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Discussion Starter #1
which and why? assuming same price? im lookin at the jba shorties and high flows, but at mopar supercenter the longtubes are goin for a steal price.

where are the main differences? in performance and sound?
 

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shorties normally will have no effects on o2 signals.
Shorties give you a more low end ponies and sometimes very little 1-3 hp at high end.
Long tube is the opposite , You can sometimes lose horsepower at low rpms but gain massive 10+ at higher rpm.
 

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For daily driving shorties might be the way to go, but if you do any racing of any sort whether it be track or street I would reccomend you get long tubes. I wish I would of gone with long tube. My JBA shorties didn't make a big difference in sound, I would think the long tubes would have a better sound. Mopar supercenter has a great price for the long tube.
 

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x2 i think mopar is the way to go right now. Although tbryne or someone is offering one of those "call us for a cheap price " on kooks. "too cheap to post" things. Blah
 

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I think longtubes give you a better sound. As for performance, there probably not much of a difference.
 

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shorties normally will have no effects on o2 signals.
Shorties give you a more low end ponies and sometimes very little 1-3 hp at high end.
Long tube is the opposite , You can sometimes lose horsepower at low rpms but gain massive 10+ at higher rpm
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Why does it seem that most here state that LTs are good for HighRPMs and Shorties are good for LowRPMs. Am I missing something? Please read:

Headers 101 ( Header Basics - A Guide To Understanding )

You have probably heard words like: back pressure, scavenging, tuned length, merged collector, rotational firing order, compatible combination and many others that meant something, but how they relate to a header may be a little vague. This article should give you a basic understanding of how a header works, what the terminology means, and how it plays a part in the header's performance gains.

The first misconception that needs to be cleared up is that a header relieves backpressure, but a certain amount of backpressure is needed for optimum performance. Just the opposite is true. A good header not only relieves the backpressure, but goes one step further and creates a vacuum in the system. When the next cylinder's exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term "Scavenging" means.

The first consideration is the proper tube diameter. Many people think "Bigger is Better", but this is not the case. The smallest diameter that will flow enough air to handle the engine's c.c. at your desired Red Line R.P.M. should be used. This small diameter will generate the velocity (air speed) needed to "Scavenge" at low R.P.M.s. If too small a diameter is used the engine will pull hard at low R.P.M.s but at some point in the higher R.P.M.s the tube will not be able to flow as much air as the engine is pumping out, and the engine will "sign off" early, not reaching its potential peak R.P.M. This situation would require going one size larger in tube diameter.

The second consideration is the proper tube length. The length directly controls the power band in the R.P.M. range. Longer tube lengths pull the torque down to a lower R.P.M. range. Shorter tubes move the power band up into a higher R.P.M. range. Engines that Red Line at 10,000 R.P.M. would need short tube lengths about 26" long. Engines that are torquers and Red Line at 5,500 R.P.M.s would need a tube length of 36". This is what is meant by the term "Tuned Length". The tube length is tuned to make the engine operate at a desired R.P.M. range.

The third consideration is the collector outlet diameter and extension length. This is where major differences occur between four cylinder engines and V-8 engines. The optimum situation is the four cylinder because of it's firing cycle. Every 180 degree of crankshaft rotation there is one exhaust pulse entering the collector. This is ideal timing because, as one pulse exits the collector, the next exhaust valve is opening and the vacuum created in the system pulls the exhaust from the cylinder. In this ideal 180 degree cycling the collector outlet diameter only needs to be 20% larger than the primary tube diameter. (Example: 1 3/4" primary tubes need a 2" collector outlet diameter.) The rule of thumb here is two tube sizes. This keeps the velocity fast to increase scavenging, especially at lower R.P.M.s. Going to a larger outlet diameter will hurt the midrange and low R.P.M. torque.
The amount of straight in the collector extension can move the engines torque up or down in the R.P.M. range. Longer extension length will pull the torque down into the midrange.

