Stock Air Box removal

**Thundoug Hemi** · 07-04-2004, 02:52 PM

I just spent an hour pulling out the stock fatory air intake silencer assembly. This located below the air filter. When see where the 300C pulls air FROM now, you will wonder how they make 340 HP with this very restrictive set up. If you If you remove this assembly and the remove the blanked off "vent" that is located in the lower front fascia, you will have fresh air entering this newly created plenum. Removing the air box does require removing the driver side wheel and poping the rivets the hold the wheel wells. Once you get in there its only one bolt holding the assembly.You also have to cut off the foam gasketed tube that connects the silencer to the air cleaner, but this is only plastic and an be cut with a hack saw. I will be working on a vent tube to connect this newly opened vent to the stock air cleaner assembly, in which I will install a K&N stock filter replacement. The result will be a true Ram-Air setup. I will post some more details and some pics when I am done. This should be a real low buck mod that I am betting will be as good as the aftermarket units that will come out.

**DrDeville** · 07-06-2004, 02:02 PM

Hi Doug,

Thanks for the idea, and the report.

What differences in sound and performance have you noticed?

Best,

George Ferguson

**Thundoug Hemi** · 07-06-2004, 02:09 PM

You can defintately hear more of a gulp now that the stock air intake box is gone. Performance is really hard to say since (A) your really only gonna realize HP gains at upper RPM's so seat of the pants is hard to go by and (2) FROM what I read here, its gonna take some time to have the computer "learn" to adust the mixture to compensate for increased flow. Cooler air should be an immediate benefit, since I am sure there is some sort of air temp sensor used to set the mixture.

**lvd2340** · 07-06-2004, 05:55 PM

If anyone wants to know here's the directions FROM the service manual on air intake removal:

REMOVAL
Filter Element Only
Housing removal is not necessary for element (filter) replacement.
Loosen clamp and disconnect air duct at air cleaner cover.
Pry over 4 spring clips (5) FROM housing cover (3) (spring clips retain cover to housing) .
Release housing cover (3) FROM locating tabs (4) on housing and remove cover (3).
Remove air cleaner element (filter) FROM housing.
Clean inside of housing before replacing element.

Housing Assembly
Loosen clamp and disconnect air duct at air cleaner cover.
Lift entire housing (1) assembly FROM 4 locating pins (2).

**Thundoug Hemi** · 07-06-2004, 06:02 PM

That last post is only telling you about the filter assembly. If you do the following items above, you will have the air cleaner off, and then if you look down, you will see that a 3" or so tube comes up INTO it. That leads down INTO a "box" which sucks air FROM the closed off area behind the wheel well. That's what I removed and modified. Once I install duct work FROM the front fascia up INTO the stock cleaner assembly.....I will have isolated intake to fresh cool air. Add in the K&N filter and now we are breathing.

**DoctorBobby** · 07-07-2004, 02:43 PM

Where did you attach the K&N. In the wheel well or in the MAS filter box?

**DoctorBobby** · 07-07-2004, 03:36 PM

I did exactly this about 4 weeks ago and added an AIRAID throttle body spacer (with a few mods) and a tornado. I have the K&N conical filter in the MAF box with the filter placed in the top lid opening with 3" rubber flex. The MAF box just sits now above the 3" hole wher I gutted everything beneath it. I also removed the black plastic piece on the part next to the fog lamp and installed a mesh so at velocity, outside cold air is being rammed INTO the plenum not just ambient. Afier I did all this I had the vehicle DYNO'd at 355 BHP and 289 Torrque, unfortunately, I had no original baseline. There is a quite a noticable gain in HP. My gas mileage jumped about 2.5 MPG FROM 12.2 to 14.7 around town and FROM 21 FWY to 24.3. To reset the computer I disconnected the battery ground for a few minutes. I have driven it this way now for around 1500 miles. So far so good.

PS: I did not remove the tire, just cranked the wheel to the far left. It was tight but it worked.

**fluxanimator** · 07-07-2004, 04:03 PM

Originally Posted by DoctorBobby

Afier I did all this I had the vehicle DYNO'd at 355 BHP and 289 Torrque, unfortunately, I had no original baseline. There is a quite a noticable gain in HP.

289 torque? Hopefully this is a typo. Isn't stock 390?

**snickle** · 07-07-2004, 04:08 PM

289 at the wheels, is not too bad for 390 at the crank.

**DoctorBobby** · 07-07-2004, 04:41 PM

Sorry, I meant 389 Torque.

**C4me** · 07-07-2004, 04:49 PM

WOW !? No loss and only gain !? There is always loss through the trans and differential. Always. So If you have gained that much with an intake ..... And, be very careful that you don't pick up water through that very low and open intake.

**DoctorBobby** · 07-07-2004, 05:31 PM

Here is the bottom line. At the Rear Wheels on three tests:
BHP Rear Differential:
295.3
294.5
295.9

Torque
324.8
323.6
325.2

Add 20% for Auto Trans and your FLYWHEEL is:
355 AVG
289 AVG

Chrysler boast of HP anf Torque is at the flywheel.

Hope this helps.