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Pretty nice gains from the ETS elh. Lets keep in mind, its also on a car with an ETS turbo kit.
Was surprised with the low/midrange gains, thought the big tube would only aid flow up top! Will be interesting to see the difference in back pressure with my new BNM headers, not as big ID as the ETS but hopefully will see a drop so we can push a couple more psi.
 

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Good point KillerB; you reminded me of something Ive always thought was funny my car has been on single scroll setups and twin scroll setups. I noticed when getting tuned my single scroll tunes have always looked like a typical bigger turbo sti where things have more of a top end. And my twin scroll tunes seem to resemble a stock turbo sti with more midrange and things tend to fall of up top.

Just to be clear I think its a matter of opinion, where one offers the option of increased spool and the other offers higher power. Sure my twin scroll setup doesn't make peak power but I do like the response. For example when my car was on my last single scroll set up and I would rip turns I would get on the throttle sooner in the corner to help things get spolled up and by corner exit I would have all of the boost under my foot. The first time I rounded a corner on my TS setup I almost spun out because It spooled during mid turn instantly. The car feels much more like a na car on the TS manifold as most of the lag is gone, all of the boost and power are under my foot at all times which I enjoy. While driving fast I dont have to pre plan as much with the turbo which lets me focus on driving.
I see I haven't weighed in (as I recall). I have an 8374 with small TS turbine housing, IWG, 3" exhaust (no mufflers) my own TS up-pipe. I'm running stock bore, 272 cams and full porting/+1 valves. 100-105 octane gas.
Cams, valves and fuel really haven't weighed in on this conversation as far as I can tell. Too many assumptions/generalizations and not enough data/facts in detail as to what people are doing!
I can provide more data, but I wanted to say that I get to 300 FPT by 3,600 RPM's on this setup. That's better than my Blouch 2.5 XTR did on FR 1.5 headers with stock STI DAVCS cams and mildly ported heads.
Torque peaks at 400 @ 4,000. HP starts to fall off at 6,800. My torque stays almost flat from 4K till 6.5K, dropping only 20 FPT. My butt dyno says my sub 3K lb. car pulls hard and steadily like a train through the close ratio gearbox through 5th. It's sweet on a short straight!
Saying all this, I'm going to try a 3582 in my '07. Tial .92 turbine housing and big compressor housing. Another old, highly modded Full Race header in the mix. A funky Dom cam mix, big valves, porting and NA intake. Probably 500+ HP, high RPM capable engine.
 

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Do the shorter primaries on the KB ELH have reduced benefits from exhaust scavenging? I am trying to figure out how primary tube length is designed and how it affects the performance of the ELH listed in this thread. My understanding from doing some readings is that longer primaries produce more torque before the peak, and benefit more from exhaust scavenging, while shorter primaries produce more torque after the peak. However, I don't really understand how this all fits in with the design of the KB ELH which is optimized for volumetric efficiency/quicker spool. Are shorter primaries that much more beneficial on turbocharged applications? Thanks in advance, I am very interested in header design and would like to learn more.
 

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Just got my BNM ELH back from ceramic coating and installed them. Fitment was perfect! Yet to go back to the tuners but the difference is noticeable...faster boost response, quieter and smooth linear power delivery. Motor seems far happier and even running a couple of degrees cooler.

59564
 

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Do the shorter primaries on the KB ELH have reduced benefits from exhaust scavenging? I am trying to figure out how primary tube length is designed and how it affects the performance of the ELH listed in this thread. My understanding from doing some readings is that longer primaries produce more torque before the peak, and benefit more from exhaust scavenging, while shorter primaries produce more torque after the peak. However, I don't really understand how this all fits in with the design of the KB ELH which is optimized for volumetric efficiency/quicker spool. Are shorter primaries that much more beneficial on turbocharged applications? Thanks in advance, I am very interested in header design and would like to learn more.
There are many factors that play into the equation. Some you have no control over (like space available, head design, bore/stroke, etc., etc...).

Many people make the mistake of comparing turbocharged headers to turbocharged headers. Some even make turbocharged headers to non-turbo criteria for some reason. Don't fall victim to this. If you want optimized performance follow a design optimized to the application.

I'll let other manufacturers chime in on their design here if they care to. My design strategy with our headers was all about transferring the maximum energy from exhaust port to turbine housing. Pressurized Manifold (turbocharged) engineering and design principles steered the design. A simple single question is only going to give you a simple response to a single aspect, when there are many others. Scavenging, flow, turbulence, sound, velocity, heat loss, volume, collector type, tube sized, transition ratios, and so on and so on will determine where power is made and how much. For example, you want a wall of torque and care less about high RPMs, then you want a BIG tube 'race' header. It will provide best low RPM scavenging in trade for mid-high RPM efficiency and performance. Different designs produce different results.

Our design aims to have the least volume to pressurize (can't build boost until the manifold has pressure to spin the turbine), the least amount of tubing to reduce thermal losses, symmetrical primary tube design to promote even scavenging, rotary firing order collector design so each cylinder is exposed to the same collector scavenging effect, largest and least amount of bends to induce the least amount of turbulence, matched port sized (every size transition is a turbulent loss of flow/energy), and the use of 321 stainless (alloyed with titanium) provides improved thermal properties over the more common 304. 321 allows us to make a strong product without having to use thick walled 304 schedule pipe (they often call it tube) like many others out there; Thick walled headers can weigh 35+ pounds, ours is 12-14 depending on design and options.

