The Smokey 15% MPG increase question?

[Painless]

We would need to know more about the zx2's electronics to fathom this further.

My truck does not have MAF, it uses a MAP and IAT sensor. Upon startup, before the engine turns over, the MAP is used to determine air pressure at equalisation with the outside air. When the engine is running, the intake air temp and manifold pressure are used to determine air / fuel requirements. Temp and pressure within a known volume (engine CC) should allow the computation.

I don't see how air restriction will allow fooling the ECU to think that air pressure is lower, surely such a determination woud need to be made before engine start when inside and outside air pressure is equal.

Its also possible that the restriction is simply operating like a block of wood under the gas pedal, by only allowing so much throttle depression.

All theory, of course.

[BoyntonStu]

Stu.. may i suggest an experiment if one is possible..

(i'll start off with this disclaimer.. I don't know for sure if it's possible to test this theory, so don't flame me for a brainstorm HAHA)

is air FLOW the same or relative to DENSITY ??

on your ZX2 it's an 'older' designed car without all the over engineered electronics (such as Russ' cursed truck) you never did tell us what your 'other car' is..

What i propose is an experiment (Again, if it's possible) where we consider (or prove) the relation to density and flow.

My belief is that you have restricted the FLOW on your ZX2 and the computer has just assumed that your air filter is clogged up and somehow has allowed MPG increase (that's 100% confirmed).

This flow reduction (again, IMO) isn't synonimous with less density.

The vehicle's MAP sensor would determine density.. (hence absolute pressure) and the MAF sensor determines air flow.

I believe the ZX2's were 'pre-MAF' .. in Ford's time, they weren't very keen on MAF sensors.. however the O2 sensors could compensate for the reduced FLOW by detecting the extra fuel (loss of 'air') and adjusting accordingly.. I believe your specific situation is luck (with the computer)

On a newer vehicle, they've incorporated MAF sensors to 'see' how much air is flowing to more 'efficiently' adjust the A/F trims, or at the least, light a CEL when the dang air filter gets clogged up.. (hence the light when you restricted the air flow on your other car)...

what i propose is an experiment (if it's possible) to determine the relationship between air flow and air density.

don't ask me how we'd try it, because, as i said before, i'm just a brainstormer LOL...

just my .02
mike

Mike,

AFAIK The ZX2 is equipped with all the modern ECU bells and whistles.

The other car is 2 years newer and I believe that I might have restricted the air too much when the light went on.

When you drive a car from sea level to the mile high city of Denver, what happens?

Put another way, when an athlete trained at sea level competes in Denver, what happens?

The air in Denver is thinner and the air pressure is lower.

Boiling Point, temperature at which the vapor pressure of a liquid slightly exceeds the pressure of the atmosphere above the liquid. At temperatures below the boiling point (b.p.), evaporation takes place only from the surface of the liquid; during boiling, vapor forms within the body of the liquid; and as the vapor bubbles rise through the liquid, they cause the turbulence and seething associated with boiling. If the liquid is a single substance or an azeotropic solution (a mixture that has a constant b.p.), it will continue to boil as heat is added without any rise in temperature; that is, boiling occurs at constant temperature regardless of the amount of heat applied to the liquid.

When the pressure on a liquid is increased, the b.p. goes up. Water at 1 atmosphere pressure (760 torr, or about 14.7 lb/sq in) boils at 100° C (212° F), but when the pressure is 218 atmospheres (165,000 torr, or 3200 lb/sq in), the b.p. reaches its maximum, 374° C (705° F). Above this temperature (the critical temperature of water), liquid water is identical to saturated steam. See Pressure.

If the pressure on a liquid is reduced, the b.p. is lowered. At higher elevations, where air pressure is less, water boils below 100° C. In Denver, Colorado, which is 1.6 km (1 mi) above sea level, the b.p. of water averages 94° C (201° F). When the pressure on a sample of water falls to 4.55 torr (0.088 lb/sq in), boiling occurs at 0° C (32° F), which is the normal freezing point.

Thinner air affects the MAP sensor.

Thinner air does not cool the heated sensing element as much as thicker sea level air would.

The ECU understands that if it supplies the same amount of gas as it would at sea level, the 14.7:1 ratio would become richer; say 14:1.

To compensate for the thinner air, the ECU cuts back the gas and the engine is happy again at 14.7:1 but with less power.

My ZX2 does not seem affected with the reduced power until it reaches 70 MPH. It will go faster, but with less acceleration.

My solution: Use a butterfly valve immediately after the air filter that will open automatically when the accelerator is pressed beyond a set point.

I bought a door lock solenoid and when the throttle cable reaches a certain position, a micro switch will fire the solenoid and open the butterfly.

When disengaged, the butterfly will spring back to its "closed" position.

The "Closed" position is somewhere between 25% and 50% restriction.

The "closed" position will be the point where the engine smoothly idles and where the best MPG is achieved.

I am working on it.


I hope that this explains it.


