Courtesy of forum member dndrsn on Corvette Forum.

C5 CORVETTE COLD AIR INDUCTION MODIFICATION

Do this mod at you own risk.

I make no claims as to the safety or effectiveness of this modification.

Please follow all safety protocols when working on your vehicle.

This Tech Tip covers the alteration of the Airbox and radiator shroud
only, disassembly and removal of these items is assumed to be
common knowledge of the DIY’er, however there are instructions to
be found on the forum relating to installation of aftermarket induction
systems which would illustrate this information.

This mod was done with the car on rhino ramps.

Summary:

This modification was done to introduce ambient temperature air into
the intake system of a C5 Corvette, utilizing stock parts and
purchased extras keeping the expense to a minimum.

The following pages will attempt to explain how to invert and alter the
airbox, mark its position on the radiator shroud, produce a template
to mark the position of the filter frame on the radiator shroud,
marking and alteration of the radiator shroud, assembly and
attachment of the airbox to the radiator shroud.

The level of competence to perform this task will include general
knowledge of your vehicle, the use of ramps, various hand tools, an
electric drill and cutting tools.

Purchased extras will include a K&N or similar type of washable filter,
24” cable ties, a rubber grommet, and a plastic plug.

1. Disconnect the battery at the negative terminal.

2. Remove Airbox assembly, MAF, and airbridge.

3. Disassemble the Air box.

Here are the parts that you will keep for the mod:



Here are the parts we won't be using:



4. Clip off nubs.

Here are a couple of locators that will be disoriented when the lower
section of the airbox is flipped over. You may want to clip these off:



5. Mark Location of box on radiator shroud.

On this step you will want to clean the radiator shroud of oil and dirt so
masking tape will stick to the surface.

Reassemble the airbridge with the bottom part of the airbox flipped upside
down, leaving the clamps loose install the airbridge assembly to the
throttle body, airbridge grommets to the pegs on the radiator cover,
leaving the inverted airbox resting on the radiator shroud. The airbox will
not rest flatly against the shroud.

Slide a sheet of poster board between the airbox and radiator shroud and
secure with masking tape. Wiggle all the clamping connections until they
are properly in place, square up the airbox and snug the clamps.

The bottom edge of the airbox will be hovering about an inch above the
shroud, you will have to push it down to the paper to mark its placement.
The rubber coupler on the airbox will bend to accommodate this,

With a pencil mark the perimeter of the airbox. Marking the sides and bottom
positions on the paper will be sufficient.



6. Prepare the airbox.

Remove the assembly from the throttle body and remove the box from the
MAF.

Because you have inverted the box, the 1” hole in the side of the box will
have to be plugged and another hole will have to be drilled into the other
side. I used a 1” OD ¾” ID grommet and a ¾” plastic plug I found at
Lowe’s in the blue cabinets in the hardware section.

Try to put the hole in the same location on the other side. There are
gussets inside the box where you will be making the hole, you may want
to remove these first with a Dremel. They will eventually have to be
removed so the grommet will seat correctly.



7. Remove radiator shroud.

Links to instructions to remove the shroud can be found on the forum.

Essentially you just disconnect everything connected to the shroud and all
the fasteners holding it to the car. There are two plastic pins with push
nuts holding the shroud at the sides. Don’t try to remove the metal
retainers, just pop the plastic bolts from the metal frame underneath the
shroud. These things are not worth the trouble saving, when the shroud is
reinstalled just use cable ties at these points.

There will be strips of weather-stripping at the sides of the shroud. If they
are loose this is a good time to reglue these to the frame.

8. Make template.

The position of the box marked earlier on the shroud is not the correct size
for the opening in the shroud, it is to locate a template that you will make
from the filter frame. The filter frame will fit snugly in the opening that you
cut in the shroud and will rest on a lip at the top of the frame.

Use a piece of poster board that is a couple inches bigger all around than
the filter frame. It does not have to be exactly in the center of the poster
board, just generally centered.

