4-2-1 vs. 4-1



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Live Manikins
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#1
Heres another one for you CC techs...whats the differences between the two...advantages/disadvantages

im gonna be lookin around for one in the near future (within 3 months), and i wanna know the differences, and how much it matters as far as which known company i buy it from. im not lookin for the cheapies on this one, i just wanna know if it matters which top companies you get it from
 


BioHazard the Reaper

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#2
ok well with a 4-2-1 you get a better flow, becuase the bottle neck is not so big, and so quick as in a 4-1, so you will keep power with 4-2-1, to where with a 4-1 you will have high flowing ehuast all of sudden bottlenecked into one pipe...i think DC headers are pretty good and you can get a 4-2-1from around 299-500 bucks, heres a site http://www.modacar.com/products/Honda/Civic/MODAHEA/ theres also a bushel full of other sites....but this site has good prices
 

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#3
bio, where did you get this information, because it is incorrect. both designs flow about the same, but there is a marginal difference in where the extra hp is. in most cases, a 4-2-1 design gives a bit less peak hp, but it gives a bit more mid range torque. were talking like trading 1-2 hp for 1-2 lb/ft of torque, so the effect is indistinguishable between the two. a 4-1 tends to give more peak hp, but with fewer gains down low. again, 1-2 hp in trade for 1-2 lb/ft of torque. now depending on the rest of the setup of the car, you can easily find that these numbers are reversed. if i blindfolded you and told you to drive one car with 4-2-1 and one with 4-1 you wouldnt be able to tell the difference between the two. if your installing it yourself (which i suggest, its pretty easy) get a 2 piece 4-2-1 design. it flows just as well as the others, but when you can unbolt the 2-1 collector, it becomes much easier to slide into place. go with dc, simply because they have proven themselves the best, they make good power gains, and they are priced decently.
 


caddy

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#4
Originally posted by "handlebarsfsr"

bio, where did you get this information, because it is incorrect. both designs flow about the same, but there is a marginal difference in where the extra hp is. in most cases, a 4-2-1 design gives a bit less peak hp, but it gives a bit more mid range torque. were talking like trading 1-2 hp for 1-2 lb/ft of torque, so the effect is indistinguishable between the two. a 4-1 tends to give more peak hp, but with fewer gains down low. again, 1-2 hp in trade for 1-2 lb/ft of torque. now depending on the rest of the setup of the car, you can easily find that these numbers are reversed. if i blindfolded you and told you to drive one car with 4-2-1 and one with 4-1 you wouldnt be able to tell the difference between the two. if your installing it yourself (which i suggest, its pretty easy) get a 2 piece 4-2-1 design. it flows just as well as the others, but when you can unbolt the 2-1 collector, it becomes much easier to slide into place. go with dc, simply because they have proven themselves the best, they make good power gains, and they are priced decently.
I believe you are correct except for one thing. The 4-1 header makes strong midrange and good LOW end torque, not high end. It lies the with backpressure or vacuum power it has when it crosses over into one pipe. Here's a helpfull article quote from JDMCIVIC:

"An exhaust header takes the exhaust air from your engine and sends it to the exhaust. It is crucial to have a very efficient header on a B16 because of the amount of air that it moves while in the VTEC range. Headers come in 2 varieties: 4-into-2-into-1 (4-2-1) and 4-into-1 (4-1). The difference lies within their piping design. A 4-2-1 header goes from 4 tubes right off of the head, those 4 tubes turn into 2, and then the final 2 tubes merge into 1. A 4-1 design has the 4 tubes off the head converging into 1. Ususally this occurs at the collector, or the end of the header where it meets the catalytic converter. In general 4-1 header designs yield good low range and incredible midrange output (15hp and 15lbft to the ground at 5700rpm on a DC 4-1 header). The 4-1 design lacks on the high end compared to the 4-2-1 design, but only by a few horsepower. Since 4-1 headers are designed pretty much the same, you can expect the same amount of horsepower from pretty much all of them. The power difference can vary by the size of the collector. DC Sports' USDM header utilizes a 2.25" collector, which will bolt to your stock catalytic converter. JDM headers like the DC 4-1 JDM and JDM Integra Type-R 4-1 have a 2.5" collector, for which you will have to get another catalytic converter to fit the bigger piping. Design plays a pivotal role in the power output of 4-2-1 headers however. It appears the the longer the header takes to combine into 2 tubes, the better it does in the low and midrange. DC Sports' 4-2-1 design has the header combine into 2 about 1/2 way in the disign. That header gives fairly dissappointing numbers and it only bumps stock horsepower by about 4 or 5 horsepower to the ground throughout the whole powerband. However, Comptech's 4-2-1 header produces dyno graphs like DC Sports' 4-1 header. This is achieved by Comptech making their header combine into 2 about 3/4 of the way down the header. By doing this, it flows air quickly like a 4-1, but it also combines the air more smoothly like a 4-2-1 configuration. Toda, SMSP, and Spoon use just about the same style of 4-2-1 header.

