Aero Performance Exhaust

I thought cold air makes it adjust to richer.

Not really. In a vehicle with electronic fuel injection, the system monitors the volume and temperature of the air entering the engine's intake system and then adjusts the duration of the fuel injector pulses to try to maintain a ratio of 14.7 parts air to 1 part fuel.

There is no such thing.

The volume of air doesn't change with throttle opening, only the density changes. A vehicle with electronic fuel injection [the system] will monitor either air density (MAP Sensor) or air mass (Mass AirFlow Sensor).

How much air is in a cylinder with a volume of 2 liters at a pressure of

29.9 inches of mercury absolute? How much air is in a cylinder with a volume of 2 liters at a pressure of 11 inches of mercury absolute?

Even at wide open throttle?

Cold air is denser, it contains more oxygen molecules, the injector pulse width is (typically) increased to maintain correct fuel stoichiometry, which is not necessarily "richer."

I was trying to explain in *simple* terms to the OP that the contraption she described was not going to improve her fuel economy. At 1:15 AM, I was tired enough that my description wasn't quite accurate.

No, but in the context of the OP's post inquiring whether a device would improve fuel economy, I'm assuming that the OP has enough brains to figure out that driving with a WOT doesn't do much to improve fuel economy.

Ahh. Not much incentive to sell it.

Probably get a plain old 93-94 Corolla as a second car for the better gas mileage.

Wouldn't it have been easier and simpler to explain that her Corolla has an intake air temperature sensor and that the inlet to her air cleaner housing is already ducted to air outside of the engine compartment?

Do you know the approximate throttle angle where most manufacturers program in extra fuel for acceleration (iows, what *they* consider to be WOT)? It's surprisingly low...

Perhaps

No, care to share the info? My guess is 50% throttle opening.

That's a good guess.

Since you are so current, I'm assuming that you work at a dealer service department. What area or region do you work in?

It has been 15+ years since I worked in the business and so I have some catching up to do and appreciate your "lessons."