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This is a discussion on getting new wrx soon have questions within the New Member Hangout forums, part of the Community - Meet other Enthusiasts category; Originally Posted by 11blackSTi Yep. Didn't mean to open up this can or worms...The one I have is designed to ...

  1. #16
    Master Baiter EJ257's Avatar
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    Quote Originally Posted by 11blackSTi
    Yep. Didn't mean to open up this can or worms...The one I have is designed to have the MAF in the same spot and same size plumbing so they say it will run fine. My take on that is that it is designed to work as the stock one is. One might ask me why it is on there if it doesn't improve performance...Well I will respond by saying that my carbon fiber trunk trim cover doesn't improve my performance either, but it still makes me happy when I see it. That being said, IF my intake was causing me problems, wouldn't I have some kind of sign before the engine when caplunk?
    What intake do you have?

    If you didn't have a WBO2, you wouldn't know your car was running leaner than it should (shy of detonation, but you wouldn't know if it was caused by too little fuel or too much timing). Whether you heard/felt the detonation events, it's a crap shoot, but you could go on thinking the car is fine until you get a tank of bad gas and are looking at a $3K+ bill.
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    Quote Originally Posted by EJ257 View Post
    What intake do you have?

    If you didn't have a WBO2, you wouldn't know your car was running leaner than it should (shy of detonation, but you wouldn't know if it was caused by too little fuel or too much timing). Whether you heard/felt the detonation events, it's a crap shoot, but you could go on thinking the car is fine until you get a tank of bad gas and are looking at a $3K+ bill.
    Perrin.

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    Master Baiter EJ257's Avatar
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    Quote Originally Posted by 11blackSTi
    Perrin.
    I just brought this up in another thread...Perrin intake requires 10+% rescaling to the MAF in some cells.
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    Quote Originally Posted by EJ257 View Post
    I just brought this up in another thread...Perrin intake requires 10+% rescaling to the MAF in some cells.
    Ya i did some research on it my self and past users of this CAI ended up having problems.. I think one guy on another Forum did this intake and a down pipe which obviously is even worse but his AF ratio ended up being 16:1.. I always thought Foam filters where never that great either.. Still doing more research on it tho..

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    MAINEiac 11blackSTi's Avatar
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    Quote Originally Posted by EJ257 View Post
    I just brought this up in another thread...Perrin intake requires 10+% rescaling to the MAF in some cells.
    Can I monitor this via AP?

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    Quote Originally Posted by EJ257 View Post
    What intake do you have?

    If you didn't have a WBO2, you wouldn't know your car was running leaner than it should (shy of detonation, but you wouldn't know if it was caused by too little fuel or too much timing). Whether you heard/felt the detonation events, it's a crap shoot, but you could go on thinking the car is fine until you get a tank of bad gas and are looking at a $3K+ bill.

    Sorry, but you need to listen to what Matty is saying here; he's correct. While LTFT are adjusted during CL fueling, you need to obtain the relationship between what the MAF reads (just voltage) and the actual amount of air the intake is bringing into the motor. This relationship is called MAF calibration, and must be accomplished with a Wideband O2 sensor (unless you have the ability to hold CL fueling for 10 seconds at a time in every RPM/load band). If the intake is only bringing in more air, this is not a problem since CL fueling will adjust for this difference. However, typically intakes will change the fluid dynamics of the within the MAF housing. The MAF attempts to obtain the total mass of the air flowing into the motor by determining the heat absorbed off of a metal filament in the MAF housing. Without a proper calibration, the representation of the amount of heat lost by the filament cannot be directly compared to the total airmass being consumed by the motor. Note that this is not a problem with MAP-based airflow calculation.
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    Quote Originally Posted by 11blackSTi View Post
    Can I monitor this via AP?
    Unless you have a Wideband O2 sensor, it is for naught.
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    Quote Originally Posted by 11blackSTi
    Can I monitor this via AP?
    You can do some logging to see how much rescaling you'd need to do in CL fueling. Without a WBO2, you wouldn't be able to scale OL fueling, which as I mentioned earlier, is where the most damage would be done.
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    Quote Originally Posted by EJ257 View Post
    You can do some logging to see how much rescaling you'd need to do in CL fueling. Without a WBO2, you wouldn't be able to scale OL fueling, which as I mentioned earlier, is where the most damage would be done.
    Zax -
    Don't be sorry! I'm glad you guys are giving me your input so I can make sure I don't mess my car up!

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    Wow, that's a ton of info...greatly appreciated guys...looks like installing the Wide band I bought just became my top priority next week.

