Discussions of HP as measured on a dyno or boost response/RPM as measure in the car during an accel leave out one important factor toward good drivability and time to speed road performance. That unfortunate truth is all turbocharged engines must first perform N.A. before they can deliver boosted performance.

Some increase compression ratio. Why? Obviously to make the motor stronger N.A. so it can better pull itself up to that magic time when the boost needle responds. However, ultimately this motor will make less power on a dyno than one of 7.5:1 C.R.

No one wants be “off boost” but it is a fact to be dealt with. Most component evaluations on turbocharged engines require on road performance comparison and subject driver input of drivability. These considerations can make your Porsche motor respond like the performance engine it is, or frankly a bunged up high torque diesel wantabe.

Throw away the boost indicator and give it a try.

One thing I should have said, is that I think RarlyL8 new offering is a very nice effort in combining the advantages of an equal lentgh system (nice off boost response) and short total length (higher efficientcy on a tubocharged engine). It should be close to a "best of both worlds" system IMO.

1100Sport,

I think we are mostly on the same page.

I have wondered if the Carrera and 930 headers are differed in size. Thanks for that info.

So the 3.2 Carrera headers are larger ID than the 930's? The SSI has about the same tube ID as the SC and turbo's?

On an SC the SSI's will make more HP than the stock headers. Not so on a 3.2 except briefly at about 3000rpm.

An exhaust change has been reputed to be the biggest reason for the HP jump from the 3.6 964 to 993 (250 v 272). That SC/3.2/3.3/3.6 C2 cross over is very suspect. (I think AFM to MAF is part of it though one 3.6 expert says not so much.)

The arguments for equal length (SSI) seems to be they are going to help pre-boost power.

Pre-boost is before 2000rpm.

The 3.2 N/A data I have seen dose not seem to support that the SSI improves normally aspirated operation before 2000rpm. Thus, how can we expect it to help on a turbo.

As you noted NA 3.2's do however respond well to increasing tube ID over that of SSI's 1.5".

This is supported by the SW HP numbers where SSI's made 10hp less at 3500 and 9hp less at 6000rpm than 1 5/8's-1 3/4's. Lets call it 10 hp.

Unfortunately larger tube size lowers boost response on a turbo.

Also, on a turbo, SSI's are only equal length on the primary tube so it is no longer a fully equal length system unless a split turbine is used.

With a turbo we are nearly doubling air flow through the intake side when running 1 bar. I do not know if we can interpolate from this that if a 1.5" on a 3.2 costs 10 hp that on a 3.3 930 it might cost around 20 hp?

I think it gets back to low overlap cams are not as effected by back pressure at low rpm nor benefit as much from savaging.

I do accept that going to a K27-7006 with its larger hot side and slightly smaller and older compressor than a 7200 is good for about 20hp mostly do to less back pressure.


We are all just guessing at what the differences or advantages might be at this point but that is how we learn.


I am thinking it mostly comes back to a couple of things.

True equal length are better at getting the gasses out any motor, NA or turbo/ and should result in lower back pressure and thus more HP.

A smaller volume header (including WG circut) will pressurize quicker for faster boost response.

It will be difficult to match the factory's quality and heat exchanger system.

Larger tube ID's will better support higher levels of HP.

Smaller tube ID's will reduce header volume and aid boost onset.

Past that, it comes down to getting a good execution of these basic's as to a system design and hard dyno data that is repeatable as to which is best for the intended use.


In principle I currently believe:

That a properly sized true equal length 930 system (Brian's, Prototec, Mode, Vision, Marco's...) will make for solid HP gains at most operating points on boost and possibly transition.

Smaller volume shorty headers should result in earlier boost onset. M&K or Vision if they still do so converted 993's are my favorite.

I do not care for the WG circuit on the B&B style headers as I suspect it leads to over-boost potential on some cars nor the collector however, there smaller volume and elimination of the funky stock crossover are potential improvements.

Stock or converted 993's will probably be best choices for heat.

