Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
I Currently own five carburetor controlled vehicles (3 Imperials, a 1967 Polara and a 1953 Ford tractor) and have thought for a long time that it would be very useful to be able to measure the air/fuel ratio for these vehicles to try to optimally tune the carburetors.
After doing a fair amount of research I decided to set up a portable kit to try measure air / fuel ratios.
I installed the gauge in the housing of an old Sears engine analyzer meter which no longer worked and used the electrical connectors from that gauge with attached alligator clips to power the device. The only trick is that you need to attach an oxygen sensor bung to your exhaust system somewhere.
My first trial of this system was on the 1953 Ford tractor and I had planned to replace the exhausts pipe so a weld in oxygen sensor bung seemed the obvious choice there. The kit from APSX comes with the bung and a plug which is very nice.
Once I get comfortable with the air / fuel ratio kit I also plan to use it on my Imperials (1969 and 1964 to start) To this end I ordered clamp on oxygen sensor bungs which should be easier to install on an exhaust in the car. https://fitechefi.com/products/60012/
So far I have installed the oxygen sensing kit on my tractor and it seems to do exactly what it is supposed to. It has a very quick response and a air / fuel range of 9 to 19.
The reason that I am posting this information here is fro general information and more importantly to see if any on the members of the club have any input on what air to fuel ratios should be used for old Imperials.
I realize that this is a very complicated subject.
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
I think that's a great idea. Please keep us posted of your findings with this experiment. I'm also planning something similar.
I had an O2 sensor bung installed on the passenger-side exhaust pipe for my Windsor, and plan to hard-wire a WBO2 gauge into the car for the same purpose. (I may upgrade the engine to EFI in the future, so there's a second reason to have the O2 sensor bung.)
Of course, once the carb settings have been optimized, the gauge shouldn't be required anymore, so I can see the advantage to making the gauge portable. Since you'll want to monitor this inside the car during cruise and acceleration, a cigarette lighter adapter for power might be a good idea.
Joined: Mon Oct 10 2005, 09:48PM
Location: Calgary Alberta Canada
Posts: 305
I have done a few Carb to FI modification and has used the AEM wide band sensor. And have tuned up a few carb using a wide band sensor.
There is a tail pipe clamp that you can get that should work well for testing. Saves welding in a bung. Innovate Motorsports 3728 Exhaust Clamp is the one i have.
You will find the carbs are quite sloppy in the AFR control.
Joined: Thu May 01 2008, 11:15AM
Location: Chicago,IL
Posts: 2868
a/f ratio....for idle tuning the O2 gives you data, but the optimal setting is still done with the vacuum gauge. With the WBO2 you'll be able to monkey with leaner jets and lazier power valves/rod springs to see the a/f as you try to lean it out to see what #'s you can live with as you take power out to gain mpg. Even without the O2 on my Charger I've experimented power valve opening points and moved up 4 jet sizes and lost about .75 mpg but the car is much more satisfying to drive, a trade I'm happy with.