Bad00SS

I was cleaning out my air filter on my Z and noticed if you take the 2 push pins out of the plastic air damn you can spread it open and it goes right to the outside air. I would think this would get alot more cold air in the motor if you could hold this spread apart or trim it. has anyone done this? the car never sees rain. ever.

MTPZ06

It can cause surging/MAF turbulence if you're still on a stock tune...but it is effective at feeding cold air to that area.

Unreal

Vette air scoops work awesome.

FNBADAZ06

I've used this mod on my car, and after logging several events this is my take.

1) this will cause some drivability issues due to the turbulent air now reaching the airbox, which will cause some bucking at lower RPM at low loads.

2) during the summer months, the close proximity to the radiator allows hot air from the radiator to be pulled into the airbox, significantly raising the air temps well above ambient.

3) for drag racing purposes in the winter months when air temps are below 60 degrees, this can provide a direct path for cooler dense air to reach the engine. Even with the radiator heating the air at the inlet, it quickly drops down to ambient once the run begins...much faster than with the shroud closed.

For the best of both worlds, a dedicated ram air CAI like the Vette Air or LG unit will be a superior way of providing cold air as it pushed the air inlet away from the radiator.

Bad00SS

I find it hard to believe hot air from the radiator could make it around that shroud when its opened up and actually effect IAT's when the car is moving. maybe at a stop light. but not moving. this has to be an improvement.

JoesC5

I have the Vette-Air scoop. It goes through the radiator shroud, and picks up air some 3"-4" in FRONT of the A/C condenser, and is right behind the grill. A better solution than popping the shroud open at the bottom.

It will cause problems with the MAF, so I added a flat diffuser plate on the Vette-Air's discharge opening, so the incoming rush of air would not hit the face of the filter element directly.

I also added the "wings" from an Airaid CAI to the top of the radiator shroud to help cut down any hot air from spilling over from the engine compartment into the air breather compartment when stopped.

TRSCobra

The vette air scoop works well with the halltech filter and beehive shroud. The incoming air hits the rubber top of the filter and prevents MAF turbulence issues.

JoesC5

I wasn't willing to trade the best air filter available(the factory stock Donaldson PowerCore) for an oiled cotton gauze filter.

jayyyw

Instead of spending ~$130 on the vette air scoop, I propped the shroud open with some flat aluminum and screws. Seemed to have cleared up some surging I had around 12-1500rpms.

db2xpert

Vette Air works very nicely on the street or for drags.
Not good for road racing as it blocks airflow through the radiator.

MickVette

I did and the performance gains were really good. It did increase low speed surging etc as described above, but I was able to tune most of that out with a lot of trial and error...mostly error. I also installed methanol injection at the same time. I can manually spray the methanol if I feel the intake tamps need to be pre-"cooled" prior to getting on it. The car ran ~164.5 in the 1/2 mile which is pretty good for a H/C/I/E car with a modest cam. I had the center lower section blocked off to do some previous tuning troubleshooting and forgot to open it back up during the 1/2 mile or I might have been able to hit that elusive 165mph. DANG!!!! Here is a video as I tuned the car during the 1/2 mile:

Opened the inlet on the bottom of the air box along with opening the NACA duct area (not shown):


Starting to mold the back (high pressure) area of the air box to the air filter:


Another view:


How it currently looks (except with a methanol injection line feeding the plastic ducting in front of the throttle body):

The_Raging_Bull

I agree with your observation, and understand the concern over turbulence.

However, I've seen some examples of where folks tried to open this slot open up using various rotary tools.

To a fault, each effort looked absolutely terrible; with lots of debris, and lots of control issues with a high speed tool. It looked like a hack, not like a clean CNC cut job.Having worked in labs all my life, I came up with a method I've tested on some plastic just like under the hood. I have yet to apply it to my car since you only have one chance to make it perfect; and I wanted to perfect my technique before attempting it on my Z.

At any rate you need to build a template i.e. a wood guide around the hole that you can use to guide a tool around as you cut out the opening. My method? Use a smaller spatula, heated to glowing with a propane torch to cut and trace around the template until the cut is complete.

Once cut I've been able to finish dressing my trial cut-outs to look pretty good. Not CNC good, but way better than anything I've seen with a dremel or other rotary tool. It all comes down to how well you build your guide. Like you I dont drive in the rain ever; so there's no issue with water going into the engine. However the small spatula and guiding by hand with a template gives a very stable way to cut a hole that looks pretty good. Instead of rotary debris, some melted plastic extrudes along the cut. It looks like flashing and will break off leaving a clean cut melted/solidified surface behind it.

Once I try the method in the car, I'll take pictures and post.

Comments?? Perhaps a internal baffle can be placed to re-direct the air so it doesn't upset the MAF boundary air layer.

MickVette

Another way:
I used an electric heat gun to soften the plastic and was easily able to rough cut mine with a sharp knife (shown in the above pictures). I went back and trimmed everything very smooth later (not shown).

I did construct a baffle to lessen the turbulence at the MAF and it definitely helped a lot with drivability. I removed it for the 1/2 mile race and tried to see if I could tune it to run smoothly and was successful enough to keep it removed. My only concern is heavy rain with an opened NACA duct hitting directly on the air filter.