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Really interesting article on A/F meters and exhaust leaks.

Moss Motors
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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
I found this looking for other info but found it really interesting and well explained: http://blog.innovatemotorsports.com/how-an-exhaust-leak-affects-wideband-o2-sensor-readings/

Adrian



Home built Eaton M62 Supercharger with 7.6psi boost, 8:1 compression, custom "supercharger" cam from Schneider Cams, Mikuni HSR48 Carburetor, cold air intake, ported head, matched manifolds, CB Performance computerized ignition, Fidanza 9 pound flywheel, Maxspeeding rods with Teflon wrist pin buttons.

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tahoe36c Avatar
tahoe36c Paul Hruza
Panama City, FL, USA   USA
1969 MG MGC GT "Little Red Rocket..."
1972 MG MGB GT "Tiny Dancer"
2002 Harley-Davidson Dyna
Good Stuff Adrian!!!

I have one of Innovative's Wideband sensors installed in the 2 inch Bell exhaust... But have yet to use it. I will be sure the new system is "airtight"!

Thank you!



Edited 1 time(s). Last edit at 2019-02-11 07:58 AM by tahoe36c.


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O2 Sensor Bung.JPG    53.7 KB
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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
Glad you enjoyed it Paul. My old exhaust was clamped together and had some minor leaks. My new system is all welded so It should be a bit more air tight. If I recall correctly you have the Moss TT system? The flanged joints on that setup should be pretty tight.

Adrian



Home built Eaton M62 Supercharger with 7.6psi boost, 8:1 compression, custom "supercharger" cam from Schneider Cams, Mikuni HSR48 Carburetor, cold air intake, ported head, matched manifolds, CB Performance computerized ignition, Fidanza 9 pound flywheel, Maxspeeding rods with Teflon wrist pin buttons.

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tahoe36c Avatar
tahoe36c Paul Hruza
Panama City, FL, USA   USA
1969 MG MGC GT "Little Red Rocket..."
1972 MG MGB GT "Tiny Dancer"
2002 Harley-Davidson Dyna
Adrian,

Actually it is the Bell System that I ordered directly from the UK... The slip joint connections seem to be well made but I will ensure the unit is leak free. I plan on installing the type of clamps shown in the picture. They are also stainless...


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Exhaust System 01.JPG    53.1 KB
Exhaust System 01.JPG

Exhaust Band Clamps.jpg    42 KB
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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
That looks a lot better that the typical exhaust clamp that mashes the pipes. I believe you can also get some sort of sealer for exhaust joints.

Adrian



Home built Eaton M62 Supercharger with 7.6psi boost, 8:1 compression, custom "supercharger" cam from Schneider Cams, Mikuni HSR48 Carburetor, cold air intake, ported head, matched manifolds, CB Performance computerized ignition, Fidanza 9 pound flywheel, Maxspeeding rods with Teflon wrist pin buttons.

tahoe36c Avatar
tahoe36c Paul Hruza
Panama City, FL, USA   USA
1969 MG MGC GT "Little Red Rocket..."
1972 MG MGB GT "Tiny Dancer"
2002 Harley-Davidson Dyna
Exhaust Joint Sealer sounds like a great idea! I had not thought of that one... I'll have to purchase some prior to the installation. Thanks again Adrian. thumbs up smileys with beer

B-racer Avatar
B-racer Jeff Schlemmer
Shakopee, MN, USA   USA
1950 Willys Jeep Pickup "Ratrod"
1971 MG MGB ~ For Sale ! ~
2014 Dodge Charger
Solid article, especially this point:
"If the engine is running lean, there will be excess oxygen in the exhaust because there was not enough fuel present in the combustion chamber to completely burn it. In rich conditions, the opposite is true."

I'm surprised they didn't test the reversion you see when using a tailpipe mounted sensor. That results in the same skewed idle readings you see in test #1, and everything else falls into place the way it should, like baseline. The real info here is that you can test the skew in your meter given your circumstances and fairly reliably tune around that skew. The other truth is that you can take 3 different Innovate meters and none will read the same, so you will always need to tune around your specific oxygen sensor.

Walker Acousti/seal part number 35959 is a good exhaust sealant for sealing minor imperfections that disrupt AFR readings. Its not good for sealing warped manifolds or torn gaskets.



jeff@advanceddistributors.com

tahoe36c Avatar
tahoe36c Paul Hruza
Panama City, FL, USA   USA
1969 MG MGC GT "Little Red Rocket..."
1972 MG MGB GT "Tiny Dancer"
2002 Harley-Davidson Dyna
Pretty much a common sense issue regarding O2 levels based on mixture. Just remember the "Triangle of Fire"

O2
Fuel
Spark

Less fuel will always mean "leftover" O2 right?

And visa-versa

pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
In reply to # 3889818 by tahoe36c Pretty much a common sense issue regarding O2 levels based on mixture. Just remember the "Triangle of Fire"

O2
Fuel
Spark

Less fuel will always mean "leftover" O2 right?