Engines that "Red Line" at 10,000 R.P.M. would only need 2" of straight between the collector and the megaphone. This is just enough length to straighten out the air flow before it enters the megaphone. This creates an orifice action that enhances exhaust velocity.
In the case of V-8 firing order, the five pulses fire alternately back and forth from left to right collector, giving the ideal 180 degree firing cycle. Then it fires two in succession into the left collector, then two in succession into the right collector. If the proper collector outlet diameter is being used (two sizes larger than primaries) the two pulses in succession load up the collector with more air than it can flow. This results in a very strong midrange torque, but causes the engine to "sign off" early, not reaching its potential peek R.P.M. The improper firing order on a V-8 engine results in the need to use large diameter collectors so the engine will perform well at high R.P.M.s. Unfortunately the large diameter collectors cause a tremendous drop in air velocity, resulting in less scavenging through the entire R.P.M. range.
Often cams are used with extended valve timing to help the exhaust cycling. This results in valve timing overlap (Intake and Exhaust valves both open at T.D.C.) which causes a "Reversion"cycle in the exhaust. When this happens, exhaust actually backs up into the cylinder causing intake air to be pushed back out the intake. This reversion causes "Standoff" (fuel blowing out of the Intake) at low R.P.M.s. This whole improper cycling has resulted in a number of "Cure Alls" to help stop this reversion and standoff.
The plentum intake was created to stop the fuel "Standoff". Then came "Anti Reversionary" Cones in the exhaust tubes, and stepped tube diameter in the header, extended collector lengths and even plentums in the exhaust tubes.

In this chain of events beginning with improper firing order, a series of cures has developed, each one causing a new problem.

The optimum cure to this whole problem is to correct the exhaust firing cycle. The two cylinders that fire in succession into each collector have to be separated. This can be done partially by a "Tri-Y" header, where the four primary tubes from each bank merge into two secondary tubes (separating the two pulses firing in succession) and finally collect into a single collector. This type of header helps, but the two pulses are still coming back together at the collector.

The second optimum cure is to cross the two center tubes from each bank, across the engine running them into the collector on the opposite side. This makes the firing cycle in each collector 180 degrees apart, the same as a four cylinder engine. Once this firing order is achieved, the small collector outlet diameter can be used and the "High Velocity Scavenging" at low R.P.M.s cures the reversion problems and eliminates the need for extreme cam duration.

This sounds so easy, you are probably asking why wasn't this done from the start?

If you have ever seen a set of 180 degree headers you would understand.
On today's cars, with space virtually nonexistent, crossing four tubes either under the oil pan or around the front or rear of the engine presents major problems. On racing applications where it is possible, there is still the problem of keeping the tube length down to a reasonable 32" long. If that's not enough challenge, then try to arrange the tubes into each collector so they fire in a "Rotational Firing" pattern. Then you have, what has been called "A Bundle of Snakes".

Arranging the tubes to fire rotationally adds to the scavenging capabilities. The exhaust gas exiting one tube, passing across the opening of the tube directly beside it, creates more suction on that tube than it would on a tube on the opposite side of the collector.

The next problem is "Turbulence" in the collector. When four round tubes are grouped together in a square pattern, so a collector can be attached, you notice a gapping hole in the center of the four tubes. The standard method in manufacturing headers is to cap this hole off with a square plate. This plate in the center of the four tubes creates dead air space, or turbulence, disrupting the high velocity in the collector. This problem is solved by using a "Merge Collector". This collector is formed from four tubes, cut at approximately an 8 degree angle on two sides. When the tubes are all fitted together they form a collector with a "Pyramid" in the center. This has eliminated the need for the square plate and has taken up some of the volume inside the collector, speeding up the air velocity.

Other methods of curing this problem are: fabricating a pyramid out of sheet metal and welding it over the hole between the tubes, or squaring the tubes on two sides so they fit together forming a "+" weld in the center eliminating the hole all together.

You can see that there are a great many factors that go into making a good header. When the header, intake system, and cam timing are all designed to operate to their maximum in the same R.P.M. range, then you have a "Compatible Combination". This combination can be tuned to deliver maximum power at any desired R.P.M. range.

These are some of the "Basics" you need to know about building a good high performance header. There are many other adjustments that can be made to fine tune a header, but this should give you a basic understanding of how all the components work together
 

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you hear it cause its true. Based on the car however but a charger is one that it is true on and so are neons. Look at dynos from almost everyone one of the vendors on the forum.
 

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I have had both now running the complete JBA system with shorties and I love it. Way more bottom end! If I autostick and roll around 20mph and punch it, I lay rubber. The sound is awesome and the price for the complete set up from HHP is great. call Josh at HHP and he will walk you through your decision based on what you are looking to do to the car.
 

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also erb3 did you not notice that the paragraph you bolded in your post is almost word for word what i said in the post your complaining about?
 