I am sure the vote of support is appreciated by Brian.


As to equal length increasing efficiency and power on boost I totally agree.

In my opinion, saying that Brian's or any equal length system will contribute to off boost response is a stretch without testing or some other technical cause in support of such a position like reduced volume via greatly reducing the WG circuit lengths and or smaller tube id's.

I might hope, and it may very well be, that we see an improvement over a stock late 930 header in all such areas as it dose have its weaknesses (cross over & long J pipe).

However, it would not think it should be expected to make improvement pre-boost over a well designed lower volume non equal length system.

If better pre-boost operation were an expectation of equal length 930 headers, the others that came before would have been screaming so from the highest roof tops. After all B&B proved 930 owners will spend a fortune in search of less lag.

It just seems to me concluding such would be more a leap of faith than logical conclusion.

Please do not get me wrong. I think Brian's system is potentially the best new product to some along for a 930 in some time and may buy one some day as it is targeted right inline with my goals.

:eek:

I just don't understand how you can think this can be a leap of faith instead of a logical (actually it's been proven) conclusion. We're not colliding neutron's here, this stuff has been around and proven for over half a century.

Equal length primary's have been proven since.......the 60's, maybe even before that.

Furthermore, B&B headers are not considered a fortune, actually they're considered more of a modest-priced solution. If you want to scream about headers, check out a set of Bob Holcomb's equal length turbo headers.

Please don't use volume when talking about intake or exhaust tracts. It implies that the closer one gets to a zero diameter pipe, the more power can be extracted by the turbocharger. Exhaust primary size is calculated by number of cylinders, displacement, port size and target operating rpm range.

It's really quite simple so let's not over think this.

1.) An ideal header for a turbocharger will have the shortest primaries possible.

A turbocharger is driven by the velocity and energy of the exhaust gas.

2.) It will incorporate equal length primaries to aid scavenging (correct spelling) and insure exhaust pressure pulses do not overlap, which build up back pressure on overlapped cylinders and create uneven exhaust pulses fed to the turbine.

The length of the primaries before the joint is determined by calculating the desired rpm operating range and pipe diameter. The traveling pressure wave out one primary pipe will create negative pressure in the adjacent cylinder which will aid the scavenging of exhaust when that cylinder's exhaust port opens.

3.) And there's the quandary; Doing both without compromise, is impossible.

Study the turbo'd CART and F1 engines. The engineers of these engines squeezed every possible HP out of the engine and........they had equal length primaries.

I do appreciate the support. Building shorty headers would've been much easier and cheaper.
The equal length portion of my design was spawned from my experience with the SSI based 930 system and the high-end systems such as Mode. In a nut shell these are the points I considered:

> The torque gained by an equal length system on an otherwise a stock engine is small when compared to the baseline of all systems. Headers only add ~15WHP to a stock engine so any increase by definition will be small.
> Short tube headers will give you that 15HP bump using the cheapest least complex design. Great from a business standpoint.
> Old racecars use shorty headers. They do not operate off boost and will never see a daily work commute. Getting the exhaust to the turbo fast is their function.
> Headers on a turbo engine are enablers. They allow other modifications to work optimally. The better the header design the more potential for optimal performance.
> Optimal performance (to me) does not mean the most horsepower but rather the most broad torque band.
> Street cars spend 90%+ of the time off boost and need as much torque below threshold as possible to enhance driveability and driving pleasure.
> Driveability improvement comes from a complex combination of the right components working perfectly together in a high state of tune. Headers are but one piece of this formula. Anything less than the perfect compromise in a header design will take away from the desired result.

That last point was/is my main focus. All headers make more power than the stock system. Equal length headers have the potential to give back even more in torque which translates to driveability and more usable power. How much more depends on the engine build and tune.

I've owned the "Old Sled" for 22 years and have learned much about modding a 930 in that time. But the one thing that you need to know before you start is how you are going to use the car. I learned it the hard way.

