After installing my Nismo CAI I removed the inner panel between the bumper cover and the radiator wall to increase air flow to the cavity containing the filter cone. I'm sure a lot of people did the same but I still wasn't satisfied that the filter was getting all the air it could, so I constructed the following air dam to direct air toward the filter.

 

Here's a picture of the parts removed.

 

Next, I created a template for the new ram out of heavy card stock. It took a while, pasting bits and pieces together, then transfering the final design to a clean sheet, but here's the final template.

 

Then I went looking for some heavy vinyl stock. As I was giving up after visiting 3 hobby shops and a few home improvement centers, I walked past the perfect substitute - a black vinyl trash can . The cost, $2.65. Perfect.

I used the curves and contours of the trash can where I would have had to bend the stock vinyl anyway, and used the bottom of the can instead of the upper tab you see in the template. Here's the final product uninstalled.

 

Here's a picture installed, under the car, as viewed from the right looking left toward the ram.

 

And this view is straight up from the bottom where you can see the real shape of how the air flows.

I used all existing mount points and fasteners left over from the inner panels that I removed in the first place.

Can I tell a difference in the butt dyno? No, but my G-Force Pro Comp. tells me that I'm seeing a 6.5 RWHP gain where Nismo only claims 5.5 RWHP.

So 1 RWHP for $2.65 and a few hours labor. This is probably the most efficient mod $/HP ever.

 

Damn dude nice job keep up the good work and watch out for heavy rain

 

Good point about heavy rain. I shaped the trailing edge of the ram so that is actually slightly in front of the element. water spray should be minimal from the dam.

I suspect that I'll get more rain spray in from the bottom through all of those little holes in the pan which is part of the fender liner. At first I thought of blocking them, then I thought better since they would allow any standing water to drain.

 

Do you have a picture from the front of the car? Is it channeling air from the bottom?

 

No, it channels air from the front grill.

The bottom edge matches up to the engine cover pan. Here's a picture of it from the front. You can't really see anything, but that's the point, it looks like it's a stock part.

 

and from this angle, you can just make out some of the filter cone back in the bumper cover cavity.

 

Very cool DIY

 

How did you make that with the vents in it? Very cool!!!

 

Nicely done. I want to do the same.

 

Vents?

It actually sits directly behind the existing bumper cover slats. Is that what you're seeing?

Take a look at the template shown above. The left edge is what curves around facing forward, butting up behind the vertical slat in the bumper cover. The funny looking oblong in the lower left of the template fits into the center portion of the bumper cover below the grill.

I've also used some of the remaining material to block off the filter cavity from the engine compartment. I measured the temperature of the cavity at speed and at rest without it, and will measure the temperatures again tomorrow (when the ambiant air is the same) with the new shroud to see if it helps. If it makes a significant difference, I'll post the pics of that as well.

Roark

 

OK, as I promised and as requested, here are some pics of the heat shield, the fender liner taping, and results from testing with the G-Tech Pro Competition.

The cavity that the heat shield is going to block...

 

and from the inside...

 

The shield itself not installed

 

and this one installed.

Sorry, but this is the best pic I can make. This mat black polyeurathane (LDPE) just doesn't show up for the camera. I like the fact that it blends in with the stock materials myself.

 

Here's a mod I took out. Basically, I taped up all the vent holes in the fender liner with aluminum tape. At speed this creates a bit of positive pressure in the filter cavity thus more air to the throttle body.

Unfortunately for me, this actually lowered my power a bit below 50 mph, so not good for autocrossing. When I get this car on a road coarse (VIR in November I hope) I'll tape this back up. It's easy to do, and fairly easy to remove.