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post #101 of 106 (permalink) Old 08-30-2010, 04:11 PM
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Maybe the extra power allows for the AFM to be engaged longer since the same power comes from a lesser throttle percentage. Just a thought.
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post #102 of 106 (permalink) Old 08-31-2010, 08:51 AM
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Originally Posted by RevvHigh View Post
I have never really understood the physics behind this. More air permits more gas to maintain the same mixture. More gas = more boom = more power. I don't see how adding in more air, whether by adding a CAI, or hood cut out, or whatever, to achieve a bigger explosion, can in any way improve fuel economy. The hypermiler guys who tune their little 4-bangers for max MPG actually prefer hot air in the intake and MORE restrictive intake boxes so there will be less air and less gas.

Maybe I'm just dense... but can someone explain this to me?? How is getting more power and spark in the combustion chamber supposed to improve your MPG?
The easier it is for an engine to make power, the more efficient it is. An engine that makes more torque/power at a specific RPM than another engine of similar displacement will be more efficient - it can move the same weight with less effort.

This has absolutely nothing to do with the hood vents though. The hood vents have nothing to do with the intake. They only give hot engine bay air a route to escape, as they're in a negative pressure zone and therefore have no "ram air" effect.

Also, mr_didgers has already discussed that in practical terms, CAIs have no effect on everyday closed throttle fuel mileage. Under closed loop conditions the ECM will adjust the throttle opening based on MAF readings in order to only allow the specific amount of air that will maintain the stoichiometric ratio of fuel/air. If a CAI allows more air through, then the MAF will detect this and the throttle body will close more to compensate. It is only under open loop conditions (WOT), where the ECM switches to fuel tables rather than MAF and O2 sensor readings, that the CAI is allowed to shine.

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post #103 of 106 (permalink) Old 08-31-2010, 09:47 AM
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Originally Posted by Gavine View Post
Maybe the extra power allows for the AFM to be engaged longer since the same power comes from a lesser throttle percentage. Just a thought.
That is a good thought. Between the cooler air and lessened restriction, the throttle shouldn't need to be as far open while cruising, and it should stay in the range for AFM to activate more often. Hmm...

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post #104 of 106 (permalink) Old 11-04-2011, 07:59 AM
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Did this last night while I was double checking the clamps on the RamJet. As soon as I got to work I put my hand right by the vent and could feel a nice amount of heat coming out. Thanks for the writeup!
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post #105 of 106 (permalink) Old 11-10-2011, 08:59 AM
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As soon as I got to work I put my hand right by the vent and could feel a nice amount of heat coming out. Thanks for the writeup!
Nice! This may move up the "to-do" list.

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post #106 of 106 (permalink) Old 05-28-2019, 03:39 AM
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Awesome write up I just completed this mod in no more than 15min...I’ve got a 25min commute to work so I’ll see how hot the engine bay is after driving...has anyone noticed cooler temps on any of the gauges through the software screen on the information center?

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