basic666

the fact that people are still buying them after reading your extensive rant about it just shows how much it mattered.

Also it seems like you have problem reading, like i said, another butt dyno from another thread specifically mentioned they heard NO SOUND difference after installing other branded headers. So clearly the design and shape of the headers have to do with its performance, whether its sound or increase in HP.

But ya, keep on preaching like all the other keyboard warriors here like your opinion actually matters.

spdracerut

Go back and reread what I wrote. The Moody diagram and internal pipe flow was in reference to the IPD plenums. Reading comprehension is a thing. And looking at what you wrote, "the Vektor has over ANY other design with their oval tubes, equal length pipes and of course super model welds". You did not state oval entrance section transitioning to round tube. You said oval tube.

Below is the best pics I could find of the three headers quickly and their entrance sections.



With flow entrance sections, a nice radius on the entrance prevents flow separation/turbulence/pressure drop entering the tube. A step in the flow and a sharp transition causes the flow separation region labeled as vena-contracta in the diagram.


FYI, Vena contracta is the point in a fluid stream where the diameter of the stream is the least, and fluid velocity is at its maximum, such as in the case of a stream issuing out of a nozzle. It is a place where the cross section area is minimum.(taken from wiki). Anytime you take a fluid, accelerate it and decelerate it, there are going to be losses. Long story short, steps in flow are bad. Sharp transitions are bad.

spdracerut

This comment could be applicable to NA engines and header design. For NA engines, headers are acoustically tuned to create pressure waves that correspond to specific engine speed ranges. As the frequency depends on the length and diameter of the tube, yeah, you typically give up one part of the rev range to gain in others. There are tricks to create pressure waves of different amplitudes at different frequencies. Tri-Y headers and a step expansion in tubes.

In these headers, you can see the expansion steps:

basic666

spdracerut, don't bother wasting your time on him. if you haven't noticed already - the troll acts as if he's super scientific and would settle at nothing less than actual test/dyno results, BUT anytime you counter his opinions with actual facts or scientific information, the troll goes silent

4 Point 0

It's as if you have never owned and modded a car before and you have zero understanding of what Stage 1 and Stage 2 are. Headers are made for Stage 2 not Stage 1.

Stage 1 is just a tune. A mild tune, no mods necessary. Its conservative.
Stage 2 typically means "Improved Exhaust flow and improved intake." Knowing that a car is going to have improved intake and exhaust, the tuner tunes slightly more aggressively......Ie adding boost and timing.
That causes more exhaust gasses. The Stock flow may not be able to get rid of it fast enough to take full advantage of the extra boost. But when you have added better flow such as Headers, and either catless bypass or sports cats, you get a better scavenge, giving you full benefit of the Stage 2 Tune.

No one needs the ECU cracked, to develop a better flowing header. Just making a set equal length and having a proper collector so that pulses are not colliding, is an improvement. This is enough for me, even if they never had the pretty welds you are so infatuated with. (I promise I won't call your headers ugly. )

This is just basic modding. Stage 1, slight tune. Stage 2 improve exhaust flow and add more tune. It's not my job to prove anything for you. I am not selling anything. These are not my products. I am free to buy whatever I want, whenever I want. You don't have to buy anything at all. No one cares.

Psorcery

To be fair, we haven't really seen solid dyno figures and gains consistently from multiple sources.. While I don't fully agree with what he says, he does have a point.

spdracerut

There are certainly some questions such as: how does the stock ECU behave? Built-in load limits? How does it adjust to changes in volumetric efficiency? How was the car dyno tested? Under what conditions? ambient air, coolant, oil, header temps? How was the fan setup?

Two major ways to analyze this: go to scientific principles and data.

Let's start with data. Fabspeed posted their in-house dyno quite a while ago. Let's say you don't trust that. Vektor has posted their early development dyno done at a different shop's dyno. Vektor also had MotoIQ test it and they used World Motorsport dyno. Say you don't believe either of those. The one guy in Brazil who bought headers posted up his dyno results (timewonka on instagram). Say you don't believe a random guy in Brazil, there's scientific principles to go on. Please note every single dyno shows power gains.

Does anyone need a dyno to tell them a catless pipe is going to make more power than the stock cat? No, because it's the basic scientific principle of removing an exhaust restriction on a forced induction car. NA cars do have a bit differently due to acoustic tuning where a bigger exhaust could actually hurt power. But anyways, you don't have to be a rocket scientist to see that the aftermarket headers have flow advantages compared to stock.

4 Point 0

+1 Well said.