CAI question ?
10-25-2006, 02:42 AM
#1
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CAI question ?
Just ordered the Granatelli CAI w/ calibrated MAF (410040-P) kit. With only 1K miles on my 2006GT, and lots of factory warranty left, my objective is to go with a no-tune CAI (to avoid any Dealership warranty hassles). Now the question: Without any re-tuning, won't the air/fuel ratio lean out? (leaner-than-ideal 14:1 air/fuel ratio)? I have heard that just replacing air filter ONLY to a higher flow assembly, the air/fuel ratio leans out at an alarming rate. If this is true, how does this Granatelli CAI (with no tune) deal with this lean fuel condition? Thx
10-25-2006, 03:48 AM
#3
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RE: CAI question ?
That's cool... I thought the calibrated MAF sensor was just working with the ECM to prevent a CEL throw. With more air flowing through the TB, I would think that the air/fuel mix would be leaner... are you saying this calibrated MAF also works with the ECM to kickup the fuel mix (even slightly) to accomodate the increased airflow? If not, I was struggling with how the air/fuel ratio stays the same as the stock intake?
10-25-2006, 07:59 AM
#4
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RE: CAI question ?
If your worry is warranty issues, u could put a car back to stock tune w/ the tuner before you go in. I heard you need a tune because your changing the air flow and it freaks the computer out.
10-25-2006, 10:36 AM
#5
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RE: CAI question ?
The GMS CAI uses a new MAF calibrated to the flow volume of the new intake tube. The reason you need to tune with other CAIs is that the MAF is measuring based on the volume of air coming through. When you increase the volume of flow the ratio that the MAF is sending to the ECM is screwed up. This is why you need to reprogram the ECM.
With the GMS, the new MAF is set up for the volume of airflow that is provided with thier kit so you are sending accurate MAF numbers to the ECM. I bet if you put a GMS MAF in a stock setup it would throw a CEL but for a rich condition!
Well at least that is how I understand it!!!! YMMV.
Paul
With the GMS, the new MAF is set up for the volume of airflow that is provided with thier kit so you are sending accurate MAF numbers to the ECM. I bet if you put a GMS MAF in a stock setup it would throw a CEL but for a rich condition!
Well at least that is how I understand it!!!! YMMV.
Paul
10-25-2006, 01:31 PM
#6
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RE: CAI question ?
ORIGINAL: pachary
The GMS CAI uses a new MAF calibrated to the flow volume of the new intake tube. The reason you need to tune with other CAIs is that the MAF is measuring based on the volume of air coming through. When you increase the volume of flow the ratio that the MAF is sending to the ECM is screwed up. This is why you need to reprogram the ECM.
With the GMS, the new MAF is set up for the volume of airflow that is provided with thier kit so you are sending accurate MAF numbers to the ECM. I bet if you put a GMS MAF in a stock setup it would throw a CEL but for a rich condition!
Well at least that is how I understand it!!!! YMMV.
Paul
The GMS CAI uses a new MAF calibrated to the flow volume of the new intake tube. The reason you need to tune with other CAIs is that the MAF is measuring based on the volume of air coming through. When you increase the volume of flow the ratio that the MAF is sending to the ECM is screwed up. This is why you need to reprogram the ECM.
With the GMS, the new MAF is set up for the volume of airflow that is provided with thier kit so you are sending accurate MAF numbers to the ECM. I bet if you put a GMS MAF in a stock setup it would throw a CEL but for a rich condition!
Well at least that is how I understand it!!!! YMMV.
Paul
Yes that is pretty much correct, their MAF sensor is already adjusted for use with that specific intake tube, so yes it does adjust the fuel mixture to compensate for the additional air coming through, hence the comparable HP gains to a CAI with a tune. More Air+More Fuel=More Power. It doesn't just "trick" the ECM.
10-25-2006, 02:48 PM
#7
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RE: CAI question ?
ORIGINAL: DoctorQ
Just ordered the Granatelli CAI w/ calibrated MAF (410040-P) kit. With only 1K miles on my 2006GT, and lots of factory warranty left, my objective is to go with a no-tune CAI (to avoid any Dealership warranty hassles). Now the question: Without any re-tuning, won't the air/fuel ratio lean out? (leaner-than-ideal 14:1 air/fuel ratio)? I have heard that just replacing air filter ONLY to a higher flow assembly, the air/fuel ratio leans out at an alarming rate. If this is true, how does this Granatelli CAI (with no tune) deal with this lean fuel condition? Thx
Just ordered the Granatelli CAI w/ calibrated MAF (410040-P) kit. With only 1K miles on my 2006GT, and lots of factory warranty left, my objective is to go with a no-tune CAI (to avoid any Dealership warranty hassles). Now the question: Without any re-tuning, won't the air/fuel ratio lean out? (leaner-than-ideal 14:1 air/fuel ratio)? I have heard that just replacing air filter ONLY to a higher flow assembly, the air/fuel ratio leans out at an alarming rate. If this is true, how does this Granatelli CAI (with no tune) deal with this lean fuel condition? Thx
10-25-2006, 05:20 PM
#8
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RE: CAI question ?
I ordered it directly from Granatelli. Price bumped up a bit from the August special.. $325 for Satin finish... $375 (410040-P) for Polished. Very helpful/knowledgeable technical staff there. Doc
10-25-2006, 06:12 PM
#9
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RE: CAI question ?
The best way it was described to me is that there are 2 different ways a CAI works.
It can increase the volume of air flowing through the tube and past the MAF sensor, in which you need a tune or different sensor to pick up that change.
The other way is to increase the Rate of air flow through the tube and past the MAF sensor, in which you do not need a tune for.
Reason for needing a tune with the increase of volume is the stock MAF sensor isn’t calibrated for that unknown volume of air passing through per second. With the increase rate of air version the MAF sensor can detect an increase in the rate of air flow as long as the volume is the same.
Another way to put it is if you have a tube of a specific diameter you can increase the rate at which the air flows through it but not the volume of air. A 5” section of a 4” diameter tube is only going to contain so much air, given temperature is constant. The stock MAF can detect that. But take a 5” section of a 4 ½” diameter tube and you have a different condition that the stock sensor isn’t set for.
Hope I made sense
It can increase the volume of air flowing through the tube and past the MAF sensor, in which you need a tune or different sensor to pick up that change.
The other way is to increase the Rate of air flow through the tube and past the MAF sensor, in which you do not need a tune for.
Reason for needing a tune with the increase of volume is the stock MAF sensor isn’t calibrated for that unknown volume of air passing through per second. With the increase rate of air version the MAF sensor can detect an increase in the rate of air flow as long as the volume is the same.
Another way to put it is if you have a tube of a specific diameter you can increase the rate at which the air flows through it but not the volume of air. A 5” section of a 4” diameter tube is only going to contain so much air, given temperature is constant. The stock MAF can detect that. But take a 5” section of a 4 ½” diameter tube and you have a different condition that the stock sensor isn’t set for.
Hope I made sense
10-25-2006, 10:51 PM
#10
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RE: CAI question ?
Great posts.. thx. So this leaves me with another question: I have seen a number of posts which claim their CAI help elicit INCREASED fuel mileage (MPG). If the GMS MAF sensor tells the ECM to kick up the fuel a bit (since the air side of the equation has increased, ECM would need to increase the fuel mix to maintain the air/fuel ratio), doesn't this mean you you are running a richer mix, thus are consuming MORE fuel? The increased rwHP has to come from somewhere, and that somewhere is increased fuel... thus, how could MPG increase (sounds like it would be the converse). ????