I would love to hear how the ECM can control air flow?! ECM looks at a couple of things, IAT (Intake air temp), speed density or MAP sensing, fuel flow to get to a predetermined air/fuel ratio (first and second bank), knock sensors and a base map fuel/ignition curve. Theres technically no way to "limit" the amount of air an engine ingests… this is based off engine size (piston/stroke), valve timing and thats about it. The TB does not magically close to limit the amount of air to keep a desired air flow. In fact MAP/speed density has no "actual" way of measuring air like a MAF system which can calculate how much air is being ingested by how it cools the MAF sensor wire etc. MAP/Speed density is basically guessing based off a pre determined table and vacuum etc. Sure VVT can decrease valve timing enough to limit air flow slightly but not in the way that it makes a huge difference.
The computer guesses at the incoming air from the MAP sensor, uses IAT and the 02 sensors to regulate A/F ratio and uses IAT/knock sensors to help with knock. Of course Im not going to bring up valve timing, base timing curves, load values, fuel maps, engine temps etc. But basically OEM mopar has gotten the base tables mapped out very accurately and then uses the sensors to make fine tune adjustments depending on fuel quality, ambient air temps, location/altitude etc.
You can in fact increase the amount of air ingested into the engine which will squirt more fuel to get the desired A/F ratio with the stock tuning… however due to the base fuel curves the ECm will compensate and only allow the desired A/F ratio… a tuner would benefit as they can edit the A/F and timing tables etc to created a better environment for power.
As far as the guys who say that engines are maxed out this is true. OEM needs to get there engines as efficient as possible… but efficiency does not mean max power. The fact is that when you decrease engine temp you can decrease IAT temps which means cooler intake charge = Denser air = more fuel = less detonation = more power. But an engine that runs at 160*F is less efficient than an engine that runs at 200 - 220 *F, the higher engine temps burn more of the fuel increasing efficiency. OEMs can only do so much since there hands are tied behind there backs as they have to follow strict guidelines/requirements.
CAI can work, depending on design and how inefficient the stock intake design is. K&N isn't a horrible filter they got a bad wrap due to the oil in the filter getting on the MAF sensors causing the measurements to be off, but they use a looser fiber which allows more air flow but more/larger particles to pass through… they counter this with oil in the filter but again its no the best filter design. I like the dry high flow filters personally. Now the Vararam is not technically just a CAI… its also a RAM AIR… forcing air into the TB/intake Vs sucking it changes the game. The fact is that air ramed into the engine is denser than air sucked in, more air means the ECM needs to richen the A/F to keep the same A/F ratio… more air + more fuel = bigger bang = more power. Same principle as forced induction and NOS, the added air which is under pressure (Above atmospheric pressure) allows more fuel and air to be ingested causing a bigger hotter bang = more power. NOS is the same thing but but adds the NO2 of nitrogen/ 2 parts oxygen to the existing intake charge allowing more fuel to be added for a hotter bigger bang. The Vararam like all real RAM airs can create more power than a standard CAI.
This can have a negative affect on MPG tho… more air = more fuel = more fuel burned per RPM. But the increased power can also mean you require slightly less RPM to maintain the same speed so you can actually offset the increased fuel demand for slightly better MPG. This is something the OEM's can't "gamble" with, they need something thats going to work.
Also remember that the HEMI's have a inherent problem with the PCV system sucking in oil causing some nasty gunk in the TB and intake… therefore on the valves and Spark plugs. This is a problem that Mopar won't address, prob because they get LOTS of money getting people coming in to get there TBs cleaned after 15K miles or spark plugs changed out due to being gunked up. Lets not forget while they try to be efficient they also need to make there money in the end. Would I say the oil catch can "increases MPG and efficiency" no not immediately but it will in the longer its on.
Smaller DIA exhaust promotes backpressure which actually increases low end power and tq but limits Max power. OEMs take this into account as most people in a factory DD car/truck don't spend all there time at redline, smaller DIA also creates less noise which they have to meet a certain Db level. Again just another point that OEM is about efficiency not power even if the efficiency is only in a narrow RPM range.
OEM's have a point where they think the benefit of a MPG potentially is not worth the cost then they won't do it. BUt say for that guy that drives ALOT of highway in his truck might benefit from a aeropackage that includes ground effects to the front bumper, undercarriage panels and longer/lower sides to help reduce the amount of air drag on the truck… Again they look at the big picture but I can tell you that some aero mods to the RAM would most likely net some increased MPG gains that would be noticeable. They are basically moving bricks with big front end acting like a wall. 10 years ago you never saw 18 wheelers wit those fancy fiberglass side skirts under the cargo bins or the wings at the back which help with air resistance… they won't put those on if they didn't make a noticeable difference. Just saying some mods will benefit some more than others and that the OEM doesn't do "everything" to squeeze max efficiency/power out of the motors.
Sorry for the long post and thanks for listening.
