what do you think about this header..

We may earn a small commission from affiliate links and paid advertisements. Terms

i'm just wondering how the welds are gonna be.. i dont want some fucked up welds like half the shit on ebay.. and this is way cheaper than a DC 4-1 and its concealable
 
well crap i wont my d series to look stock also so ill look around but i would get it
 
i think i may try it out.. i want a 4-1 instead of a 4-2-1
 
exactly. 4-2-1 provides great low end torque, while 4-1 provides top end.

depends on what you want, honestly. personally, if you're going to get a header, get something worth getting, like all that expensive stuff. i wouldn't go through ebay. ebay makes me sick. well not really, but i'm just weary of that shit.

some good examples of great headers are sparc (spark?), rmf, and greddy (imo, i have a 421 on my car and i lurve it, as opposed to a dc 4-1 i had previously. grr) just to name a few.
 
when i put my 4-1 header on i didnt lose any low end response whatsoever.
 
from the looks of it it looks like mine. i love it, it made just as much hp and tq as my friends oem itr.

the price is a little steep i payed $145 shipped 1 year ago on ebay.
 
I wouldn't pay what he is asking. The seller looks shady to me.

BTW, it's 4-2-1 that increases mid-range to upper and 4-1 that produces more low-mid range. Most 4-2-1 lose power in lower RPMs (DC especially). Not always true, but every engine bay has a different story before that header made it there.
 
thank you, Captain! That's like saying a 10 dollar bill is better than a 5 dollar bill. Although, if someone was selling their SMSP header on Ebay (like it would ever make it that far, lol, those things are on backorder), I'd have to say that would be better than OEM. So your statement is not always the case. I'm just being argumentative, don't mind me.
 
It's fine!

Here's some food for thought regarding header selection.

Consider the firing order of our engines, the principles of exhaust flow, and the current typical header build, OE & aftermarket.

It's 1 3 4 2, but they make the headers merge at 1 and 4, and 2 and 3.

This is generally to attain CARB legality, as merging the cylinders in that fashion allows cooling of the exhaust gases which helps lower emissions levels of the engine, cat or no cat.

The idea of modifying an exhaust has more to do with creating more efficiency in the evacuation process and the elements of heat dispersion\retention. I believe we're getting into thermal dynamics.

Hotter exhaust gas has more energy and is able to evacuate more quickly (i'm a laymen trying to help other laymen, I may say something wrong in trying to simplify the concept for everyone), which is what provides more power. So, retention of heat is paramount. Heat retention from the header also reduces ambient air temperatures under the hood, which helps the coolant out, and also helps reduce the temperature of the intake charge if you utilize a short ram intake system. As the exhaust pipes merge the pulses of gas pass each other in order. If one pulse of gas traveling through a tube passes another, it will create a slipstream effect behind it, fundamentally minimizing the amount of effort it takes for the trailing pulse to follow, or a vacuum affect. This is majorly hindered by the design of a MAJORITY of aftermarket headers as the pulses don't get to meet this way because the collector's merging pattern.

So here we go. An unequal length long primary 4-2-1 header seems to be the option providing the most potential power gains from OE. The unequal length ensures that there is an amount of "stepping" during merges, effectively stream lining the path for each pulse to it's ideal location. If the number 1 tube terminates before the number 3 and they merge with each other to the "2" in the 4-2-1, the 1 pulse will pass the 3 exit shortly after the number 3 pulse exits the tube into the merger. Their will be a lower pressure system behind the number 1 pulse causing a vacuum behind it, effectively reducing the amount of effort to evacuate the number 3 pulse from the tube (and the two of them collectively as well).

Now imagine that the 2 and 4 pipes merge into 2 the same way, after this, the 2 remaining pipes merge at unequal lengths into one tube, with the 3+1 terminating just before the 2+4 pipes, effectively creating an even lower pressure system as a "whole" pulse behind them to suck the 2+4 pulse behind it will less required evacuation effort. This effectively increases the exiting velocity of the exhaust gas which raises power significantly compared to a 1-4\2-3 design which once again, is designed this way considering CARB, NOT performance. Here's how it works..

I forget why the increased exhaust heat affects emissions, but to tame it, they conjoined cylinders that DON'T fire together to limit the amount of heat building up together. Two exhaust pulses occupying the same area cause the pipes in that area to remain heated longer with less opportunity to cool, so, the flipped merging design allows the pipes and exiting charges to run at much lower temperatures effectively helping to reduce emissions (for whatever reason it works that way).

Efficient engine design and tuning will eliminate the crap emissions from you exhaust, as well as giving your more power and better MPGs + reliability. There's not always a sacrifice for power, sometimes, the benefits chain link like this!
 
None of what you said makes a lot of sense. It is true that exhaust scavenging effectiveness is what will make the header perform better, and that is what most head fabricators strive to improve. I don't know if what you said regarding emissions is true, because I have no background in combustion chemistry. But, regarding power, a header design is a parametric design which depends on where you want to make the power at. This is a key question for the 4-2-1 headers, because this affects how large your primaries are, the primary lengths, and which tubes merge together where. From this information, you could reverse engineer the header and figure out what type of engine performance you would have.

The stock oem headers are designed not only for performance, but also for manufacturing costs. If the engineers designed the car with zero financial considerations, and only a performance goal, we'd all have better cars, but they would cost a LOT more. Luckily, the cars that are coming off the line today are reaping the benefits of advances made by previous models, and so we are getting better performing cars for less money today. My 1991 acura integra cost somewhere around 14k off the lot when it was new. A similarly priced (in today's dollars) car is a MUCH better car for the money.

Regarding scavenging, 4-1 headers are a little less efficient than 4-2-1 headers at the design point (wherever that may be), but are better over the entire rev range, because the equal length tubing and single merge collector allow for increased scavenging at all exhaust flow velocities and temperatures. It is also easier to design, as two parameters (1 merge versus two, design point) are eliminated from the design analysis, hence why most header fabricators like RMF and SMSP opt for the 4-1 rather than the 4-2-1. It is also more material, and so, in a market as large as America (vs the smaller jdm marker), Honda decided to save a gillion dollars by using cast manifolds with less piping, rather than the JDM 4-1 ss header in their Type R models. That is my guess, so take it as you will.
 
i'm looking to be in the range of 180-190 whp..

its a daily i'd like to have fun with occasionally
 
i already have a DC.. so i'm probably gonna stick with it.. its a 4-2-1 and it'll help the low end from my b16 a little more
 
Stick with your DC for sure.

For the money it would cost you to replace a header (with one that likely wouldn't do much of anything compared to the one you are replacing) you can just make more power, or gain more overall speed by placing that money somewhere else under your hood or in your car.
 
Back
Top