Re: Mopar CAI vs. K&N
I'm not a tuner but I do have a few thoughts on Cold Air Intakes.
Q) It will not increase performance by itself without other mods.
A) It will increase airflow providing it outflows the stock system you took off. In most cases, the stock air box and filter flow more than enough in the lower rpm ranges which is why you don't see aftermarket CAI having a HP increase in those lower rpm ranges. And in some cases, the stk. air box setup may be better than the aftermarket CAI system. If that happens then the stock system is more than enough for your setup. How would you know? Test it on a dyno.
Q) your OEM engine management computer will negate the effects of the slightly increased airflow after a couple of weeks. The OEM tune will adjust the fuel and ignition curves back to OEM parameters as designed.
A) You need four things to make an engine run, air, fuel, spark and compression. Then the fifth element would be an Engine Management System (EMS). If you increase airflow, the EMS has no way of removing this extra air flow. So it has to compensate for the extra air flow by increasing the pulse width of the injector. How does it know it has extra air flow? The O2 sensor will sense this leaner condition. The EMS has short and long fuel trims where it can add or subtract fuel when it deviates from what it is commanding. The problem with this, the percentage of correction is small. So as long as your modification doesn't reach the limit you won't get a "CHECK ENGINE" light.
A CAI adds approx. 1-4% extra HP, not enough to reach the limit of your short fuel trims but also in the range of dyno error (up to 6%). K&N's CAI has dyno results that show a HP increase. If they ran that test a few more times the HP increase could vary immensely. Hence K&N ran the test and probably stopped at the highest number they got for their setup and that's what you see on their web site.
Q) To realize any noticeable gains w/a quality CAI...... improved exhaust flow to go along with that improved intake flow must be coupled w/ a good tuner to change fuel and ignition curves to suit the increased airflow.
A) The added parts above will probably have a power loss in the lower rpms. To make up for this loss of power, you'll need to add more timing/advance. And that's what the tuner will usually do in this area. In some cases his changes may necessitate the use of higher octane fuel.
I installed a K&N CAI today on my 5.7L Overland, hoping for a dyno appt. this week to test against the stock setup.
2014 Jeep CG 5.7L Overland: 304rwhp & 337rwtq & email@example.com (K&N CAI, Diablosport inTune, Pedal Commander)
1994 Mustang Saleen: 890rwhp & 771rwtq