I, like many others have, been all over the map with what is cool at the time, what the big race tuners use, what you hear here, and what you see in the pictures in the books. Then I thought, I'm never going to run Daytona, go 200 MPH, drive DE's, or run the Miracle Mile. So after 3 exhaust systems, 2 cam changes, 4 turbos, 2 clutches, and 3 ignitions I realized, I'm just an old fart that likes to get to the store and from lite to lite quickly.

I did 2 mods that completely transformed the car. The first was an 8:37 ring and pinion, shortened 2nd & 3rd gear. The second was the icing on the cake, the right headers. This car has incredible low end response and nearly zero lag. It is truly the most fun you can have with your cloths on.



http://forums.pelicanparts.com/uploa...1263436623.jpg

Cole

I have nothing technical to add so I'll just post some pics of interesting Japanese exhaust systems.

http://image.blog.livedoor.jp/autoen...d/3d14d99c.JPG
http://image.blog.livedoor.jp/autoen...1/b13d7977.JPG

These guys have some interesting looking stuff.
ボルケーノVolcano　オフィシャルウェ㠃–サイト　ãƒ�ルシェ マフラ-カスタムビルダー PORSCHE　MUFFLER CUSTOM BUILDER
http://www.volcano-jp.com/img/TOP/tako.jpg

Those "935" headers are from Reid Washbon Racing. Probably not cheap but truly a work of art.. they use 321 and inconel 625! on there turbo exhausts. SmileWavy

Reid Washbon Racing Exhaust Systems & Components

"Exhaust components fabricated from alloy 625 can be made with wall as light as .020 without sacrificing strength & durability even at elevated temperatures"

Mamma mia..

Do not make a header by welding cylinder runners to a straight pipe. Lots of flow separation from at the edges of the junction. SAE paper 2000-01-0290 has a great sequence of Schlieren photos illustrating this. (Have you seen those pictures of model aircraft in supersonic wind tunnels? The ones that show the shock wave? That's a Schlieren image). After 120 years of internal combustion, that's the level of analysis exhaust pipes are subjected to, and this paper is 10 years old. You can imagine what goes on now, especially with variable valve timing thrown in. Smashing gnats with sledgehammers.

That was my point. This old 934 design is no more than a glorified log exhaust. Yes it works but damned near anything will work on a turbo engine as we see with the OEM 930 systems. Corky Bell talks a lot about this type of exhaust system in his turbo books.

That'll work! If there was a way to weld three 30mm tubes to each side of a standard mini-foot flange, I wish they would show it, as that would be the ultimate. Your concept is darn close.

There's too much talk about scavenging on this thread. Forgetaboutit. Pulse conversion is where it is at for big boost. Man, BMW re-did their V8 for turbocharging last year. Changed the heads, cams, cam drive, and manifolds just to get short turbo manifolds on the INSIDE of the V. Unbelievable.

http://forums.pelicanparts.com/uploa...1263441769.jpg

I tried to swear off this thread, but this is just too much. A production motor with cast manifolds.

I'm sure there are still some Ferrari engine engineers around from the early 1980s F1 days who will tell you how they started with that belief but finally moved the turbos from within the Vee to outboard (like everyone else) just to keep up in the rapidly escalating turbo HP race. Once that BMW engine gets to the power levels of F1, 15HP/cubic inch for a transient, road course duty cycle, I'll listen.

I had that belief at one time, it all sounds logical and pulse recover has its applications. Then I had a discussion with Ed Pink, look him up. He explained his experience with these manifolds on high performance motors and why he would not allow one retro-fitted to one of his turbo Cosworth Indy engines.

It goes like this: You blue print the combustion cycle components to make all cylinders operate under the same conditions, at all times. This doesn’t just mean the block related components but the air system also. When you’ve made every effort to achieve this you can reliably pull high HP. As it relates to exhaust, his comparative testing (yes he tested log manifolds that were the previous standard on turbo Indy motors) showed anything less than equal primary pipes (whatever length) gives you misfires on random cylinders at random RPM and misfires become more critical and damaging as power density increases.