And visa-versa

Yup. Oxygen doesn't burn. If there's not enough fuel to pair up with the oxygen it goes out the pipe. If the engine fails to fire altogether, the charge is blown out the tailpipe the same as it went in...14 pounds of air and one pound of fuel.

Adrian



Home built Eaton M62 Supercharger with 7.6psi boost, 8:1 compression, custom "supercharger" cam from Schneider Cams, Mikuni HSR48 Carburetor, cold air intake, ported head, matched manifolds, CB Performance computerized ignition, Fidanza 9 pound flywheel, Maxspeeding rods with Teflon wrist pin buttons.

Gerald O Avatar
Gerald O Gerald O'Docharty
Wake Forest, North Carolina, USA   USA
1978 MG MGB
Wideband sensors, in the two branches of the downpipe let you monitor the 'inner' and 'outer' cylinder pairs separately. Helps to be sure the cylinders are getting equal fuel distribution. If you don't trust the sensors are matched, you can swap the connectors and compare.



Here's a sample run through the gears with the above two sensors. Dual HS6 carbs.





Edited 2 time(s). Last edit at 2019-02-11 02:48 PM by Gerald O.

tahoe36c Avatar
tahoe36c Paul Hruza
Panama City, FL, USA   USA
1969 MG MGC GT "Little Red Rocket..."
1972 MG MGB GT "Tiny Dancer"
2002 Harley-Davidson Dyna
There are normally only two carbs feeding four cylinders... But considering my options;

If I am using two 40DCOEs (4 carbs) with the same internals for the Derrington, I am pretty sure they are providing the same mixture. Same goes for the HS6s. With them it's all about the depth of the jet in conjunction with the lift pin test (which works perfectly on rebuilt carbs....).

With this in mind only one sensor is really required downstream for all four cylinders if you set up your carb/carbs properly. Not saying you are incorrect, just sayin' I trust my talent to balance carbs. And have seen the results to show the O2 sensor is not really a requirement, just an upgrade to help "tweek" your goodies!!

Let's just say I was taught to tune them long before any O2 sensor ever even existed. All I really need is about 2 feet of 1/4" ID rubber hose to get the same results this sensor shows. LOL... I suppose that makes me an old "analog guy" who only wants/needs to be "digital" for the fun of it!!! smileys with beer



Edited 2 time(s). Last edit at 2019-02-11 07:04 PM by tahoe36c.

Benny Avatar
Benny Ben E
San Diego, CA, USA   USA
In reply to # 3889648 by B-racer Walker Acousti/seal part number 35959 is a good exhaust sealant for sealing minor imperfections that disrupt AFR readings.

I’ve been using that stuff for years....it’s great on slip-jointed exhausts.

It has a lot of “body”, so you only barely have to snug up your clamps to get a perfect seal. Then the exhaust just pulls apart next time you need it to.

Gerald O Avatar
Gerald O Gerald O'Docharty
Wake Forest, North Carolina, USA   USA
1978 MG MGB
In reply to # 3889993 by tahoe36c ...Let's just say I was taught to tune them long before any A/F meter ever even existed. All I really need is about 2 feet of 1/4" ID rubber hose to get the same results this sensor shows.

I kind of doubt that, since A/F meters have been around since the 1940s. I have one in the shop from 1947.

tahoe36c Avatar
tahoe36c Paul Hruza
Panama City, FL, USA   USA
1969 MG MGC GT "Little Red Rocket..."
1972 MG MGB GT "Tiny Dancer"
2002 Harley-Davidson Dyna
I seriously doubt you had one in your car is what I am saying....

Since 1947??? Then history must have not known you since I am reading it was Bosch who first developed one in the late 70s.... BRAVO for you!!!! See link below.

The first automobile O2 sensor was introduced in 1976 on a Volvo 240. California vehicles got them next in 1980 when California's emission rules required lower emissions. Federal emission laws made O2 sensors virtually mandatory on all cars and light trucks built since 1981.

I started tuning the B with a rubber tube in 1982... Pretty close I'd say!!! LOL....

I also have one of these for fun as shown below. You can shove the sensor up the tailpipe, strap the box to the bumper and run the wires into the car to read the results... Old School.

http://www.walkerproducts.com/o2-sensor-training-guide/history/



Edited 3 time(s). Last edit at 2019-02-11 06:57 PM by tahoe36c.


Attachments:
Exhaust Gas Analyzer.JPG    44.8 KB
Exhaust Gas Analyzer.JPG

tahoe36c Avatar
tahoe36c Paul Hruza
Panama City, FL, USA   USA
1969 MG MGC GT "Little Red Rocket..."
1972 MG MGB GT "Tiny Dancer"
2002 Harley-Davidson Dyna
The "Cambridge Indicator" was an example of an early type "Exhaust Gas Analyzer", but it was NOT an O2 sensor!

"Used by older aircraft, the Cambridge Mixture Indicator displayed air-fuel ratio by measuring the thermal conductivity of exhaust gas. It was manufactured by the Cambridge Instrument Company.[6] This device was installed on airplanes in the 1930s, including the Lockheed Model 10 Electra flown by Amelia Earhart on her last flight."

https://en.wikipedia.org/wiki/Exhaust_gas_analyzer

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