MAF Patch

[BOTTLE FED]

I guess I need to install the "MAF Patch" based on what I have read. I have a blown car that is going lean at 12000hz (5200 rpm) because my MAF only reads to 11250.
Where can I find the instructions for this?
Thanks

[Chris@HPTuners]

The MAF Patch is only needed for early E40 ECM's. Go to Operating System parameters, and if the patch is there set it to applied. You must do a write entire to apply the patch to the E40 operating system.

Chris...

[BOTTLE FED]

When I look in HP - OS, it list a 1 bar MAF - enhanced. Is that what they're referring to? It has "Not Available" beside it.
I have a 98 C5, and my MAF table runs out at 11200, but I'm already at 12000 by 5200 rpm
Can I "activate" it, and if not, what other option do I have besides SD? I would like to keep the MAF if possible

[Google]

Run a 4" MAF tube

[BOTTLE FED]

Run a 4" MAF tube

Not familiar with that; My charge pipe is 4", but not sure how that would give me any more range (Not disagreeing at all, just haven't heard of it before.)

[Chris@HPTuners]

When I look in HP - OS, it list a 1 bar MAF - enhanced. Is that what they're referring to? It has "Not Available" beside it.
I have a 98 C5, and my MAF table runs out at 11200, but I'm already at 12000 by 5200 rpm
Can I "activate" it, and if not, what other option do I have besides SD? I would like to keep the MAF if possible

sorry i thought you were talking about the MAF patch for E40.

Most people would run SD.

[Exidous]

If you stick to MAF/SD then get a bigger bore MAF tube. I run mine through a 4" MAF housing and hit a max of 8500Hz. Granted I am not FI but it may give you the overhead you need.

[Google]

Not familiar with that; My charge pipe is 4", but not sure how that would give me any more range (Not disagreeing at all, just haven't heard of it before.)

MAF heats up, as air goes through the maf it cools it. The more it's cooled, the computer see's it is getting more air. So having a bigger maf tube will keep it hot and (Trick) the computer into thinking its less air.

[69lt1bird]

MAF heats up, as air goes through the maf it cools it. The more it's cooled, the computer see's it is getting more air. So having a bigger maf tube will keep it hot and (Trick) the computer into thinking its less air.

If he has a 85mm truck or Z06 MAF that does not work. A LS3 card style will lower the frequency put that still not fix his issue. 2 Bar OS and 2 Bar MAP is the only right way to do it.

[muayyadf1]

If he has a 85mm truck or Z06 MAF that does not work. A LS3 card style will lower the frequency put that still not fix his issue. 2 Bar OS and 2 Bar MAP is the only right way to do it.

What will 2 Bar OS and 2 Bar MAP do in this case?

[Frost]

What will 2 Bar OS and 2 Bar MAP do in this case?

they eliminate the MAF for SD.

[BOTTLE FED]

How difficult is a SD tune to do in the WOT area?
Do you have ANY drivability issues when there is a big chage in the temp?

[transamdroptp08]

SD tuning is just tuning your VE table.

[BOTTLE FED]

SD tuning is just tuning your VE table.

Right, but how do you get the upper ranges done (on a blown motor) without damaging something? Like you do with the MAF?

Does it present any issues with major changes in the weather?

[transamdroptp08]

You can go thru the VE table and set everything to a rich state and then lean it out as you make logs of pulls in boost. You usually want 2-3 pulls in one gear from 2g RPM's to redline WOT.

As far as drastic changes with weather you should be fine if you are running a 2bar SD CL (correct me if I am wrong). The problem comes in when you run full time OL.

I have a 2bar SD tune and it runs fine in different weather.

[smithers]

MAF heats up, as air goes through the maf it cools it. The more it's cooled, the computer see's it is getting more air. So having a bigger maf tube will keep it hot and (Trick) the computer into thinking its less air.

lol, Im sorry, but I have to say, that is a horrible answer and quite wrong.
I know this is off topic, but going to a larger diameter tube actually SLOWS airflow, thus registering a lower frequency, giving you more range if you max out the MAF frequency.
A few go with the Slot style, LS7 Hitachi Sensor, the larger the tube (4"+) the slower the velocity of the air. More air in the engine, slower speed, lower frequency, within range.

The other factor is the ECM being the limitation, which properly, requires going SD with the appropriate Baro Sensor upgrade as many state.

[Google]

lol, Im sorry, but I have to say, that is a horrible answer and quite wrong.
I know this is off topic, but going to a larger diameter tube actually SLOWS airflow, thus registering a lower frequency, giving you more range if you max out the MAF frequency.
A few go with the Slot style, LS7 Hitachi Sensor, the larger the tube (4"+) the slower the velocity of the air. More air in the engine, slower speed, lower frequency, within range.

The other factor is the ECM being the limitation, which properly, requires going SD with the appropriate Baro Sensor upgrade as many state.

thats what I said.. been drinking? But I do not think slower airflow or slower velocity = more airflow.

[Google]

I googled it... no pun.. ok a little pun.

http://en.wikipedia.org/wiki/Mass_flow_sensor

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 General Motors division (GM) was the first car company to use the hot wire sensor.[citation needed] 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

Cold Wire MAF

The GM LS engine series (as well as others) use a "coldwire" MAF system (produced by AC Delco) where the inductance of a tiny sensor changes with the air mass flow over that sensor. The sensor is part of an oscillator circuit whose oscillation frequency changes with sensor inductance; hence the frequency is related to the amount of air (cubic feet per minute) passing over the unit. This oscillating electrical signal is then fed to the car's ECU. These MAF units (such as the one pictured) have 3 pins, denoted +, - and F. F carries the square-wave frequency between - and F. They are powered by +5 VDC from the ECU's regulated power supply.
The mesh on the MAF is used to smooth out airflow to ensure the sensors have the best chance of a steady reading. It is not used for measuring the air flow per se. In situations where owners use oiled-gauze air filters, it is possible for excess oil to coat the MAF sensor and skew its readings. Indeed, General Motors has issued a Technical Service Bulletin, indicating problems from rough idle all the way to possible transmission damage resulting from the contaminated sensors. To clean the delicate MAF sensor components, a specific MAF or Electronics Cleaner should be used, not carburetor or brake cleaner. These are alcohol or CFC-based solvents, rather than the harsh petroleum distillates used in the other cleaners... The sensors should be gently sprayed from a careful distance to avoid physically damaging them. Manufacturers claim that a simple but extremely reliable test to ensure correct functionality is to tap the unit with the back of a screwdriver while the car is running, and if this causes any changes in the output frequency then the unit should be discarded and an OEM replacement installed.