May 1, 2007

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Mmfp_0705_01_z Intake Add_horsepower
How do you add 67 hp to your average 5.0L Ford? The answer is just II easy.
Mmfp_0705_02_z Intake Edelbrock_performer_rpm_II
The new Edelbrock Performer RPM II featured revised runners and plenum volume to offer even more performance than the previous RPM version.
Mmfp_0705_03_z Intake Install_motor_on_dyno
Our test mule consisted of a CHP 306 equipped with a set of Holley aluminum heads, a Comp Xtreme Energy cam, and a stock 5.0L H.O. intake manifold. Here the motor was installed on the dyno with the lower manifold in place.
Mmfp_0705_04_z Intake Ford_tfi_distributor
MSD supplied a billet Ford TFI distributor for our test mule to ensure accurate ignition timing.
Mmfp_0705_05_z Intake Install_matching_upper_intake
We then installed the matching upper intake along with the throttle body and mass air meter.
Mmfp_0705_06_z Intake Runing_tests
We ran a 70mm Cobra mass air meter and computer from Ford Racing Performance Parts. The meter and computer were run with the matching 24-pound injectors.
Mmfp_0705_07_z Intake 70mm_billet_throttle_body
Accufab supplied this 70mm billet throttle body.
Mmfp_0705_08_z Intake Test_results
On the dyno, the modified 302 produced 318 hp and 354 lb-ft of torque with the stock 5.0L upper and lower intake.
Mmfp_0705_09_z Intake Installing_injectors
After running the motor with the stock intake, we swapped on the new Edelbrock Performer RPM II. Shown is the lower manifold installed along with the injectors and various sensors.
Mmfp_0705_10_z Intake Graph
Stock H.O. EFI Intake vs. Edelbrock Performer RPM II-306 FordThe graph shows the new Edelbrock Performer RPM II intake greatly improved the power output of the 306-cube test motor. The new intake upped the power peak from 318 hp to 385 hp, a gain of 67 hp, measured peak to peak. Near 6,100 rpm, the gains were as high as 87 hp. That is the kind of power you associate with a nitrous system or a good set of aftermarket cylinder heads.

The Problem with sequels, especially ones that follow a huge box-office success, is that it's difficult to reproduce the original magic. Arguably the most influential movie ever made (at least according to this author), was Jaws, which literally grabbed a nation and dragged it under for a feast. Not surprisingly, the bean counters demanded a sequel. In all fairness, the audience (including your author) was ready and waiting for more marine mayhem. Unfortunately, even the catchy tagline "Just when you thought it was safe," an increase in realism (discounting the 3D disaster), and a better behaved Bruce (the mechanical Great White) did little to improve upon the original.

Not having the salty Quint character surely hurt the later versions, but sequels by nature are a tricky business. Where the original Jaws kept people safely on the beaches, the sequels (especially 3 and 4) kept people from the theaters. Such is the gamble when attempting to recreate the magic offered by the original.

While the successive shark pictures yanked the teeth from the original, sequels in the automotive world can be a wonderful thing. Edelbrock's new Performer RPM II intake certainly fits into this second group of sequels, where the follow-up is an improvement over the original.

Actually, it's not surprising that the new Performer RPM II for fuel-injected Ford Windsor motors offers more performance than the original Performer RPM. Not content to stand on past success, Edelbrock continues to improve the breed, even if it means redesigning a product that has already proven itself.

Anyone familiar with Edelbrock knows about the three-tiered approach to performance. Given a stock powerplant, the Performer lineup of components offers a sizable gain in power. Stepping up to the Performer RPM series brings greater power potential. While the Victor Jr. components offer dramatic power gains, they are for more serious combinations.

Remember, there is no free lunch, as shifting the torque curve to increase top-end power often reduces low-speed torque. It depends on where you want peak power to occur. For most street applications, the Performer and Performer RPM components offer the best overall power curve, something verified during dyno testing of the new Performer RPM II intake. The revised design featured altered runner size and length along with a change in plenum volume. The improved flow rate and change in runner length greatly improved the power potential in the new design. Testing has shown gains of up to 20 hp or more compared to the already impressive Performer RPM intake combination.