I’ve witnessed and done many things demanded of a turbocharger and engine that took away from ideal power production. This is more the norm than the exception. Only BMW engineering know the numerous reasons they moved the turbos here but my prediction is like Mr. T said: “Pain”.

This is gold! Especially on full race motors with high overlap cams.

This hints at it but no one has said anything about how equal length system helps to equalize temperatures at the exhaust ports.

-----

As to keeping each bank split into a split scroll turbo. One resource noted that this works very well on a 4 cylinder motor and is a significant advantage that warrants the effort. It was noted that on 6 it may not be of significant value.

For us I would guess it is a solid way to mitigate running unequal length secondary tubes with equal primaries.

-----

Glad to hear someone else say 'scavenging' dose not so much apply to turbo exhaust.

I suspect equal length is more about orderly exit of the exhaust pulses which reduces back pressure, increases VE, and thus power.

An extra 15hp, if that is the case, for equal lengths and more ballanced air flows / temps at each cylinder to me is worth the effort.

It might even me more if used in combination with the right turbo hot side. I suspect most 930 owners are suffocating the hot side in the name of less lag.

I suspect there could possibly be 40 +/- hp that could be freed up on a 425whp motor that is running a 7200 hot side based turbo with a change to equal length system and a larger turbine.

-----

Yes, equal length is the ideal turbo exhaust for making power!

But, lower volume is strongly correlated with reduced spool time. (See graph at start of this thread.)

I still have not seen a credible source that says equal length reduces spool time over a well designed non-equal system.

This is why I would say making the assumption that any such system will do so is a 'leap of faith' until proven with repeatable tests that control for boost level and AFR.

It could very well be I just could not find any experts that confirm this and am mistaken.

What I have read is that unequal length has the potential to create higher pressure spikes at the turbine that can have the effect of accelerating a turbo quicker.

------

Comparing a K27-7006 turbo to a K27-7200 might not be that different than comparing a well designed small volume header to a well designed equal length 930 system.

One should spool faster, the other should makes for more hp.

------

For the track the 7006 & equal length's are going to be a better fit.

For commuting, the 7200 and a decent low volume header is probably a better fit.

One might mix the two for a better average.

-----

Either turbo or header is probably an improvement over the stock units for the track or commuting.


Again, I am a big fan of what Brian is doing and it is what I would choose given my goals.

;)

Here is one of the better turbo exhaust articles from a I have seen that is from a turbosystems engineer at Garret.

Turbo Exhaust Theory

It dose say:

I belive this is in support of reducing exhaust volume.

Latter he notes:

This supports that equal length can help 'boost response'.

Unfortunately he is not very direct in discussing the trade offs between lowest volume and a balanced system.

There is a bunch of other neat stuff in the article to.

Admittedly, my understanding regarding the benefits of twin scroll turbos is strictly in the 4 cylinder department; what you said does make sense regarding the impact of pulses on engines with fewer cylinders. The more degrees between each pulse does, at least mathematically, mean that the pulse wave of a given "bang" is less likely to get clipped by the wave of the next "bang", as well as having fewer degrees of overlap of the tails of the waves.

Regardless, all of the Japanese pocket rockets use divided twin scroll turbo with equal length headers and the dyno runs on NASIOC and EVOm all tell the truth in these applications that a pulse tuned turbos spool and transient response are MUCH quicker than the same turbo running merged shorties. That said, the length from head to turbo in these cars is so much shorter than our cars, that the exhasut volume between the two is negligibile, so you get the best of all worlds.

If anyone outh there is running a divided twin scroll turbo in a 930, it would be telling to see the difference in spool between a divided, equal length exhaust and a merged, equal length exhaust on the same turbo (apples to apples). For me, the debate is academic, as my motor is still a long way from built and I am already all-in on the turbo and exhaust selection.

