Headers and o2 sensors

[snapfrank]

what iv seen of the headers on my 2001 is that will bolt on i need two bungs as the pic in lower case. headers sold for my car with the 2 o2 sensors are at the same place that i have should in the pic. i will try it and let you know. now is it a 18-1.25 or 18-1.5 bungs i need 986 2001 us model.

[manolo]

Its M18x1.5 for the sensors.

[Lightning]

You can use one of those locations on the header to install the leading O2 sensors.

If you don't put the trailing O2 sensors behind the remaining catalytic converter, you WILL get a Check Engine Light (because the ECU checks to see a difference in O2 readings between the leading and trailing sensors) and it won't go away.

As far as re-flashing the ECU, it depends upon your country's emissions testing laws...

[snapfrank]

so do i move them like in the pics or back all of them 1 space

[snapfrank]

there are two o2 holes so it should work if i add 2 bungs on my headers, what do you think.

[Lightning]

Originally Posted by snapfrank

so do i move them like in the pics or back all of them 1 space

Yes, attach one to a bung on the collector of the header and one to a bung on the rear of the catalytic converter they way you have it shown in the diagram.

[Johnny Danger]

Snap Frank,

If you don't mind me asking, what do you hope to gain after all of this ? Once you decide to eliminate the oem headers and pre-cats, and your done running new O2 sensors, creating bungs and likely chasing cel's until you're cross-eyed, you'll still be left with a set of very restrictive 400 cell secondary cats. Unless you plan to go "catless", and that would not be advisable for both emissions, as well as performance concerns, in my opinion I think that you are heading in the wrong direction. Unless you have planned out a "system" that involves high quality headers of a proven design along with lower cell cats (expensive !!!!!) of equal attributes, quite frankly, I don't think you stand to gain anything with what you are attempting to do. Perhaps, a better decision would be to leave the existing headers and pre-cats alone, and simply delete and by-pass the secondary cats. In my experience, by doing so you'll stand to free up the exhaust flow a little bit more, shed some unnecessary weight, and perhaps most importantly keep the vehicle OBDII compliant.

[snapfrank]

like this


Johnny Danger, nice reflection, i just want to use that headers, but it that does not work i will but back the old manifold on and that all. it's just to passtime that i want to put it on my car, but i will think about what u said.

Originally Posted by Lightning

Yes, attach one to a bung on the collector of the header and one to a bung on the rear of the catalytic converter they way you have it shown in the diagram.