so, when pV=nRT

p= pressure into cylinder
V= volume of cylinder
n= amount of gas (air)
R= constant (gas property)
T= cylinder temperature

using arrow analysis, p is raised and V is constant. this requires n to increase as R is constant and T is constant

there is usually a vacuum on the intake due to the engine breathing. if you lower the flow obstacles (CAI install), the vacuum will lower (say 10" hg to 5" hg...#'s are made up). this results in higher inlet pressure to the cylinder...therefore your amount of air into the cylinder is raised.

I stand schooled. I still have problems with the reasoning that thais0n got from Outlaw. The computer has to relearn how to run the engine right? So why can't it learn that at idle, the A/F mix is different and make it a little fatter? As long as it's within the factory min/max, I don't see why a CEL would get thrown.

I am a bit paranoid about my truck. I paid ALOT of money, so I want it to last a long time. 1 CEL with my Volant and it would be on eBay for sale. Same with my exhaust (although how that would throw a CEL?). When I get a custom tune or an Edge, I'll be the same way. My A/F mix will be very conservative. I really only want a tuner for the transmission. My 5.4 makes alot of power right now.

A good example of the carb A/F mix and altitude changes occured in the Bullrun Episode 9 (Charger & Mr. Angry).

got any pics up yet? I'm trying to picture a 2 piece, but it just isn't working for me

 

Hmmm ... looking at the simple math, and looking at the application and the operating mode where said CEL appears (idle), I'm not sure this totally applies.

At idle at least, so little volume is used that any difference in the restrictive properties of the stocker versus the CAI would be infinitesimal, as would any effect on pressure.

Also - at idle, the throttle plate is virtually closed - this is orders of magnitude more restrictive than any intake, rendering those differences moot, viewed form the egine as an air pump (a suction pump in this case).

The '04's had very strict limits on fuel trim correction threshold before a CEL was set; the correction would still be made, but a CEL was set nonetheless.

Also, are you certain that formula holds for a vacuum system - which is what a N/A intake really is. I'd appreciate knowing.

Good posts, guys.

Cheers
Bubba

 

That's what I read from Aaron's explanation too, the correction was made but the 04 PCM is a bit of a Chicken Little and cries that the sky is falling when it sees how much of a correction it had to make.

 

good point. I knew that the idle air intake was the same with a CAI or a stock system, but I could not for the life of me think of a way to justify it.

I looked on wikipedia for a few minutes, but I couldn't find proof if the formula was true in a vacuum or not. I'm going to say yes, because a vacuum is a form of pressure...

 

I just installed the new two-piece tube I received from Aaron and fitment is ALOT better. Like someone else, there is more slack on the MAF wire now, and things are sitting alot more square. I think some additional smaller corrections could be made to get things perfect. But I am alot happier with the fitment now.

I have a big mod day tomorrow so I am going to take a bunch of pics for you guys.

Still no CEL. From what I have been reading the 04s are very sensitive to changes to the A/F mix. So if we chalk up the initial CEL that I had to the computer making large adjustments that were outside of the factory parameters, should I feel somewhat more comfortable that I have gone a week with no CEL - meaning that my truck is now running inside the strict A/F mix parameters for the 04s?

 

I think the only thing that will really make you comfortable is the dyno pulls w/ an EGA that have been suggested previously.

Side note: The gas formula works for all regular conditions. Vacuum is relative, as is pressure. It's just a matter of the reference point used. Most of us regular folks use gauge measurements, meaning relative to atomosphere. Scientific types use absolute measurements quite a bit, meaning relative to a perfect vacuum.

 

Yeah, the gas law works for all cases, even a pure vacuum where p = zero. The formula indicates that at a pure vacuum, either there are zero gas molecules and/or the temperature is at absolute zero where the gas molecules have zero atomic movement.

 

Thaison and hmfic, how are you guys liking yours? I installed mine on saturday morning and so far no CEL's or problems. I have noticed that I get some kind of drone around 2500 rpms in 2nd gear. I did notice that under light to partial throttle it seems to pick up a little better. Just wondering what you guys are observing compared to my setup.

 

Thanks, Torque, VFR & Tylus!

Cheers
Bubba

. <--- my compliant sig lol

 

I dont think I would call it a drone, I can hear the intake. With my Airaid and Volant, they were more of a drone...i could feel it in the pedal - a slight vibration. And sometimes it got really loud. But with the outlaw...i feel its more of an intake groan than a drone.

 

Is it loud enough that you must raise your voice to be heard or talk in the cab without the radio on while driving?

 

No its not that loud. I never had to turn up the volume or talk louder.

Imagine the difference between sitting idle and then accelerating with your magnaflow. You can hear it, but its not loud.

 

Cool. That might not be too bad. Thanks.

 

I'll 2nd that.. I do here a drone just for a brief second that ktexas mentioned though. I noticed the rubber 90 degree elbow is rubbing against the fire wall insulation which I think is enhancing that.

 

For anybody running the outlaw,
Do you have a problem with the rubber 90 degree elbow that comes out of the throttle body rubbing on the firewall.

I hear a rattling noise coming from the engine compartment, that increases with bumps. I can only hear it at slow speeds. It started the day I put the outlaw on. I assumed it is the rubber elbow. I've double checked everything for tightness.