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Discussion Starter #10
being a header newbie, that was an extremely informative post that really helped me understand a lot of the terminology that ive read more than on more than one occasion trying to figure this out.

but in between working and reading this all at the same time im worried i may have missed a key point...

by the way, i work as a mechanical engineer who calculates and designs ductwork and ac systems and sizes ac units of every time. airflow and pressure are one of the number one things i work with.

so long tubes are longer, with larger diameter. to me it is obvious that a larger diameter equals more flow. but in order to achieve that flow it cannot be too big. so when your engine isnt pumping out as much exhaust(low rpms.. i think?) you want smaller tubes to keep that vacuum, as well as achieve optimal pressure inside the tube for the best flow out the end of the pipe towards its final destination

as you reach higher quatities of exhaust. you need larger diameter to keep proper pressure inside the tube and keep your flow maximized towards the end of its path.

if your pipes are too big. you cant achieve a perfect flow because each cycle of exhaust just fills the header. and it does not flow and create a vacuum. thus slowing your exhaust and not pulling it out of the cylinder.

so the way i see it.... a shorter tube needs a larger diameter in order to achieve the same flow and pressure (whice create the vacuum.. which creates the fastest flowing exhaust)that a longer tube with a smaller diameter has.
but a short tube has less area and length to have tubes that big, and not enough length to create a vacuum at higher rpms.


i understand ac very well, and i think a lot of it applies. but there are many factors that go into this(such created by the engine) that i do not understand.

but to MY(and i reiterate.. im no expert.) logic the longer tubes will have a better vacuum with more exhaust. thusly higher RPMS.

PLEASE CORRECT ME IF I AM WRONG! i do not want this to be taken as fact. but it is how i percieve this all. which is why i asked the question in the first place.
 

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also erb3 did you not notice that the paragraph you bolded in your post is almost word for word what i said in the post your complaining about?
Are you sur??? The bold paragraph clearly states that shorties are going to move the power band higher in the rpm range while proper designed lt's will provide more power lower in the rpm range. I've seen this discussion several times on all the boards but I've been around racing for a while. Case in point we recently strapped a blower to a small block dragster. Throughout the tuning process and changing several aspects of the drivetrain we still could not hook up. The car experienced violent tire shake at launch. Since we were running pullies at a 1 to 1 ratio we didn't want to further de-tune the engine and loose more power. As luck would have it one of the long tube headers broke at a weld from the violence of the engine. This gave us an opportunity to run some borrowed shorties. The result, less power at the lower end of the power band alowing the car to launch and then rocket into the traps. I'll see if I can get a before and after graph from the race pac. I know each engine is diff but I've alwayse been told shorties for high end and lt's for low end power....Peace!
 

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This is what it will come down for me, the short vs lt argument- which one WON'T throw a code? As of right now, the mopar set looks the most attractive.
 

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being a header newbie, that was an extremely informative post that really helped me understand a lot of the terminology that ive read more than on more than one occasion trying to figure this out.

but in between working and reading this all at the same time im worried i may have missed a key point...

by the way, i work as a mechanical engineer who calculates and designs ductwork and ac systems and sizes ac units of every time. airflow and pressure are one of the number one things i work with.

so long tubes are longer, with larger diameter. to me it is obvious that a larger diameter equals more flow. but in order to achieve that flow it cannot be too big. so when your engine isnt pumping out as much exhaust(low rpms.. i think?) you want smaller tubes to keep that vacuum, as well as achieve optimal pressure inside the tube for the best flow out the end of the pipe towards its final destination

as you reach higher quatities of exhaust. you need larger diameter to keep proper pressure inside the tube and keep your flow maximized towards the end of its path.

if your pipes are too big. you cant achieve a perfect flow because each cycle of exhaust just fills the header. and it does not flow and create a vacuum. thus slowing your exhaust and not pulling it out of the cylinder.

so the way i see it.... a shorter tube needs a larger diameter in order to achieve the same flow and pressure (whice create the vacuum.. which creates the fastest flowing exhaust)that a longer tube with a smaller diameter has.
but a short tube has less area and length to have tubes that big, and not enough length to create a vacuum at higher rpms.


i understand ac very well, and i think a lot of it applies. but there are many factors that go into this(such created by the engine) that i do not understand.

but to MY(and i reiterate.. im no expert.) logic the longer tubes will have a better vacuum with more exhaust. thusly higher RPMS.

