AFR bung location

[M5guy]

I want to install an AFR meter on my new engine. I am using one of Brian’s Zork tubes for my post turbo exhaust system. Where should I locate the bung for the sensor?

Thanks

[Bucketlist]

Originally Posted by M5guy

I want to install an AFR meter on my new engine. I am using one of Brian’s Zork tubes for my post turbo exhaust system. Where should I locate the bung for the sensor?

Thanks

Here is mine:

[Lyle O]

As above, my understanding is anywhere after the turbo is best, so where Steve has it should be your guide...

[M5guy]

Thanks! Looks like a good spot. We are going to have to remove the Zork to modify it so we will drill and weld then. With a bigger turbo unit (BW S200) the Zork comes out a little cockeyed and needs to be cut and rewelded.

[Pesch]

Here’s where I put it, so far so good with the help of a heat break bung.
I also added a copper shield (heat sink)



It’s tight with the bumper but it fits.

I was burning countless sensor with an Innovate setup at stock location (pre-turbo), now with “colder” gas, heat break and PLX, it seems more durable.

[Alan L]

You can see it can be a tight fit - so you need to sort the angle out to clear the vehicle and try not to kink the wire too much. Ideally it should be in a near upright position - so water does not condense on the end of the sensor. Mine is on a zork - about 50mm after the turbo flange. You want to stay reasonably close to the turbo if possible - to get stable readings, ie as far off the open end of the tube as possible. So those factors pretty well determine where it is going.
Alan

[mark houghton]

Just to chime in on another option, though not necessarily the best. I put mine post-muffler, as far in from the end of the tail pipe as possible (about 10" in my case)....at the risk of erroneous lean readings at idle due to low exhaust volume and the possibility of ambient air sneaking in. Once past idle it seemed the gas volume was sufficient to preclude any exposure from ambient air and my readings were steady. Even if the readings weren't entirely accurate, at least it would err on the safe side reading leaner that actual if it was picking up any ambient air.

Again, not optimal location but it's what I did for what it's worth.

[flightlead404]

Originally Posted by mark houghton

Just to chime in on another option, though not necessarily the best. I put mine post-muffler, as far in from the end of the tail pipe as possible (about 10" in my case)....at the risk of erroneous lean readings at idle due to low exhaust volume and the possibility of ambient air sneaking in. Once past idle it seemed the gas volume was sufficient to preclude any exposure from ambient air and my readings were steady. Even if the readings weren't entirely accurate, at least it would err on the safe side reading leaner that actual if it was picking up any ambient air.

Again, not optimal location but it's what I did for what it's worth.

FWIW I have a dual outlet muffler and at idle one side seems to draw air in, the other side a little of both. This would definitely lead to wrong readings at idle.

Above maybe 1,500 rpm or so this problem disappears.

[mark houghton]

Innovate still markets a tail pipe clamp affair for mounting their sensors. I wonder how much research went in to it?

"Patent-pending, Venturi-effect, tapped exhaust clamp for obtaining accurate lambda measurements in non-cat autos or other engines".