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Discussion Starter #1
I recently purchased and install a Cobb Tuning SF intake... after wards i heard that it needs to be tuned with this intake using the Accessport... Is it bad to run my car without the tune?

Please help, i need to fix this problem ASAP if it turn out it is a problem
Thank you!
 

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The Cobb SF intake is one of the better ones out there. They claim it requires no extra tuning but only a wdeband gauge would be able to confirm that.
 

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Take it off until you can tune for it. Problem solved.
 

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Take it off until you can tune for it. Problem solved.
This ^

It's definitely a great intake, I absolutely love mine. Just remove it until you can get the car tuned. Then, get it tuned and have the intake put on at the same time.
 

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Discussion Starter #6
I just ordered the Cobb AP so it will be coming shortly... in the mean time will it be bad to leave the intake in for ~5 days or so until the intake comes? Or should I spend the time to install the factory airbox again and then once the chip comes reinstall the Cobb intake
 

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I'm sure you know the old saying "better safe than sorry".

I'd imagine that it would be ok as long as you don't drive it too much or too "spiritedly". I'd try to stay out of boost if you do drive it.
 

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Captain James of the SS Impreza has gone down with
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I'm sure you know the old saying "better safe than sorry".

I'd imagine that it would be ok as long as you don't drive it too much or too "spiritedly". I'd try to stay out of boost if you do drive it.
Yes.

I just ordered the Cobb AP so it will be coming shortly... in the mean time will it be bad to leave the intake in for ~5 days or so until the intake comes? Or should I spend the time to install the factory airbox again and then once the chip comes reinstall the Cobb intake
The reason that people say that the cars need a tune after an intake is because the intakes are larger in diameter than the stock airbox. This means that more air is flowing through your intake and it will throw off your MAF and cause your car to run super lean because the ECU doesn't correct for the larger amount of air coming through. That is where the danger is. However, the Cobb claims to be the same diameter as stock so you shouldn't have to worry about it. But to be on the safe side, don't romp on it.
 

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Discussion Starter #9
I don't have a garage unless I go to my buddies house, I Will be driving about 200 miles this weekend, because it is cold out and I lack a garage I would rather not remove it unless nessacary. If I baby the car will it be okay. Ivr considered all posts but I want whats easiest and best for my car. Right now
I'm leaning toward removing it until i receive the access port
 

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Yes.



The reason that people say that the cars need a tune after an intake is because the intakes are larger in diameter than the stock airbox. This means that more air is flowing through your intake and it will throw off your MAF and cause your car to run super lean because the ECU doesn't correct for the larger amount of air coming through. That is where the danger is. However, the Cobb claims to be the same diameter as stock so you shouldn't have to worry about it. But to be on the safe side, don't romp on it.

you will run lean homeboy. Remove it!
 

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Good man :tumbup:
 

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I had to register just to reply to this thread.

There seems to be some mis-information or mis-understanding on how a MAF works. More air coming into the intake and passing through the MAF is not going to make the car run lean. The ECU receives a voltage reading based on the amount of air the MAF sensor is detecting and adjusts fuel accordingly. This is the benefit of MAF and how newer cars obtain better MPG and drive-ability. The ECU takes the voltage reading and does some other calculations based on the 'tube diameter' that the MAF resides in. That is why if the intake tube is larger, a tune is required. The ECU needs to be told the new diameter so the fuel calculations are done correctly. If (and I don't know this for certain) the COBB intake uses the same diameter intake tube as factory, a tune is not required. The ECU will take advantage of the extra airflow as much as it can adjusting fuel accordingly.

To clarify, if the intake tube is larger and the ECU isn't reprogrammed, then the ECU doesn't have a proper measurement of the amount of air entering the engine and a lean condition can occur.

I hope this makes sense and clears up any confusion.
 

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If (and I don't know this for certain) the COBB intake uses the same diameter intake tube as factory, a tune is not required. The ECU will take advantage of the extra airflow as much as it can adjusting fuel accordingly.