BoyntonStu

[daddymikey1975]

Stu.. it explains differences that air pressure has on boiling point of water. The real explanation I'm searching for is how altering the FLOW of air equates to 'simulating' an altered density of air. how is flow related to density??

i understand how air is thinner as altitude increases, etc. i'm just not sure how to wrap my mind around restricting flow = less density (as far as the computer knows)

I DID find this useful though.. I went to yahoo search and typed "how does a MAP sensor work" and ran across this on a page:

Function
The MAP sensor monitors pressure changes (vacuum) in the manifold. As the pressure changes, the voltage changes put out by the MAP sensor changes. The higher the vacuum or pressure is in the manifold, the lower the voltage put out by the MAP sensor. The voltage reading goes to the PCM, to tell the computer to advance or retard the ignition timing as needed.
Types
There are two types of MAP sensors. The typical MAP sensor senses pressure (vacuum) in the manifold. The second type of MAP sensor helps the PCM estimate air flow in addition to pressure changes in the manifold. This type of MAP sensor is found on vehicles with speed density fuel injection.

Seems as though you have the second type on your zx2

what type of car is the 'other car?'

and the excort had a much more basic electronics setup than Russ' truck. (for example)

it has everything needed to be 'emmisions compliant' and obd2 compliant, etc.. but there's DEFINITELY not much trickery involved like what russ ran into to make the computer (in your car) act how you want it to act.

Ford has always subscribed to the KISS philosophy with the electronics in their cars (i can attest to this first hand)

mike

[BoyntonStu]

Stu.. it explains differences that air pressure has on boiling point of water. The real explanation I'm searching for is how altering the FLOW of air equates to 'simulating' an altered density of air. how is flow related to density??

i understand how air is thinner as altitude increases, etc. i'm just not sure how to wrap my mind around restricting flow = less density (as far as the computer knows)

I DID find this useful though.. I went to yahoo search and typed "how does a MAP sensor work" and ran across this on a page:

Function
The MAP sensor monitors pressure changes (vacuum) in the manifold. As the pressure changes, the voltage changes put out by the MAP sensor changes. The higher the vacuum or pressure is in the manifold, the lower the voltage put out by the MAP sensor. The voltage reading goes to the PCM, to tell the computer to advance or retard the ignition timing as needed.
Types
There are two types of MAP sensors. The typical MAP sensor senses pressure (vacuum) in the manifold. The second type of MAP sensor helps the PCM estimate air flow in addition to pressure changes in the manifold. This type of MAP sensor is found on vehicles with speed density fuel injection.

Seems as though you have the second type on your zx2

what type of car is the 'other car?'

and the excort had a much more basic electronics setup than Russ' truck. (for example)

it has everything needed to be 'emmisions compliant' and obd2 compliant, etc.. but there's DEFINITELY not much trickery involved like what russ ran into to make the computer (in your car) act how you want it to act.

Ford has always subscribed to the KISS philosophy with the electronics in their cars (i can attest to this first hand)

mike

Mike,

Hot wire sensor (MAF)

A hot wire mass airflow sensor determines the mass of air flowing into the engine’s air intake system. The theory of operation of the hot wire mass airflow sensor is similar to that of the hot wire anemometer (which determines air velocity). The Buick motor division (GM) was the first car company to use the hot wire sensor. This is achieved by heating a wire with an electric current that is suspended in the engine’s air stream, not unlike a toaster wire. The wire's electrical resistance increases as the wire’s temperature increases, which limits electrical current flowing through the circuit. When air flows past the wire, the wire cools, decreasing its resistance, which in turn allows more current to flow through the circuit. As more current flows, the wire’s temperature increases until the resistance reaches equilibrium again. The amount of current required to maintain the wire’s temperature is directly proportional to the mass of air flowing past the wire. The integrated electronic circuit converts the measurement of current into a voltage signal which is sent to the ECU.

If air density increases due to pressure increase or temperature drop, but the air volume remains constant, the denser air will remove more heat from the wire indicating a higher mass airflow

=================

If the air is restricted, the cooling will be less.

The MAF is tricked into thinking that the air density is less.

The questions is whether or not our cars use a heated wire MAF?

I believe that the ZX2 uses a heated wire. (I cannot see a paddle)

I may be wrong.

Worth a 10 cent try?

BoyntonStu

[cully]

check out here http://en.wikipedia.org/wiki/Mass_flow_sensor

you also get a cold wire sensor The sensor is part of an oscillator circuit whose oscillation frequency changes with sensor inductance

[BoyntonStu]

check out here http://en.wikipedia.org/wiki/Mass_flow_sensor

you also get a cold wire sensor The sensor is part of an oscillator circuit whose oscillation frequency changes with sensor inductance

"you also get a cold wire sensor The sensor is part of an oscillator circuit whose oscillation frequency changes with sensor inductance"

How do we utilize this information?

BoyntonStu

[daddymikey1975]

"you also get a cold wire sensor The sensor is part of an oscillator circuit whose oscillation frequency changes with sensor inductance"

How do we utilize this information?

