Nameless Performance Equal Length Stepped Header

[Dimman]

Originally Posted by Calum

So infinite baffle to speaker guys... Interesting!

Um, your turn to explain.

[regal]

Originally Posted by Calum

What I said was meant to be a rhetorical question to point out the possibility that it was incorrect to make the assumption that the removal of the cat allowed for big gains because of the restriction to flow and not because of increased tube lengths allowed for better scavenging. I have little doubt that you understand this much more then I do, but I do understand the generalities.

I do appreciate that you typed that though.

Termination boxes are new to me in this context though. Could you expand on that?

I think a main benefit of getting rid of the OE cat is you can push the tuning farther. You don't have to worry about overheating the thing and you can push the vvi farther to stop the obnoxious EGR affect this engine has. Plus you are removing a significant source of heat heating up the heads.

[Calum]

Originally Posted by Dimman

Um, your turn to explain.

TL;DR instead of a box tuned to keep the driver under control, which restricts output, a baffle is used to separate the front and rear waves.

With larger drivers, the mass of the cone becomes a concern as it's inertia can add it's own distortion to the output sound. To combat this drivers are typically placed in boxes sized so that the air pressure & vacuum they build while they operate is used to assist the drivers suspension to prevent unwanted movement of the cone. The compromise though, is that the smaller the box, the more it restricts low frequency output. The bigger the box, the less accurate the sound is.

Some drivers are designed with sufficiently stiff suspensions and can be placed in what is called an infinite baffle setup. You can't just leave a drive to play in open air as the front pressure wave would cancel out the rear negative pressure wave. But an IB is designed to add nothing else but a separation of the two waves, as if there were in infinitely large wall between the waves. Ideally there's no suspension tuning contributed at all. (see how going from one discipline to another can get confusing really quickly ) This means the low frequency output isn't restricted and things can get loud and still be accurate.

IB setups help to cool the voice coil allowing for more power to be passed through it. But they also make it easier to bottom out the voice coil and damage it. Again, lots of compromise.

In a house IB would consist of a VERY large box build for a driver. But in a car, IB setups are typically accomplished by putting a piece of MDF between the rear seat and the trunk, sealing the two areas from each other as much as possible, and just mounting the driver to that wall. They can end up taking up less trunk room then a traditional setup, and either be more effective, or use less power to get the same effect. Less power is nice because it's hard to generate that much power in 12 volt system.

And then there's port tuning for boosting specific frequency ranges, crossover designs to provide phase shift to combat the phase shift from the box design, isobaric chamber designs, folded horns....

[Raven604]

Originally Posted by Calum

TL;DR instead of a box tuned to keep the driver under control, which restricts output, a baffle is used to separate the front and rear waves.

With larger drivers, the mass of the cone becomes a concern as it's inertia can add it's own distortion to the output sound. To combat this drivers are typically placed in boxes sized so that the air pressure & vacuum they build while they operate is used to assist the drivers suspension to prevent unwanted movement of the cone. The compromise though, is that the smaller the box, the more it restricts low frequency output. The bigger the box, the less accurate the sound is.

Some drivers are designed with sufficiently stiff suspensions and can be placed in what is called an infinite baffle setup. You can't just leave a drive to play in open air as the front pressure wave would cancel out the rear negative pressure wave. But an IB is designed to add nothing else but a separation of the two waves, as if there were in infinitely large wall between the waves. Ideally there's no suspension tuning contributed at all. (see how going from one discipline to another can get confusing really quickly ) This means the low frequency output isn't restricted and things can get loud and still be accurate.

IB setups help to cool the voice coil allowing for more power to be passed through it. But they also make it easier to bottom out the voice coil and damage it. Again, lots of compromise.

In a house IB would consist of a VERY large box build for a driver. But in a car, IB setups are typically accomplished by putting a piece of MDF between the rear seat and the trunk, sealing the two areas from each other as much as possible, and just mounting the driver to that wall. They can end up taking up less trunk room then a traditional setup, and either be more effective, or use less power to get the same effect. Less power is nice because it's hard to generate that much power in 12 volt system.

And then there's port tuning for boosting specific frequency ranges, crossover designs to provide phase shift to combat the phase shift from the box design, isobaric chamber designs, folded horns....

Woah what wuuuut

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[Dimman]

@Calum You mentioned confusion between disciplines, but there is a lot of relevant similarities here, too.

Sound and air pressure/vacuum are interrelated. And air pressure/vacuum are interrelated with power.

I'm trying to formulate a (speaker) port sizing question for you in a way that relates to headers/exhaust tubing. Or maybe the horn design is relevant. Maybe later, though.

Think of Yamaha's disciplines. Music and power.

[Calum]

Originally Posted by Dimman

@Calum You mentioned confusion between disciplines, but there is a lot of relevant similarities here, too.

Sound and air pressure/vacuum are interrelated. And air pressure/vacuum are interrelated with power.