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    Quote Originally Posted by EJ257 View Post
    What intake do you have?

    If you didn't have a WBO2, you wouldn't know your car was running leaner than it should (shy of detonation, but you wouldn't know if it was caused by too little fuel or too much timing). Whether you heard/felt the detonation events, it's a crap shoot, but you could go on thinking the car is fine until you get a tank of bad gas and are looking at a $3K+ bill.
    What would you define as a "tank of bad gas?"

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    Quote Originally Posted by zax View Post
    Sorry, but you need to listen to what Matty is saying here; he's correct. While LTFT are adjusted during CL fueling, you need to obtain the relationship between what the MAF reads (just voltage) and the actual amount of air the intake is bringing into the motor. This relationship is called MAF calibration, and must be accomplished with a Wideband O2 sensor (unless you have the ability to hold CL fueling for 10 seconds at a time in every RPM/load band). If the intake is only bringing in more air, this is not a problem since CL fueling will adjust for this difference. However, typically intakes will change the fluid dynamics of the within the MAF housing. The MAF attempts to obtain the total mass of the air flowing into the motor by determining the heat absorbed off of a metal filament in the MAF housing. Without a proper calibration, the representation of the amount of heat lost by the filament cannot be directly compared to the total airmass being consumed by the motor. Note that this is not a problem with MAP-based airflow calculation.
    One confusion that I have is how the engine is pulling in more air if the exhaust is exactly the same? Is my exhaust flowing more freely due to the new intake? If not, then isn't the air moving through the whole vehicle at the same rate, thus the air/fuel ratio is not being affected? Only asking these questions because you guys know more about this than me and have seen more/compared more before and after data on only intake upgrades on stock ECU and compared to know that this does indeed change the AFR. Thanks for the info!

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    Quote Originally Posted by 11blackSTi View Post
    One confusion that I have is how the engine is pulling in more air if the exhaust is exactly the same? Is my exhaust flowing more freely due to the new intake? If not, then isn't the air moving through the whole vehicle at the same rate, thus the air/fuel ratio is not being affected? Only asking these questions because you guys know more about this than me and have seen more/compared more before and after data on only intake upgrades on stock ECU and compared to know that this does indeed change the AFR. Thanks for the info!
    I could tell you coming from American cars just like me! Maybe im wrong! But in lets say a Mustang you would be 100% right. And it would even adjust it self to the new AF mixture! But with these Turbo cars even if you dont change the exhaust that new leaner air will change things.. a Turbo is designed to Force air and exhaust gas into the engine and the whole system is tuned and set at specific peramaters from the factory so if you change one like Air you have to adjust the Fuel as well if not it can do damage! there are so many complex things going on in these systems i dont even fully understand it all yet! Ive researched your CAI and from what i found it will make your car run lean. I would at least get an AP to do adjustments and read your peramaters! Like i said im learning too but these aint no American Muscle cars that will adjust by themselves.. Please know that i dont want to see you do Damage to your engine!

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    Quote Originally Posted by Zman13 View Post
    But in lets say a Mustang you would be 100% right. And it would even adjust it self to the new AF mixture!
    Uh, no. All modern cars adjust to the optimum AFR whilst in Closed Loop fueling. Open loop fueling (when the ECU deems the fueling enter open loop) utilizes a preset target AFR at that particular load and RPM that is scaled only by Long Term fuel trims and other atmospheric adjustments. Mustang GTs after 1993 utilize an MAF system to determine the ingested air mass. Many Fox bodies utilized MAF, but a few actually came with Speed Density calculation (MAP sensor, IAT sensor) from factory. This means a modern Mustang GT is just as susceptible to AFR scaling as any other modern CL:OL Fuel Injection system.
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    Quote Originally Posted by zax View Post
    Uh, no. All modern cars adjust to the optimum AFR whilst in Closed Loop fueling. Open loop fueling (when the ECU deems the fueling enter open loop) utilizes a preset target AFR at that particular load and RPM that is scaled only by Long Term fuel trims and other atmospheric adjustments. Mustang GTs after 1993 utilize an MAF system to determine the ingested air mass. Many Fox bodies utilized MAF, but a few actually came with Speed Density calculation (MAP sensor, IAT sensor) from factory. This means a modern Mustang GT is just as susceptible to AFR scaling as any other modern CL:OL Fuel Injection system.
    Ya but they adjust better and up to a wider range! Plus Mustangs and some others come running a little rich from the Factory not lean!

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