To clarify, if the intake tube is larger and the ECU isn't reprogrammed, then the ECU doesn't have a proper measurement of the amount of air entering the engine and a lean condition can occur.

I hope this makes sense and clears up any confusion.
It isn't only Intake tube size, it's also the orientation of the MAF within the intake that can skew readings. So while you are correct, there are more variables than just diameter
 

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It isn't only Intake tube size, it's also the orientation of the MAF within the intake that can skew readings. So while you are correct, there are more variables than just diameter
I can see what you're saying and I've not seen the COBB intake in person. However, it would be assumed that the orientation of the MAF sensor in the intake tube should be a similar orientation as it would be in the stock intake tube. The orientation would have to be severely different and therefore likely no where near operating efficiency to impact A/F ratio's. However, I'm new to subarus and exceptions always exist.
 

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I can see what you're saying and I've not seen the COBB intake in person. However, it would be assumed that the orientation of the MAF sensor in the intake tube should be a similar orientation as it would be in the stock intake tube. The orientation would have to be severely different and therefore likely no where near operating efficiency to impact A/F ratio's. However, I'm new to subarus and exceptions always exist.
Don't assume that, there are a lot of intakes (Injen for example) that cause so much turbulance at the MAF that they are extremely difficult to tune for. At a bare minimum, I would datalog if I chose not to tune for an intake, just to be sure everything is Okay.
 

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It isn't only Intake tube size, it's also the orientation of the MAF within the intake that can skew readings. So while you are correct, there are more variables than just diameter
What do you mean by "orientation?" The MAF is directional and it's not going to matter where I put it as long as it gets air flowing across it in the proper direction and is far enough behind the filter to eliminate turbulance.
 

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I had to register just to reply to this thread.

There seems to be some mis-information or mis-understanding on how a MAF works. More air coming into the intake and passing through the MAF is not going to make the car run lean. The ECU receives a voltage reading based on the amount of air the MAF sensor is detecting and adjusts fuel accordingly. This is the benefit of MAF and how newer cars obtain better MPG and drive-ability. The ECU takes the voltage reading and does some other calculations based on the 'tube diameter' that the MAF resides in. That is why if the intake tube is larger, a tune is required. The ECU needs to be told the new diameter so the fuel calculations are done correctly. If (and I don't know this for certain) the COBB intake uses the same diameter intake tube as factory, a tune is not required. The ECU will take advantage of the extra airflow as much as it can adjusting fuel accordingly.

To clarify, if the intake tube is larger and the ECU isn't reprogrammed, then the ECU doesn't have a proper measurement of the amount of air entering the engine and a lean condition can occur.

I hope this makes sense and clears up any confusion.
So you had to register to give bad advice? Interesting. OP, if you're going to change the intake on your car, tune for it.

"Our system utilizes several unique features in an effort to maintain optimal flow for performance while minimizing turbulence that can cause engine management problems. From a custom conical cloth air-filter element, we use a CFD-designed velocity stack leading to an unique air flow straightener grid. This straightener grid is specifically designed to smooth the incoming air flow as it passes the Mass Air Flow sensor for precise readings. This eliminates the "dead spots" experienced by other aftermarket intakes due to turbulence. NO other aftermarket Subaru intake system utilizes these critical design elements."
Source: http://cobbtuning.com/products/?id=5886

Hardware Requirements:​
Stage2 + SF - Otherwise stock vehicle with turboback exhaust with high-flow catalyst and COBB Tuning SF Cold Air Intake System. The addition of any other hardware may make the vehicle perform poorly. This is NOT a generic cold air intake calibration; this mapping is specifically adjusted to the COBB Tuning SF CAI.

 

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What do you mean by "orientation?" The MAF is directional and it's not going to matter where I put it as long as it gets air flowing across it in the proper direction and is far enough behind the filter to eliminate turbulance.
It absolutely does matter where you put it. It has to be placed where it won't see turbulent air. If it's placed too near the filter or near a bend in the tubing, it could cause problems. Would you consider that a fair statement?
 
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