Nameless Performance Equal Length Stepped Header

[Dimman]

Originally Posted by Symbiont

Right, I don't expect it to go away completely, but smoothing it out a bit would be awesome. Honestly, I love the low-end grunt of the engine, but the 'twin peaks' are always on my mind when driving aggressively.

I really don't want to do much with the cams. I probably won't do more than an I/H/E and a tune, with a possible change in the suspension later on down the road.

But what is acceptable for smoothing it out? Would you trade some of the low peak's torque for more in the midrange or up top?

[Symbiont]

Originally Posted by Dimman

But what is acceptable for smoothing it out? Would you trade some of the low peak's torque for more in the midrange or up top?

If absolutely necessary to make tradeoffs, I would love to 'transfer' a bit of the lower end torque to fill in that gap to make the torque curve more linear. The smoother, steady acceleration would fit my driving style a lot better.

Since base Tq would be raised anyway as a result of the bolt-ons, per the initial tests, there shouldn't be a noticeable change at the bottom of the curve, and it only gets better from there.

[Dimman]

Originally Posted by Symbiont

If absolutely necessary to make tradeoffs, I would love to 'transfer' a bit of the lower end torque to fill in that gap to make the torque curve more linear. The smoother, steady acceleration would fit my driving style a lot better.

Since base Tq would be raised anyway as a result of the bolt-ons, per the initial tests, there shouldn't be a noticeable change at the bottom of the curve, and it only gets better from there.

This is true. They raised it across the board on the dyno sheet, and the new 'dip' is close to the old peaks. Now will come the trickier part of tuning the shape of the curve.

[R/TErnie]

Originally Posted by Coheed

Since there are no designs yet developed, all tests are against the OEM piece. Development will continue.

Then that answer is No.

[R/TErnie]

The dip is clearly a tuning "feature" there to allow the engine to pass emissions. If you look at the Ecutek stock ignition and fuel maps you can see the ignition timing retarded and the fueling reduced.

This is not related to Helmholtz resonance because the ignition timing would advance with the reduction in fuel. It's pretty dumb and it's pretty obvious that it's in the tune. When the software for tuning is released I think you'll see some nice gains in that area... and further gains up top where the tune is altered to keep the catalysts happy.

Kind of tough to design a header around and engine that cannot be tuned. I promise the AVCS maps are just as funky as the stock ignition and fuel maps.

[Dimman]

Originally Posted by R/TErnie

The dip is clearly a tuning "feature" there to allow the engine to pass emissions. If you look at the Ecutek stock ignition and fuel maps you can see the ignition timing retarded and the fueling reduced.

This is not related to Helmholtz resonance because the ignition timing would advance with the reduction in fuel. It's pretty dumb and it's pretty obvious that it's in the tune. When the software for tuning is released I think you'll see some nice gains in that area... and further gains up top where the tune is altered to keep the catalysts happy.

Kind of tough to design a header around and engine that cannot be tuned. I promise the AVCS maps are just as funky as the stock ignition and fuel maps.

Clearly...

[OrbitalEllipses]

Originally Posted by industrial

Sound is absolutely important to me. More so than making power or weight or cost.

+I want some additional exhaust noise. I like the sound of the auto factory exhaust the best so far.
+I want some power. Tbh, my expectations were pretty low. I was expecting around 30whp from header, exhaust and tune. You guys seem to already be there without a tune...
+I want at least 1 high flow cat.
+Lighter than stock would be nice, but I'd rather have something durable and properly heatshielded.

-I will not buy an exhaust that will wake up the neighborhood when I drive home at night.
-I will not buy an exhaust with rasp.
-I will not buy an exhaust that drones.

I don't mind paying more for good quality stuff. I never buy Chinese knockoffs.

Pretty much this. The exhaust I buy has to be livable in volume and great in tone; has to have one cat to make me feel not so terrible and for emissions; has to make power; and I'm absolutely willing to sacrifice some of the weight for that.