Popular 4-2-1 header manufacturers include: DC Sports, Comptech, SMSP, and Spoon
Popular 4-1 header manufacturers include: Honda of Japan, DC Sports, and Mugen"


Hope this helps!
 

Team 4R

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#5
dyno charts i've seen have stated the 4-1 (dc sports), on a lightly modified motor, makes better power across the entire range versus the 4-2-1(dc sports), albeit slightly in the low and middle areas
 

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#6
i stand by what i said about headers, because i know it to be correct. that article you found is absolute bunk. 15hp anf 15lb/ft of torque from nothing but a header?? maybe on a big block v8 with crappy stock headers you can see those kind of gains, but come on, there just isnt that much to be gained out of a header. a header, just like intakes and exhausts dont "make" any hp. they give you more hp because they simply allow the engine to breathe a bit better. they do not alter any of the internal workings of the motor like a change in cam or c/r will. you would be very, very hard pressed to get 15 hp and 15 lb/ft of torque out of i/h/e combination. most of the time you get half that amount of hp out of i/h/e. if their ricer logic is correct, your looking at gains of 45 hp and 45 lb/ft of torque for and i/h/e setup, and everyone here knows thats bullshit. im sorry man, but there just arent those kinda gains to be made on ANY honda engine with just a header.
 

knockoff

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#7
Originally posted by "handlebarsfsr"

i stand by what i said about headers, because i know it to be correct. that article you found is absolute bunk. 15hp anf 15lb/ft of torque from nothing but a header?? maybe on a big block v8 with crappy stock headers you can see those kind of gains, but come on, there just isnt that much to be gained out of a header. a header, just like intakes and exhausts dont "make" any hp. they give you more hp because they simply allow the engine to breathe a bit better. they do not alter any of the internal workings of the motor like a change in cam or c/r will. you would be very, very hard pressed to get 15 hp and 15 lb/ft of torque out of i/h/e combination. most of the time you get half that amount of hp out of i/h/e. if their ricer logic is correct, your looking at gains of 45 hp and 45 lb/ft of torque for and i/h/e setup, and everyone here knows thats bullshit. im sorry man, but there just arent those kinda gains to be made on ANY honda engine with just a header.

i wish i could get 45 hp & 45 lb/ft torque from my i/h/e... hell i probably lost some power :(
 

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#8
i doubt you lost hp, probably gained like 1-2 or whatever, but its definitely not 15 from a header alone.
 

caddy

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#9
I disagree. Those are PEAK gains not overall gains. Peak gains mean crap. Also, it was on a B16 which because of the design of the head flows quite a bit of air. Yes you're right that it doesn't MAKE horsepower, but alows it to flow better, but with an efficient header design, a vacuum flow from one tube will "pull" the exhaust from the following tube to allow exhaust to escape quicker. Secondly, nowhere in that article did it say "just a header". As you add intakes, exhaust etc,. you MUST eliminate bottlenecks throught the system. If four lane highway converges to one lane, it's still moving as fast as that one lane. So when you say its bullshit that the engine makes 15 EXTRA horsepower, yes that is correct. But if you say that it is bullshit that one point in the POWERBAND it can make an extra 15 hp then you are mistaken. Look at it this way. My car when stock, made a peak of 102 crank hp at 5800rpm. Well at 4500 rpm that engine is making around lets say 87 hp (hypothetically of course) well what if helping the engine flow help you hit that 102 hp at 4500rpm instead. The engine still make 102 hp, but at 4500rpm, you have a gain of 15 horse. So yes i agree with you that it's bullshit that the engine can make an extra 15hp overall, but it is true that 15 hp can be gained at some point in the power band. Which is what the article was meaning. On that note, an i/h/e combo will not give you and extra 45 hp and no you wont be beating Dodge Vipers with your honda with that. Unfortunately, it's like the Car Stereo world. People who don't understand the meaning peak watts and continous watts will think that their 400watt Jensen is more power full than someones 100watt Rockford Fosgate. And here I am on a rant. I'll stop now.
 

caddy

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#10
Sorry at the beginning I said peak gains mean crap. Well they don't if you have those peaks in the right area in your powerband. That's why many enthusiasts fine tune their ECUs and cam gears and fuel pressure for tiny bits of hp here and there. whatever, ill stop now
 

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#11
Originally posted by "caddy"

