Three-Valve Intake Manifold Dyno Test - Three's A Crowd

There is no question that the DOHC 5.0L Coyote engine has taken Mustang performance to new levels, and the spotlight, but if you have a Three-Valve 4.6L, there are still a lot of performance options available to increase the fun factor. Ported heads, larger camshafts, and boost can all take you to the next level—but even with an intake manifold as efficient as the stock one, performance can be limited.

Since it's introduction in the Mustang in the '05 model year, the Three-Valve 4.6L has had an amazing amount of support from the aftermarket. During its infancy, new parts seemingly hit the market every day. Among the slew of appearance upgrades and basic bolt-on performance parts, some hardcore go-fast goodies were designed and manufactured for those looking to go quicker and faster than most Mustang owners.

C&L Performance, Ford Racing Performance Parts, and JPC Racing each released an aftermarket intake manifold for Three-Valve Mustang engine. The designs are different, but the goal is the same—more power. The intakes are now within $200 of each other, but how do they perform? This month we are going to test each one on a naturally aspirated Three-Valve so you can see the results. Next month we will bring you the same test on a supercharged Three-Valve so you can see how horsepower is affected with boost.

All vitals, including timing, water temp, and cam timing were monitored using the SCT Live Link data logging software. All of the horsepower numbers are shown using the SAE correction factor, and the multiplier was the same 0.98 for each run. We used a Ford Racing Performance Parts throttle body (PN M-9926-3V) and a JLT Performance cold-air intake (PN CAI3-FMG05) as a constant for all testing.

"We (C&L Performance) have spent four years developing this intake manifold,” explains Lee Bender, owner of C&L Performance. "The first flow testing for our original production runner designs took place in May 2007. The manifold has gone through two completely different sets of tooling and two different runner configurations since the original design.

The C&L intake is a beefy piece. Its cast-aluminum construction, removable plenum cover (under side), and thick mating surfaces (cylinder head and throttle body) make it the heaviest in the group, but there are serious advantages to its design. C&L's cast intake will hold loads of boost, and has provisions for direct-port nitrous nozzles.

"By implementing individual port bosses for a direct-port system, our manifold allows enthusiasts to safely run as much nitrous as they are comfortable with, without fear of backfires, fuel accumulation, or fuel puddling issues,” adds Bender. He also tells us the intake can be iced at the track to chill the incoming air for additional power, although any gains will be seen for a very short period of time. The heat properties of a cast aluminum intake can also rob power when the intake becomes heatsoaked.

The final result was 375 rwhp and 318 lb-ft of torque, for a peak gain of 8 rwhp and 11 lb-ft of torque. Below 3,000 rpm, the C&L intake gained as much as 8 hp and 8 lb-ft, but the most impressive part is that it starts gaining hp at 4,200, and keeps gaining till you hit redline, with gains as big as 12 hp and 11 lb-ft through much of the second half of the graph.

"The Ford Racing intake gives you more plenum volume with shorter intake runners,” Kershaw adds. "The stock intake has about a 14-inch runner and the new intake's runners are 9.5 inches.”

"We designed the intake back in 2005 to fill a void in the market,” explains Burcham. "We wanted a big open plenum with shorter runners. It made good power through all of our testing, so we put it into production.”

"The design change was based around price,” says Burcham. The sheetmetal intake works well, but it's expensive to build and takes a long time to assemble. The cast intake's design hasn't changed much from the original, but there are some cosmetic updates. A lot of the corners and edges are more round. The throttle body plate is billet and allows you to run a larger throttle body by simply switching the mount. We've also added a provision for an IAT sensor in the plenum. This is designed for centrifugal supercharged and turbocharged cars with the sensor in the MAF before the blower or turbo.”

The cast version of the JPC intake laid down 381 rwhp and 316 lb-ft of torque for a peak gain of 14 hp and 9 lb-ft. The JPC intake's graph is slightly peakier than the graph with the stock intake. The JPC intake makes more power in the higher rpm range, but shows gains and losses in the low to mid-rpm range. At one point, the JPC is down by as much as 7 hp and 8 lb-ft, but a few hundred rpm later, it's up by 17 hp and 18 lb-ft.