I was looking at SRT's exhaust and their axleback section has less bends; I don't pretend to know anything about exhaust tuning, but that was something I liked. I understand your section bolts to the stock midpipe, perhaps some of us will be willing to replace that? That brings me to my final point: compatibility. I never bought any TurboXS exhaust pieces because it was "proprietary" in that you needed adapters to run certain parts with other brand parts. Sometimes I like to mix and match, I don't like being forced into using certain parts for compatibility's sake (I think APS Australia did the same thing).

I don't own any Nameless parts because you didn't have a GD chassis exhaust system when I had my WRX; I want to own some Nameless parts for my BRZ! I'm a big fan of how you guys operate, your attitude, and what I've seen. Make some parts I can't refuse to buy!

[Jason@Nameless]

Haven't read all of the new posts yet. We did test the header against another design with different primary and secondary diameters and we are by no means done in terms of testing. Our next test is going to be the existing design with secondaries length matched to the primary, they're about 1/2 of the primary currently, clearly a suboptimal solution for keeping the catalytic converter in the stock location. This was something that in preliminary discussions many of our SCCA Solo 2 customers were interested in seeing based on Solo2 Rules.

R/TErnie, I'm not entirely sure why you think it's tough to design a header around an engine that cannot be tuned yet. We have evaluated all of the details of the factory cam timing range on intake and exhaust and the variance in terms of primary and secondary diameter across that range as well as the overall primary and secondary length don't change enough to make a major impact on the phsyical design of the header. Our header is making pretty substantial power as-is, I'd say. And it seems to me that the overall design of the header is going to work whether the engine is tuned or not. A tune doesn't alter cam timing out of the available range of advance/retard of the cam timing and spark angle doesn't impact header mechanics as far as I know. The overall length of the system is based on target power and port centerline length which also is static.

I apologize if I gave the impression that the dip was related to resonance, it is clearly not, but the resonance may certainly be related to a change in ignition or cam timing. My goal was to simply reduce that for sound sake. The concept of scavenging by altering the acoustics of the pipe that I mentioned were related to a secondary design that we have been looking into. There have been a few companies who have been successful at accomplishing this. All of this is not an attempt to correct some harmonic imbalance in the engine that we assumed was causing the torque dip. If you look in other threads our assumption is just the same as yours - that area is for economy at cruise. Our goal was to simply increase the midrange torque to ameliorate this issue until a tuning solution comes about. At that point, the gains we see by having a good mechanical design on the header will be just as good if not better than they are on the stock tune.

As for the AVCS maps being just as funky as the stock ignition and fuel maps, I can adjust my calculations to the full range of adjustment of the AVCS and the design constraints make only slight changes which still land in the primary and secondary length ranges as well as the primary and secondary diameters. What would you allege would change mechanically in our header design based on cam timing changes? Altering target peak HP rpm, port centerline length, as well as lobe center angle (LCA) change the length slightly, but as LCA goes up, the range of optimal primary and secondary length widens, landing my pipe sizes in the range just as well as it does when LCA reduces and my pipe sizes are designed within that constraint.

I suppose I'm not understanding your point. It's far beyond my intention to act like I'm an expert on this, I'm not by any means - which is why we have asked for input. This community is pretty awesome and has a number of people on board who have a lot of knowledge and real world experience with a variety of similar applications to the FA20 engine. So please, let me know what your thoughts are on this rather than asserting that building a header that makes power on a non-tuned engine would not work on a tuned engine. Because quite frankly, I am not following the important part - the 'Why?'

As for LC being a small place, yeah pretty much BFE. I've lived here for 9 years and have worked in the Aircraft Industry (Fixed Wing/Rotorcraft Aeromedical Systems Design & Manufacturing) as a Mechanical Engineer, Motion Control Industry (Absolute & Incremental Linear and Rotary Encoders, Accelerometers and High Accuracy Inclinometers) as a Senior Mechanical Engineer and Director of Engineering as well as the Automotive Industry (EFI Ancillary Control Systems, as well as the type of thing we do here with another sport compact company). I've not worked at ETS. My business partner John did indeed work at ETS for a number of years, but it's just coincidental that I bought property and a home in the same town that they were located in.

The other thing I would point out is that comparing to the factory header specifically, there is no trade off in a well designed tri-y design. There may very well be a trade off when we compare the stepped 4-1 design vs. this stepped tri-y design, but as things stand, there is a steady gain of power across the powerband as well as a substantial increase in torque across the powerband as well.

