Air/Fuel Ratio Oxygen Sensor Targets?
#1
Air/Fuel Ratio Oxygen Sensor Targets?
I just installed O2 sensors in the exhaust systems of 2 carbureted 455’s.
Both engines are mild builds, 800 cfm Qjets, with HEI, and factory duals. In big street cars, a ‘66 98 and a ‘66 Starfire.
In CA, our gas is about 10% ethanol, which I gather means I should aim at a stochiometric ratio of 14.1:1 or so instead of 14.7:1 as you would for pure gasoline. I suspect that %’age of alcohol means richer across the operating range.
I can dial in the idle to 14.1 no problem, but what are the air/fuel ratio goals I should aim at for part throttle cruise, acceleration, and WOT?
Opinions?
I understand qjets well, but I’m new to this information as inputs to tuning them.
Thanks in advance for any guidance
cf
Both engines are mild builds, 800 cfm Qjets, with HEI, and factory duals. In big street cars, a ‘66 98 and a ‘66 Starfire.
In CA, our gas is about 10% ethanol, which I gather means I should aim at a stochiometric ratio of 14.1:1 or so instead of 14.7:1 as you would for pure gasoline. I suspect that %’age of alcohol means richer across the operating range.
I can dial in the idle to 14.1 no problem, but what are the air/fuel ratio goals I should aim at for part throttle cruise, acceleration, and WOT?
Opinions?
I understand qjets well, but I’m new to this information as inputs to tuning them.
Thanks in advance for any guidance
cf
#2
I just installed O2 sensors in the exhaust systems of 2 carbureted 455’s.
Both engines are mild builds, 800 cfm Qjets, with HEI, and factory duals. In big street cars, a ‘66 98 and a ‘66 Starfire.
In CA, our gas is about 10% ethanol, which I gather means I should aim at a stochiometric ratio of 14.1:1 or so instead of 14.7:1 as you would for pure gasoline. I suspect that %’age of alcohol means richer across the operating range.
I can dial in the idle to 14.1 no problem, but what are the air/fuel ratio goals I should aim at for part throttle cruise 14.5 or so, acceleration 12.5-12.8, and WOT Same 12.5-12.8?
Opinions?
I understand qjets well, but I’m new to this information as inputs to tuning them.
Thanks in advance for any guidance
cf
Both engines are mild builds, 800 cfm Qjets, with HEI, and factory duals. In big street cars, a ‘66 98 and a ‘66 Starfire.
In CA, our gas is about 10% ethanol, which I gather means I should aim at a stochiometric ratio of 14.1:1 or so instead of 14.7:1 as you would for pure gasoline. I suspect that %’age of alcohol means richer across the operating range.
I can dial in the idle to 14.1 no problem, but what are the air/fuel ratio goals I should aim at for part throttle cruise 14.5 or so, acceleration 12.5-12.8, and WOT Same 12.5-12.8?
Opinions?
I understand qjets well, but I’m new to this information as inputs to tuning them.
Thanks in advance for any guidance
cf
#3
I can't help on this but do have a question on the subject. I have been interested in this for a while but not studied up on it yet. Do you have a recommendation on what kit to use or any information about doing this?
#5
Don't mean to steal the thread, maybe I should ask in another one... With the Jetfire models we are flying a little blind. They have a single bbl side draft carb and turbo setup. Most of them run lean with no jets or needles available. I have played with our automatic car by drilling the jet and also playing with the needle. I have it running nice but I am sure it is to rich now as I am sooting up the turbo turbine. Would it be worth the money to aid in this or is there a better way? The plug readings are all over the place with the water injected. At least they are not like I am use to seeing with ATV race engines.
#8
14 to 1 is good, even pushing 14.7 at idle, cruise. Moderate load, 13-1, WOT 12.5 to 12. E85 is crazy, like 8-1 but good for boost and high compression. Timing, cam, compression will play a factor but I assume you know that
#9
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84oldsDelta88
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June 24th, 2009 03:40 PM