Holley Sniper - Oxygen Sensor Location

[GA Architect]

To those who have installed the Sniper EFI units, please post up some photos of where you tapped the exhaust line to install the Oxygen Sensor's weld bung. That would be for individuals that run the OEM exhaust manifold, as well as individuals that run headers.

 

[imyahucklbrry]

To those who have installed the Sniper EFI units, please post up some photos of where you tapped the exhaust line to install the Oxygen Sensor's weld bung. That would be for individuals that run the OEM exhaust manifold, as well as individuals that run headers.

You getting prepped to do this?

 

[Steamer]

I mounted it here attempting to protect it from the deep water I play in and from lots of branches I encounter. I thought about adding some sort of extra protection but never did. I'm 3" down from the bottom of the flange to center of bung. I thought the clamp on style mount was a good idea in case the threads got buggered up when a sensor change might occur, and the threads are rusted up by then. A replacement clamp on would be an easy change out. The clamp-on that came with mine wasn’t a good fit on my 2" pipe. I only have a stick welder and didn't trust myself on the thin pipe so I brazed it in. So far so good.

 

[GA Architect]

You getting prepped to do this?

YEP! I just can't leave well enough alone. However, it is being done for a reason. A reason that I hope will come to light next Spring. The planning & logistics has already begun.

Note: I'll keep all the old parts and pieces, should the EFI not work out, I can reinstall them.

 

[thecrazygreek]

My first install was on a stock manifold and I installed it in about the same spot Steamer (above) did, except 180 degrees the other way, facing towards the front of the vehicle.

My new install a couple weeks ago is on my rig with headers. Duel style, that combine just about where the bell-housing is. I did take a couple pics of that, I will try to dig them up and add it here so you can see. But I installed it about 3 inches past where they combined. For clearance I clocked it at about 10 o'clock looking towards the front of the rig. The first install was with a weld in bung, and the second was with the clamp on style. So far the clamp on style is working great.

 

[Downey]

02 sensors are very heat sensitive, and can detect an exhaust pulsation in a single Header tube, that's why we always wanted to position the sensor into at least 2 opposite firing tubes we running Headers. Also, with Headers you loose 600 to 700 degrees between Head and bottom collector, you don't want to read that loss. Without Headers Steamers location (above) is perfect, up close to the engine where you have not lost much heat.

 

[thecrazygreek]

Here's the pic of the location with my header. My hand is holding the connector to the sensor. I was mocking it up at the time.
I was happy that the wire was long enough to reach that far without adding an extension. Had plenty of length.

 

[SteveH]

Mine is right where Steamers is, and works well with my AFI TBI.

 

[mrboatman]

My first install was on a stock manifold and I installed it in about the same spot Steamer (above) did, except 180 degrees the other way, facing towards the front of the vehicle.

I installed it the same as @thecrazygreek but I used the clamp on version. And this is a F engine.
JP

 

[456z]

Downey, Your post has peaked my curiosity. If I am reading your post correctly you are using two separate o2 sensors when using headers ? Then if you are do you just wire the o2 sensors in parallel or do these EFI kits have inputs for more than one sensor. Mike

 

[Downey]

Downey, Your post has peaked my curiosity. If I am reading your post correctly you are using two separate o2 sensors when using headers ? Then if you are do you just wire the o2 sensors in parallel or do these EFI kits have inputs for more than one sensor. Mike

No, use only one 02 sensor, mounted close to exhaust manifold, or high up on a Header collector, not into a single Header pipe that merely gets a exhaust pulsation.

 

[456z]

I understand now. Thank you

No, use only one 02 sensor, mounted close to exhaust manifold, or high up on a Header collector, not into a single Header pipe that merely gets a exhaust pulsation.

 

[Steamer]

fwiw. On page 9 of “This PDF” it gives Holley’s recommendations for the O2 sensor installation.

 

[Dizzy]

I hope that the next F/2F header is more O2 sensor friendly.

For those who swim in the stream, would a heated sensor work off of a 2F air rail connection?

 

[White Stripe]

O2 sensors are water proof. I've dunked mine lots of times. Make sure to put anti seize on the threads.

 

[GA Architect]

To close this one out, below is a photo of where I installed the O2 bung. Note, that is not a crack in the exhaust manifold, just a shadow from a casting flaw.

 

[Fj moneypit]

I put mine after the collector only because I have a new exhaust and muffler going in and I’ll use a weld in bung and placement will be different. It works great where it’s at.

 

[mattressking]

Per Innovative's instructions:

"Ideally, the O2 sensor should be placed at least 24 inches downstream from the cylinder head exhaust ports. This ensures that the O2 sensor takes its measurements after the exhaust gas from each primary merges into a common collector. "

"Positioning the sensor too close to the exhaust ports can expose it to high exhaust gas temperature (EGT) as well as over-cooling from the high-velocity exhaust gas flowing over the sensor. Likewise, if an engine runs excessively rich, an oxygen sensor that’s positioned farther downstream is less prone to fouling. Although these extreme conditions aren’t a concern in most street applications, placing the sensor farther down the exhaust tract is rarely detrimental."

"Once establishing how far downstream in the exhaust system to position the wideband O2 sensor, the bung should be mounted between 9 o’clock and 3 o’clock. Condensation buildup can destroy a sensor very quickly, so mounting the sensor between 9 o’clock and 3 o’clock protects it from water build-up at the bottom of the exhaust pipe. If there is sufficient space between the top of the exhaust pipe and floorboard, mounting the sensor at 12 o’clock is ideal."

 

[Suprasoup]

Late to the party but here's where mine are installed.


First one is behind the collectors of a 6-1 header. '76 2f engine. 12 o'clock position. Innovate LC-2 wideband. Megasquirt 2 v3.0.

Test engine so original exhaust on a '83 2F. Roughly 12 o clock position as well. Innovate LC-1 wideband. Megasquirt 2 v3.57

So what we building??!!

 

[GA Architect]

So what we building??!!

Installing a Holley Sniper 2300 on a 2F.