I disagree. Those are PEAK gains not overall gains. Peak gains mean crap. Also, it was on a B16 which because of the design of the head flows quite a bit of air. Yes you're right that it doesn't MAKE horsepower, but alows it to flow better, but with an efficient header design, a vacuum flow from one tube will "pull" the exhaust from the following tube to allow exhaust to escape quicker. Secondly, nowhere in that article did it say "just a header". As you add intakes, exhaust etc,. you MUST eliminate bottlenecks throught the system. If four lane highway converges to one lane, it's still moving as fast as that one lane. So when you say its bullshit that the engine makes 15 EXTRA horsepower, yes that is correct. But if you say that it is bullshit that one point in the POWERBAND it can make an extra 15 hp then you are mistaken. Look at it this way. My car when stock, made a peak of 102 crank hp at 5800rpm. Well at 4500 rpm that engine is making around lets say 87 hp (hypothetically of course) well what if helping the engine flow help you hit that 102 hp at 4500rpm instead. The engine still make 102 hp, but at 4500rpm, you have a gain of 15 horse. So yes i agree with you that it's bullshit that the engine can make an extra 15hp overall, but it is true that 15 hp can be gained at some point in the power band. Which is what the article was meaning. On that note, an i/h/e combo will not give you and extra 45 hp and no you wont be beating Dodge Vipers with your honda with that. Unfortunately, it's like the Car Stereo world. People who don't understand the meaning peak watts and continous watts will think that their 400watt Jensen is more power full than someones 100watt Rockford Fosgate. And here I am on a rant. I'll stop now.
your welcome to say anything you'd like, but there just isnt 15 hp to be gained from a header. heres the quote i was working with " In general 4-1 header designs yield good low range and incredible midrange output (15hp and 15lbft to the ground at 5700rpm on a DC 4-1 header). " this article is saying NOTHING about intake, exhaust, cam change, etc, they are saying that by only changing the header you get 15 hp and 15lb ft of torque, and that just doesnt happen. most gains from i/h/e come from top end, not midrange. at midrange rpm, the stock stuff flows fine. its only when the engine is pushing the maximum amount of air (top end) where the stock stuff is a bottleneck and you really see the gains of the breathing mods. at 4500rpm on your car, a header may get you 1 extra hp. at 4500rpm, your engine isnt flowing enough air for there to be a problem with the stock stuff, its at 7000 rpm that the stock stuff hurts you. go look at the dyno graph of someone with a stock b16 and only a header, or even i/h/e. the stuff does almost nothing before vtec kicks in, and only after that do you really see gains of more than a hp or two.
 

O.Z Chi

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#12
Be careful about getting ceramic coated DC headers ... the coating tends to flake off after a couple of years of use. I recommend the Comptech headers only because of their OEM fitting, CARB compliance, and stainless construction. Stainless tubes, however, have their own problems and are subject for another thread. ;)
 

caddy

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#13
Originally posted by "handlebarsfsr"

caddy said:
I disagree. Those are PEAK gains not overall gains. Peak gains mean crap. Also, it was on a B16 which because of the design of the head flows quite a bit of air. Yes you're right that it doesn't MAKE horsepower, but alows it to flow better, but with an efficient header design, a vacuum flow from one tube will "pull" the exhaust from the following tube to allow exhaust to escape quicker. Secondly, nowhere in that article did it say "just a header". As you add intakes, exhaust etc,. you MUST eliminate bottlenecks throught the system. If four lane highway converges to one lane, it's still moving as fast as that one lane. So when you say its bullshit that the engine makes 15 EXTRA horsepower, yes that is correct. But if you say that it is bullshit that one point in the POWERBAND it can make an extra 15 hp then you are mistaken. Look at it this way. My car when stock, made a peak of 102 crank hp at 5800rpm. Well at 4500 rpm that engine is making around lets say 87 hp (hypothetically of course) well what if helping the engine flow help you hit that 102 hp at 4500rpm instead. The engine still make 102 hp, but at 4500rpm, you have a gain of 15 horse. So yes i agree with you that it's bullshit that the engine can make an extra 15hp overall, but it is true that 15 hp can be gained at some point in the power band. Which is what the article was meaning. On that note, an i/h/e combo will not give you and extra 45 hp and no you wont be beating Dodge Vipers with your honda with that. Unfortunately, it's like the Car Stereo world. People who don't understand the meaning peak watts and continous watts will think that their 400watt Jensen is more power full than someones 100watt Rockford Fosgate. And here I am on a rant. I'll stop now.
your welcome to say anything you'd like, but there just isnt 15 hp to be gained from a header. heres the quote i was working with " In general 4-1 header designs yield good low range and incredible midrange output (15hp and 15lbft to the ground at 5700rpm on a DC 4-1 header). " this article is saying NOTHING about intake, exhaust, cam change, etc, they are saying that by only changing the header you get 15 hp and 15lb ft of torque, and that just doesnt happen. most gains from i/h/e come from top end, not midrange. at midrange rpm, the stock stuff flows fine. its only when the engine is pushing the maximum amount of air (top end) where the stock stuff is a bottleneck and you really see the gains of the breathing mods. at 4500rpm on your car, a header may get you 1 extra hp. at 4500rpm, your engine isnt flowing enough air for there to be a problem with the stock stuff, its at 7000 rpm that the stock stuff hurts you. go look at the dyno graph of someone with a stock b16 and only a header, or even i/h/e. the stuff does almost nothing before vtec kicks in, and only after that do you really see gains of more than a hp or two.
By the way that wasn't the whole article, that was just a paragraph. Anyways, this is just turning into a penis contest. :nod:
 




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