Autoblog Project Garage: Cold-air intake, Part I
In the quest to improve performance, few modifications provide the horsepower-per-dollar payback of a proper cold air intake. The issue here is that the factory usually designs for a different set of priorities than us enthusiasts hold dear; that in itself isn't evidence of poor engineering, but trade-offs are often embraced by those of us looking to go fast. In other words, this modification isn't for everyone, but it can reward handsomely.
For the price of a couple hundred bucks, an hour or so of your time, some increased maintenance effort in the future, and a the loss of some foul-weather tolerance, you too can enjoy the benefits of additional fresh air. The first photo in this post represents what our 1996 Impala SS looked like about eight years ago; one of our first modifications was to yank both resonators and replace them with a K&N conical filter and some PVC sewer pipe, as shown below.
This setup has served well in front of two engines and several different levels of build-up, but it has the distinct draw-back of sucking in a lot of hot air from the underhood area. As well, the filter resides in some real estate that we wanted to use for some other items (it's hinted at in the photo, so keep your eyes peeled for some additional posts in the future).
To remedy the issue, we investigated a variety of cold air intakes, and ended up with the "Ram Air Induction System". It uses a scoop mounted in the front lower air dam to pull in cool air, and routes the intake charge to the throttle body using the vast space between the rear of the radiator and the front of the engine. Seriously - there's enough room to stand in between the water pump and electric fan assembly.
Here's what the system looked like after we cut open the box and rifled through the contents a bit.
Needless to say, caution is required during the unpacking process to ensure removal of all packing material.
We officially kicked off the project by yanking the old filter and air tract.
Next, we remove the mass airflow sensor (itself a larger part, swiped from a GM F-body) from the old intake. The rest of the pieces were then set aside (meaning that the stuff got stuck on whatever shelf happened to be clean at the time).
Do not anger the twin 58mm throttle bodies, lest they consume all of your air. And yes, we really need to find some stainless steel cap screws to replace the rusty eyesores that BBK included with the throttle body.
Our next task was to mark the location of two holes that will be punched in the intake elbow. Wait - why would we be attacking our new intake with a drill bit?
Oh - there's the answer, and the makings of several future Project Garage write-ups.
To make life easier, a large C-clamp was used to flatten a section of the elbow. Note the T56 transmission mainshaft assembly in the background.
A bit of masking tape was used to protect the powdercoat finish.
Using a vise to hold the C-clamp makes life a bit easier for those that don't have three hands.
There we go - a nice flat spot, and almost where we wanted it! Hey, no one here claims to be an expert sheetmetal guy.
A view from the underside.
We tried to use the C-clamp method for the second flat, but it failed miserably. The ball peen hammer never lets us down, so we put it to work with a bit of help from a propane torch. That did a number on the powercoat.
A quick hit of semi-gloss black spray paint makes things look all better again.
A horrendously expensive Uni-Bit - worth every penny - was then employed to punch the required 9/16" holes in the intake elbow.
Here's what the throttle body will get to stare down for the rest of its life.
And here's a shot from the side. Yes, we mocked up the assembly underhood, and yes, it looks like everything will fit, thanks to those trick Aeroquip right-angle fittings.
Since we're not quite ready to play with the spray just yet, a pair of 1/8 NPT plugs go into the bungs, and seal up with the assistance of some Teflon pipe compound.
Stay tuned for Part II, where we install the hardware on the car.