PLEASE CORRECT ME IF I AM WRONG! i do not want this to be taken as fact. but it is how i percieve this all. which is why i asked the question in the first place.
I am not an engineer but I do know from experience a heavy car like ours needs low end torque to get moving. I hated my Mopar LT's because I did not have the low end the car was a dog on the line and under WOT off the line it would not start pulling till 3500-4000 rpms, which does not do a guy much good in traffic, awesome on the highway not so much in town. After switching to the shorties I could feel the difference, the car pulled right away and got stronger through redline, sure I don't have that surge of pull around 3500-4000, is it slower no it is more balanced and pulls just as strong as before. If you are looking for max power go with the LT's if you are looking for power you can use daily and enjoy go with the shorties. I wish I had a dyno in my area so I could show the difference but I don't but I am sure you can find a dyno chart on a pair of long tubes and compare them to the JBA's dyno sheet on their website
 

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Just to add a little. With the lt's on the car and launching with tire shake the car was putting down 7.20's at 190+. The best run with the lt's was a 6.90 at 206mph. With the shorties and good launch the car is laying down 6.70's and trapping at 199-201(we slowed the top end down a little due to track issues). Now that we have the right combo we are tuning the car back up to get it to a 6.60 or even 6.50 if the tires keep sticking.
 

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shorties normally will have no effects on o2 signals.
Shorties give you a more low end ponies and sometimes very little 1-3 hp at high end.
Long tube is the opposite , You can sometimes lose horsepower at low rpms but gain massive 10+ at higher rpm.


also erb3 did you not notice that the paragraph you bolded in your post is almost word for word what i said in the post your complaining about?
wicked: I'm not complaining. Can you explain how what you said is word for word what I posted in bold? Read your post.:knockout:
 

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Discussion Starter #16
my car is a daily driver. to work and back, with average traffic. im leaning towards the shorties for the rpm in the lower ranger. but the main reason i ask is because ive heard both. even tho theres been more first hand experience to prove the shorties/low end arguement rather than the opposite.

PlumC, how do you feel your car does in the high rpm range? it doesnt get choked up does it? especially compared to stock. you have the full jba setup correct?

and id really love to hear more input from experts or at least people with real experience about my half brained post about my perception of headers.

thx for the input tho, everyone.
 

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I'm sure this is too obvious, and probably extremely technically daunting. But, if someone came out with a variable geometry header, the discussion would be over.

Wouldn't that me a neat item? The exhaust system could tune itself based on conditions. Modern engines already do that with timing, A/F ratios and all that, the air intake opens and closes based on necessity.

Now back to our regularly schedule reality show . . .
 

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my car is a daily driver. to work and back, with average traffic. im leaning towards the shorties for the rpm in the lower ranger. but the main reason i ask is because ive heard both. even tho theres been more first hand experience to prove the shorties/low end arguement rather than the opposite.

PlumC, how do you feel your car does in the high rpm range? it doesnt get choked up does it? especially compared to stock. you have the full jba setup correct?

and id really love to hear more input from experts or at least people with real experience about my half brained post about my perception of headers.

thx for the input tho, everyone.
In the upper rpms is does not feel like it's falling off in any way. It still pulls hard all the way to redline. What I can tell so far is that MDS seems to stay on much longer then before, meaning I can cruise at 85 and still be in economy mode where as before 80 was usually max, this tells me it's breathing better. The sound is great and and the drone you hear about is not that bad actually you get use to it after a day or two. I have the complete package from High Horse Performance, JBA shorties, high flow cats made by magnaflow, JBA catback.

What I would do is talk to Josh at http://www.hhpracing.com/ I would have kept the LT's on if I was planning more mods like a cam and heads but that is way down the road and I wanted the best bang for my buck. They build lots of LX and he is very honest and will listen to your concerns and give you the best advice, as will many other vendors here.
 

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a.this is our cars
Engines that are torquers and Red Line at 5,500 R.P.M.s would need a tube length of 36".


i think we are agreeing on different points in the discussion and that is causing some confusion.

The power band is going to change based on the header period. TRue

Going to big on any of the tubes is stupid, True but were not "building" a header we are buying, and most aftermarket are around 1 7/8 diameter.

In the upper rpm's the long tube is going to be better, in my opinion and lower rpm's the shorties. aka if you want to leave fast get the shorties, if your a track racer get the long tubes as your gonna spend most of your time n the upper rpm's

Tons of factors come into play. Heat builds up better in the shorties and heat is what scavenges the exhaust flow. However there is even less restriction in a long tube set up that is done right. With headers its give and take. There is no perfect answer cause no matter what you get your giving up something. Aftermarket parts on the ca also play a factor. Your not gonna see a long tube header on a turbo car for thousands of reasons.

With that being said for pure hp, you can t beat long tube. How many drag cars have stock manifolds on them as opposed to 3.5 ft of equal lenght tubing coming out of each port?
 

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Here is a dyno sheet on the JBA's complete system.

http://products.jbaheaders.com/assets/dyno/06charger57dyno1.jpg

I can not locate one for LT's, but if you look at the graph you can see how the bottom end builds more torque in this system in the lower rpms and then runs flat just like stock but building more
 
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