locating an O2 sensor in a side pipe

[bobcowan]

Originally Posted by eschaider

One of the fixes for the problem is to take the flange on the headers (between the engine and side pipes) and move the flange back an inch. After you have moved the flange back make a stainless square block that will fit between the headers and the side pipes. Mill out the center of the block leaving a large square opening. Weld an O2 sensor bung in a horizontal position.

Assemble the headers and side pipes with the stainless block and gaskets between them. Tighten everything up, screw in your sensor of choice and go for it! Your sensorial be where the calibration engineers wanted it, in terms of distance from the exhaust port so warm up and signal delay will be "normal" in calibration engineer terms.

Ed

I can't imagine this would be good for header performance. I'm guessing that you'd loose all or most of your pulse vacuum.

Originally Posted by eschaider

Most of the sensor manufacturers will caution us about sensor placement that allows moisture to collect in the sensor. They will encourage either a 3 o'clock or 9 o'clock sensor positioning. A 2 o'clock or a 10 o'clock sensor positioning will also work but a 4 o'clock or 8 o'clock sensor positioning is not recommended because of the potential to collect water.
Ed

I have read this before. I think I've even said this before. And it makes logical and engineering sense. The sensor pictured above has been there more than 6K miles. No codes, so I'm guessing they're working OK.

My FFR had the sensors in the same place for about 12 years without any problems.

I suspect it's not as big of an issue as we think it is.

The advantage to placing the sensor in the collector is that it samples four tubes/cylinders. Yes, it's kind of a long way from the chamber. But the computer can easily compensate for that and give a good accurate signal.