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jc91sc
08-24-2007, 11:46 AM
I recently picked up a set of the "headers" from the 1997 V6 Birds to replace a set of "headers" I'd gotten from a 1998 V6 Stang. NOW, when I got the Bird version, I noticed a stark difference in the sizes of the two immediately. The Mustang headers are larger in diameter, the individual tubes are longer, and the collector is larger as well. I've already gotten the Stang headers modified to clear the steering column on the driver's side, so fitment is no longer an issue...

My question is, in going with one of these *I've heard BOTH flow better than ported manifolds, but aren't quite as good as a set of Kooks or something to that manner* which is a better flow and fit for the SCs? I've seen them both used and have heard claims that support each, but with me having BOTH in hand, which should I use and which should I let go? Thanks in advance.


James E.
[email protected]

nickleman60
08-24-2007, 12:13 PM
My question is, in going with one of these *I've heard BOTH flow better than ported manifolds, but aren't quite as good as a set of Kooks or something to that manner* which is a better flow and fit for the SCs? I've seen them both used and have heard claims that support each, but with me having BOTH in hand, which should I use and which should I let go? Thanks in advance.


James E.
[email protected]

Dave Dalke did a flow test on early and late model stock manifolds, mustang manifolds and headers and the mustang manifolds by far flowed the worst,94/95 manifolds weren't far behind the headers so my opinion would be not to use them and use your ported stock manifolds.

XxSlowpokexX
08-24-2007, 04:52 PM
ohhh booooooyyyyyy....Lets just say

If the tubes look larger...and the collector is larger...It will flow more. I would stick to the stang headers. The kooks headers of course are substantially better with larger mandrel bends and if full lenght a real collector. If you want me to explain why a cast iron SC manifold SC wont flow as well I can.

But I'd say just use your judgement. I dont believe there are any independant dyno tests that had been conducted on the same day under the same conditions to really verify which will make the most power.

So my vote is..Larger collector..larger and longer primary tubes....Go with the stang

rzimmerl
08-24-2007, 06:02 PM
alot of good info here, thanks to Dave D. for some more great free information.

http://www.sccoa.com/forums/showthread.php?t=84828&highlight=header+test

Dahoopd
08-24-2007, 07:03 PM
I am actually using a set of Mustang headers just because they can be coated and I dont have to port them. I cant believe an unported set (for those of us that have no patience or the means) of SC manifolds will out flow a mustang tube manifold stock to stock. Plus I get a little blingy out of it.

jc91sc
08-24-2007, 09:32 PM
Dave Dalke did a flow test on early and late model stock manifolds, mustang manifolds and headers and the mustang manifolds by far flowed the worst,94/95 manifolds weren't far behind the headers so my opinion would be not to use them and use your ported stock manifolds.

I've heard information to the contrary...everything I'd read previously on the matter said either of these flow BETTER than the ported manifolds.

Damon, I was leaning that direction...thanks.

Mike8675309
08-24-2007, 09:50 PM
I've heard information to the contrary...everything I'd read previously on the matter said either of these flow BETTER than the ported manifolds.

Damon, I was leaning that direction...thanks.

Believe what you will, but Dave actually flow tested them recently and found out some facts.

Randy N Connie
08-24-2007, 11:11 PM
Dave did air flow bench testing .On the center tube
of all the headers if I remember right.

He did not do testing with a engine dyno. The out come
would have some hugh differences.

Daves Air flow bench test gives results for ONE HEADER
TUBE ONLY.not a complete header system.

Testing on a engine dyno with each header installed and
tested. with this type testing you would see the huge
difference in heat expansions rates, back pressures
differences, collector effects differences, scavageing
effect differences, etc. truer differences results between
the headers being tested.

Using a flowbench to test headers is fine to do and use.
If this is the only tool you have. But it is not going
to tell you which header is best to use in the real world.


Thanks Randy

Mike8675309
08-24-2007, 11:19 PM
Check the thread linked by someone above. I believe dave checked each tube, thus the table he has for the differences in flow across each tube.

I believe Dave made it very clear, the results were exactly that, results with no direct correlation to a specific level of performance beyond the flow achieved in the particular testing circumstances.

Of importance from the charts was the lack of balance within the tubes for the stock early SC manifolds. The 94/95 manifolds showed the best balance of the stockers.

The mustang headers were not impressive.

Here is a link to the post with the word doc in it that has the tests.
http://www.sccoa.com/forums/showpost.php?p=594137&postcount=21

jc91sc
08-24-2007, 11:23 PM
Dave did air flow bench testing .On the center tube
of all the headers if I remember right.

He did not do testing with a engine dyno. The out come
would have some hugh differences.

Daves Air flow bench test gives results for ONE HEADER
TUBE ONLY.not a complete header system.

