4-2-1 or 4-1 header
 

right now im trying to decide on a 4-2-1 or a 4-1. i dont know what i would gain more from. i have a aem cold air and a hayame rear section exhaust on a 95 civic ex.

4-2-1, more collection

4-2-1 :yes: Actually, D16Z6, 4-1 would work well also.

i forget which is which, but do some research. I know that one or the other has better top end while the other one has better low end. (smack me if i'm mistaken ) :loco:

It depends on if you want top end or bottom. If you wanna get rid of that little studder at the beginning when you launch I would go for the 4-1. But for top end as you are tooling down the road, and in a high RPM situation, I would go for the 4-2-1.

4-1

6 more post to 2nd gear

actually, it's opposite. 4-1 for top end, 4-2-1 for low/mid

actually, it's opposite. 4-1 for top end, 4-2-1 for low/mid

yeah what VRGNCD5 said...4-1 is best for cars that are forced induction..

.. yea 4-1 turbo headers dawg.

has anyone actually seen any performance related data concerning the 4-1, and 4-2-1? or are you just basing this on rumors and internet misconceptions.

just wondering.

please note that I was being sarcastic about the 4-1 turbo headers.

I can't speak for anyone but myself. Have I seen performance data, no. But I have experienced it. So im basing my statement on experience and what I was told by the tech's at DC Sports:cool:

try to find a sportbike magazine from the early nineties. there was a lot of discussions about 4-2-1 vs. 4-1 systems. 4-1 gives more top-end, 4-2-1 gives more mid-range. back in the days, all sportbike race pipes were 4-1. but as sportbikes became more and more capable of spinning up tires and had top-ends that fewer and fewer riders could use, 4-2-1's became popular. in roadracing, they help with drives out of corners. so now most race systems are 4-2-1 as well. akrapovic i believe is one of the few 4-1 pipes left (and they are usually credited with giving the best #'s).

for a vtec car, i'd go 4-1 because the midrange sucks to begin with. build on its strengths (but that's me).

Re: 4-2-1 or 4-1 header
 

4-2-1 would be low end while a 4-1 would be high end... the 4-2-1 is similar ot the Tri-Y designs in the muscle cars of the 60s that are still used today, and designed to help low end torque. Again these are headers for something different, but airflow should be airflow... besides... what diff do headers really make anyways? If used with a combo of other small upgrades they can add UP TO 5% more power to whatever application used on..

welcome to Hs, i hope someone will make up their mind on which one!

get a header and make it into a turbo manifold. you know what to do from there.

i would go with 4-1

actually ur all wrong
4-2-1 or 4-1 doesnt make the top end or low end power. it has hardly anything to do with it. it has to do with ease of installation and weight

what makes the difference is length of the primaries and secondaries, how short or long the collector is at the end of the header, and how smooth the merges are.

the longer the primaries are, relative to the length of the secondaries the more low to mid range hp output will be
so if u want high rpm hp then go with something that has short primaries and longer secondaries,
if u want fairly equal increase across the dyno then get even length primaries and secondaries

the merge from the primaries to secondaries has to do with the restriction in air, so the smoother they are,the less backpressure u will get.

the length of the collector has to do with HP numbers as well
if it is short then it will aid in top end hp numbers, if it is slightly longer then there will be a boost in midrange hp output. it also has to do with velocity of air, meaning backpressure, the smoother it is then the less back pressure there is and better hp numbers ye shall receive.

iF ur car is lowered more than 1 1/2 inches do NOT get 4-1 header, *if it is box style* the 4-1 header has bends from the primaries that will cause ground clearance issues

hope this helps
i am still debating on which header to get

the bisimoto puts out 8-12 whp on stock motor but runs 600- 750 for the painted model, plus it has to be welded to fit to the exhaust.

the COMPTECH, Landspeed Powercore, and DC SPORTS header all give around 7 whp *as tested from SCC and import tuner magazine.

i like the JG EDelbrock model as well along with the 3 listed above. it has many great features

IMO the rest are kinda iffy. they all have there issues
i am awaiting emails from several off brand headers but i think they will be a joke anyways

i think for the 400-500 u spend on a header may be worth 7 whp
but then is 750 worth 12 whp?

Definetly get SS over Ceramic, u will have miscolortation *which IMO looks tight as shit, some exhausts do that as well*
ceramic rusts to damn much.

again i hope this helps

It was in a sports compact issue a year or two ago. The 4 into one losses a little of bottom end but man does it rip v tech ....I love the 4 into one but what do I know im just a mushroom here..

opps didnt read the second page of replys .....yeah what ever ravingcivic said

Well that is as backwards as I have heard it.. maybe imports are different like I said before, but airflow is airflow.. Longer primaries should be for high end power (look at topfuel dragsters and see how long their primaries are.. and they operate in the 7500-10000 rpm range). A little more backpressure with give you more low end tq (4-2-1) while less with give you more high end (4-1). This concept is a 40 year old concept.

And a ceramic header if coated properly will not rust.. if the product is garbage I wouldn't buy it anyways...