Michael Galimi
June 1, 2009
Here It is! The new C&L Three-Valve intake manifold picked up great horsepower on a mildly modified '06 Mustang GT.

During the summer of 2008, C&L Performance made a surprise announcement--it was nearing completion of a high-flow Three-Valve intake manifold.

The company is long known for its MAF sensors and high-quality cold-air intake kits, so some might see the move to intakes as unusual, but according to Lee Bender of C&L Performance, it was a natural fit for the company. "This was a natural progression for us. Before development of this product began, we had designed a new complete intake manifold assembly for the Two-Valve 4.6L engine, which was used in the '99-'04 Mustang GT. However, all business indications pointed towards the Three-Valve market as being the future for our company. While other businesses have been working on a Two-Valve intake, we are now releasing a Three-Valve manifold."

The in-house test mule that C&L used was a completely stock Three-Valve Mustang GT, and C&L's Lee Bender provided us with this dyno graph of the intake tested on said vehicle. Above 4500 rpm, the new intake really takes off. Add some cams or some boost (or both) and there is some real horsepower to be gained.

Bender and his crew of airflow specialists started with a clean sheet of paper. The team worked first with computer modeling, then moved to real-world mock-ups. Bender offers insight to the long development road. "The basic design of the intake manifold has remained relatively unchanged throughout the development process. This is because the original criteria for the product dictated that it have both a long runner path for each port, as well as a flow capacity that exceeds the current needs of all Three-Valve Mustangs. This is the key to making the product flexible enough to be beneficial for basically everyone, from a completely stock application to a more serious high-horsepower application with upgraded heads and/or some form of supercharging. It took over a year to get to the point where an actual intake was bolted on a Three-Valve and tested on the chassis dyno and on the street."

Bender kept us in the loop as he coordinated the design and manufacturing groups. Each step of the way the team was faced with two ultimate questions. First, can it be manufactured and marketed at a reasonable cost? Second, will it work as intended? For the record, the intakes are 100 percent American-made.

"With the this all-new intake manifold and the subsequent release of C&L's all-new cylinder heads for these engines, we expect to continue this legacy of innovation in the Fordperformance aftermarket. The development of this product has been a long road for us, as we have spent just over three years time making all of the necessary adjustments to fine-tune the product for final release," comments Lee Bender.

"The biggest challenge in making this product a reality was getting the tooling configured properly. This is a very large casting, and is much more difficult to produce than anything that we have ever done before," says Bender. Before a bolt was turned on a car, the intake was optimized on the flowbench, where it significantly out-flowed a stock intake, but still carried long runners for healthy low-to-mid-range power, in addition to the higher rpm flow capabilities.

"Our proprietary computerized flowbench was used throughout the development cycle to ensure our goal for total airflow was met," proclaims Bender. "Our original goal was to have both balance among the runners, as well as a minimum flow capacity of 315 cfm per runner. In the end, testing has shown that none of the runners flow less than 317 cfm, with the average port flow typically in the 325 to 330-cfm range. An important design criterion was that all ports for each respective side of the manifold must use the exact same core. This means that even with minor casting variations, all of the runners on each respective side of the engine are basically identical to each other. This is not something you will typically find in most intake manifolds, even in the aftermarket."

In-house testing was conducted on a stock '07 Mustang GT, and it picked up 15-17 hp at the tires. We got our hands on a production piece to check things out for ourselves. Judgment day for independent testing of the intake came on a chilly day this past winter. C&L had just made the final revision, acquired a patent, and started production, and we received one of the first intakes off the assembly line. The installation and testing was performed at Evolution Performance. Some might know the shop for its work in the Shelby GT500 segment, but it is a full-blown speed shop catering to Mustangs of all years.

While C&L chose to focus on a stock car as a "worst-case" scenario, we wanted to try the intake on something that was a little more worked. A naturally aspirated combination is a true indication of whether or not an induction component is effective, since the engine relies on the Earth's atmosphere instead of being force fed.

Fred Cook of Evolution quickly offered up a few cars that fit our mindset--naturally aspirated, stock short-block, and real-world. We settled on a '06 Mustang GT equipped with a custom tune by Jon Lund, BBK long-tube headers and cross-pipe, Flowmaster American Thunder mufflers, a C&L 95mm Racer air intake, and a pair of Comp Cams Thumpr TH265LL camshafts and Cam Phaser limiters were installed.

The base plate for the plenum is removable for access to the runners for porting. This also leaves the door open for C&L to offer larger plenum base plates for more racy combinations.

The baseline in this trim produced a rather impressive 341 rwhp and 317 rwtq, but there are two things to note; the car features an automatic transmission, and Evolution has a Mustang dyno. Both items generally knockdown the output slightly when compared to a stick-shift car tested on a DynoJet chassis dyno. This is an A-to-B comparison, so we kept the variables equal and repeated the results to ensure accuracy.