Testing on a engine dyno with each header installed and
tested. with this type testing you would see the huge
difference in heat expansions rates, back pressures
differences, collector effects differences, scavageing
effect differences, etc. truer differences results between
the headers being tested.

Using a flowbench to test headers is fine to do and use.
If this is the only tool you have. But it is not going
to tell you which header is best to use in the real world.


Thanks Randy

That makes sense...that would explain why the stock NON ported manifold would show a better flow than either the ported or the Stang and T-Bird headers. There's less space and a more direct route, so they'll flow in the path quicker and more effeciently when backpressure, heat and all those other day to day variables aren't present.

James E.

jc91sc
08-24-2007, 11:25 PM
Check the thread linked by someone above. I believe dave checked each tube, thus the table he has for the differences in flow across each tube.

I believe Dave made it very clear, the results were exactly that, results with no direct correlation to a specific level of performance beyond the flow achieved in the particular testing circumstances.

http://www.sccoa.com/forums/showpost.php?p=594137&postcount=21

I don't think Randy was referring to one tube ONLY, but each tube INDIVIDUALLY. It's hard to get an idea of the overall flow if you take it one tube at a time....

I really, REALLY appreciate your input, BTW. My question to you, Mike....what are you currently running on your SC?

Randy N Connie
08-25-2007, 12:25 AM
Mike:

I am not trying to knock Dave testing. He did a fine job
flow testing for the results he was looking for. But his
results are not complete enough to discribe the worth
of a right or left side of a complete header system..

You can only test one cylinder at a time on the average size
flowbench.or in this case ONE HEADER TUBE AT A TIME.

This type testing will not take into consideration of all the parts
of a complete header system. The main one being scavageing
effects of the collector...

His post is well writtin of what I remember, but very miss leading
to people that are not in the know, of properly conducted set ups
of airflow reaserch.

Not because Dave Is tring to miss lead anyone.
But from reading other post about his header testing.It has been
miss leading to some. Because they are not fulley understanding
his type test results....ARE NOT COMPLETE.


Randy

jc91sc
08-25-2007, 08:49 AM
That's just as I'd thought...that's not gonna really tell which is best overall.

XxSlowpokexX
08-25-2007, 10:32 AM
Believe what you will, but Dave actually flow tested them recently and found out some facts.

Ok Ill say it in the simplest terms possible

On a v6 headeryou have three tubes....Ends at collector.

In a v6 manifold you have three openings that all end in a common chamber that eventually ends at the colector

If you flow one tube at a time..

The header will net you flow for that individual tube
The manifold will net you flow for that opening into a common chamber that is meant to share two other ports.

Now someone explain to me how testing one opening is going to prove anything...especially in an exhaust manifold.

Mike8675309
08-25-2007, 12:30 PM
Proof is in the final product. Testing and theorizing on it is of limited value. Static flow tests on each port provide some insight about the maximum flow these manfolds can flow related to how our motors will use them.

Two givens to throw in to the mix.
#1 - Typical tuned header design will not apply to a forced induction motor at wide open throttle. (The intake charge is already above ambient pressure. The intake charge creates a high pressure area, causing the open exhaust valve to be a low pressure area. This pulls the exhaust & intake charge toward the exhaust valve until it slams closed. No scavenging necessary.)
#2 - The best exhaust system you have built for Wide Open Throttle is not going to be the best system for the street. (What allows the highest exhaust velocity at 5000rpm under full load is not going to be the best power producing exhaust at 3000rpm at part throttle.)


On my 90, which is essentially stock, I have stock 90 manifolds with the collector ground open a little more. Then custom dual 2.25 stainless steel pipes straight into a 3" stainless steel pipe, bent around the stock 90 gas tank terminated into 2.5" stainless steel pipe into two 19" long Borla mufflers. I'm going to add a 2 into 1 resonator when I start working on that car to tone down the noise a bit but otherwise that's what it will stay. I don't see the 90 going to the track anymore.

On my 93, I currently have stock manifolds with the collector ground open a bit more, 2.5" down tubes to a Magnalow 2 into 1 resonator, that goes 3" to 2.5 out into 2 magnaflow mufflers. This is the system on the car when I purchased it. I had expected to get some custom headers, but he disappeared, so I'm saving for Kooks full length headers that I'll have coated. At the back will be borla mufflers. In the middle I haven't decided yet. I'm going to do some thinking on that yet to try to work on optimizing exhaust velocity through the system while accepting a trade off to keep the noise down on a street/track car.

Flex
08-25-2007, 02:14 PM
I agree with Randy and Damon. I also have no intention of knocking Dave or his efforts in the testing he performs on any aspect of SC performance.