Maybe 9 months from now I will be the one doing the comparison, but until then, I'll hold out hope someone else will. :)

Copbait 73 quoting the infamous Ed Pink;
It goes like this: You blue print the combustion cycle components to make all cylinders operate under the same conditions, at all times. This doesn’t just mean the block related components but the air system also. When you’ve made every effort to achieve this you can reliably pull high HP. As it relates to exhaust, his comparative testing (yes he tested log manifolds that were the previous standard on turbo Indy motors) showed anything less than equal primary pipes (whatever length) gives you misfires on random cylinders at random RPM and misfires become more critical and damaging as power density increases. ...

Keith:
"This is gold! Especially on full race motors with high overlap cams."

He was talking about the turbocharged Cosworth Indy Engine. High overlap cams are not a good solution for any turbocharged engine.

Garrett Engineer:
"getting the boost up early is a much more effective way to torque than playing with tuned primary lengths and scavenging"

Keith:
"I belive this is in support of reducing exhaust volume."

This is a complete leap. How can you jump to that conclusion? There are so-o-o-o many factors that cause a rise in boost early.

Sorry guys. I'm outta' here. This debate about the benefits of equal length headers has just really gotten out of control. It's been proven for decades, and this debate thing just goes on, and on and on, and on....

I have complete faith in Brian's new product. I believe it would be d@mn near perfect if it had a centrally located turbo flange, but our crammed 930 rear-ends make it difficult and costly (cosmetically and financially) to do otherwise. I can't wait to see Brian's dyno results so we can put this trampled debate to rest.

An engine designed from the ground up to be turbocharged, the Chevy-Ilmor Indy V-8. Now I'm outta here. :D
http://forums.pelicanparts.com/uploa...1263519014.jpg

+1

I am a student, not an expert, and on a journey where I learn more about my favorite subject, Porsche's, in part by the hearing of others ideas.

Sometimes personalities get in the way including mine. If this has happened I am sorry.

I only seek the truth.

If you go back and look carefully for it you will see I am a big believer in equal length headers and Brian's new system.

The best.

Supercharging would make this conversation moot. LOL.

Never speak in absolutes. Have you seen the overlap numbers on the 2.1 RSR Turbo??? Big, like 'S' cam big. Definitley not good for a street engine, but any engine? :D

If interested in seeing them, I can dig them up, but not handy now.

Cheers, guys. Interesting thread, this.

I suppose, thinking about this logically, aside from all the other benefits of twin turbochargers (quicker spool), with fewer exhaust pulses (3 in our 6-cylinder case) per turn of the crank, I suppose this allows for shorter-length primaries?

Taking this line of thinking to its ultimate conclusion, then, we could have a tiny turbo for each cylinder? ;)

I agree with Werk1 on Brian's system - its the best for the street & for built motors that will be used on varying tracks and situations. Like I said on my tt motor, its equal length for many reasons - and it works incredibly well.

Brians equal system with a zork is the ticket - i'm only doing the 935 headers as I have to fill the spot where there is no bumper on my K3. Otherwise i'd be in brian's system in inconel without a doubt.

Brian, are you thinking about doing anything for the 993 turbo? I'd be interested in a nice set with heat if they'd offer a benifit over stock

Eventually. My focus is of course the 930 and 965. I've been working on a 965 system for some time and will finish it after the 930 heat exchangers are done.
The 993tt system could easily be adapted for tt 930/965 by just flipping the flanges which makes that project more viable than just as a replacement for the stock exchangers.

If you look close at Brian's design, the turbo flange is centered between the collectors, since both sets of equal length primaries are offset to the drivers (US driver ;))side.

True equal length primaries and secondaries, packaged for a 930.

Here is some interesting exhaust theory points of interest I came across elsewhere:

"...
Boundary Layer

The thin layer of air against the walls of an exhaust pipe. This layer buffers the effect of both the temperature and speed difference between the gasses inside the pipe, and the walls of the pipe itself.

Turbulence, your number 1 flow restriction

Turbulence is any gas not moving in a uniform direction (normal to the flow field), or against the overall flow of the other gasses in the pipe. It is by far the number one restriction in most pipes. It is also more common than you probably think. Almost any bend in pipe causes significant turbulence. (The turbulence comes in the form of vorticity when the pressure and density gradients are not alligned. The greater the mis-allignment, the greater the vorticity.)

