I already did the search thing and I could not fin the answer to my question?
Wut kind of header is my car using? ( 97 accord SE 4 cycl)
Is there much difference between 4-2-1 and 4-1 header ?... grrrrrrr

 

in that application there is really not that big of a difference. 4-2-1 gives a little more low end power and 4-1 gives better high end. You won't really notice a difference on a stock application though. I believe the ex is the only one with a 4-1 and the other models are 4-2-1

 

the ex is 4-2-1 and lx is 4-1, it's another reason the ex makes more power. it's the reason why a aftermarket header on a lx has more gains than an ex.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by btlfed1 &raquo;</TD></TR><TR><TD CLASS="quote"> 4-2-1 gives a little more low end power and 4-1 gives better high end. </TD></TR></TABLE>

thats not true

 

Nick, ya, it's true...kinda.

The 4-2-1 is the best for the Accord since it does not rev high enough to take the best advantage of teh 4-1 design. It is a low-end baised design....but when we talk low end, we mean bellow 6800rpm.... the 4-1 design works really well on integras, s2000s, and other high reving cars that spend a ton of time above 6800rpm....otherwise a 4-1 design is pretty much useless.

All designs, 4-2-1, 4-1, cold air, short ram have power ranges....which mod you choose depends on the motor, how high it revs. For example, a race civic will run better of a short ram intake - given that it can get cool air as well (but even cool air doesn't have as much effect in the real world as they market it to be)....but a race accord if not motified to rev higher, would do a LOT better with a cold air intake (longer pipe = lower power curve).

Anyhow, in short, 4-2-1 is best for an accord, but yes...4-1 and 4-2-1 do give respectable gains - given the propeper engine.

 

header horsepower increase characteristics and where they are in the power band/rev range is not dependant on the design meaning a 4-2-1 vs. a 4-1, either can be designed to do whatever u want

conventional off the shelf headers, lets say DC Sports for example, has designed their 4-2-1 to optimize flow in the lower to middle ranges, but when the rpms increase and enter the "high end" of the rpm range flow may not quite be optimal for max high end horsepower, follow me so far?

the DC Sports 4-1 on the other hand is more optimized for higher end flow, whether or not the lowend and midrange isnt quite as good as the 4-2-1, i have no idea, u would have to dyno for yourself

the reason why people usually say "4-2-1 = midrange, 4-1 = high end" is because that in most cases based on how mass produced headers are built this is the case.

But...

a header that is 4-2-1 that is optimized for highend power and a 4-1 that is designed for low end can be built as easily as the opposite can be

it all has to do with the size of the primaries (the piping that comes right off the cylinder head), how far out they come before they begin to turn down, the angle of the bends, the type of collector and the size of it
another big factor is the subframe of the car, oil pan etc, that stuff is a big reason for various designs

there is a very good header company known as SMSP, they build headers for hondas, their prototype h22a prelude header was a 4-1 it didnt fit right, so the production version will be a 4-2-1 so it fits better and its been designed to out perform the 4-1 on the top end

so if you are talking about a DC Sports header, then yeah a 4-1 will probably be better for high end HP than a 4-2-1 will be, but if you are talking about headers in general then that statement is completely incorrect

hope that helps

 

or to say it in an easier way, it all depends on how the header is designed.
Believe it or not, header design is a complicated process, that takes a lot of R&D to get what you want. Primary tube size and length, secondary tube size and length, radius of bends, placement of bends, collector size and location (as well as style), which cylinders are merged together, material, coatings, the actual head design and flow rate, volumetric efficiency of the motor, the list goes on and on. It all has to be taken into account and tested.

That's why I personally like the smaller companies (like SMSP, Prospeed, and so-on) more than mainstream companies (like DC Sports, Greddy, and so-on). The smaller ones usually put more thought into it. The bigger companies just want to get something out that does a little better than stock to make money.

 

you should also mention that the SMSP header is about 3x the cost of a DC or Greddy header. i assume prospeed is similar. not many people will pay $1,000-1,200 for a header.

DC and Greddy make a decent header for a affordable price.

 

yeah, the dc and such are less expensive, but that's because not as much work goes into it. but yeah they're decent for the price.

 

they also produce parts in larger volume too.

you also must remember that DC and Greddy design the header to be a direct bolt-on. the SMSP H22 header require using a 2.5 inch cat high flow cat. i assume prospeed is not deisgned to bolt to the stock cat either. since that's where a big power gain is coming from.

 

OK, since my car is SE I think it has the same engine as LX, so it must be using 4-1 header.
Can I change it to 4-2-1 header ? Will it cost problem to my car?
Judging from your guys post, I will say that for Street 4-2-1 is better ? since I am not gonna go to track racing