i bought an ss exhaust manifold and it has an 02 sensor bung on the headers but i have the factory downpipe with 2 o2 bungs already. so where should i put the upper o2 sensor, in the header or in the downpipe?

 

preferably in the manifold. the reason why there's one in the manifold is because its there for the stock #1 o2 sensor and the other one is in the downpipe, the 2.2's have both sensors in the downpipe.

 

but why should the #1 o2 sensor go in the manifold? so it can read the exhaust gases quicker?

 

you want it as close to the head as possible so as to get the most accurate reading. also less chance of having more then 1 leak adding air to the system

 

oh ok. thats where i put it and used an extra o2 sensor to block off the #1 o2 sensor bung on the downpipe. and my tuner said that i dont need it retuned because the computer will recognize the new headers. is that true?

 

ok i need to correct you, its a manifold not a header (not being a dick).

and ya going from a 2.2 manifold to a 2.4/2.0 manifold shouldn't require a retune

 

ok. can i ask what the difference is between the two?

 

differen't castings and differen't port sizes i do believe

 

no. whats the difference between a manifold and headers? lol

 

oh hahaha castings, usual equal length runners are the 2 biggest difference's

 

just found this on some random website, which should help a bit.

Exhaust manafold and headers serve the same function they just work a little different. Exhaust manafold take the exhaust out of the heads and rout them to the exhaust. But when the exhaust comes out of the head into the exhaust manafold it crams it in without a direct rout to make the exhaust flow smoothly. Headers take the single exhaust ports on the head and run them into the right direction to make the transfer a little easier. They have short tube headers and long tube headers. The "shortys" are easier to install because they are usaully direct fit. The long tube headers work a little better but usually requires the exhaust on the car to be modified to make room for the extended header.

 

oh ok. so basically headers flow easier and manifolds cram the pack in and force it to the rest of the exhaust.

 

yup basically. there's alot more detailed info on but that is the basics of it.

 

ok thanks. i really appreciate it.

 

np i got nothing better to do here at work lol