Cold Air Intake Comparisons: Cold Score

Horse Sense: The cold-air intakemarket is big business because it's an affordable modification that canreap big gains on a box stock car--especially the '05 Mustang. Withnearly 200,000 '05 Mustangs hitting the streets--a reported 70 percentof them are V-8 GT models--this is a super competitive market forcold-air-intake designers and sellers.

As difficult as it is to pull off, we love to do product evaluations ofthe most likely parts our readers will buy, install, and keep on theirMustang for many years. And no product fits this description better thanthe ubiquitous cold-air intake. This simple device has one purpose: toget more air into the engine to increase efficiency and therefore allowmore horsepower to be generated with a simple parts swap. No car begs tobe modified like the '05 Mustang GT with its overachieving 4.6-literThree-Valve modular engine chugging out 300 hp in factory trim.

As was the case when we compared all available cold-air systems for the'03 Cobra (May '03, p. 170), we are constantly amazed at cold-air intakedesigners' creativity at getting more air into the awaiting engine. The'05 Mustang is the hottest car in America, and those creative juiceswere running overtime. Generally, most cold-air systems specific for the'05 Mustang offer a larger conical filter in the general underhoodvicinity of the stock airbox utilizing what Ford has already engineeredinto the car. (We had one obvious exception to this, as you will soonsee.) Some kits offer larger-diameter intake tubing as a freer-flowingconduit for the intake charge.

Once you get past the general design of these cold-airs, there is agreat deal of difference in materials utilized, price range, andnecessary tuning (itself a big cost factor) to make it work with theoften-finicky '05 Mustang computer programming. Our goal was to get asmany '05 cold-air intakes as we could find; put them all on the same caron the same day on the same dyno; use a scientific testing procedure tosee how they stacked up; and report back to you with the goods.

Several of the manufacturers of '05 Mustang-specific cold-air intakes wecontacted for this story chose not to participate. Our intent is not todraw attention to them, but we want our readers to appreciate theconfidence of the companies that chose to be a part of this 5.0 Mustangand Super Fords magazine test and evaluation.

Methods

We contacted MD Motorsports in Cincinnati and outlined our plans. MD isone of the top SCT tuners in the country, and, as such, has access to'05 Mustang software before most shops. In addition, they already had anumber of '05 Mustangs on their dyno, tuned them with positive results,and were interested in working on our comparison. The thing that sealedthe deal was the pending release of SCT's new '05 Mustang data-loggingsoftware (which turned out to be critical in the successful completionof this story), and MD would be the first in the nation to have accessto it.

We gathered contact information for the companies producing an '05Mustang CAI and sent an invitation to participate in the comparison. Inaddition to formalities, each letter contained the following informationon our testing protocol:

"To keep this test as accurate as possible, we will adhere to thefollowing testing protocol: The same car will be used for all testing onthe MD Motorsports chassis dyno. Rear-wheel horsepower will be measuredin 100 percent stock form. The car will then be tuned to a set air/fuelratio and set timing level. Each cold-air will be installed according tothe manufacturer's instructions. Rear horsepower will again be measuredwith the cold-air in place with run conditions (coolant temperature,inlet-air temperature, timing, air/fuel ratio, and so on) as close aspossible to the baseline pull. All efforts will be made to adjust theair/fuel ratio to the exact same as the baseline run to avoid thisvariable causing a change in horsepower. This testing procedure will becontinued for all of the cold-air systems submitted for the story, whichshould ensure we have the same weather, car, testing facility, andtuning for equal comparisons."

As one would expect, several manufacturers had questions about ourtesting procedure. Most told us it would be impossible to keep theair/fuel ratio the same given the funky-smart '05 Mustang computer. Andwe agreed to a point because of the given variability with the car,weather, tune, computer, chassis dyno, and other factors out of ourcontrol. Still, with a solid scientific testing program withstate-of-the-art equipment, as well as a skilled '05 Mustang tuner atout disposal, we were confident the task was doable.

Some of our participants didn't want any tune for their cold-air intake.Not only does this flaunt their engineering skills, but it also pointsout what a cost savings these systems are when a full dyno session witha custom computer flash can cost $200-$500, depending on the hourly ratefor your speed shop. We followed these manufacturers' wishes, and haveprovided rear-wheel horsepower measurements with just the cold-airbolted into position. But we also gave Ken Bjonnes the creativeopportunity to see what he could do; so you'll also see a dyno numberthat resulted from the CAI and an MD Motorsports tune.

Lee Bender of C&L offered an interesting way to verify our system. Sincehis kit comes with a DiabloSport Predator tuner with a well-testedprogram already installed, he suggested we install his tune, use thePredator to record timing and air/fuel, then copy that program with anSCT tune-up. Getting a rear-wheel reading from each tune would give usan idea of how much variability there was in the system with respect tothe computer changing the timing or air/fuel during a pull. Also, itwould reveal how much variance we could expect from pull to pull. Therear-wheel variance was unquestionably the scariest part of thisevaluation.

With so much reputation, respect, and money riding on our results, wedidn't want a false reading to unfairly judge one of our participants.To that end, Ken made back-to-back pulls that couldn't vary by more than2 hp. This was quite repeatable with each system, but we still set ourvariance at a possible 5 rwhp. That's a lot (almost 2 percent), but it'srealistic when you're dealing with chassis dynos, computer-interpreteddata, correction-factor changes, and weather conditions. From the startof our test to the end--some 10 hours--the temperature rose from 86 to 103degrees, and the SAE correction factor (used to correct for such weathervariations) moved from 1.02 to 1.03.

Our test car was bone stock (with the exception of a ZEX nitrous systemyou may see lurking in the back of some of our photos). The fuel tankwas filled with 93-octane fuel, and our target air/fuel was 12.6:1.Following the above-described protocol, Ken Bjonnes of MD Motorsportsset about tuning the car while his partner, Brandon Alsept, and our oldfriend, Tim Probst, got to the task of installing/swapping the kits.

Subjective Evaluation

At first glance, this would appear to be a straight-up horsepowerwar--but it isn't. The cold-air is an integral part of an entire systemand is typically one of the first upgrades on a serious '05 Mustang.Therefore, the cold-air is usually the longest-lived part on the car, soyou have to live with it through several stages of buildup. Beyond that,there's much more to the cold-air than how it affects horsepower gains.To add to the value of all this hard work, we wanted to expand on thisconcept, so we gathered a panel of five judges (made up of a materialsengineer, a Mustang racer, a Mustang street enthusiast, a 10-second '04Cobra owner, and a general hot-rodder) to help us evaluate each system.

We asked our judges to score each system on a scale of 1 to 10 (10 beingthe best) on ease of installation, value, appearance, overall qualityand merit of design, and expected durability. We've included the boxscores for each system to better inform you about each kit and how itdid in a category more important to you. We cautioned our judges not toinfluence each other, but we wanted them to discuss each system openlybefore they voted in case one of them caught something that should bepointed out before voting. As it turned out, the subjective evaluationgreatly enhanced our study, as it honed in nicely on the strengths andweaknesses of each system without directly comparing them.

Each cold-air prototype from our participants in the study has beennoted. They were labeled as such for our judges so that these earlyproduction units wouldn't adversely affect the evaluation.