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View Full Version : General MAF question....


sloLs1
12-17-2005, 05:05 PM
Why is it that on most turbocharged vehicles the Mass air flow sensor is located on the intake tube for the turbo???? Why isn't it located right before the TB like on N/A cars? :confused
sloLs1
12-17-2005, 11:02 PM
???
RedGSX
12-18-2005, 12:57 AM
So one can tell if they small boost leak easier? possibly, because metered air is important as to the GM MAF were you can get away with small leaks a little more cause it's before any air is getting metered. .02cents
sloLs1
12-18-2005, 11:18 AM
So one can tell if they small boost leak easier? possibly, because metered air is important as to the GM MAF were you can get away with small leaks a little more cause it's before any air is getting metered. .02cents


so technically speaking... i could mount the MAF in the intercooler piping before the TB???
indyzmike
12-18-2005, 12:24 PM
I am not a tech but, as air pressure changes, the oxgyen content related to volume also changes.

The ecm does not measure the amount of oxygen entering an engine to determine the correct amount of fuel to mix. It uses the volume of air, and the pressure of the air entering the engine to calculate the amount oxygen entering the engine.

It is much easier to monitor air volume at the relatively constant pressure before the turbo, and calculate oxygen volume using that data, than to monitor air volume at the rapidly changing pressures after the turbo, and have to calculate oxygen volume from that data.

As always, any corrections or additions are welcome.
sloLs1
12-18-2005, 01:16 PM
I am not a tech but, as air pressure changes, the oxgyen content related to volume also changes.

The ecm does not measure the amount of oxygen entering an engine to determine the correct amount of fuel to mix. It uses the volume of air, and the pressure of the air entering the engine to calculate the amount oxygen entering the engine.

It is much easier to monitor air volume at the relatively constant pressure before the turbo, and calculate oxygen volume using that data, than to monitor air volume at the rapidly changing pressures after the turbo, and have to calculate oxygen volume from that data.

As always, any corrections or additions are welcome.

so basically.... it's easier for the ECM to calculate the the correct amount of air entering the engine and then to calculate the correct amount of fuel to inject. now that we got that straight... could you put the MAF in the intercooler piping before the TB?? would it work??? would it run really crappy??? This is just one of those questions that i can not sleep over!!! I am going crazy because of how it works!! maybe i am just a little weird :banana1: !! Thanks for your help!
RedGSX
12-18-2005, 01:42 PM
Dsm's have been doing it for years. It's called MAF Translator, where your taking a GM Maf and a translator and connecting if to the dsm maf connector. Here is the explanation of what it is. Translator (http://www.machv.com/maftranslator.html) and also Jake at topstreet sells these and would help you install it, not sure if they work on an evo ecu. I wouldn't see why not.
sloLs1
12-18-2005, 03:14 PM
Dsm's have been doing it for years. It's called MAF Translator, where your taking a GM Maf and a translator and connecting if to the dsm maf connector. Here is the explanation of what it is. Translator (http://www.machv.com/maftranslator.html) and also Jake at topstreet sells these and would help you install it, not sure if they work on an evo ecu. I wouldn't see why not.

Yes my friend has used it before on his DSM... but i was going to be doing a custom set up on my toyota pickup and needed to know if it were to work... :confused
fly5150
12-18-2005, 07:47 PM
i'd seriously give Jake a call. He Turbo'd his toyota and did a ton of research on what did and didn't work.
sloLs1
12-18-2005, 09:29 PM
i'd seriously give Jake a call. He Turbo'd his toyota and did a ton of research on what did and didn't work.

yes i am going to!!! i will most likely stop by his shop when i come home in 5 days :banana !! but i have ants in my pants!!! it's killing me because it's such a simple issue but yet not a very common problem! Oh well geuss i will wait to talk to the expert!!!
indyzmike
12-19-2005, 12:00 AM
Oh well guess i will wait to talk to the expert!!!

Let us know how it works and good luck! My explaination is wrong because I did not take the wastegate into consideration. Air going through the maf, entering the turbo, but not entering the engine. :confused I would like to know if the map sensor is what tells the ecm the boost pressure. Anyone have a link to a site on how this works?
number1
12-19-2005, 03:12 PM
Of course it will work, I know one of the reasons they put the MAF pre-turbo is because of oil in the intake can destroy a MAF instantly. Figuring that the vehicle has to be around for some time with hard miles put on it and the seals will start to leak. Cost them money.

Pressure changes that are very quick can lead to values that are out of spec and cause problems.
sloLs1
12-19-2005, 03:21 PM
Of course it will work, I know one of the reasons they put the MAF pre-turbo is because of oil in the intake can destroy a MAF instantly. Figuring that the vehicle has to be around for some time with hard miles put on it and the seals will start to leak. Cost them money.

Pressure changes that are very quick can lead to values that are out of spec and cause problems.


Thats what i was thinking... but wasn't sure. But why would people do the conversion on lets say a DSM?? It will allow them to run a BOV but then wouldn't it screw up the MAF like you stated before??? I geuss this is a very controversial topic!! thanks for the input!
SMOKDU
12-19-2005, 04:09 PM
what mass air meter. hehe.

bigstuff 3 baby
fly5150
12-19-2005, 06:00 PM
Mustang...... Thats like the easiest car in the world to mod (bolt parts onto)
Whats the challenge in that. :D
sloLs1
12-19-2005, 06:44 PM
Mustang......
Whats the challenge in that. :D

making them faster than a LS1!!!


:crying i miss my Camaro!
number1
12-20-2005, 10:33 AM
A MAF will allow the use of a vented BOV and the MAF is a more precise way of measuring incoming air than a karman vortex MAS. Just install the BOV before the MAF and you will be fine. If you run too much boost, the reversion pulses in the intake system can effect the MAF measurements, but lingenfelter does it, so it is probably the best way.
nitrous
12-20-2005, 11:48 AM
The MAFT, WOW. That is the oldest gadget in MAF spoofing. If you have ability, you would be much better of changing the MAF tables in your ECM directly.
sloLs1
12-20-2005, 02:21 PM
A MAF will allow the use of a vented BOV and the MAF is a more precise way of measuring incoming air than a karman vortex MAS. Just install the BOV before the MAF and you will be fine. If you run too much boost, the reversion pulses in the intake system can effect the MAF measurements, but lingenfelter does it, so it is probably the best way.

well we will see what happens... but that makes sense. I am only going to be running 10psi max. so i should be fine. thanks for your input!