Reduced turbulence = increased flow.

The only other real restrictions are changes in velocity. If the gas must speed up quickly it will require energy to do so. That energy usually comes in the form of pressure; backpressure in the case of an exhaust system. This pales in comparison to bad turbulence, but it's still worth noting.

Believe it or not, it really isn't the size that counts.

Size is only a factor in a very complex equation when it comes to gas flow. ... A larger pipe tends to have a more stable boundary layer because the gasses inside it are flowing more slowly. If the gasses are moving too quickly it rips off the boundary layer constantly, causing turbulence. The more stable the boundary layer, the less the turbulence, the better the flow. Corky Bell was probably referring to the boundary layer when he stated that there was a specific exhaust (and intake) gas velocity that ought not be exceeded.

Thermal coatings help stabilize the boundary layer by decreasing the difference in temperature between the boundary layer (which is about the same as the pipe) and the inner gasses (which are much hotter). Having a more even temperature reduces the effects of convection between the hot and cool gasses, which reduces turbulence, which reduces backpressure. Neato

Now to the last problem ... bends!

Whenever the gasses move through a pipe at an angle there is turbulence. This is because the diameter of the outer edge is much larger than the inner edge.

That difference in diameter means that in order to go through the bend at the same angular rate the outer gasses must move at a higher linear rate. This either causes backpressure because the outer gasses have to be accellerated, or it causes turbulence from shear forces because they don't speed up. Either way it's not ideal. ...


...because of the swirling pattern of the gasses exiting the turbine, the first 18-24" of exhaust pipe does not follow the rules in the same way that the rest of the pipe does. It does still follow the rules however, just the swirling that increases the local exhaust gas velocity considerably. ..."

The most relevant thing I have gotten out of this thread is that Brian's set-up creates a lean condition, suggesting that it works really F#cking good at flowing exhaust.

That to me is more important than academic would-have could-have.

Brian built a header system which looks like it really works. A equal length, and pretty freaking short system as well.

If we really wanted to answer all these questions we would be taking donations from all the people at this board to pay for Brian to test his system versus a B+B versus a Euro and also American stock set up. The rest is just making academic assumptions.

That is my two cents worth.

That would be great, if he had the dyno for a day, and had all the headers there, and simply swapped them and run each of them on the car, all on the same day, that would be invaluable information! I don't even have a single turbo motor now, but i'd be up for chipping in something to cover the costs.... What are we looking at Brian for a day renting the dyno and a day of your time? Do you have access to all of the different headers to test? Stock US, Stock Euro, B&B, GHL etc

I think the verdict is clear for those who don't have a vested interest in something they want to sell to others:

1. scavenging is not as important as reduced volume for a sports car.

2. Equal length is not as important when you are not using a divided turbine housing. If equal length
can be achieved without excessive flow losses and volume increases, it is overall beneficial.

3. Pulse conversion is the best way to improve response. This requires a completely divided system wth both sides isolated from each other. In this case equal length is required, along with a divided turbine housing. The collector volume on each side should be minimized as much as good fabrication practice will allow.

Yes, yes-- the lean AFR at idle could be an indication of a nice potential improvement!

Or an exhaust leak, or an air leak after the metering plate, or an offset to the O2 sensor due to contamination.

I apologize but this thread was not intended to be a Brian v B&B vote!

Nor a mine or my friend's is best and yours suck, thread!

It was intended to help me and hopefully others explore the theory(s) that differentiate a good equal length from a good low volume design.

Brian's is not the only equal length 930 header builder and there are actually quite a few. However, until now most have been to expensive for most and or to make them a popular choice.

We are lucky to have Brian's new system coming on line.

However, theories are just that.

I would truly expect Brian's new true-equal lengths to blow away the stock late/euro 930headers!

I also truly hope they blow away B&B style units on lag and VE. I suspect this is a strong probability.

