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JPC Racing Three-Valve Intake - Short Running
MM&FF Tests The Jpc Racing Three-Valve Intake On A Supercharged '06 Mustang GT.
"This intake is not meant for the guy with a stock engine. It was designed specifically for a healthy Three-Valve street or race engine-particularly a supercharged one," commented Justin Burcham of JPC Racing when we asked him about the JPC intake for Three-Valve modular engines. This was the first mass-produced aftermarket Three-Valve intake available for sale-it went on the market over a year ago.
Moreover, this isn't our first glance at the piece, as we first saw this intake nearly three years ago as a raw prototype when it went through rigorous real-world testing on dozens of different Three-Valve engine combinations. Now, only after extensive R&D, we're finally ready to present a real test the way you'd expect from us.
JPC teamed up with Custom Performance Engineering to bring the intake to market and the final design is a proven performer. It's been revised, refined, and finally cast into an intake that will help your Three-Valve breathe easier, enabling more horsepower and performance from many '05-present Mustang GTs.
As many times as we have been to JPC Racing, this is the first time we have actually conducted an official MM&FF test on this product. Our one request to Burcham was that he hand an intake over so we could independently test it against the stock intake.
The JPC intake was shipped up to Dez Racing (Seekonk, Massachusetts), where Mike Dezotell (Dez) and Brian Machie handled the installation and chassis dyno testing. Dez dug up a suitable candidate for this intake comparison, a supercharged 2006 Mustang GT with a 300ci stroker engine that features forged pistons (9:1 compression), steel rods, and a steel crankshaft. The short-block was more than capable of handling a decent amount of horsepower and rpm. The upper half of the engine features Fox Lake-ported Three-Valve heads, stock camshafts, stock intake and throttle body, and a Vortech H.O. kit (SQ-trim and air-to-water Vortech Powercooler).
The JPC intake was just right for this combination given its larger cubic inches and the supercharger huffing into the potent mod motor. The car cranked out 515 rwhp (sans meth injection and on pump gas) and peak horsepower came at 6,500 rpm. The stock camshafts are in place and are probably hurting the engine's potential for 7,000-plus-rpm pulls. Despite the 6,500-rpm limit, the mid-range numbers with the JPC intake far exceed the stock intake. "This is typical of short-runner intakes because the power band is shifted up. The runners are also slightly larger than stock to aid in airflow," stated Burcham.
The installation was simple and thanks to our test car being equipped with an -8AN feed line, the JPC intake went on in less than two hours. Experienced mechanics can probably get it swapped in an hour or so. We ordered the intake with new JPC Racing fuel rails and Steeda charge motion delete plates. Burcham sent us a set of delete plates that were milled down a quarter-inch to clear our stock hood. Those with a cowl hood or similar rise in the center can get away with uncut delete plates.
We continued to employ the stock throttle body for two reasons. First, the intake was designed to enhance the airflow behind the throttle body. According to Jordon Gartenhaus of Custom Performance Engineering (CPE), "The throttle flange inlet measures 62 mm to take advantage of larger-than-stock throttles, and features a diverging taper that expands into the plenum. This diverging taper, or diffuser, allows for a gradual expansion in volume, which preserves kinetic energy, but the angle is low enough as to not induce flow-separation. This reduction in energy loss when entering the plenum will result in lower required boost pressures for forced induction applications, which reduces the intake air charge and increases engine pumping efficiency." Gartenhaus and his CPE team worked side-by-side with Burcham on the design and manufacturing of this intake.
We also kept the stock throttle body because continual testing has shown little gains in centrifugally supercharged applications. JPC offers the intake with a single opening for those customers who have (or want) to use a single-blade throttle body.
One look at the intake and people quickly assume the short-runners will kill low-end power. Conventional theory about short-runner intakes versus long-runners dictates that the torque will decrease slightly at low rpm because the runners are tuned to flow more efficiently at higher rpm.
