What is the difference of the 4:1 and 4:2:1. I was told by an Acura tech that my A-pipe was going out bc of rattling around 4k rpms so instead of just fixing that i am getting DC headers. Which is the best for an Integra GSR.

 

4-to-1 and 4-2-1, do not pertain to header "ratios". They basically describe the "amount" of tubes of each section of your header.

 

a 4into 2 into 1 header is good for midrange power, while 4-1 is good for peak power at the expense of some low end power/torque. it depends on which header is best for YOU not the GSR in general. Will you be using this as a drag only, then get the 4 into 1, auto X you prob. want 4-2-1, etc.... PLEASE learn to use the search function in the upper right - this has been covered (prob) 1000 times before, and you could have answered your own question - best luck

 

THNX. true true