Where to mount an AFR sensor

[ronstory]

All--

I'm looking to add a wide-band AFR gauge to help with tuning this pesky engine. Any suggesting on where to mount the sensor? Normally, you want to mount the sensor at the collector to get a sample representing all the cylinders.

Anyone done this recently?

Thanks,
Ron

[joe_db]

All--

I'm looking to add a wide-band AFR gauge to help with tuning this pesky engine. Any suggesting on where to mount the sensor? Normally, you want to mount the sensor at the collector to get a sample representing all the cylinders.

Anyone done this recently?

Thanks,
Ron

The only O2 sensor install I have seen is drilled into the forward end of the manifold. If you want the other end, you could use a plumbing T and drill+tap a plug for the T. You want it on the up-side, i.e away from the water.

[ronstory]

That's a great point. If I welded in a bung a on 1.25 black pipe as it leaves the exhaust manifold, I could sample all cylinders.

On the "easy path", could just drill&tap an 18mm hole... that is easy. Not to mention if the accuracy seemed off, I could put in the those stainless threaded bung plugs to seal it off and move it to the exhaust stack.

Regarding the engine you saw, is the O2 sensor just drilled/tapped in centered the round casting raised portion found on the very front of the exhaust manifold?

Thanks,
Ron

[joe_db]

That's a great point. If I welded in a bung a on 1.25 black pipe as it leaves the exhaust manifold, I could sample all cylinders.

On the "easy path", could just drill&tap an 18mm hole... that is easy. Not to mention if the accuracy seemed off, I could put in the those stainless threaded bung plugs to seal it off and move it to the exhaust stack.

Regarding the engine you saw, is the O2 sensor just drilled/tapped in centered the round casting raised portion found on the very front of the exhaust manifold?

Thanks,
Ron

Yes it is.

[edwardc]

It's even easier if you have an MMI manifold. There are ports on both ends, with a blank plate over the unused one. Easy peazy to remove that plate and drill & tap it on the bench.

[ronstory]

That almost sounds like cheating. 😎