Again. We are going to build a NUMBER of other header designs to test. This is something that is quite fascinating to us and we thought it'd be a good approach to discuss these design ideas with the community and get their feedback and act as the hands in the process of changing a theoretical discussion on the forums into visible, real world testing of a number of products, bringing enthusiasts in on the development process and not being afraid to speculate about things even if they pan out to be false or inconsequential.

If I questioned every possible thing that went through my brain and didn't write it out in this thread for fear of being wrong or saying something that wasn't perfectly thought out, there are a number of ideas that may never come to fruition. I'm not afraid to make mistakes in a discussion. I'm certainly not afraid to speculate about things that are beyond the scope of my understanding, it's just part of my own learning process.

Here's the thing - I want to be open about this process and I can't do that if I'm not willing to postulate. So I may say some things now or in the future that aren't well thought out. I do think that acoustics and resonance can impact power, and that use of one or more helmholtz and other styles of resonator could feasibly positively impact scavanging. Case in point:

[ame="http://www.youtube.com/watch?v=1Fr00GjghnU&feature=relmfu"]ThermalPulse 180 - 18 Valveless Pulsejet High Throttle - YouTube[/ame]

There are a number of resonator designs used in the gas industry that impact flow and gas velocity based on changing pulsewaves in a compressed gas system. Why not fiddle around with some of these while we're at it? Or at least think about them. Might seem kinda wild, but they probably said the same thing about Alfred Büchi's ideas. Or Daimler or Rudy Diesel for that matter. What's the harm? Invest some money in something to test that doesn't pan out?

We're already invested in making a damn header and exhaust that doesn't sound like a bag of chainsaws (the funny part about this statement is that I know that video above is still running as you're reading this). I have always hated that when we have designed exhausts to the factory header and then somebody swaps out a catless 4-1 and our exhaust note goes to shit. And perhaps you can explain to me why our dual helmholtz axleback exhaust on the Genesis makes more power than a straight pipe or most of the catback systems on the market? I can't get my head around it, to be honest, unless the resonance of the exhaust is improving flow better than allowing the exhaust pulses to simply exit an open pipe. Obviously tuned exhaust length and the primary/secondary/tertiary harmonics of a length of tube at a given diameter have an impact on power, perhaps the use of the helmholtz simply makes the sixth harmonic act like the fourth.

Bottom line: the next step is to test this design without a cat and with the appropriate secondary lengths as calculated based on the data we have for the specs on the engine.

Jason

[Jason@Nameless]

Originally Posted by jamal

Wouldn't it have been way easier to just take a perrin header, cut off the end, and put on a new bend and collector?

Trolololol.

I'm not taking the bait on this one.

[Jason@Nameless]

Originally Posted by OrbitalEllipses

I was looking at SRT's exhaust and their axleback section has less bends; I don't pretend to know anything about exhaust tuning, but that was something I liked. I understand your section bolts to the stock midpipe, perhaps some of us will be willing to replace that? That brings me to my final point: compatibility. I never bought any TurboXS exhaust pieces because it was "proprietary" in that you needed adapters to run certain parts with other brand parts. Sometimes I like to mix and match, I don't like being forced into using certain parts for compatibility's sake (I think APS Australia did the same thing).

Two notes on this and I'm going to put them in bold because it seems like nobody is reading what we have written on this:

1. Our single exit 2.5" straight pipe makes the same power as the bed of snakes.

2. Our full exhaust system w/ factory midpipe made the exact same power as our full exhaust system with 2.5" midpipe

Forget what your eyes tell you about how an exhaust flows based on how it looks. A well laid out mandrel bent system will flow just as well as a straight shot system. Not only that but our exhaust is dual 1.75" out the back and still flows the same as the single 2.5" x 14" long track pipe. If you don't believe me, ask BMW GmBH about their inconel S38 bed of snakes headers:



One thing to note, we have done quite a bit of testing on the Y design in the back as well as its orientation relative to the final bend in the primary exhaust circuit. When you lay it out horizontal relative to a planar bend before it, you load up one of the two circuits more than the other. Here's our original muffler delete design for the hatch - it was extremely biased to the passengers side:



For that reason we run the Y vertically rather than horizontally. There is a purpose in almost everything that we do in our designs.

