Front end & Cold air intake/Exhaust/Snorkel ???

No, they wouldn't. MAF sensors measure air mass, hence the name. There is less density at elevation so the MAF sensor doesn't need to be changed IF it's calibration is correct for the duct size it's installed in. There is this thing called a manifold pressure sensor, too. The air pressure inside the intake changes far more based on throttle position than altitude. The MAF sensor is calibrated for a specific size duct. If that duct size is increased the computer will calculate fueling based on the original calibration and it will result in a lean condition. The ECU may compensate for that through closed loop feedback from the O2 sensor(s) and eventually learn a long term fuel trim correction, but those LTFT are a coarse adjustment intended to shift the fueling curve slightly to optimize. They are not intended to and do a poor job of compensating fueling for hardware changes that effect fueling throughout the rpm/load envelope. They also do not help much (or at all depending on the ECU programming) for open loop operation, which is high load/mid and high rpm conditions. That's where it's especially critical to be correct.

I'm not going to post more specifics on the subject here, the relevant info has been provided. If your want to discuss further, PM me.

 

What about air box inlet size? Same filter, same duct at the mass airflow sensor. There’s a pressure differential on either side of the filter. At altitude there can be 30-40% less air mass. The ecu registers this lack and feeds less fuel. Given the pressure differential on either side of the filter, a filter that restricts less(either by increased surface area or lowered filtration) combined with an intake diameter and source that optimize temperature, density, and free passage of air you can get some of that loss back but there’s a reason forced induction is so popular in the mountains, it works way better at replacing that lost manifold pressure.

 

Agreed, but the pressure delta across the oem filter is very small and it is not a restriction to mass flow. Isn't the v8 tundra filter and v6 Tacoma filter the same area? The factory intake optimizes temp, it's a CAI. Pretty much every modern vehicles uses a "CAI" design.

 

A day or two ago I watched a video showing a measurable dyno increase just by changing to the TRD intake nozzle rather than the entire kit. I totally agree that stock is a CAI but if removing the Charcoal filter can also produce significant gains then there must be that much flow loss with it in place. I’m not advocating it’s removal, just pointing out that the evidence I’ve seen points to more than a minimal pressure differential on either side of the filter. Engineering aside, bean counters also play a role in the outcome of design trade offs so there’s a limit on how big an air box can be. We already know that for fleet fuel economy reasons vehicles aren’t always optimized for power. Fuel mapping, duct size, filter size, air box size, engine bay volume, parts cost all are prey to the gods of gas and profit. Some things we can mod, some mods require other mods. It’s taken for granted that any forced induction mod will require some kind of tune to work well or even at all so it’s possible it could also be necessary at the lower end of the scale. FOR ME the cost and trouble aren’t worth the minimal gains and the noise just makes it worse. Some people shell out $ just for a battery clamp with TRD magic embossed on it so why not shell out hundreds for a few horses you’ll lose with under inflated, oversized tires along with some added noise. Maybe they do it on purpose to stimulate interest in aftermarket mods. Not out of any generosity towards AFE et al but to allow the wiggle room for those mods that enthrall us so much and hold our interest. Nah.

 

Could I trouble you to link the video? I have been searching religiously for independent dyno testing on systems, and it's strange that this truck has been out so long and there isn't a lot of dyno information that isn't from manufacturers. The tune dynos are about all I can find. I will do some IAT and RPM/MPH tests on my bluedriver when my truck is finally built. One issue with bolt ons discussed here is the time is takes for ECUs to "recalibrate", so testing performance within an hour or two on the same day in the same environmental conditions may not be representative of the performance differences(for better or worse) once the ECU finally adjusts, so picking a day after a few hundred miles with the closest possible conditions would be the best route from what I understand. Another issue with CAIs of concern, mine anyway, is filter efficiency. Ideally, you would select a filter that cleans as well or better than the stock filter with increased surface area to allow a bit more air in and delay clogging as long as possible. All that said, it's a lot easier to make things worse on modern vehicles than better than the factory offering. These are just the musings of a random internet person though.