I believe that from a standard of ultimate performance, the work he is doing greatly benefits this community and will allow those who are seeking maximum performance to attain it.

I just don't understand how it would be possible to flow test only one port at a time on a cast manifold as all three merge into one prior to reaching the collector. This ultimately is only flow testing as well. A set of heads can flow huge numbers on a flow bench but does this necessarily mean a reflective gain in performance once installed on a motor?

Putting any flow bench testing on air flow aside, I can add some info.

I spent a lot of time on the V6 Mustang etc. boards from 2003 on. My first bird was an N/A car that I was hopping up a bit.

The "header" of choice was what Ford installed and the Mustang header we are talking about. Early cars had cast manifolds and the 99+ cars came with a tube header that looked like the cast manifolds.

ALL testing (and many went to the dyno the check for gains) showed that the single port Mustang header out performed both the cast manifold and the later split port offerring. This cheap swap became a source of 7-10 hp on the later cars.

Now if an N/A car can benefit that amount from this manifold, how can our boosted cars not? I have just had this discussion with a local buddy whom Dave is graciously coming up to help build up his motor.

We looked at the dismal 1 7/8" opening in the 94/95 manifold's "collector" that could at most be opened to 2" maybe 2 1/8". What good is it to have 2.5" or larger downtubes and possibly 3" exhaust when the obvious bottleneck is where the exhaust immediately exits the motor?

The best "cast" header Ford ever made came on the late 60's 427 cars. Aside from the extreme weight savings, it was a given that aftermarket headers offered a huge gain in flow and power on those cars.

The Mustang collector can be opened up to a true 2.5" and the brutal welds where the primaries meet should be ground down with a carbide burr prior to coating.

Mike8675309
08-25-2007, 05:29 PM
Naturally aspirated cars never have an intake charge entering the cylinders at a pressure above ambient. Our motors when under load are always above ambient air pressure. That is the largest difference.

Dave used some sort of plug to isolate the tubes he wasn't testing, at least that is what he wrote in the thread linked above. I would highly suggest reading through what he wrote as he clearly discusses the limitations of his test results.

One item that I keep in mind when looking at exhaust systems on forced induction vehicles is exhaust velocity. When looking at what keeps the exhaust moving out of the cylinders, you need to look at restrictions, and maintaining exhaust velocity.

XR7 Dave
08-25-2007, 08:57 PM
Typical exhaust port gas average velocity is about 300ft/sec. Using the header/manifold dimensions it should be pretty simple to determine how far apart the pulses are in inches at say, 5000rpm. This exercise should answer at least some of the questions posed above.

Paul93SC
08-26-2007, 11:33 AM
If the tubes look larger...and the collector is larger...It will flow more.The cross sectional area of those individual runners where they meet the collector is still smaller than a stock manifold at any point inside them. The second problem is the drastic change in diameter from an individual tube to a very large collector area. This causes turbulence as the gases suddenly have to slow down to fill that area. As you know turbulence is not good for flow. Bigger is not always better, otherwise we all would have monster-sized headers on our engines.


This type testing will not take into consideration of all the parts
of a complete header system. The main one being scavageing
effects of the collector...Irrelevant... with the backpressure we have (and small cam overlap) there is NO scavenging period. To have any hope at all of taking advantage of scavenging you need to reduce the backpressure to nothing, and that's very hard to do (if not impossible) on our engines.

But, I got ahead of myself here... complete header system? That would mean the entire exhaust system and engine all working together in whatever configuration you have. However, you guys are all talking about these headers/manifolds in isolation from everything else! How is this relevant? Dave is the only one who has done any real-world testing at all, and while being somewhat limited in the results, is still dismissed as incorrect because a visual inspection revealed "The Mustang headers are larger in diameter, the individual tubes are longer, and the collector is larger as well." :rolleyes:


Not because Dave Is tring to miss lead anyone.
But from reading other post about his header testing.It has been
miss leading to some. Because they are not fulley understanding
his type test results....ARE NOT COMPLETE.
He never said they were. I'm confident that people here are smart enough to understand the limitations of the testing he performed. You don't give people enough credit.

Exhaust systems are complex in their design and function. There are many factors that influence how a system will respond to any particular engine. Flow is not the only factor to consider either: if it were, exhaust design would be a lot easier to accomplish. Sound waves inside the exhaust also play a critical role in determining overall performance. The following excerpts are taken from the book "Scientific Design of Exhaust & Intake Systems" by Philip H. Smith and John C. Morrison:

We can next apply the conception of sound energy to exhaust pipe pressure fluctuations. From Chapter 2, in which the flow was considered in its simplest aspects, it was commented that many designers tended to regard the kinetic energy of the gas discharge as the main factor of scavenging; earlier statements give evidence of this. This kinetic energy is easily explained and, if it were the sole criterion, efficient scavenging would no doubt be simplified.

