what's the different between 4-1 and 4-2-1 ??

 

just like it sounds, the 4-1 is 4 pipes that merge into one, the 4-2-1 goes from 4, to 2, then to 1

wait, I'll go get pics

4-1 (all 4 merge into 1)


4-2-1 (notice the differences)


this is another example of a 4-1 header(shorty) but is a bit more rare


As far as power production goes, typically a long tube 4-1 is more focused top end gains, while a 4-2-1 will provide more mid range and slightly less top end gains.

4-1 are also known to have a bit worse ground clearance (as mentioned in the pic )

 

i know wat it is
but i know one get more power and one gets mpg

 

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