A friend of mine told me that the 4-1 are better because the 4-2-1 blow the gasket where you connect the two. Which is the better of the 2?
This is not correct… 4-1 has better flow characteristics, and a 4-2-1 can leak at the joint… Oops, I guess your right
blow the gasket??? :shrug: i wouldnt worry about that
4-1 is better for top end power - high revving motors/fully built motors.
4-2-1 is better for midrange power - stock/mildly built motors
damn schu got there first :dance:
thanks a lot fellas…thats exactly what I needed to know
Bwahahahahaha… Yeah I have never hard about a blown gasket either… there is not enough pressure in those tubes to blow the gasket. the gasket can get hard over time and get brittle, but thats about it
Schu
Besides, that gasket being there is the difference between a 1 piece design and a 2 piece(doesn’t matter if it’s 4-2-1 or 4-1). Other than that, what those other guys said.
-nino
cool…thanks again
Back in the day when I had a SOHC Vtec, I had a 4-2-1 2 piece DC header and I used to blow those seals all the time! They suck! I suggest if you want a 4-2-1 then get a 1-piece header!
4-1 header is better if you are looking for topend! 4-2-1 is good for lowend torque and midrange power
These are incorrect statements. Both can be good for either type of motor (fully built or near stock). However, the flow characteristics of a 4-1 header is good for top end and not a lot of midrange. And the flow charateristics of a 4-2-1 header make good low mid range power, but typically not as good top end as the 4-1.
If 4-2-1 headers were not good for built motors, why are Hytech, SMSP, Toda, JUN, JG Proflow, etc all 4-2-1s? The difference between a header made for mild mods and a header made for a built monster is the size of the primaries, secondaries, the merge section, and the collector. Obviously the larger diameter versions for a highly modified/built engine.
There are also a couple things someone hasn’t mentioned much of. First off, there are many 1 piece 4-2-1 headers (including DC Sports), but they are not as easy to install. Typically requiring you to remove your crossmember to get them in.
The other thing is the ground clearance issue. On DAs a 4-1 header is going to leave you with much less ground clearance than a 4-2-1. This is only an issue if your car is lowered and you care about your header. Because from personal experience, no matter how careful you are you will scrape or dent your 4-1 header eventually.
Here’s some pictures of the clearance difference between a a DC JDM ITR 4-1 (First picture) and a JUN 4-2-1 (Second picture). Use the oil pan as a reference to how low the header sits.
i stand corrected. :whip:
sorry for mis-informing anybody, but thats what i was always told.
thats what i was getting at. my bad
Don’t worry about it. I wasn’t calling you an idiot or anything. Just a mild correction 
not to one-up dan but there’s an even more comprehensive review of header design on team-integra.net. my next header will probably be the comptech tig 4-2-1.
actually i ran a search maybe 3 months ago and theres a very good write up on here… forgot what i was searching for tho…
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end of story. the best headers, or should i say, the best quality, highest perfroming headers on the market are all 4-2-1. sms, hytech, dtr, etc. lastly, i’ve actually seen the difference of the dc jdm 4-1 vs. dc 4-2-1 2 piece on the dyno. and to be painfully honest, the performance difference is very small. i’m am convinced that the 2.5" collector makes the difference in power. choose wisely and don’t follow the trend. i look at it this way, why waste my money on a header that is going to get mangled within a few days of purchase because it hangs too low (dc jdm 4-1) when i can buy a header that makes 1.1whp less and not have to worry about scraping. just my .02.