When the exhaust valve opens, there is a high-pressure release of gas into the port and pipe. This imparts kinetic energy to the column in front of it; as the "bung" or slug of pressure reaches the end of the pipe, the energy is transferred to the region of the exhaust port, causing a rarefaction which pulls out the residuals concurrently with a rise in port pressure as the kinetic effect decreases.

It is by no means inferred that this proposition is incorrect; it forms an essential part of the process. But superimposed as it were on the flow as a whole is the presence of the pulsating wave motion, in consequence of having an elastic medium to deal with. Whereas the gas column as a whole may be moving in the pipe at an average speed of 200~300 ft per second, a much higher speed is obviously attained at the wave pressure peaks.

In a great many writings on engine design, emphasis is put on the kinetic energy of the exhaust outflow as an aid to auto-extraction of the residuals. While it is possible that, particularly in the past, automobile engineers have tended to emphasize this effect while largely ignoring the significance of the wave motion, this may have been due to the kinetic effect being more explicable"

Now back to the topic at hand, namely exhaust manifold design, and again from the same book:


The designs proposed are intended to incorporate the following as essential:

1) A "primary" pipe from each cylinder exhaust port, of adequate diameter to give minium flow restriction, with adequate gas velocity, and of a length aimed at either independence or favourable interaction, depending on the design of the system.

2)A method of uniting these pipes into a common outlet, which will prejudice the foregoing requirements to the least possible degree, and will preserve favourable wave-action so that it is likely to increase the torque over the top 50% of the power curve.As you can see, there is a lot more going on here than just bigger pipes. Experience with a N/A Mustang V-6 engine is not relevant to an SC for the reasons stated above.

Exhaust theory is real heady stuff. However, you can take away from all of this the fact that any street exhaust system will be a "compromise" between performance and sound abatement. The biggest gains we can achieve is to reduce the backpressure we all have, and that means decreasing flow restrictions. Bigger pipes can flow worse than a smaller-piped system that's well designed. This is why Dave's tests are relevant.


I just don't understand how it would be possible to flow test only one port at a time on a cast manifold as all three merge into one prior to reaching the collector.It is very relevant because only one exhaust valve is open at any given time. The other two in that bank are closed and basically "cap off" those runners. Dave's test reveals the flow characteristics of any individual runner as the exhaust gas slug would see it. What his tests will not reveal is all the other factors that influence these slugs of gas as they leave a real-world engine and flow through the entire exhaust system; but, he clearly stated this in his findings.

Miller
08-26-2007, 12:27 PM
Bigger is not always better, otherwise we all would have monster-sized headers on our engines.


Im gonna go out on a limb here, and say its the price that scares people away.. i know i cant afford them!

CMac89
08-26-2007, 01:08 PM
The correct rhetorical question would be, how long is that cross sectional area retained? Whenever you compare exhaust manifolds to long tube headers you have to match the lengths up. If your headers are 42" from flange to collector then you have to account for 42" with exhaust manifolds. That accounts for whatever downtubes you are using.

You're saying that exhaust from three ports being merged together in a matter of a few inches into a two inch diameter collector with 2 1/4" downtube is better than three individual 1 5/8" merging into a three inch collector? Rule of thumb is to retain the minimum cross sectional area of the exhaust port, throughout the full length of exhaust, AT LEAST.


The second problem is the drastic change in diameter from an individual tube to a very large collector area. This causes turbulence as the gases suddenly have to slow down to fill that area. As you know turbulence is not good for flow. Bigger is not always better, otherwise we all would have monster-sized headers on our engines.

Since what you're saying is supposedly right, then I'm going to take my $1500 custom stepped headers off of my race car and put some ported stock manifolds on. Hey, they are bigger than an SC's exhaust manifold so maybe i'll get more horsepower. You found a clue for my extra tenth.

That isn't how a merge collector works. If you have turbulence, then you need a larger collector. The exhaust gasses try to expand, hugging the whole inside diameter of the collector. Within the merge, there is an extreme vacuum. Scavenging is terminated, in a long tube header, through pulling a vacuum on the exhaust port. Doesn't matter if scavenging isn't a plausible factor, a vacuum is still created against the exhaust valve whenever it closes. This vacuum pulls exhaust out of the cylinder. This is where header lengths and tube diameters play a huge role in. Since these motors are forced inducted it becomes similar to exhaust functions and volumed of a larger cubic inch motor. Therefore, they need similar exhaust.

An exhaust system goes way deeper than how much they flow. In which, I have explained. Physics do not change whenever there's an SC involved. Headers have been proven best over fifty years ago.