In short, the goal was to maximize VE. If you can maximize VE across the engine's gas flow range, you make power EVERYWHERE in the rev range because it just makes the engine more efficient by means of more even EGTs/AFR from cylinder-to-cylinder, and less energy loss from exhaust port to turbine inlet. This improvement scales with power output. In other words, you may see a gain of 20whp if you car is capable of 300whp, and 40whp if your car is making 600whp. The higher the exhaust gas flow potential, the more impact and improvement on VE has.

Also, don't assume a header has a bottleneck. You see a lot of people looking for 'the biggest tube header' because it flows more. The problem with falling victim to this marketing is that it's just not true. The exhaust port is always going to be the biggest bottleneck per exhaust event, and the volute of the turbine (by design to create pressure) is going to choke flow. A well designed header should not have a capped flow capacity. Our header has happily run on many cars making well over 1,000whp.
 

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Just got my BNM ELH back from ceramic coating and installed them. Fitment was perfect! Yet to go back to the tuners but the difference is noticeable...faster boost response, quieter and smooth linear power delivery. Motor seems far happier and even running a couple of degrees cooler.
I really want to run Evan's ELH to compliment my rotated kit, but I dont want to wait 2 years for it. Looks great!
 

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Discussion Starter · #47 · (Edited)
Alright gents, i finally made the plung and went for an ELH. I used my own thread here as a guide lol. I chose to go with the HKS ELH. Now before anyone calls me out on it, ill be the first to say yes I know ive talked some trash about it at some point on here. I made my choice for this based on the information and numbers posted here, and how budget friendly this piece is. I already know its not the best out there but this suits my needs and more importantly my pocket. If budget wasnt an issue then it would have been the KB manifold. If time wasnt an issue then i would have gone for the BNM 4-1 ELH provided Evan could make a 1.5" ELH. Unfortunatly, that piece is about a 12 week wait period and that wont work with my timeline.

Anyways heres the meat and potatoes, the HKS 4-2-1 ELH. The box comes with gaskets, hardware, and a heat shield with clamps. Although i dont think the gaskets are as great like the grimmspeed gaskets, the ones provided will do just fine. Also included was some heat protectant wrap to put around the oil pan. One other thing to mention, I was surprised how thin the piping is. I guess thats also why this piece is so light compared to my previous set up of a ported oem manifold with crosspipe.

I went ahead and took some measurements prior to install just to verify the numbers. Not that i think HKS would lie but id figure id confirm for myself. They are pretty much spot on give or take some positioning of tool. It was kind of hard trying to hold the caliper steady while trying to take a picture with the phone at the same time.

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I wasnt too fond of the heat shield due it causing a rattle so i took it off. Here is a shot of it a day later after install. I will be installing the heat wrap around the oil pan as soon as i have time.

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Great choice! Ive had an hks header for 20k miles now and still going strong. I gained 17whp/33wtq on stock turbo/block compared to oem uel header on 93. It really mellowed out the sound and drives smooth with improvements in mid/top end power. Congrats on choosing a great header!
 

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Discussion Starter · #49 · (Edited)
Great choice! Ive had an hks header for 20k miles now and still going strong. I gained 17whp/33wtq on stock turbo/block compared to oem uel header on 93. It really mellowed out the sound and drives smooth with improvements in mid/top end power. Congrats on choosing a great header!
Thanks! Now thats what i want to here! Curious, did you wrap or coat yours for it to last 20K or did you leave it bare as i did?

I agree that its so smooth now while driving. I have it paired with my invidia catless dp and my Greddy Evo3 exhaust. The car just sounds sooo different. The cold start sounds amazing, so smooth. I will say that my rumble is pretty much completly gone with this exhaust combo. The only time i get a hint of the classic subie rumble is on cold start. I will also add that i dont have any rasp thankfully. All in all, the tone is just different and hard to explain. It will take some getting used to but its already growing on me.

Im scheduled for a retune on the dyno in 2 weeks. Im curious to see what gains i get out of this. Im not chasing numbers so even if i get a little bit ill be happy. I also added a perrin turbo inlet to the car today. I noticed right away that the spool of the stock turbo is quicker. Boost came in like lion lol. Im not sure if its due to the header or the inlet, probably both lol. Either way, i cant wait to hear this thing scream on the dyno. The sounds of ELH + EWG will be incredible 🙃
 

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Killer B released their new Holy Header Max VE. I'm interested to see how this performs, especially compared to the original, on a typical street build that isn't making crazy power. It will obviously perform better on the high power builds 😁

Killer B Holy Header (Original):
0.065" 321 SS
1.5" Primary ID (1.63" OD)
1.85" Secondary ID (2" OD)

I believe the primaries are the same on the new header, but the stepped secondary is larger by ~0.5". These numbers should be fairly accurate. Of course, you'll need a larger diameter uppipe (and larger turbo) to take advantage of this.

Killer B Holy Header Max VE:
0.065" 321 SS
1.5" Primary ID (1.63" OD)
2.35" Secondary ID (2.5" OD)


 
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Discussion Starter · #54 ·
Just out of curiosity I don't see the IAG ELH, any reason ?
Yes as Karlot mentioned, i dont know if anyone has it. If they do, it would be great for them add to the collection here. I too have also herd its a rebranded Tomei. It sure does look awfully similar :)
 

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Yes as Karlot mentioned, i dont know if anyone has it. If they do, it would be great for them add to the collection here. I too have also herd its a rebranded Tomei. It sure does look awfully similar :)
That makes a lot of sense, I guess that is why both of their ELH and UELH headers are listed as "out of stock" I guess that means that they are not made by them, onsite.
 

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There are many brands that come out of the same overseas factory, in Taiwan if I remember correctly. They all mimic the old OEM JDM Twin scroll header design from the late 90s, including the IAG variant. There are variations among them, but the designs are fundamentally the same.
 
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