Portable Air/Fuel Ratio meter

[Dana67Dart]

I have been looking for a tailpipe sniffer A/F ratio meter.

Found this video.



This let's you put your O2 sensor into the fixture, insert it into your tail pipe, hook it up to your A/F ratio meter

Exhaust Clamp - P/N: 37280 > Universal Accessories > Innovate Motorsports

 

[diymirage]

I'm not sure if I would trust that

O2 sensors have a relatively short range of where in the exhaust they can be placed in order to be accurate...and I think this overshoots it by about 6 feet

 

[Dana67Dart]

Don't know?

I was watching a show (don't remember which one) and the were dynoing a car and that's what the used in the tail pipe.

It would be fairly easy to calibrate it by putting it in the tail pipe of a car that has an O2 sensor and read it's output vs the portable one.

 

[billccm]

Mechanical engineer I work with made this and I tried it.
It needs to be in the tailpipe with the car running for quite sometime before the AFR readings are stable. I think it worked well for a shade tree solution.

 

[67Dart273]

Yeh if you read over some of the DIY EFI literature (and add on O2 setups) they talk about how the sensor needs to be quite warm to function properly.

I believe most any of the older "tailpipe" sensors were pretty much made for idle settings.

 

[AJ/FormS]

I worked for a Harley Shop for a while. The shop had a sniffer that we rammed up the pipe for dyno runs, but it had to almost go up to the cylinder heard, into a part of the pipe that we were 100% sure was sealed to both the head and full-length. Harley guys run pretty big cams, and atmospheric air is always trying to flow back up the tailpipe, until the rpm gets up.

 

[Mattax]

The Bosch WBO2 sensors are warmed up electrically and the Innovate controllers show this process and then switch over to the AFR or Lambda when its ready. It takes about a minute.

The distance up the tailpipe depends on the engine and the exhaust flow.
A car with a large diameter exhaust is going to have atmosphere pushing up the tailpipe or collector when the volumetric pulses are slow and less frequent. Shouldn't be an issue on a stock '67 273, but at idle, for a number of reasons, AFR from WBO2 always should be considered suspect and at the end of the tail, even more so.

I have that adapter and one issue with use can be the tailpipe's turndown. It just won't go in all the way to the clamp.