While we know Edelbrock had done its homework on the new intake, we decided to put it to the test. We selected a 0.030-inch-over 302 Ford built by Coast High Performance. The 302 featured a stock block and crank but was augmented with forged pistons and rods. The CHP 302 received an Xtreme Energy XE274HR hydraulic roller cam (0.555/0.565 lift, 224/232 duration and 112 lobe separation) before being topped off with a set of Holley SysteMAX aluminum cylinder heads.

The Holley heads featured free-flowing ports, a 2.02/1.60 stainless steel valve combo, and 64cc chambers. The 64cc chambers produced a compression ratio of 8.8:1 on our CHP 306. To put the new RPM II EFI intake to the test, the motor was also equipped with a stock 5.0L Ford H.O. upper and lower intake combination. A 70mm AccuFab throttle body was used on both intakes, as was a set of 24-lb/hr injectors, and a Ford Racing Performance Parts Cobra mass air meter and matching computer. The power output of each combination was optimized by altering (read: tuning) the ignition advance curve. In both cases, the motor made the best peak and average power with 34 degrees of total timing. As always, we protected our test motor with 5 quarts of Lucas synthetic oil.

The modified fuel-injected 5.0L engine was run on the engine dyno at Westech. Equipped with the stock 5.0L H.O. upper and lower intake, it produced 318 hp and 354 lb-ft of torque. Given that a stock 5.0L Ford was designed to produce peak power near 5,000 rpm, it was not surprising that the stock intake limited peak power to just 5,100 rpm. The smaller-sized, long runners of the stock EFI intake helped the motor produce impressive torque at low and mid-rpm, bettering 300 lb-ft from 2,500 to 5,400 rpm. The peak of 354 lb-ft occurred at 4,400 rpm, but the motor produced 350 at 3,500 rpm. In fact, the torque curve was fairly consistent from 3,400 all the way to 4,600 rpm. After reaching a power peak of 318 hp at 5,100 rpm, the power leveled off and eventually dropped down to just below 300 hp. Given that the stock intake was designed to support just 225 hp, that we made 318 hp was indeed impressive.

After running the modified 5.0L with the stock intake, we swapped the new Edelbrock Performer RPM II and were immediately rewarded with extra power. Installing the RPM II was no more difficult than any intake swap, requiring removal and replacement of the injectors (and rail), the various sensors, and the 70mm AccuFab throttle body and tapered EGR spacer. No tuning was performed other than ensuring the total ignition timing was kept constant, as the mass air meter-equipped motor produced a near-perfect (and identical) air/fuel ratio throughout the rev range. Just as with the stock intake, we ran the hydraulic roller motor from 2,500 to 6,000 rpm. After the dust settled, our RPM II showed its worth by upping the power peak to a whopping 385 hp.

Imagine that: Adding the Performer RPM II intake resulted in a gain of 67 hp (peak to peak). The peak torque was up as well, from 354 lb-ft with the stock intake, to 368 with the Performer RPM II. Near the power peak of 6,100 rpm, the Edelbrock Performer RPM II outpaced the stock intake to the tune of 87 hp-a sweet sequel indeed.

Note from the supplied power curves that the Performer RPM II intake began its charge at 4,000 rpm and never looked back. Below 4,000, the stock intake was actually slightly better, though only by a small margin. Equipped with the stock intake, the 306 produced peak power at just 5,100 rpm. Adding the RPM II shifted the power peak from 1,000 rpm to 6,100. Oddly enough, the torque peak occurred within 100 rpm for the two intakes, indicating the stock manifold was effective at low and medium engine speeds.

With little loss in low-speed power and a huge gain in post-4,000-rpm power, the Edelbrock Performer RPM II intake looks like it has officially earned its place among the other Performer manifolds. In fact, with 67 additional horsepower, it looks like the sequel is even better than the original.