just wandering what the differences in the 2 headers were... and if there were any significant reasons one would be better than the other.

tia.

well, to state the obvious, 4-2-1 goes from 4 pipes from the head to 2 pipes to 1 pipe to fit on the cat pipe. 4-1 just goes from the 4 pipes to 1 for more compression.

get the 4-2-1.

if you do a search i did a whole thing on this awhile back

4-2-1 creates a bit more torque down low, smoothes/evens out the powerband

4-1 youll lose a little down low, but gain it up top...


long tube header imo if someone ever decides to release one

Originally posted by ajna_star
4-2-1 creates a bit more torque down low, smoothes/evens out the powerband 4-1 youll lose a little down low, but gain it up top... long tube header imo if someone ever decides to release one

Fast fabrication in Sept/Oct most likely. They just finished making the Neon ones (a 3rd party manufacter is making em in mass quantity).

Originally posted by 420a-Tnthewerks
well, to state the obvious, 4-2-1 goes from 4 pipes from the head to 2 pipes to 1 pipe to fit on the cat pipe. 4-1 just goes from the 4 pipes to 1 for more compression. get the 4-2-1.

A header will have nothing to do with compression or altering it in any way. 4-2-1 creates a lil more backpressure helping you keep your low end. 4-1 seems to be more popular since when you are racing your are always in the higher range of the rpm range and thats where the 4-1 seems to shine. Either one will look better than the stock manifold and a header is a great supporting mod for port/polish work or cams........

Originally posted by justinator

Originally posted by 420a-Tnthewerks well, to state the obvious, 4-2-1 goes from 4 pipes from the head to 2 pipes to 1 pipe to fit on the cat pipe. 4-1 just goes from the 4 pipes to 1 for more compression. get the 4-2-1.

A header will have nothing to do with compression or altering it in any way. 4-2-1 creates a lil more backpressure helping you keep your low end. 4-1 seems to be more popular since when you are racing your are always in the higher range of the rpm range and thats where the 4-1 seems to shine. Either one will look better than the stock manifold and a header is a great supporting mod for port/polish work or cams........

eh, yeah, i couldn't think of the word to use and it was 4 in the morning. i could not think straight for the life of me right then. i even forgot that i posted here until right now.

"normally" a 4-2-1 , because of the size of the "secondary" pipes, and the length from the exhaust valve to the "merge", or 2 section of the 4-2-1, will make more mid range power than a "normal" 4-1 header, the idea is to keep the exhaust velocity up at low rpm which produces low to mid range power, the problem with this style header is that the "merge" usually comes too soon, making the "primary" tubes too short, and giving back some of the low end power that this style header was intended to make,
A 4-1 header "normally" makes a higher peak number and not quite as much through the mid-range, however this style header if carefully designed can make atleast as much mid range and a whole lot more top end power. another thing that can be done is to build a "correct" long tube header and then use a 4-2-1 style collector, that way the primaries are long enough to give the midrange your after, and because your seperating the exhaust pulses through the collector, i.e., merging 1-4, and 2-3, so that the secondary pipes have only one pulse at a time going through them, it doesnt really lose any of the top end power like a normal 4-2-1 would, you just dont get as much of a scavenging effect for the overall "boost" in power as you can with a properly designed long tube 4-1,Im not sure if any body makes a "properly" designed longtube 4-1 header for the 420a?
Ive seriousely considerd it a few times, just not sure if enough of you would be interested to justify the time and money that would go into building a bunch of longtube headers, sorry to hi-jack this thread but lets take a poll to see how many people would be interested in a long tube header for the 420 ?

Originally posted by FastFabricationssorry to hi-jack this thread but lets take a poll to see how many people would be interested in a long tube header for the 420 ?

werent you supposed to build one like 6 months ago?... theres was tons of posts on it, and tons of people interested