Another major thing to consider is that catback exhausts that have equal primary and secondary circuit sizes tend to drone like crazy inside the cabin. They sound wicked outside the car, but they'll rattle change in the map pockets in your doors at the same time.

Plus, why would you want to buy system that includes a midpipe that does absolutely nothing for you when you could be using that money to buy a header that does everything. Just sayin, we're one of the only companies who won't sell you parts that you don't need. Our slogan isn't Function/Form for nothing.

Orbital, your point about forward and backward compatibility to factory parts is something that is at the foreground on every single design we build. The only thing that would convince us to develop a standalone system that is all-or-nothing is if there was a major gain to be had. And on this car, that does not exist unless it involves an extremely radical header and overpipe design.

And I'm sorry we didn't get the GD exhaust released before you got your BRZ. You would have loved it. Going to release that in the next week or two. :-D

J

[Calum]

Originally Posted by Jason@Nameless

There are a number of resonator designs used in the gas industry that impact flow and gas velocity based on changing pulsewaves in a compressed gas system. Why not fiddle around with some of these while we're at it? Or at least think about them. Might seem kinda wild, but they probably said the same thing about Alfred Büchi's ideas. Or Daimler or Rudy Diesel for that matter. What's the harm? Invest some money in something to test that doesn't pan out?

We're already invested in making a damn header and exhaust that doesn't sound like a bag of chainsaws (the funny part about this statement is that I know that video above is still running as you're reading this). I have always hated that when we have designed exhausts to the factory header and then somebody swaps out a catless 4-1 and our exhaust note goes to shit. And perhaps you can explain to me why our dual helmholtz axleback exhaust on the Genesis makes more power than a straight pipe or most of the catback systems on the market? I can't get my head around it, to be honest, unless the resonance of the exhaust is improving flow better than allowing the exhaust pulses to simply exit an open pipe. Obviously tuned exhaust length and the primary/secondary/tertiary harmonics of a length of tube at a given diameter have an impact on power, perhaps the use of the helmholtz simply makes the sixth harmonic act like the fourth.

Bottom line: the next step is to test this design without a cat and with the appropriate secondary lengths as calculated based on the data we have for the specs on the engine.

Jason

Jason, you keep this up and you'll need one of these.

Originally Posted by Jason@Nameless

The only thing that would convince us to develop a standalone system that is all-or-nothing is if there was a major gain to be had. And on this car, that does not exist unless it involves an extremely radical header and overpipe design.

J

[Dave-ROR]

Originally Posted by Dimman

I think they've hit everything except B which we may see some positive results on with alternative configurations.

As for the placebo comment, I understand it is real. I'm just speculating based on gearing and rpm drop, not having driven one yet, that under 'soft' and 'hard' driving it wouldn't be too apparent.

Some insight on how it is noticed, and under what conditions, could help with figuring out a solution.

I don't notice it under light throttle so much, but I also shift before it ends..

Under WOT it feels like IVTEC, the torque difference coming out of the dip is painfully obvious. It's a little less obvious going into it but still easily noticable.

[Fly Guy]

I found out that Laguna Seca has a 92 decibel sound limit and I would love to one day drive on that track. That would be my first priority. Second is the sound quality. Third is whatever makes for the best power to weight. The car would be mostly a daily driver.

[mike2100]

Originally Posted by Dimman

I personally don't think the 'dip' is a huge issue given that the car is geared to pretty much avoid it at max RPM shifts, and has the low peak for grunt when putting around town and short shifting. But placebo effect for some drivers maybe? They've seen the dip, so they 'feel' the dip?

I've been slowly coming to a similar conclusion. The dip is there but I only feel it when I'm revving through it, from low rpm to high rpm. You are right - in high performance driving you'll never see that low of an RPM. And any tuning that removes the low rpm torque bump will take away the around town low rpm driving fun.

This car really has 2 personalities: one with low rpm grunt for around town and highway spirited driving, and one for all-out balls to the wall track driving.

The dip only rears its head when tranisitioning between the 2 personalities.