I'm trying to formulate a (speaker) port sizing question for you in a way that relates to headers/exhaust tubing. Or maybe the horn design is relevant. Maybe later, though.

Think of Yamaha's disciplines. Music and power.

Yeah, when you get into the nuts and bolts of it, the disciplines are very similar.

Port sizing uses the same formula to figure out the frequency it's tuned for. It just doesn't include cam duration, speed of sound changes due to EGT and isn't worried about scavenging. But, as you eluded to, pulses in a tube are pulses in a tube. Wave guilds, transmission line, and fiber optics are all the same again. Just different frequencies ranges and speed. I'm surprised no ones developed a smith chart for acoustic.

Check out the technical articles on this site. http://mysite.verizon.net/vzezeqah/id1.html

The last time I read it they basically stole all the math directly from How To Build Horse Power Volume 1 & 2, but the point is, we use VERY similar maths to figure out how to size a waveguide, or make a sub port. The problem with a header is that it takes into consideration A LOT more things up stream of it. Cam phasing alone has to be the bane of every header designer ever.



Now that we've pulled that back on topic, has anyone heard anything about the results of this header with the Innovate Kit?

[StormTrooper]

Just that when they were talking about doing two headers, the STX legal version would fit with the s/c kit and TRD intake.....

[Gardus@Supersprint]

@Dimman very good explanation of the pressure wave / flow issue. @Calum interesting reading, I agree that there are strong similarities of tuning an exhaust and an audio system. As you said the main difference is the source which is much harder to control, with all the variable lift and timing, throttle opening, rev range etc.

I think it's basically impossibile to simulate and tune an exhaust without a very large engineering team and the specific data of the engine that only manufactures and engine builders have.
You can tune the length of pipes to have pressure waves tuned for scavenging at a certain rpm range at a certain % of throttle and load (good for example for steady speed engines for generators, I'm thinking hybrids here) but that goes out of the window as soon as you change something. I actually think that is better to limit returing waves as much as possibile so you can concentrate on flow.
In this the removal of the 1st cat is a good thing, as well as making the merging points as smooth as possible. Equal lenght is also good for the same reasons.

As for tuning the catback, you would need a machine that simulates a flow of hot gas at speed and pressures similar to an engine but without the waves, but then you won't have the noise so the perfect exhaust for performance may also sound like s*it once it's done...

[pheoxs]

Originally Posted by StormTrooper

Just that when they were talking about doing two headers, the STX legal version would fit with the s/c kit and TRD intake.....

They're only doing 1 version now. They managed to make pretty much the same power levels with their current OEM fitting design as they did with their long ass tube design that involved modifying shrouds and swapping fans.

It fits and works perfectly well with the Innovate S/C. The Vortech is still iffy, it'll be similar to the FA20Club header because it wraps up in front of the engine a bit. It'll either fit by a hair or be a hair too big for Vortech, we'll have to wait and see.

[wparsons]

Originally Posted by tennisfreak

So you're saying Jason @ Nameless doesnt know what hes talking about?

He told me himself that the majority of the gains come from a catless header and that is what I should get.

I'm not saying a pipe design could not be made to seriously f up the flow (because it could) but the stock headers and many other aftermarket headers are fine designs in themselves and there is no magical redesign of just the pipes that is going to get you a bunch of hp. The majority of the additional HP is from removing the catalytic converter.

No, and see below for why. If you could put the cat further downstream to give room for proper length primaries, then adding a cat the final hp would be VERY similar (like within 0.5 - 1hp).

Originally Posted by Calum

But was the gain in power from removing the cat due to the cat not flowing well, or because it allowed them extend the primaries and/or secondaries farther down stream?

considering what they've gone through to fit this head in the engine bay (they were considering replacing the fans and water bottle if I'm not mistaken) I'd place my bets on the extra room being where they got the gains from.

Originally Posted by autobrz

I read Jason on the forum say himself that having a proper length tubing was why the catless is better.

The cat itself isn't a restriction, but the space it takes up kills the primary length (and ability to make power).

[2superblus]

Originally Posted by chanomatik

Listening to Scooby South's video of how the NP header sounds... I think I may hold off for a while. For daily driving it's overkill.

That video is not a 100% accurate representation of how the final product will sound

[chanomatik]

Originally Posted by 2superblus

That video is not a 100% accurate representation of how the final product will sound

Oh I'm aware of that, hence why I said I "think" I may hold off for a while. Sorry, I think out loud too often and I'm fairly literal with my words. I can be swayed once the final product is out, but the initial prototype does have me hesitant.

You are correct, in all fairness one can't make a firm decision without all the facts and a prototype isn't the best indicator of the final product. It gives a good idea, though. Just look at the chopped up RWD Subaru Legacy that resulted in the FT-86.

[digital_assassin]

Waiting sucks

[SCharged]

Is this true??