BoyntonStu

a "for sure" way to tell which type of sensor (if any) your ZX2 has is to post a photo ( i can identify one visully) OR look immediately behind your air cleaner. There shoud be an 'insert' in the plenum that's got a bit of 'heft' to it and a cloth mesh screen on the intake side. There should be approx. 4 - 6 wires running across and up and down. My perception is this is the hot wire type. I'm almost willing to bet you a nice tall one that your ZX2 doesn't have the MAF sensor. I believe your car has the second type of MAP sensor that's described in my earlier post.

to directly answer your question about the oscillation type MAF.. all we'd need is a high inductance coupled circuit (that can 'see') the oscillations.. perhaps on an Oscope even... we watch the waveforms as we drive around to gather data, then we can mimic what we would like the data to be sent to the computer (most likely with a 555 timer circuit or some thing similar)

the first step though, is to verify whether or not your escort even has a MAF sensor or not...

P.S. your description of flow vs. density was lacking, HOWEVER....what you DID describe does make sense that by reducing the FLOW it will in fact fool the MAF sensor. I still don't believe that by merely restricting the flow on a car without a MAF sensor that it'll fool the car into believing it's in Denver. (although i've been proven wrong before and i'm honestly not trying to get into a debate, just searching for the magical 'why' that my 6 yr old keeps pestering me with from time to time HAHA)

i hope this helps
mike

[crewdog]

Mike,

Hot wire sensor (MAF)

A hot wire mass airflow sensor determines the mass of air flowing into the engine’s air intake system. The theory of operation of the hot wire mass airflow sensor is similar to that of the hot wire anemometer (which determines air velocity). The Buick motor division (GM) was the first car company to use the hot wire sensor. This is achieved by heating a wire with an electric current that is suspended in the engine’s air stream, not unlike a toaster wire. The wire's electrical resistance increases as the wire’s temperature increases, which limits electrical current flowing through the circuit. When air flows past the wire, the wire cools, decreasing its resistance, which in turn allows more current to flow through the circuit. As more current flows, the wire’s temperature increases until the resistance reaches equilibrium again. The amount of current required to maintain the wire’s temperature is directly proportional to the mass of air flowing past the wire. The integrated electronic circuit converts the measurement of current into a voltage signal which is sent to the ECU.

If air density increases due to pressure increase or temperature drop, but the air volume remains constant, the denser air will remove more heat from the wire indicating a higher mass airflow

=================

If the air is restricted, the cooling will be less.

The MAF is tricked into thinking that the air density is less.

The questions is whether or not our cars use a heated wire MAF?

I believe that the ZX2 uses a heated wire. (I cannot see a paddle)

I may be wrong.

Worth a 10 cent try?

BoyntonStu

Ford does use the hot wire sensor. I have over 30 years of working on Fords.

crewdog

[daddymikey1975]

Mike,


If the air is restricted, the cooling will be less.

This is absolutely true

The MAF is tricked into thinking that the air density is less.

The MAP sensor is usually the one that's responsible for 'comparing' absolute pressure (density?)



BoyntonStu

the MAF doesn't care what the density of the air is. The only thing the MAF cares about is how much air is flowing into the engine. Doesn't matter if it's denver altitude or New Orleans.

All you've done (and it DOES work for you) is reduced the air going into the engine. The computer notices this and doesn't want to flood the motor by sending in the 'normal' amount of fuel for the 14.7:1 and thinks your air filter is all clogged up - as a result you're getting better MPG.

You still haven't 'fooled' the computer into thinking that you're in Denver

I got this from Wikipedia :

A manifold absolute pressure sensor (MAP) is one of the sensors used in an internal combustion engine's electronic control system. Engines that use a MAP sensor are typically fuel injected. The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine's electronic control unit (ECU). This is necessary to calculate air density and determine the engine's air mass flow rate, which in turn is used to calculate the appropriate fuel flow. (See stoichiometry.)

(again, if I'm wrong, i'm wrong. But I believe Crewdog can attest to my claims here. I also have had my fair share of hitting my head under the hood of all types of cars for the last 15 years )

mike

[BoyntonStu]

the MAF doesn't care what the density of the air is. The only thing the MAF cares about is how much air is flowing into the engine. Doesn't matter if it's denver altitude or New Orleans.

All you've done (and it DOES work for you) is reduced the air going into the engine. The computer notices this and doesn't want to flood the motor by sending in the 'normal' amount of fuel for the 14.7:1 and thinks your air filter is all clogged up - as a result you're getting better MPG.

You still haven't 'fooled' the computer into thinking that you're in Denver

I got this from Wikipedia :



(again, if I'm wrong, i'm wrong. But I believe Crewdog can attest to my claims here. I also have had my fair share of hitting my head under the hood of all types of cars for the last 15 years )

mike

again, if I'm wrong, i'm wrong. Yes.

"the MAF doesn't care what the density of the air is. The only thing the MAF cares about is how much air is flowing into the engine."

Density = how much.

For example , consider these made up figures:

1 Liter of air with 500,000 molecules. Denver

1 Liter of air with 1,000,000 molecules. Sea Level

Same volume, different densities.

Different cooling capabilities.


BoyntonStu