I'm considering buying one, but I dont know which to get. there are 4-2-1 and 4-1 but what is the difference between them? THanks
Rachel

 

4-2-1 is exactly that the piping goes from 4 (exiting the head) to 2 (before the oil pan in front) to 1 (underneath at the cat)


4-1 same idea only no 2. 4 all the way to the cat where it becomes 1.


I like the 4-2-1 because if you have to pull the oil pan you don't have to remove the whole header just the lower section.

 

4-1 will typically produce more top end, 4-2-1 usually more low end, 4-2-1 much easier to install.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GITWIDIT &raquo;</TD></TR><TR><TD CLASS="quote">4-1 will typically produce more top end, 4-2-1 usually more low end, 4-2-1 much easier to install.</TD></TR></TABLE>

Typically. However, some 4-2-1's make more power than the 4-1's.

Search for "thegreatheadertest" in the archives.

 

If you have the sohc engine or b16, i'd say get the 4-2-1. If you have B18, get the 4-1. The sohc and b16 needs all the help it can get in the low to mid power range.

 

Where does the O2 sensor go?

 

Depends on what kinda car you have. Some cars its up by the head, some cars on just the bottom of the header, some cars on the header and on the cat. It varies.

 

http://bob123e.tripod.com/thegreatheadertest/ great link.

 

if your ride is seriously low, I would steer away from the 4-1 header. It hangs lower