Exhaust Gas Analyzer

[John P]

I'm looking for a universal type that I can easily switch between my '67 Beetle and '71 911, WITHOUT the need for a weld-in bung or bolt-on flange for an O2 sensor. Something like you see at chassis dynos, where the probe goes inside of the exhaust pipe, where I could easily (and temporarily) switch it between the two cars for fine tuning on the street.

Both cars have a single muffler with a single tail pipe.

Suggestions?

Thanks, in advance.

JP

[65bug]

Hi John,
     That's a great question! I have the LM1 meter and I could NEVER get the same readings with the probe inserted into the tailpipe vs. the welded in bung that I eventually did.
     They do sell a hanger and claim you need that hanger to get the o2 probe back up into the muffler far enough to eliminate and outside air skewing the readings. Apparently it holds the probe back far enough into the muffler to get accurate measurements!
      As the muffler pulses you do get skewed readings as outside air does enter the end of the tailpipe! I have seen it with my own eyes.
      Mark Harney really helped me to understand how the meter works(Thanks again Mark) and there is a bit of a learning curve to understand how these meters work.
      Are you in So. Cal. John? You are more then welcome to borrow my meter...........
     

[jgerock]

Unfortunately, I've never seen a "portable" one.  After screwing around trying to get the A/F ratio right in my fuel-injected BMW, I installed a bung, Bosch 02 sensor and wideband gauge from AEM.  I purchased the "kit" from Summit Racing for about $ 200.  It was well worth the money.

[Bruce Tweddle]

Something like you see at chassis dynos, where the probe goes inside of the exhaust pipe,

This probe isn't an O2 sensor, it's a true exhaust gas analyzer that simply takes a sample of the exhaust gas then directs it into the machine.
The problem you will have with an O2 sensor at the tail pipe is at that location, the exhaust is too cold.  When they are cold, they don't give proper readings.  The bad thing about that is you don't know when it's doing that, so you are constantly scratching your head.
The second problem is that the exhaust sample at the tail pipe isn't 100% exhaust.  Like Todd said, air always gets drawn into the tail pipe, diluting the sample.

[martin]

The best solution is to weld in a bung and leave the sensor in it on each car and switch the gauge/controller. Properly tig welded, the exhaust finish won't be damaged and hopefully you can pick a spot out of sight.
I have an older PLX gauge. The new ones look pretty good, here is a link to it, along with their expandable system.
http://www.plxdevices.com/wideband.html
I like the CA company, there is a funny vid on youtube of the CEO taking delivery of his new Lamborghini while at work.

[so67vw]

I have a sensor that if put in when my LM1 is in my truck... I read from another location with my ECU.... I have seen people make a short stub of an adapter (like a flange extention) that is just long enough to get a bung in at the collector....

[John P]

Thanks for the replies. I'm bummed - but not surprised, as I suspected as much - that the proper solution is to weld a bung in each car.

Cheers,

JP