Bad mpg?

[Antonm]

The 6.2 will draw more air and require more fuel for a given afr.

Again,,, not true.

You can (and do) change how much air the engine takes in with the throttle body.

A 5.3 at 80% throttle making 200hp will be drawing in more air, and burning more fuel, that a 6.2 at 20% throttle making 70hp, and both engines can be running the same AFR doing while doing this.

Since you can't seem to understand this very basic concept, nothing you say on the topic can can be taken seriously.
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[Antonm]

Fuel flow rate is dependent on afr. There is only a specific range of afr where a combustible mix can occur.

And yet again, wildly untrue.

Fuel flow rate is dependent on however long the PCM tells the injectors to say open. The tuner can adjust this as they fit by adding or subtracting fuel. AFR is a result, not cause.

And you can run an engine as rich as in the 9's for afr (taking gasoline here with a stoichiometric value of 14.7, other fuels will have a drastically different stoichiometric value,), or a lean as into the 16's (for a little while before it melts something anyway). Yes the efficiency values will change (a lot), but the range at which an engine will run is fairly broad

Engines ran for a long time on carburetors that could not compensate for changes in density altitude, yes they were less efficient that they otherwise could have been, but we ran engines that way for literally a century.
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[Antonm]

A 5.3 will have 5.3L x 1kg/L = 5.3 kg of air. To get 14.7 afr, then the fuel will have to be 5.3kg/14.7 = 0.36 kg fuel. 5.3 kg air/ 0.36 kg fuel = 14.7.

This is true ONLY at wide open throttle.

At literally any other engine operating condition the amount of air taken in is regulated by the throttle body, hence why these engine have a mass airflow meter in the intake track, so the PCM knows how much air is in the engine at any given time.

So yes, at wide open throttle, the 6.2 will produce more hp, and burn more fuel that the 5.3 at the same afr, that's another one of those self-evident statements.
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[blanchard7684]

Again,,, not true.

You can (and do) change how much air the engine takes in with the throttle body.

A 5.3 at 80% throttle making 200hp will be drawing in more air, and burning more fuel, that a 6.2 at 20% throttle making 70hp, and both engines can be running the same AFR doing while doing this.

Since you can't seem to understand this very basic concept, nothing you say on the topic can can be taken seriously.
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you are changing the terms of the discussion.

Now you are comparing 200 hp vs 70 hp.

Your original claim was that at same power level, the 5.3 and 6.2 will be using the same fuel. My previous post, refuted this with exceptional clarity.

 

[blanchard7684]

And yet again, wildly untrue.

Fuel flow rate is dependent on however long the PCM tells the injectors to say open. The tuner can adjust this as they fit by adding or subtracting fuel. AFR is a result, not cause.

And you can run an engine as rich as in the 9's for afr (taking gasoline here with a stoichiometric value of 14.7, other fuels will have a drastically different stoichiometric value,), or a lean as into the 16's (for a little while before it melts something anyway). Yes the efficiency values will change (a lot), but the range at which an engine will run is fairly broad

Engines ran for a long time on carburetors that could not compensate for changes in density altitude, yes they were less efficient that they otherwise could have been, but we ran engines that way for literally a century.
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What is programmed into the ECM isn't a wild guess. It is based on a known or experimentally verified amount of air flow at any given RPM.

Fuel flow is dependent on air flow.

 

[Antonm]

You can see then that the 5.3 will have less fuel than 6.2 at same afr.

So...with less fuel in this equation P = n x Q x fuel flow rate, it will not have the same power, P, as a 6.2 at the same afr.

This is a continuation of your statement about each engine taking in different quantities of air, (5.3l vs.6.2L) which the only time that will be true is at wide open throttle.

So lets say the 5.3 was taking in 80% of its max airflow because that's where the drivers foot has the throttle body positioned (5.3 *0.8 = 424),,,now let say a 6.2 was taking in 20% airflow because that's where its driver has the throttle body positioned (6.2*0.2 = 124),,, so now, assuming that we target the same afr, and adjust fuel flowrate via injector pulse width accordingly, which engine is taking in more air and burning more fuel?
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[Antonm]

you are changing the terms of the discussion.

Now you are comparing 200 hp vs 70 hp.

Your original claim was that at same power level, the 5.3 and 6.2 will be using the same fuel. My previous post, refuted this with exceptional clarity.

At the same power level, the 5.3 and 6.2 will be using the same amount of fuel.

Heck, any engine with the same efficiencies, regardless of configuration or overall displacement, will use the same amount of fuel at a given power level.

Because as was pointed out earlier, Power is efficiency times fuel flow.
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[blanchard7684]

This is true ONLY at wide open throttle.

At literally any other engine operating condition the amount of air taken in is regulated by the throttle body, hence why these engine have a mass airflow meter in the intake track, so the PCM knows how much air is in the engine at any given time.

So yes, at wide open throttle, the 6.2 will produce more hp, and burn more fuel that the 5.3 at the same afr, that's another one of those self-evident statements.
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You are missing the point of that post.

The assumption was equal air density (simplified to 1 kg/L). The density will be different at different throttle positions. But between 5.3 and 6.2 at any given throttle position the density won't vary enough to make a difference in fuel flow rate.

 

[Antonm]

What is programmed into the ECM isn't a wild guess. It is based on a known or experimentally verified amount of air flow at any given RPM.

Fuel flow is dependent on air flow.

Absolutely , and airflow is dependent on where the drivers right foot is.

So each engine isn't actually taking in its full displacement worth of airflow unless,,,,the driver has it a wide open throttle.

So, at part throttle (where we actually drive) if the smaller 5.3 has its throttle open further such that's its taking in the same amount of air as the 6.2 is, then both engines will be taking in the same volume or air, and the PCM will therefore inject the same amount of fuel,,, and the same amount of power will be produced ,,,,,shocker.
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[blanchard7684]

This is a continuation of your statement about each engine taking in different quantities of air, (5.3l vs.6.2L) which only the only time that will be true is at wide open throttle.

So lets say the 5.3 was taking in 80% of its max airflow because that's where the drivers foot has the throttle body positioned (5.3 *0.8 = 424),,,now let say a 6.2 was taking in 20% airflow because that's where its drive has the throttle body positioned (6.2*0.2 = 124),,, so now, assuming that we target the same afr, and adjust fuel flowrate via injector pulse width accordingly, which engine is taking in more air and burning more fuel?
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This example doesn't impact the discussion. We are discussing same power level. 80% throttle in 5.3 will not have same power as 6.2 at 20% throttle. One will be using more fuel and for the same engine speed will also have a much lower afr.

Remember that the original quote you took exception to was that the 5.3 and 6.2 can't make same power at safe afr.

You said this wasn't true because both will be using same fuel. I've proven this false.