Tubular Exhaust Manifold

getblown5.9 said:
not quite as fancy but i got mine on this weekend.

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holy oil feed line!! :eek:
 
of course no problems... you could put a 1" hose in front of it and the center section is only going to flow what it's going to flow. Just odd to see such a huge oil feed! LOL
 
Forrest Nearing said:
of course no problems... you could put a 1" hose in front of it and the center section is only going to flow what it's going to flow. Just odd to see such a huge oil feed! LOL
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Hey now it is what I had on hand in the garage so I used it :D.
Brandon
 
it looks really big on my truck without the spacer to move the turbo down too...it sticks way up LOL...im jut glad that i didnt have to cut that freaking braided hose and put those fittings on...ill never ever buy that junk again. its not a show truck, and rubber hose with push-locks or more than enough for me!
 
Hey Guys,

First... just want to say that all you fabricators have done some very nice work getting these manifolds together! I have not yet finished reading this thread as I'm trying not to miss any pertinent information or opinion.


COMP461 said:
The equal length runners make a big difference, especially in spooling. The primary reason is that you direct each pulse towards the volute of the turbo and the turbine wheel without diluting them. a log manifold allows the pulses to somewhat cancel each other out , and also allows them to put a pressure wave back up the other cylinders as they open their exhaust valves , and this pulse wave acts during what little overlap that exist in a diesel.
The work looks great , it’s a great representation of the cast log manifold in a header.
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Exhaust theory has been around long enough that it can hardly be called theory anymore.... Tuned or equal length primaries have a proven history, both on the dyno and in application. The tuned lengths importance on the pressure pulse of the exhaust flow, is not about the flow itself (doesn't hurt obviously) rather being about equally spaced pulses so that the tuned primaries are more efficient at doing what the designer intends. These equally spaced pressure waves (pulses) act on the turbine wheel in the most efficient manner... net result: quicker spool = more power (sooner). Header flow = more power (later) ... of course there are some other parameters that can effect the total outcome (PSI + fuel for example).

This whole debate really applies to those builders/designers that have to extract every advantage from a given set of parameters. Most of us (well me anyways) are just the average weekend warrior and really don't have to have that last 10HP to compete.

Anyway... I think this is my first post here, so I'm going back to finishing this thread and working on my 69 Ford Cummins Crew Cab.

HRDROKN
 
Although i can not quote from published documents due to losing my extensive book colllections to a basement flood a few years ago, I can still impart some of that knowledge on header design

the equal length theory has been around as long as racing

It is however a misnomer to think it is the end all and be all.

Why - because the tuned length only works in a very narrow rpm band - of about 5-800 rpm - and anything outside of that range is just as disruptive as unequal lengths is to air flow and resonance tuning

However - if one has the time resourses and a dyno one can design a header to make up for the irregularities in the various ports, both intake and exhaust that is substantially a better compromise than equal length is..

This is accomplished by varying the pipe diameter, even to using several pipe diameters by stepping, in the same pipe length, as well as using varying pipe lengths in the same header, and or cylinder bank.

It can also be useful to pair different cylinders than one normally would, in order to gain an increase in pulse modulations or a decrease as the case may be

This kind of experimentation can extend the useful tune range by as much as another 1000 rpm in many instances according to research done by more than a few shops

It is a fine line in a pressurized motor (turbo or supercharged) between too little and too much pipe diameter - which will kill resonance and pulse modulation faster than unequal length will

It has been shown that a little too small is preferable to a little too big in a pressurized motor as the hp losses are less.

Keeping the piping short, and wrapped has also shown better results in many cases, rather than worrying about tuned length.

At the end of the day it is about all around drivability, or purpose built, brief rpm range, all out hp attempts. i think all around drivability would be the preferred premise and results most of us would want

In reading the various posts - one sticks out in my mind - a loss of 200hp under the curve - does that mean same overall hp, but a straighter line where the median hp was 200 less or does it mean the curve straightened out but was longer or prolonged and the peak hp was more by some margin or or or ??

For us pullers, and possibly even the draggers, more peak hp and less bottom end might prove to be a good thing, but on a street truck a loss of 200 hp in the driving range would be downright terrible

Can someone clarify the 200hp statement?
 
On JLiberts truck he was running the beta 3rd gen style header, which didn't have the pulses split. He lost 100-almost 200 hp in the lower RPM range then ramped up to 10 more peak hp past 3k. I haven't seen the graph yet, but he said it made the power further and longer in the powerband, it didn't hit a wall in the higher rpm range, I am not sure if he ran to 4k or 3500 though.

What this tells me is the tubing diameter is too big for a street truck and better for a puller or race truck, we are fighting flow verses velocity. I will try some 1.25id runners instead of the 1.5 I use now and split the pulses, then see what happens.

I think the 2nd gen manifolds will be the ones to really shine, especially Tjs and Nicks that are using a T4 flange.

I really appreciate everyone's input!:Cheer:
 
Bodie, did JLibert notice significantly worse spool with his 3rg gen manifold or was there other issues at work causing the loss under the curve?
 
I really havent had a good chance to talk with him, but that is all it really can be. My sotp meter tells me I have faster spool. I guess I need to buy a data logger and really put all this stuff into actual numbers. I am trying to talk the old lady into letting me get a race truck so I can really test.

My buddy has a 95 12v 2wd single cab I have been after for a while, maybe one of these days he will give in.:bow:
 
All dyno runs done on Brown's Diesel's Dynojet 248, uncorrected. All runs were started at 10 psi boost, and 60mph in 6th gear / NV5600. No optical pick up, so no rpm/TQ readings.

677 stock manifold, 687 Armstrong manifold.

Erick at Brown's diesel has the graphs. (Erick, send em over or post them when you get a chance.)

I picked up 10hp on top, and the power didn't fall off as sharply after peak. The power curve was noticably smoother at higher RPMs, which you can see when the graphs are posted. However, hp under peak was down significantly.

On my truck with an A5K and Flux 2's, It was noticably harder to make 10psi with the header than it was with the stock manifold used in the initial testing. Peak boost numbers remained similar. EGT differences are too subjective to measure, so I won't attempt to provide potentially inaccurate information in that regard.

As Bodie mentioned, a pulling truck that doesn't see less than 3000 rpm would likely benefit from this design, but the power losses under the curve aren't suitable for a daily driver equipped like mine.

I've had the Armstrong manifold on my truck for over a week with no adverse issues.

The exhaust sound is slightly different than the stock manifold at idle, and quieter and smoother sounding at higher rpms.


Bodie, get me a manifold with the smaller tubing, and I'll dyno again under the same conditions. I plan to sell this manifold, or send it back to bodie to get fitted with the smaller diameter tubing.

-JP
 
Had mine on for a week now. No problems, had it close to 2000 degrees several times with no issues yet.
 
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