Can someone explane to me clearly what is the difference between theses two types of headers ? And which one would be best for my 93 civic Si hatchback with Cold air intake and Catback exaust ??

 

it depends on your budget and where you want to make power (in a relative sesne).

 

budget is not an issue, but i don't have enough for FI yet

 

The 4-2-1 header is mainly used for giving mid to low-end torque.
The 4-1 is designed for high-end torque

The 4-2-1 will take a while for you to even feel anything
The 4-1 is more of a feel it when you stomp type of thing

(even though a header will give you a max of +2 HP :chuckles:, but still better than a stock header )

 

thats only coz stock civic headers are actually pretty well flowing.. when compared to other makes of cars... when i put a header on mine it gained 20 HP. and it only has 110 stock.

 

what would be better for a vtec civic?? would i loose my low end torque with 4-1 header ?

 

its pretty much up to you. You wouldnt lose your low end, youlle just be gaining some highs.
What are your plans with this car?

 

:lmfao: I am afraid that not even v8's get 20 horses to the wheels with a header. Anyhow 4-1 is where its at, think about how many times you will ever use the rpm's below 3k in racing. The low-end doesnt matter then does it. You gotta think where your powerband is and why it is where it is.

 

really, it doesn't make much of a difference if i/h/e is all you plan to do.

If you do more meaningful mods like upgraded cam or headwork or higher compression pistons, the 4-1 will help extract the most from these types of upgrades. Likewise, a header will be helpful if you plan to use nitrous. IMO, buying a header for an internally stock d-series motor is just kinda silly.

 

I am with you...I have the 4-1 JDM header on my b16a, and I felt a lil if any difference over stock. I dont think it even comes close to mattering on the D series what so ever... there isnt enough flow really to matter...save your money for either a swap or turbo...a header is a waste of money.