under presure or not. A turbo header is so critical like on a N/A engine but any time you can give a nice path for the air to go it will benifit.
 
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