I traced the outside of the frame on the board, then drew a parallel line
inside of that to compensate for the lip on the frame.

I think this is the most important step of the process. The frame needs to
fit snugly into the hole in the shroud resting on the lip of the frame. If you
don’t get this template right the first time do it again.

Lay the frame on a piece of poster board and trace the perimeter making
indications where the two notches will be. Draw a parallel line 4mm inside
of the line you just traced. Cut on this line to make your template.



9. Marking and cutting the radiator shroud.

Now it’s time to mark and cut the shroud.

The shape of the shroud makes it difficult to work with on a flat surface. I
placed the shroud over a trash can. This allowed clearance underneath
and let the sides of the shroud hang free. You may come up with
something better.

Make 2 V-Cuts on each side and bottom in the template. Make marks
9mm inboard of the tracing you did on the shroud where the V-Cuts are
located on the template. This will make it easier to see what you are
doing. Tape the template in place when you have it centered on the paper
on the shroud. Trace a pencil line to the inside edge of the template onto
the shroud. This is where the opening will be on the shroud.



10. Cutting the Radiator Shroud.

Remove the template being careful not to disturb the paper taped to the
shroud.

Use a razor knife to poke holes along the line through the paper and into
the shroud underneath.



Remove the paper from the radiator shroud, and using the holes
previously made in the shroud as a guide, score the plastic with a razor
knife against a straightedge. Then follow the scored line with straight
cutters.



Note: Making a rough cut hole in the shroud first about ½ inch or so
inside your scored lines will make it easier to manipulate the plastic
when making the finish cut.



11. Strap holes.

Put the frame into the shroud, the K&N filter into the frame and the airbox
onto the filter. At the bottom of the airbox are two rectangle slots, mark the
shroud with a Sharpie directly under these slots.



Mark and create holes for straps directly beneath the clips.



12. Assembly

Run a 24” Zip Tie through the clip down through the top hole and up
through the bottom hole. Repeat for the other side.



Install filter frame.



Install filter:



Install air box by sliding the ties through the slots at the bottom of the airbox
securing with the ends cut from two Zip Ties.

Do not slide these down until your have the release clips in their proper closed
positions.



Clips in closed position:



13. Strap Adjustment.

Now slide the cut ends of the zip ties down against the airbox and pull snug with the release clips in the closed position.

Release the clips and pull the ties 2 or 3 more clicks and return the clips to the closed position.

Repeat this procedure until the assembly is sealed. The airbox assembly should be snug but not tight enough so as to deform the filter frame and also to leave enough slack to change filters without having to replace the straps.

14. Installation

The shroud and airbox can now be installed into the car as a unit.

 

15. Pics of assembled system:

 

Figured I would put it here so I can link to this site/thread whenever someone is inquiring about c5 intakes.

Enjoy.

 

High quality write up.

Thanks! ~Joshua

 

Totally agree. Great job!

Keith

 

Credit for the write-up goes to dndrsn on corvetteforum.

 

I did this to my car about 5 months ago. have had no problems, even in the rain.

 

Great DIY mod. I love it when vette guys use their brains for cool stuff like this that actually is functional too.

Good Job!!

 

Here is a link to download a .pdf file of the mod. The file is 1.58Mb.

It's a free file hosting site so you may get a pop-up or advertisement with the download page.

"FLIP-TIE"

 

Thanks again for the great write-up!

p.m. sent

 

That is actually a copy of the MTI intake system which has been around since the C5's came out. it is a good place to put the air intake as it is an area of high pressure, unlike the nose which is actually a low pressure area.

The only issue is on the dyno it will sometimes heat soak and negatively affect dyno numbers. But, once underway, it should pulll in higher pressure air.

 

Yeah, that's a great write up to mod a stock air box. I've helped install several new Callaway Honkers on some of my friends' new Z06's, and their design is basically the same.....drawing air thru the radiator shroud. If I didn't already have a RM Racing intake on my car, I would be doing this mod!