A better comparison of a low volume system to and equal length might be Brian's new 'truly equal length' system to his/M&K's 993 / 930 system.

I to am looking forward to any dyno tests.

Especially if back to back.

I would just hope any such tests would be controlled for AFR and boost as these are significant variables on a turbocharged car.

It would also be interesting to fill up the different headers (stock, B&B. Brian's) with water and measure the result to see how much the internal volume actually varies between units, including WG tube. They may not be as much different volume as we think.

Again, I did not intend this to be a slam Brian's headers thread in any way. Only an educational experience for some of us that are interested and those that might follow.

The best to all.

I haven't taken this thread in a negative way. The frustration is of course the lack of application specific comparative data. As stated we need a controlled dyno test of the various sytems.
This runs into a mirad of problems, most significantly the definition of our application. I have built my engine around what I believe to be the most common upgrades for a mid-level CIS engine. That is my baseline.
Dyno testing these systems would be, pardon the pun, exhausting. You are talking small differences that are hard to see on a dyno yet easy to feel on the street. Driveability enhancement is difficult to see on a full throttle dyno pull. With each new system you would have to tweak the AFRs and be confident that the charge air temp remains the same. Not as easy as it sounds.
I do plan to do this type of testing when time permits. One thing I would like to stress is that I am not fixated on any one design just because I sell it. The designs must sell themselves. If I have made a miscalculation and find a design is substandard it will be changed.

Most likely. Going lean because you have an efficient exhaust (no matter who makes it) with a turbo stuck in the middle (sorry, exactly in the middle), makes no sense.

Nothing was changed but the headers. The existing Euro system was in excellent condition with no leaks. The new ones have all new hardware and I've detected no leakes. There is no O2 sensor or smog equipment of any kind on my engine.
The headers were responsible for the change in idle mixture. Don't know why myself as I did not expect the change to be significant. These headers are obvioulsy vastly different in design than the J-pipe configuration that was replaced, we do know that much. You can hear the pulses hit the turbo at low idle like a cammed engine.
Don I would think you should hear this cammed sound with your headers as well. Have you not experienced this?

911st: I know you enjoy the mental challenge of trying to understand things at a very high level of detail...I was not trying to hijack the thread, just for me personally the biggest thing that matters is what products are actually out there and how well they work.

I just see people saying what equal length is or what short length is and at the end of the day the only thing that matters is what the dyno says and whether the car is quicker or more driveable. To me the lean condition is EXCITING, it suggests progress towards a better flowing exhaust than a B+B for the same price. But we don't know for sure, and that is where the real research should be going right now IMHO. We all have a vested interest in finding out whether Brian's product is better on the dyno. We know it is better in quality.

Anyway I am not trying to hijack your thread. Brian says it best that we are all a bit frustrated by having to talk in theory about headers after all these years.

I guess what I am saying is what if Brian already came pretty close to the Holy Grail? That is exciting. We all want to be able to throw something onto our car to make it go faster. For a similar price as a B+B, I would rather have the system which dynos the best.

Also 911st, I don't think you personally ever made this into a thread of Brian vs. B+B, I understand that you like to think in theory about these things. It just becomes the elephant in the room when we talk about headers to compare the designs that are affordable. Companies like GHL have already gone under, so choices are pretty limited. Pretty much by default when we talk about headers anymore it is going to be Brian versus B+B.

It just seems clear that the last step in this conversation involves a dyno.

I apologize if I am jumping to the finish line and skipping all the theory behind headers, but I don't have the mental capacity to understand all the theory anyway. lol.

Given the course and length of this thread, it looks like it needs to be a business priority.

Ha! Yes it may but boy it's gotta stand in line with the other business priorities or soon their won't BE a business. Funny thing about folks wanting their orders in a timely manner ...
Now I gotta go out in the shop and assemble some headers! The last batch is done and I've got orders to ship!
The very bottom line is that headers are a good thing, and mine are quality. Any other performance bump you get is a bonus.