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Discussion Starter · #1 ·
I currently have the O2 sensor for the FI on cylinder #3 of the primary header (4-into-4), but considering moving to the sidepipe, as close to the flange as possible to get a good gas sampling.

For those that did, how did it work? Would you do again?

Thanks for the info

Dan
 

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Discussion Starter · #3 ·
331 (SBF) and 4 into 4's, standard straight
 

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I had the old 4 into 4's with a o2 sensor on a single pipe on each side. Car ran very very rich all the time. this is using a Mass-flo system on a 408. Saw the new headers with a merge collector with ball and socket flange and I grabbed them as soon as a set became available. What a difference in the way the engine runs now. A lot cleaner and quieter. I don't think you can go wrong by moving them to the side pipe.
 

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On both EFI cars, the sensor is in the collector. On the current car, I started with the sensor at 3 o'clock in the pipe, and pointed at about a 45* angle towards the front of the car. The sensor lasted about 500 miles or so. Now it's pointed about 45* towards the rear of the car. At 12K miles, still working correctly.

You can only place it in the collector if it is a 5 wire heated sensor. If it is only a 3 wire, it needs to be about 18" or so from the head.
 

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Wide band will work fine in that location. Be aware any leaks ahead of the sensor will throw the reading off. Idle and overrun are the most affected.
 

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Discussion Starter · #7 ·
Bob - I have the 3-wire supplied by FITECH.

Current plan is to fabricate a chamber at the bottom of the 4-inti-4 Primary header for the O2 sensor. I currently only have it in #3, need a better sampling point, hence the chamber.

Also still looking for a primary header, so I can modify/scavenge. Looking for a donor, top flange unimportant.
 

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Don't know about Fitech but, I discussed sensor location with Holley tech support for the Sniper and they indicated that in the flow from 4 was much more important than distance. Put mine in the passenger side pipe just in front of the muffler. Seems to work fine.
 

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Bob - I have the 3-wire supplied by FITECH.
The three wire sensors are generally not self heating; and so need to be about 18" or so from the head.

BUT.... I did find these instructions from FiTech:

Instruction Manual for the following Go EFI Systems 30001, 30002, 30004, 30012, 30061, 30062 & 30064
Oxygen Sensor Installation
The supplied O2 Sensor can be installed in either exhaust bank. The Sensor cable connects to one of the cables coming out of the ECU on the throttle body.
A. The ideal location for the Sensor is 2-4 inches after the exhaust collector. It must always be at least 18-inches from the exhaust tip. Where short or open headers are utilized, install the sensor in the primary tube of the rear cylinder. Must be at least 8-inches from the exhaust port. It will not work on "zoomie" style headers.
B.The sensor should be at least 10° above horizontal (see figure #3) to allow condensation to run off. If this is not adhered to, the sensor is susceptible to water damage. C. Never position the sensor on the outside of a bend in the tubing.


If you're using their sensor, I would follow their instructions.
 
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