Is someone going to convince me the world is flat now?

XxSlowpokexX
08-26-2007, 01:56 PM
Paul,

ALthough a factory mustang header is far from ideal as it has no real collector to speak of..Our factory SC manifolds have less then a 2 inch exit for all three ports which all share the same common area before exiting. Care to guess how much turbulence is going on in there? In the case of shorites the downtube is considered part of that system(a collector if you will)

Now without getting into any major level of detail the test method for the headers/manifolds was flawed from day 1. Even if just testing the flow of any one port they were flawed.

Its no suprise that the mustang guys have gained power going from exhaust maniflds to even factory tube headers as has been mentioned in this post.

There are many factors about header design theory we can go into however lets use them when comparing header to header..Not header to manifold as there really is no comparison.

Also if we want to talk supercharged vehicles that respond well to headers...Look no further then the 03-04 cobras..The argument can be made they are not a 3.8 and as such the firing order odd/even needs to be considered.....However the testing conducted could not have accounted for that.

I think its safe to say we all know turbulence is a no no...diameter and collector size need to be matched for the performance of a particular engine..Its also safe to say everything is a compramise

Paul93SC
08-26-2007, 02:01 PM
Cmac89, you misunderstood what I was talking about, namely the Mustang Headers. I was NOT speaking about true well-designed headers, such as Kooks. BTW, FWIW Dave's static flow tests showed Kooks-style headers flowed the best if I'm not mistaken.


You're saying that exhaust from three ports being merged together in a matter of a few inches into a two inch diameter collector with 2 1/4" downtube is better than three individual 1 5/8" merging into a three inch collector? Rule of thumb is to retain the minimum cross sectional area of the exhaust port, throughout the full length of exhaust, AT LEAST.No, I'm not.

I agree with the second part as well, and this is also stated elsewhere in the book I was drawing my information from.


That isn't how a merge collector works. If you have turbulence, then you need a larger collector. The exhaust gasses try to expand, hugging the whole inside diameter of the collector. Within the merge, there is an extreme vacuum. Scavenging is terminated, in a long tube header, through pulling a vacuum on the exhaust port. Doesn't matter if scavenging isn't a plausible factor, a vacuum is still created against the exhaust valve whenever it closes. This vacuum pulls exhaust out of the cylinder. This is where header lengths and tube diameters play a huge role in.The key here is when the vacuum is present (and how much vacuum) at the exhaust valve at the appropriate time. This changes with changing RPM. Ideally you want as much vacuum as you can get when the exhaust valve is open over the entire RPM range, but that is not achievable. The best that can be hoped for is a design that provides as much of a vacuum (or minimum backpressure) as possible (during the time when the exhaust valve is open) over the widest RPM range possible. Again, this is for street-driven cars, not dedicated race cars that operate over a narrow range of RPMs.


Since these motors are forced inducted it becomes similar to exhaust functions and volumed of a larger cubic inch motor. Therefore, they need similar exhaust.Again, you haven't stated anything I've disagreed with yet. These engines flow about the same as a 350ci V-8 and such build up quite a bit of backpressure in the stock exhaust system. In order to relieve some of that, the entire system needs to be fixed, not fiddling with manifolds that would bring marginal improvements (if any). Kooks (or similar headers) are an improvement over anything so far, but unless ALL the other parts of the system are improved accordingly, will also provide only minimal gains.


An exhaust system goes way deeper than how much they flow. In which, I have explained. Physics do not change whenever there's an SC involved. Headers have been proven best over fifty years ago.Again, no argument here. As a matter of fact this is doctrine. However, I wasn't speaking about true headers, I was speaking directly about OE Mustang version. They have poorly-made collectors and IMO are not worth the expense or effort compared to porting out OE SC manifolds.

CMac89
08-26-2007, 02:04 PM
I did misunderstand you and sorry for sounding assholish.:)

Flex
08-26-2007, 02:29 PM
This could be argued for a decade in posts. The only proof one way or another would be a dyno test or at a track to see if any manifold or header will outperform another.

Quoting from a 36 year old book is merely quoting theory from a man who is probably dust now. In order for any scientific theory to have validity, it must be proven in real world testing otherwise it is just theory.

Show me the money!!!!!!

CMac89
08-26-2007, 03:20 PM
It's already been proven. There is no debating to do about it.

I own two race cars and I have tried everything known to man, legally, to make more power out of them. All of which I have stated are facts. I made 35 more horsepower just going from a 1 7/8" header to a 2 1/4". It's basic. As far as this topic goes it may as well be as basic as airing up tires.

There aren't opinions in science, only facts. A theory is isn't an opinion either, it's an observation made by facts, in which nobody can disprove or further improve upon at one given moment.

