Programmer/Tuner + CAI = Lean?

[AJeepZJ]

Engines and their computers are by far not my strong suit so I've posted this here because I know there are a lot of technical minds and thinkers here. If we get a pretty good consensus about this, we can probably move it over to Performance Modification sub forum for future folks curious on this. Anyway, I'm sure some of you have caught Superchips caution label that warns users of pairing a CAI with the Superchips due to the possibility of causing the engine to run rich - so I have two questions.

I'm familiar with the symptoms of engine detonation. But for those who have run products like these for 1+ years, what has been YOUR experience.

My second question is more/less a technical understanding of what exactly is taking place. Based on my observations and reading, it does not appear to be a huge issue (especially here on the WK/XK forums, so is there some type of fail-safe, sensor, or some other technicality compensating or resolving what WOULD have been engine detonation.

[Matt]

An intake doesn't "force" more air into an engine and wont cause it to run lean.

The computer is constantly adjusting the air/fuel ratio and bounces back & forth between rich & lean to maintain a nominal (average) stoichiometric value. If your O2 sensor is working properly and you get a rich or lean code, that's an indication that one of the other sensors is out of range, such as the IAT or MAP.

[Matt]

For pre-detonation all engines have a knock sensor. This sensor identifies detonation long before you would notice it and retards timing to stop it.

[AJeepZJ]

Im aware that just a CAI or Programmer wont cause it to run lean, but was curious about the combimation of using both.

[AJeepZJ]

So you've kind of answered one question which is whethere there are mechanisms in place to prevent early detonation. But im still curious if the comditions are possible using a CAI and Tuner combo.

[Matt]

The combination is practically unrelated except for WOT conditions. Stock intakes flow plenty cfm for daily driving rpm's and are already "cold air". As a matter of fact some CAIs actually increase intake temp by pulling in more air from the engine compartment.

Thus, theres really nothing magical about the "combination". Only caveat is if the CAI changes the IAT mount to a location that doesn't provide an accurate reading. As long as the temp reading is good, the computer will adjust for a/f ratio.

[AJeepZJ]

Ah... You answered my next question. Which was going to be how WOT might change things. Alright, thanks!

[Matt]

Any lean codes will be related to the tuning and/or sensors that are slightly out of range that may not result in a lean code with stock programming. Most good custom tuners can usually identify bad sensors during their tuning sessions.

[Matt]

Yeah man, WOT is where intakes/exhaust/tunes start to shine in terms of "performance". The engine is basically a big air pump.... intake and exhaust are functions of RPM, but the driving force is combustion that has to be modulated by the fuel system to function properly. At WOT the fuel tables,timing,etc change to account for the speeds, chamber pressures, etc that are a lot more dynamic.