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Three-Valve Intake Manifolds - Three's A Crowd
Part 2: Three intake manifolds for Three-Valve Mustangs with boost
Last month we showed what gains were available from three aftermarket Three-Valve intake manifolds in naturally aspirated trim. This month we're going to try the same three intakes, only now we'll see what the C&L, FRPP, and JPC intakes can do with a little boost behind them.
We headed back to Boca Raton, Florida, where the crew at Blow-By Racing was buttoning up the engine install on the '06 GT of Jillian Gastright. The new combination consisted of a BBR-built 302ci modular short-block, stock Three-Valve heads, BBR Stage 2 cams (which are locked out), and a TR-6060 six-speed transmission. Boost comes from a Vortech T-trim centrifugal supercharger, which is pullied for about 18 pounds of boost.
Looking for big power, Chris Jones, owner of BBR, went to work tuning the GT with the stock intake manifold. As the test got underway, we realized we couldn't perform the test the same way we did with the NA S197. The ignition timing was the same in every run in the previous test, which made for a great apple-to-apples comparison. But this time, we adjusted timing to optimize each combo. Each manifold performed differently with only slight timing changes. We still made sure the ambient temperature and the water temperature remained as close to the same as possible.
When the tuning with the stock intake was complete, the combination laid down 645 rwhp and 543 lb-ft of torque with 17 degrees of total timing. These numbers are pretty stout, and we were excited to see what difference the aftermarket intakes would make.
As the test went on, we discovered the unported stock heads were likely a restriction, and the addition of ported heads would make the gains from each of the intake manifolds significantly larger. In a high- horsepower combination like this, every car is different, and will react differently to modifications such as manifold changes.
C&L Performance PN 720
The C&L Performance Three-Valve intake manifold was designed to work well in numerous combinations. Its cast aluminum construction makes it great for boost (or nitrous), as it can handle loads of pressure without any fear of ballooning or breaking. Its 10.25-inch long-runners give you a great combination of low-end torque and mid-range power, which is great in cars that see mostly street time. The C&L intake is also a great race option, as it can hold as much boost as you can throw at it, and if you ice the intake, the aluminum will hold the cold long enough to make the incoming air denser for more power potential, but only in very short increments of time.
The C&L was the first intake installed on Gastright's '06 GT. Given that the C&L intake has the longest runners of the group, we expected to see the least amount loss down low, and good gains up top. With these expectations in mind, Jones went to work on the tune.
The timing and fuel changes were handled with SCT software, and when Jones was finished with initial tune, the S197 laid down 649 rwhp and 561 lb-ft of torque, but looking at the amount of timing and the air/fuel curve (on the rich side) we knew there was more. After about a half dozen pulls with more power, Jones found the sweet spot and was not able to make any more power. With the timing set at 18 degrees, the end result was 658 rwhp and 572 lb-ft of torque, giving us a peak gain of 13 rwhp and 29 lb-ft of torque.
Below the peak, power and torque were nearly identical until 4,000 rpm, only losing about 5hp and 10 lb-ft of torque between 3,000 and 3,5000 rpm. Between 4,000 and 4,600 rpm, power and torque was up by as much at 22hp and 18 lb-ft of torque. From 5,000 rpm to redline, the C&L intake pulled away from the stock intake, quickly gaining about 15 hp and 15 lb-ft of torque and carrying it till the end of the run. Given the gains over stock, the C&L Performance intake manifold is a great street or race option.
Ford Racing Peformance Parts - PN M-9424-463V
Ford Racing Performance Parts has designed its Three-Valve intake manifold to be a great all-around performer at a great price. It was strong in our naturally aspirated test, and is the only composite intake in the group (other that the stock manifold). Its composite construction is great for beating heat soak issues. The downfall to this design is possible ballooning under high boost, and possible bursting in extreme combinations. According to Jesse Kershaw of FRPP, Ford Racing tested the Three-Valve intake to 2.5 bar pressure, or roughly 35 psi, and after some ballooning in the early development phases, the intake manifold has specific reinforced areas, which allow for extremely high boost levels. Even above this, the manifold will not burst. Instead, the gasket is designed to bleed off the boost and re-seal as the boost level drops. One could theoretically RTV the manifold together eliminating this "blow off" safety, but at over 30 psi, a sheet metal intake manifold might be a safer option
The intake was quickly swapped onto Gastright's GT. Jones made a baseline pull and after looking at the datalogs, he made changes to the timing and fuel curves to bring the air/fuel ratio as close to 11.7:1 (the air/fuel number used as the standard throughout the test), while making the most power as possible. When the tuning was complete, Jones made 659 rwhp and 557 lb-ft of torque for a peak gain of 14 rwhp and 14 lb-ft of torque with 18 degrees of timing.
At the start of the run, the FRPP intake showed slight gains (8hp and 7lb-ft of torque) over the stock unit, but power and torque were nearly identical from 3,400 to 4,700. At 4,700 rpm, the FRPP intake began to gain power and torque, quickly reaching the 14hp and 14 lb-ft gain, which it carried until the end of the pull. Its combination of runner length, plenum volume, and lightweight construction make it a great choice for anyone looking to add some power to their boosted Three-Valve.
JPC Racing PN 3V Cast Intake
The JPC Racing Three-Valve intake manifold was designed to benefit Mustang enthusiasts and racers looking to extend the S197's rpm range.
Although any intake manifold with runners shorter than stock should make more power in the higher rpm range, shorter runners can sacrifice power and torque at lower rpm. Justin Burcham of JPC designed this intake to be a balance of minimal low-rpm loss and maximum high-rpm gain.
Jones installed the JPC intake and began making changes to the tune. The baseline pull netted great numbers, and we were excited to see how high the horsepower numbers would be. When Jones reach max power, timing was at 19 degrees, and output was 672 rwhp and 588 lb-ft of torque, for a gain of 27 rwhp and 45 lb-ft of torque.
Given the short-runner design of the cast JPC Racing intake manifold, we expected it to show the biggest high-rpm gains, but we were impressed by how much power and torque picked up. Given its short runner length (just over 8 inches), we expected low-end power to be greatly reduced, and although the JPC intake lost as much as 13 hp and 25 lb-ft below 3,000 rpm, it was even or better than the stock intake from 3,200 rpm to redline. There is an exception of one spot where power dropped, but this could most likely be corrected in the tune.
If you race your Three-Valve Mustang and want to take advantage of high-rpm power potential, the JPC Racing Three-Valve intake manifold is the way to go.