Running too lean
#32
Registered User
iTrader: (9)
Sam I know this is a pretty late reply, but I just got my car tuned the other day. My mods are; FI test pipes, FI catback w/ new x-pipe, and g3 intakes. My baseline tune A/F ratio was 13.33 (which isn't hazardous but somewhat lean nonetheless). It put down 313whp at 260tq on my baseline, after the tune, it made 331whp and 268tq at 13.03 A/F ratio. The tuner stated this is still a relatively safe range as optimum torque / horsepower can a lot of times be found around 13:1 a/f ratio (from mulitple sources). This tune is perfect in cold weather because once the springtime / summer hits the A/F will drop into the 12s and not be too rich.
All in all I made 17whp and 8wtq (I'm happy!) on my tune.
All in all I made 17whp and 8wtq (I'm happy!) on my tune.
#34
Registered User
Sam I know this is a pretty late reply, but I just got my car tuned the other day. My mods are; FI test pipes, FI catback w/ new x-pipe, and g3 intakes. My baseline tune A/F ratio was 13.33 (which isn't hazardous but somewhat lean nonetheless). It put down 313whp at 260tq on my baseline, after the tune, it made 331whp and 268tq at 13.03 A/F ratio. The tuner stated this is still a relatively safe range as optimum torque / horsepower can a lot of times be found around 13:1 a/f ratio (from mulitple sources). This tune is perfect in cold weather because once the springtime / summer hits the A/F will drop into the 12s and not be too rich.
All in all I made 17whp and 8wtq (I'm happy!) on my tune.
All in all I made 17whp and 8wtq (I'm happy!) on my tune.
Great numbers! Any dyno sheets?
Thanks for the information. This is pretty helpful for some of us
#36
Administrator
Thread Starter
So we're back to square one now, what on earth are the MAF sensors reading? Which property of air flowing in is it measuring?
#37
Administrator
Thread Starter
Sam I know this is a pretty late reply, but I just got my car tuned the other day. My mods are; FI test pipes, FI catback w/ new x-pipe, and g3 intakes. My baseline tune A/F ratio was 13.33 (which isn't hazardous but somewhat lean nonetheless). It put down 313whp at 260tq on my baseline, after the tune, it made 331whp and 268tq at 13.03 A/F ratio. The tuner stated this is still a relatively safe range as optimum torque / horsepower can a lot of times be found around 13:1 a/f ratio (from mulitple sources). This tune is perfect in cold weather because once the springtime / summer hits the A/F will drop into the 12s and not be too rich.
All in all I made 17whp and 8wtq (I'm happy!) on my tune.
All in all I made 17whp and 8wtq (I'm happy!) on my tune.
#38
Registered User
Join Date: Aug 2009
Location: Delray Beach, FL
Posts: 170
Likes: 0
Received 0 Likes
on
0 Posts
Stupid question but, the warmer more humid climate makes the cars run more rich correct?
I have noticed when the weather here changes (slightly) the car runs better and my MPG increases by 2-3mpg.
I have noticed when the weather here changes (slightly) the car runs better and my MPG increases by 2-3mpg.
#39
Registered User
iTrader: (1)
MAF is not affected by the density of the air. The IAT feeds the ECU data which compensates for density.
#41
Administrator
Thread Starter
The MAF records the amount of air that flows past it. (It technically reads mass). This is based on a constant, which is the flow rate of the intake tube (pre-measured based on factory filters, factory intake tube, etc.). When you put in different filters or an aftermarket intake, this constant changes, which is what throws things off. E.g. a bigger diameter tube can flow more than a smaller one, but the MAF doesn't know that the tube diameter changed.
MAF is not affected by the density of the air. The IAT feeds the ECU data which compensates for density.
#44
Administrator
Thread Starter
hahaha cvt I'd need to wait around a month to get tuned coz the tuner's schedule is "full"
What sucks even more is that getting chipped means fooling the stock ECU which runs a complicated closed loop, which isn't going to happen because the ECU will be trying to override the chip and adjust back to OEM AF
See what I mean.. I need to get into the stupid ECU and play with the parameters in there rather than get a piggy back chip on outside to mess with signals coming out of the ECU
What sucks even more is that getting chipped means fooling the stock ECU which runs a complicated closed loop, which isn't going to happen because the ECU will be trying to override the chip and adjust back to OEM AF
See what I mean.. I need to get into the stupid ECU and play with the parameters in there rather than get a piggy back chip on outside to mess with signals coming out of the ECU
#45
Administrator
Thread Starter
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). This is achieved by heating a wire with an electric current that is suspended in the engine’s air stream, like 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. Unlike the vane meter's paddle sensing element, the hot wire responds directly to air density. This sensor's capabilities are well suited to support the gasoline combustion process which fundamentally responds to air mass, not air volume. (See stoichiometry.)
Some of the benefits of a hot-wire MAF compared to the older style vane meter are:
responds very quickly to changes in air flow
low airflow restriction
smaller overall package
less sensitive to mounting location and orientation
no moving parts improve its durability
less expensive
separate temperature and pressure sensors are not required (to determine air mass)
There are some drawbacks:
dirt and oil can contaminate the hot-wire deteriorating its accuracy
installation requires a laminar flow across the hot-wire
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. Unlike the vane meter's paddle sensing element, the hot wire responds directly to air density. This sensor's capabilities are well suited to support the gasoline combustion process which fundamentally responds to air mass, not air volume. (See stoichiometry.)
Some of the benefits of a hot-wire MAF compared to the older style vane meter are:
responds very quickly to changes in air flow
low airflow restriction
smaller overall package
less sensitive to mounting location and orientation
no moving parts improve its durability
less expensive
separate temperature and pressure sensors are not required (to determine air mass)
There are some drawbacks:
dirt and oil can contaminate the hot-wire deteriorating its accuracy
installation requires a laminar flow across the hot-wire
The Mass Air Flow (MAF) sensor senses the amount of incoming air (Volume) into the engine. This sensor does not regulate the incoming air, this is done by the engine throttle plates.
The HOT WIRE MAF sensor is a fully electronic unit. It senses the amount of air flow into the engine by measuring the amount of current needed to maintain a constant temperature through a very thin (70 micrometers) platinum hot wire. Hence the name hot wire MAF sensor. It also measures air by weight, since it takes into consideration the air temperature as well.
This sensor works as follows. As the air enters the intake manifold through the hot wire MAF sensor it cools down the platinum wire, which is heated at a very precise temperature. When the MAF circuitry senses the platinum wire cooling down it increases the amount of current flow through the hot wire trying to maintain a specific temperature. This varying current flow is then converted to a voltage output signal by the MAF electronic circuitry and is used as an air flow indicator by the ECM. Hot wire MAF sensors have a signal that is directly proportional to air flow. So as air flow increases so does its voltage signal output.
The HOT WIRE MAF sensor is a fully electronic unit. It senses the amount of air flow into the engine by measuring the amount of current needed to maintain a constant temperature through a very thin (70 micrometers) platinum hot wire. Hence the name hot wire MAF sensor. It also measures air by weight, since it takes into consideration the air temperature as well.
This sensor works as follows. As the air enters the intake manifold through the hot wire MAF sensor it cools down the platinum wire, which is heated at a very precise temperature. When the MAF circuitry senses the platinum wire cooling down it increases the amount of current flow through the hot wire trying to maintain a specific temperature. This varying current flow is then converted to a voltage output signal by the MAF electronic circuitry and is used as an air flow indicator by the ECM. Hot wire MAF sensors have a signal that is directly proportional to air flow. So as air flow increases so does its voltage signal output.