need more help.............

[phoenix64]

I need to know if the o2 sensors can be put in the downpipe after the turbo. Or do they have to go in the headers. I want to avoid exposing them to the heat and pressure of the headers.

[phoenix64]

I was thinking they would read more accuratly as well, becuase they would be closer to the stock heat range.

[ReodDai]

They are suppose to register the o2 coming from each bank of the engine. Putting two of them in the downpipe wouldn't be ideal but it would probably "work".

[Tiago]

put them in the headers.

[ReodDai]

Originally posted by phoenix64:
I was thinking they would read more accuratly as well, becuase they would be closer to the stock heat range.

No because they wouldn't be positioned correctly. So how would they be accurate?

[Turbo V6 Camaro]

umm put them in the headers and put you middle one (if you have 1997s have 4 :mad: ) in the down pipe

[TurboProject]

Well everyone's friend, Corky Bell says on page 134 of his book that an O2 sensor should be placed as close to the combustion chamber as temperature permits. Most of the time with a turbo it should be put right after the turbo.
I'm not satyig this is gospel, just that's what is in some liturature. Besides, what makes it less acurate if it's further downstream? As long as there aren't any exhaust leaks upstream of the sensor how are you going to have any more or any less oxygen that right after the combustion chamber?
As long as it's up to operating temp you shouldn't have a problem. And if they're heated O2 sensors then you really shouldn't have a problem.
On the MKIII toyota supras, they put an oxygen sensor in the elbow after the turbo.

[ReodDai]

Your missing the point of the o2 sensors. The TWO in the manifolds are there to get signals from each bank of the motor seperately. Older models have another o2 sensor before the catalytic converter and one after the catalytic converter. Newer models only have another o2 sensor after the catalytic converter.

There is no reason to put them further downstream. The two in the manifolds get suppose to be exactly there. The one after the ypipe is suppose to be there (if applicable) and the one after the cat is suppose to be there. Moving them around doesn't do anything but send incorrect signals back to your PCM. It would be perfectly fine to put the one that goes after the y in the ypipe into your downpipe (if applicable). Also if you do have one in that location what are you going to do put the other two manifold o2 sensors in your downpipe? So you will have 2-3 sensors in a row doing absolutely nothing useful except for maybe one of them.

[TurboProject]

The ones before and after the cat are so the computer can check how well the cat is functioning. So it can compare the sensor before and after.
The only reason to move the ones in the manifolds are if the heat is too much for them with the turbo. I only have the ones in the manifolds w/ my 3.4 and I didn't move them when I added the turbo. But I also don't give a damn about emmissions or codes. I'm not even controlling my fuel with the stock computer anymore, but I was for a good 2 years with the turbo before I switched to a different setup.
I'm gussing they have one in each bank so that with sequential fuel injection they can change one bank's a/f ratio? They'd have to change the whole bank though cuz they're just getting information in a lump sum of all 3 cylinders.

[phoenix64]

Tiago I appreciate that you are a "turbo god", but it would be nice if you could do us mortals the courtesy of explaing stuff a little bit.

As far as being more accurate, as I understand it O2's are very sensitive to temperature, so I thought that doubling the operating temperature, as well as pressure might mess up the readings. But mostly I have never seen a turbo car with the O2 before the turbo.

But really and truly are O2's that important? What could possibly get screwed up?

Your still going to know if the car is lean, only now you would have to check all 6 injectors instead of just 3. Big deal.

[phoenix64]

BTW this is the last thing before sending the headers out to be coated, so I really appreciate the responses.

[Turbo V6 Camaro]

i'm going to have a wide bad after the turbo with a out put for the PCM to keep it happy and the wide band singal is going to be up buy me so i know what going on

[ReodDai]

Tiago is hardly a turbo god lol. Get your head out of his ***. If you don't really care what the stock pcm thinks at idle/cruise(wot doesn't care about the o2s) and your reprogramming everything then just get rid of the o2 sensors in the manifolds. Just ditch the codes.

[Tiago]

its already been said. The ones for each manifold should remain on their respective headers before the turbo. The cat/emmission o2s on the ypipe could be totally deleted if you want. They don't do anything.

[1DangerousV6]

i know this isnt my place here in this turbo stuff...im supercharged...but im going with Tiago and Reod on this...i had my cat hollowed right out and it didnt effect my cars performance at all...except increasing the horsepower...i've never even got a code from the o2 in the pipe