Flex
08-26-2007, 03:32 PM
CMac,

The debate is whether or not the Mustang factory tube steel header provides a benefit as a swap to the SC.

Unless you have specifically performed a dyno run or made runs at a track with stock factory manifolds and then with the Mustang piece, you technically can't state it as fact. The results of these tests would be the only way to prove or disprove the argument.

You are incorrect when you state that theory is fact. Anyone can postulate any theory. I could theorize that I could walk on the Sun if I had the appopriate space suit. Until someone tried and failed or succeeded, I have a theory. In order for a theory to become fact, it has to be tested and the results must support that theory.

XR7 Dave
08-26-2007, 05:19 PM
Wow, such passion!

As we all know to prove anything scientifically one must first form a theory or "hypothesis" and then must set about to DISPROVE his hypothesis. When his theory or hypothesis cannot be disproven, only then can it be accepted as truth.

I feel this is a very important thing to consider. Because of this it remains fact that unless I were to take up the mission of disproving what I believe to be true, I could never hope to prove anything and hence why I will not waste my time on this.

Have fun guys. :)

XxSlowpokexX
08-26-2007, 05:27 PM
Theory can be taken many ways. In our case we are looking at theory as being both based on opinion and based on repeatable observations that may or may not of had anything to do with mathematical or logical explanations.

The reason I just left that header test alone in the first place was because I thought the parameters for testing were non logical. Based on that alone I called the results moot before even seeing them. The results were practically as I predicted they would be based on the test parameters.And after hearing about them it confired it moot.

There are mathematical models you can use to help in determineing your header choices..There are also real life experience and repeatable observations that may make you choose a certain header. And of course there are opinions...

In the end there is alot more to a header design then just what amount of air can flow through it. And if the mustang guys have had repeatable dyno experiences to state something....Theory states that...

Whatever the case may be a whopping 2 inch opening is not a good performance starting point period..And the cylinders most definitely share that common area in the SC manifold at any one given time.

http://www.sccoa.com/articles/cwexhaust.php

Even though not header related charles did an excellent writeup on teh SC exuast system pointing out variosu restrictionpoints

Paul93SC
08-27-2007, 08:01 PM
Quoting from a 36 year old book is merely quoting theory from a man who is probably dust now.It is not theory. That book is considered the bible by many engineers and designers. There is also a lot more to that book than just the few paragraphs I quoted... it is filled with scientific testing and the results obtained from those tests. I also fail to see how someone's age invalidates the research. If you can, take a look at the book yourself before judging the validity of his research.

Flex
08-27-2007, 08:09 PM
Paul,

I am not saying his theories are invalid. What I am saying is that a lot of technology has come along in the last 30 years.

Don't get me wrong, I am not saying that it's an absolute given that the Mustang headers have to be better. I am looking for the best bang for the buck same as any of us. I would just like to see a dyno run or track test that absolute proves it one way or another.

CMac89
08-27-2007, 08:37 PM
CMac,

The debate is whether or not the Mustang factory tube steel header provides a benefit as a swap to the SC.

Unless you have specifically performed a dyno run or made runs at a track with stock factory manifolds and then with the Mustang piece, you technically can't state it as fact. The results of these tests would be the only way to prove or disprove the argument.

You are incorrect when you state that theory is fact. Anyone can postulate any theory. I could theorize that I could walk on the Sun if I had the appopriate space suit. Until someone tried and failed or succeeded, I have a theory. In order for a theory to become fact, it has to be tested and the results must support that theory.

Trial-and-error IS the least effective part of an engineering process and the most effective of an uneducated person. The purpose of engineering is to create or predict a product precisely enough to deplete redundancy. Time is money and engineering saves time.

I didn't say that theory is a fact. I stated that theory was an observation CREATED from facts. An opinion is just a belief developed by feelings. If you say that you can walk on the sun while giving information to support what materials the suit was developed, insulating capabilities, other means of deflection of heat, or any other factors involved, then you have a theory. If you say you can't walk on the sun because people die in 100* temperatures then you have an opinion. I think chocolate pudding is better than vanilla; opinion, not theory.

Nobel prize nominees do not get awards for saying, "well, I tried this and this back to back and this one's better."

Flex
08-27-2007, 10:16 PM
Look bro, mud slinging and trying to insult my intelligence is kind of childish don't you think? I have two university degrees and am the President of my company so I believe I qualify as "educated".


"Trial-and-error IS the least effective part of an engineering process"

We are not engineering anything here, just trying to determine which of two already "engineered" parts are better. If you have come up with a way of determining that without performing one of the two tests I mentioned above, I'd love to hear it.

CMac89
08-27-2007, 10:31 PM
Look bro, mud slinging and trying to insult my intelligence is kind of childish don't you think? I have two university degrees and am the President of my company so I believe I qualify as "educated".