Installation of the C&L intake is straightforward; there are no quirky or mechanical difficulties. The only thing to note, care is needed when tackling a throttle body swap. Be very careful when moving the electric motor from the stock unit to an aftermarket throttle body, like the Whipple single-blade one that we used in this test. Another noteworthy item, be sure to use the C&L supplied throttle body gasket. The factory intake has an O-ring style gasket while the C&L intake uses a traditional square gasket. Those who are experienced mechanics can tackle this installation in less than two hours. Those who are not accustomed to turning wrenches can get this job done in less than three hours.

Here are the runners with the plenum plate removed.

The front-mounted throttle body feeds into a plenum, where the air is sent into the runners from the topside. A bottom plenum plate bolts on and is easily removed for porting or hiding a nitrous system. The intake itself is a long-runner style and each runner is equal in length. He also told us that the C&L runners are the same length as stock but follow a vastly different route, helping the air move quicker and more efficiently through the ports. On the outside, each runner has a boss that can be used to plumb a direct-port nitrous system (one nozzle per runner).

The intake performed exactly as Bender predicted. Output swelled to 368 rwhp and 315 rwtq, a stellar 27 rwhp better than the baseline numbers. Torque fell by 2 rwtq at the peak reading, but the curve was more aggressive and flatter than stock. The C&L intake will perform admirably at the track and on the street. This test utilized the factory throttle body, which has been proven to be quite effective in most applications.

The '06 Mustang GT we used for testing features larger Comp camshafts, BBK long-tube headers and cross-pipe, Flowmaster mufflers, a C&L 95mm cold-air kit, and a custom tune by Jon Lund. The car was built at Evolution Performance.

As a side note, we also wanted to compare the stock throttle body to a larger aftermarket one. Thankfully, Evolution is a stocking dealer for Whipple products and had a single-blade unit ready to bolt on. Adding the throttle body was quick and easy, but thanks to modern vehicle electronics, it does require additional tuning. Jon Lund fired up his laptop and worked on a new tune, using SCT software. If the ECU is not adjusted for a new throttle body, the throttle will hang open on deceleration and idle situations. The driveability can also be affected in a negative manner because the throttle blade won't be working in sync with the ECU. The throttle body added considerable tuning to the bill, which means you would spend more money when upgrading it.

In the power department, we saw a gain of 4 rwhp to bring the total to 372 rwhp. Torque remained identical at the peak at 315 rwtq. For those who lack math skills, that works out to a 31-rwhp gain with the addition of the C&L intake and Whipple single-blade throttle body.

We reused the gaskets from the OEM IMRC plates. Be sure to clean the gaskets before inserting them at the bottom of the C&L manifold.

Is the throttle body worth the extra tuning and component costs? Adding the larger one still picked up power, just not enough for the $650 price tag that comes with it, sans tuning bill. The throttle body might be worth it for those who have money to burn or for force-fed applications, but it wouldn't be a good investment in a combination like this one. While the larger throttle body smoothed the dyno graph rather nicely, the engine simply didn't need the extra air from the massive single-blade unit. It is a proven fact that the larger throttle body picks up a good amount of horsepower on a twin-screw and Roots-style supercharger combination. We did, however, fall in love with the Whipple's black finish as it matches the intake and blends in nicely. The factory throttle body looks a little out of place with a nice manifold behind it and a C&L racer cold-air kit in front.

Bender explains why the larger throttle body didn't do much better over the stock one. "The factory throttle body on these vehicles [Editor's note: '05-newer] is exactly the same size as two of the throttle bodies that came on the '86 Mustang GT, which was the first fuel-injected Mustang 5.0 with a factory rating of 200 hp. I have tried to stay away from aftermarket throttle bodies due to all of the issues that people seem to have with them. Even properly installed, the Whipple throttle body requires a good bit of tuning adjustments. If you don't retune the computer, the rpm will hang up when you come off the throttle." Nevertheless, we still dig the black-on-black look when compared to the stock throttle body.

The intake drops into place cleanly and easily. There is no need for IMRC plates due to the extended runners on the intake manifold.

Our mild Three-Valve engine loved the extra airflow, and the graphs show the difference in the upper rpm range between the stock and the C&L intake. Lund says it best: "The C&L intake allows these aggressive cam profiles to come alive above 4,500 rpm. The larger, open-plenum design allows the torque to remain nearly the same, but still pick up over 30 rwhp up top [Editor's note: intake and throttle-body upgrade]. Extending the rpm range on the Three-Valve has a whole new meaning with this setup." We didn't test a set of ported heads with the intake, but given the generous gains over the stock manifold, we're sure this combination can run deep into the 11s with the stock short-block.

The C&L intake is the first step in the company's new products for 2009. The group is feverishly at work on finishing a new cast set of Three-Valve heads to complement the new manifold. Bender tells us that the heads are completely new castings, and the goal is to have the heads flow better out-of-the-box than ported factory castings. In the meantime, producing 372 rwhp makes for an awfully fun street ride.

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