"This is typical of short runner intakes and because the runners are shorter than stock, the power band is shifted up. The runners are also slightly larger than the stock port dimension to aid in airflow. Our runners are about 33 percent shorter than stock and measure 6.9-inches in length. Again, we were shooting for an intake that had a decent runner length, but was shorter than stock to move the power curve up where it is easier to make power," noted Burcham. "Theory is great, but physical testing is the only way to know if your ideas are good. We went through a great deal of effort to keep the runners as long as possible, and since the runners are all cast with the same tooling, they're all equal-length."
Burcham and his staff tested several different designs before settling on this final product. The runners may appear short, but the real story lies inside the plenum box, where the runners extend a few inches into the center.
One theory that was put to the test was the addition of bell mouths at the runner openings in the box. Burcham explained, "if you look at any fluid dynamics book, it will explain that a bell mouth is the ideal way for fluids to enter tubes. We actually did a lot of testing on this for our own education during development.
"Several radius dimensions were tried on a flow bench to determine the ideal radius. Testing showed a 10-15-percent gain by adding a bell mouth to the end of a tube on our flow bench. One of the things that is interesting is that rounded edges are ideal for air speeds below the speed of sound and that sharp edges are good for air speeds above the speed of sound, so everything is as round as possible everywhere."
Real world testing proved the bell mouths were effective, even in this application where the fuel is added after the bell mouth openings. On the dyno, theories and real-world results clashed during our testing. Despite popular belief, torque didn't suffer, and when comparing peak versus peak output, the JPC intake gained 44 lb-ft of torque at the wheels. At one point in the curve, torque was 50 lb-ft better than the stock plastic unit! From 3,900 rpm until redline, the JPC intake produced more torque. That rpm range is where you are going to see quicker results on track, too. Below that rpm, the curves fluctuated back and forth but didn't stray too far from each other.
Moving to the horsepower side of the equation, 3,900 rpm seemed to be the threshold once again where the JPC intake's rwhp gains became apparent. Comparing the peak rwhp numbers, the JPC intake gained 23 rwhp (538 versus 515) as both peaks came at 6,500 rpm. We thought the intake would help this engine achieve 7,000 rpm, but it came back to the stock camshafts hurting the rpm capability.
Horsepower gains at the peak are nice, but the average increases were more impressive. At 5,000 rpm, the JPC intake produced 38 more rwhp, yet we saw a gain of 46 rwhp at 5,800 rpm. Generally speaking, the average power between 5,000 rpm and 6,500 rpm is where a Mustang operates on the dragstrip. "The gains will be seen on the dragstrip when the driver shifts and the rpm drops back to 5,000 rpm. An engine generally sees a 1,500-rpm drop (in engine speed) after the gear change," claimed Dez.
Here are a few facts about our testing. The 2006 Mustang GT was run on pump gas, and while there was a Snow Performance kit plumbed into the intake tract, Dez turned it off for our tests. SCT software and a handheld tuner were used to tune this beast. Dez kept the timing consistent at 19 degrees and only had to fiddle with the tune to compensate for the Steeda charge motion delete plates. Boost remained largely the same on the Auto Meter gauge that was mounted on the A-pillar. Dez said it touched 15 psi on both runs at 6,500 rpm. It is not the most scientific way to track boost pressure, but he said if anything, the new intake might have scrubbed off a half of a psi. We also have to send a big thanks to Imperial Ford, a Ford Racing dealer, for helping us with a set of stock coil plugs.
Initial testing resulted in a misfire in the upper rpm range. On advice from Burcham, Dez swapped to a new set of OEM coil plugs and we retested the two intakes. The stock coil plugs helped the engine pull smoothly to 6,500 with both intakes.
When all was said and done, the gains in the torque and horsepower were impressive. The broader curves will make for a nice drop in e.t.'s at the track. The intake retails for $1,190.00, and while more expensive than some others on the market, the gains are plentiful for the cost-especially when you get in the 500- to 600-rwhp realm. Broad gains in torque and horsepower with a peak increase of 24 rwhp and 44 lb-ft of torque is quite impressive.