"Trial-and-error IS the least effective part of an engineering process"

We are not engineering anything here, just trying to determine which of two already "engineered" parts are better. If you have come up with a way of determining that without performing one of the two tests I mentioned above, I'd love to hear it.

Yes, it would be childish if I was doing it. I never directly called you anything or insulted your intelligence. If I say "to an uneducated person" and you're educated, then the comment doesn't pertain to you. Not to worry.:)

You're right, we aren't engineering anything. It's the sciences involved in engineering that allows you to objectively approach the subject.

THE BIRDMAN
08-27-2007, 10:43 PM
Didn't Dave D say before that when his car was running a little over 400 rwhp that he swapped out his kooks for a set of ported 94/95 manifolds and after the swap his car dynoed the same #'s and also ran the same e/t at the track.Or atleast I swear that I read that somewhere on here before.If that's true then I would think that swapping to a set of mustang headers wouldn't yeild a gain in performance.Cause if the kooks didn't show a gain on a car with over 400rwhp then I don't think you would see a gain with mustang headers over ported manifolds either.


Jay

XxSlowpokexX
08-28-2007, 12:42 AM
Didn't Dave D say before that when his car was running a little over 400 rwhp that he swapped out his kooks for a set of ported 94/95 manifolds and after the swap his car dynoed the same #'s and also ran the same e/t at the track.Or atleast I swear that I read that somewhere on here before.If that's true then I would think that swapping to a set of mustang headers wouldn't yeild a gain in performance.Cause if the kooks didn't show a gain on a car with over 400rwhp then I don't think you would see a gain with mustang headers over ported manifolds either.

Unless it was conducted on the same day under the same conditions...The results would mean nothing. Call me a naysayer..But 400rwhp being pushed out 2 inch manifold peeshooters seems like a restriction to me.

Would I buy kooks headers for a stock SC?..Nahhhh more bang for the buck elsewhere..Would I try out a cheap set of stang headers...Sure

Flex
08-28-2007, 01:35 AM
Maybe one of us should write to Horsepower TV and see if they could do some dyno runs on a bunch of different manifolds and headers LOL. Dave could give us one of his beefier cars to run the tests on. What do ya say Dave. Just kidding but it would be nice especially if we could hang out with Courtney while they did runs.

jc91sc
09-18-2007, 04:34 PM
Well, I've got the Stang collector here, and it's definetly an apples and little apples comparison when you look at them both together. I'll post the rest of the pics on Flickr so you all can see the "pudding" so to speak. :D

http://www.flickr.com/photos/curry762000/sets/72157602073080709/

James E.
[email protected]

fturner
09-18-2007, 05:40 PM
All these theories, postulations and gyrations everyone is talking about over what is better etc etc is great but getting to the point of migrains.... but non of you have actually answered the original question :cool:.

Again, a discussion has been taken to a point that only the top 5 or so can benefit from the science of what is being discussed, which leaves out the other 99% of the world that don't have the funding and expertise to build the ultimate system.

Lets go back to the basics for the 99%. We have the 89-93 manifolds, ported and unported, we have the 94/95 style ported and unported. We have stang manifolds to consider. If you have a slightly higher budget available, then you start looking at Kooks Headers etc......

Dave's tests, while basic and according to some obviously child level attempts at testing what is better, can and will help the average Joe Blow to make a decision on what is better for what he is trying to accomplish. Not everyone has $30000 available to shave a 1/10th of the quarter mile for Gods sake :mad:.

Lets put it simply, I've got a '90 with the old style manifold slightly ported on the exit to get rid of that stupid compressor ring ;). I don't have giga amounts of money to throw at the car to design the ultimate lethal killer exhaust system thats fine tuned to 1 thou for X rpm range from the front to the back. I'm after a solution that will flow well from being a DD car to hitting the track once in awhile, and give me good performance all around so to speak, which I would think covers the majority around here (which is always forgotten about).

Anyways... I'll step off that well worn down soap box...... for now ;)

XxSlowpokexX
09-18-2007, 07:13 PM
I have Kooks headers and my car is slow as mollases on a cold winters day..So there

rickbtbird
09-18-2007, 08:17 PM
jc91sc,

This has been my experience.
If you’re deciding on adding intake upgrades, a wider header/manifold opening will help your exhaust exit quicker just as long as long you as have an upgraded exhaust system to support it. If you plan on keeping your stock intake system then wider collectors typically do nothing but loose needed back pressure which will result in a loss of performance. In that case, at a maximum I'd port the existing manifolds a bit but othersie the stock setup will be fine. For both stock and performance setups, add a better resonator and/or (on 89-92 SC's) a gas tank upgrade with the newer strait exhaust pipe helps but could also add do back pressure loss if you don't do some intake modes. High flow cats, downtubes and bigger exhaust pipes can be added if you do plan on major intake mods.

