If anyone gets in a jamb like I did… here’s a solution:
my air-box resonator cracked and threw a lean engine code. Unfortunately a replacement was on back-order, which I’m not complaining too much about since they are expensive.
I replaced it with a hose and aluminum adapter I turned on my lathe.
Works great, no more CEL and no noticeable change in noise resonance.

 

The unit off an 06-09 RRS also works and doesn't have the baffles on the intake tube.

 

Generally not a good idea to remove these on a NA engine.

 

Please explain more. I love learning

 

Well lets put it this way, car makers are cheap in the sense they don't add stuff for the fun of it. So if they could put a straight pipe in, they would. So why engineer a complex air chamber system to fit into the intake side of things? Well on an engine you do, in fact, get back flow of air especially when the throttle body closes quickly but this happens every time an intake valve closes. Air is a fluid, so when its flowing and suddenly stopped it will form a pressure wave and "recoil" a bit. Those champers absorb the pressure recoil and prevent those from getting all the way back to the filter, past the MAF. If it were to get that far back, when you open the throttle body again all that air has to, essentially, reverse course and there will be a delay. Keep in mind we are talking rather small amount of air overall. But it adds up and robs you of power, economy, etc. In a simple way, this is similar to water pipe design in houses where there are sometimes those anti-knock copper fittings installed that mount upright. Basically a piece of pipe filled with air. So when the water is suddenly turned off, that air filled camper can compress and take that energy from causing the entire pipe run to slam and make a noise. I remember long, long ago in the Mark VIII these was dyno proven. Resonator intake was a hot thing to do, make the car sound really nice but after much debate someone stepped in with a dyne runs to show the results. It was not a massive drop, but it was something like 10 or 12 hp - I know people that spend hundreds just to gain that much HP!

 

Great response. Clear and to the point. I just wanted to say my appreciation.

 

I have a couple good used ones in stock just in case you are looking for one

 

That's true but the RRS & LR3 equipped with the 4.4L = identical minus the body and interior yet the RRS 4.4L has a straight tube. I had one one my 06 LR3 for several years & no difference at all minus it had a slightly different intake tube sound vs the one with the baffle. I replaced mine because it had a crack in it from someone stepping on it while it was off the LR3.

 

messaged you.

 

I just modified mine today but inserting an aluminum tube right where you put the hose.