If you’re building a race car then get a credit card with a $10,000 limit and go crazy. (http://supercoupeperformance.com//Default.aspx) :D

jc91sc
09-18-2007, 11:38 PM
jc91sc,

This has been my experience.
If you’re deciding on adding intake upgrades, a wider header/manifold opening will help your exhaust exit quicker just as long as long you as have an upgraded exhaust system to support it. If you plan on keeping your stock intake system then wider collectors typically do nothing but loose needed back pressure which will result in a loss of performance.

Already have a Mac CAI, C&L 76mm MAF, BBK 75mm TB, Raised Top, going to get MannySC to port out the blower, inlet, and outlet, 5% pulley it, and 5% jackshaft it also.



For both stock and performance setups, add a better resonator and/or (on 89-92 SC's) a gas tank upgrade with the newer strait exhaust pipe helps but could also add do back pressure loss if you don't do some intake modes.

Getting custom 2.5" downtubes to go with the Carsound high flow cats, dual 2.5" in/ single 3" out Magnaflow resonator to dual 2.5" Dynomax mufflers. I think me going with the Stang headers is pretty well warranted. Thanks for the input. OH, and if you'll cosign on that credit card, I'll BURN 'ER UP!!! ;)


James E.
[email protected]

XxSlowpokexX
09-19-2007, 12:53 AM
go 3.5 inch to the rear :O)

jc91sc
09-19-2007, 09:38 AM
go 3.5 inch to the rear :O)


So dual 2.5" to 3.5"? Sounds SUPER meaty! :cool: Does Magnaflow make a resonator with those dimensions?


James E.
[email protected]

David Neibert
09-19-2007, 12:54 PM
So dual 2.5" to 3.5"? Sounds SUPER meaty! :cool: Does Magnaflow make a resonator with those dimensions?


James E.
[email protected]

You don't need to go that big....2.25 downtubes and a 3" center pipe will be plenty.

David

91bird
09-19-2007, 01:15 PM
James,
I will throw my shot in here just cause I went down this same path a while back. I pocked up a set of Mustang headders and could not believe the difference when you put them beside the SC manifolds. I cut and modified and welded the Mustang headder to fit my car and I think they work great.
My motor is heavily modified but it's not a race car and I think the Mustang headders are a good place to start. Unfortunatley I do not have any dyno numbers before and after.

Drew

mannysc
09-19-2007, 01:28 PM
jc91sc,

This has been my experience.
If you’re deciding on adding intake upgrades, a wider header/manifold opening will help your exhaust exit quicker just as long as long you as have an upgraded exhaust system to support it. If you plan on keeping your stock intake system then wider collectors typically do nothing but loose needed back pressure which will result in a loss of performance. In that case, at a maximum I'd port the existing manifolds a bit but othersie the stock setup will be fine. For both stock and performance setups, add a better resonator and/or (on 89-92 SC's) a gas tank upgrade with the newer strait exhaust pipe helps but could also add do back pressure loss if you don't do some intake modes. High flow cats, downtubes and bigger exhaust pipes can be added if you do plan on major intake mods.

If you’re building a race car then get a credit card with a $10,000 limit and go crazy. (http://supercoupeperformance.com//Default.aspx) :D

92's have the better gas tank and 70mm maf i keep reading about 92's needing the better gas tank who made up this lie that everyone keeps saying it.


92's have better gas tank straight thru sort of exh routing
92's have 70mm maf
92's have led tailights
92's have no egr
92's have bypass straight from intake plenum no switch or solinoid
92's have no SC on front bumper cover

sorry to get so offencive but i keep reading about 92's having all the so called bad stuff on them i think they run the best 92's and 93's that is

rickbtbird
09-19-2007, 02:21 PM
92's have the better gas tank and 70mm maf i keep reading about 92's needing the better gas tank who made up this lie that everyone keeps saying it.


92's have better gas tank straight thru sort of exh routing
92's have 70mm maf
92's have led tailights
92's have no egr
92's have bypass straight from intake plenum no switch or solinoid
92's have no SC on front bumper cover

sorry to get so offencive but i keep reading about 92's having all the so called bad stuff on them i think they run the best 92's and 93's that is

Yea I got my years mixed up.. 89-91...

jc91sc
09-19-2007, 03:52 PM
Thanks for the clarification, Manny! You up to doing another port job on a blower? I've got a 95 Blower that I want ported as well as it's inlet and TB openings, and the outlet. Please PM me and let me know if you'll do one and how much it is. Thanks.


James E.
[email protected]