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Dyno Testing Naturally Aspirated Two-Valve Performance - Modular Revolutions
It's Time To Dig Into The Naturally Aspirated Side Of Two-Valve Performance-So AFM Spun The Dyno Rollers, And We're Here To Tell The Tale
Horse Sense: Modular GTs have come a long way since 1996, but considering the 4.6 debuted in the Crown Vic in 1991, it's taken the aftermarket quite a long time to get excited about modular performance. Of course, most of that blame should be shouldered by the asthmatic, 215hp Two-Valves found in the '96-'98 GTs. Those certainly slowed down the excitement. Since 1999, however, these babies have been cranking out 260 horses, and it's time to get with it.
It's about time. Yeah, we know, we've had it too good for too long with the 5.0, so that meant there was less pressure to become aggressive with 4.6 performance. But there's more to life than power adders (and, believe us, we love power adders). Naturally aspirated performance is the cornerstone of making power. Once you can make power without boost or juice, you can make even more when you add either to the mix.
So why has it taken us a while to really explore naturally aspirated performance? Well, there's the aforementioned success of the 5.0, but there have also been a few parts missing from the mix-noticeably, intakes and camshafts. In 2003 that all changed, as cams began coming out of the woodwork, and the intakes were starting development outside the confines of the Blue Oval. Meanwhile, people were still busy pushing the 5.0 envelope, where the edge seems to get farther away every day. So it was just easier to add a blower, some bolt-ons, and a chip and go have some modular fun.
Additionally, modular engines are perceived as newer and more complex, just as EFI was back in 1986. The new voodoo always keeps the skittish away for a while, until they figure out the black cat can actually be friendly if you treat it right. So more and more every day, the Ford aftermarket is getting the modular cat to purr. And when Rick Anderson of Anderson Ford Motorsport called us, we knew the timing was perfect. Rick was about to embark on one of his dyno learning missions, but this time it wasn't a blower 5.0 or high-rpm 347. This time Rick wanted to finally see what kind of potential was locked up in these modular engines. He bought an '00 GT to thrash on, and we were excited to go along for the ride.
Longtime readers know we often peer over Rick's shoulder while he spins the dyno rollers. Rick is the kind of guy who's happy to spend his off-hours and weekends trying parts, tuning, and just plain experimenting to find more power from our beloved Fords. Back in the day, I got this wild idea to do a blower test and flew out to the cornfields of Illinois to see the whole process. Eventually, Rick got smart, bought a camera, and now he doesn't have to see me every day for a week.
Obviously, we have great confidence in Rick's consistency and numbers, but if you're skeptical of his tests-particularly on his AFM parts-we wouldn't blame you. Just keep in mind Rick is keenly aware there's a dyno on every street corner these days, and if parts don't work as advertised, he's just one message-board post away from a black eye. That's why he does all this testing-to make sure the parts he sells works the way he says they do.
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After testing his Frankintake, Rick tried the sometimes-maligned Bullitt intake ($1,489 with the necessary installation hardware). Sourced from the limited-edition Bullitt Mustang, this intake is quite similar to the one from Ford Racing Performance Parts, but it's designed to work with the modern PI heads. Since the Bullitt Mustang was rated only 5 hp higher than the GT in 2001, some have questioned the value of the Bullitt. Well, in our test, this intake showed quite well. Peak power grew only by 0.7 versus Rick's intake, but compared with the stock intake and Accufab elbow, it added 5.3 hp. Torque was more impressive yet. It swelled by 9.7 at the peaks over Rick's rpm-biased part (it only added 3.8 lb-ft versus the stocker, however). Though it runs out of steam at 6,000 rpm, the Bullitt was better than the stock or modified stock intake to that point.
Rick's last change before unbolting the cam covers was adding Reichard Racing's sheetmetal Two-Valve intake ($1,499). Rick got his hands on the first round-throttle-body version for his naturally aspirated combination. Similar to the old box intakes on bolt-on 5.0s, the Reichard intake throws away bottom-end power in exchange for high-rpm power. Though the Reichard added only 1.5 hp at the peak, this intake was clearly pulling much harder than the Bullitt from 5,500, until it hit the wall of the stock heads and valvetrain at 6,500 rpm. Rick tried the Reichard intake with the Stage I cams, where it again gave up torque for top-end power, stretching the power peak to 6,500 and adding 2.2 peak ponies.
Having gone just about as far as he could without tearing into the engine, Rick was anxious to see how this bolt-on 4.6 combination would respond to AFM's Stage III-ported PI heads ($1,570 with cores) and Stage I camshafts (PN 6h12; $751), designed to work well from 2,400 to 6,200 rpm. The heads feature full porting of the intake runners, ported/polished exhaust ports, and a multi-angle valve job. These examples were fitted with larger valves, ModMax springs, and the aforementioned AFM cams. Since you have to take the heads apart to do the other work, it makes sense to add the cams at the same time. One thing to keep in mind with this pull is Rick went back to the stock intake/Accufab elbow setup with the heads and cams in anticipation of running all the intakes again. That said, this combination of parts yielded the biggest horsepower boost, as it should. Peak power and torque was up 46.2 hp and 9.5 lb-ft versus the New Baseline pull, which was the last pull with all the other bolt-ons and the stock intake.
The last phase of this test-primarily because we ran out of time and space-was to upgrade the factory short-block to a new D.S.S. Super Mod short-block ($3,999.95) with flat-top pistons. According to D.S.S., Rick had been sitting on a grenade by revving the stock motor to 7,000 rpm, going so far as to warn him to always keep the oil to the full line as a precaution. The D.S.S. Super Mod engines feature forged eight-bolt cranks, steel H-beam rods, forged pistons, Speed-Pro moly rings, and Federal-Mogul Tri-Metal bearings. (For more on what goes into these engines, check out "Building Steam" on page 71 of our Dec. '03 issue.) Considering the addition of the short-block is typically just for durability-not power-the results were quite impressive. Power and torque both jumped-17 hp and 18 lb-ft at the peaks-with the new short-block-and that's without the new D.S.S. lightweight pistons, which Rick has seen produce impressive gains. The combination also received 30-lb/hr injectors and a recalibrated Pro-M meter here, but the air/fuel ratios remained spot-on.
In anticipation of testing all the manifolds at a later date, Rick moved back to the stock intake/Accufab elbow combination to try his Stage II cams (PN 15h10; $751). These cams are designed to work in the 2,700-6,500-rpm range. Combining the more aggressive cams with the ported heads proved a wise choice, as the combination made 0.5 more peak horsepower and picked up torque across the board, with a 27.4 lb-ft increase at the peak. You could attribute some of the torque gain to the long-runner intake, but the cams maintained the top-end power of the high-flying Reichard intake with the smaller cams.
Before moving into testing intake manifolds, Rick wanted to open up the last exhaust restriction by replacing the fac-tory manifolds with Bassani's trick Mid-Length headers ($649). These headers can actually be installed with the motor in the car, and they can easily be adapted to a Bassani or Bx Performance composite X-pipe. Despite their price, the Mid-Lengths were impressive to Rick because he's seen some short-tube headers fall flat, and the Bassanis pulled hard across the tach, especially pumping up low-end torque, while improving the peaks by 6 hp and 10.2 lb-ft.
After cresting the 300hp, 300-lb-ft marks, Rick decided it was time to try out Ignition Solutions Plasma Booster ignition system ($289.96). Keep in mind that the car exhibited no problems. The air/fuel ratios were consistent, the power curves were smooth and with no indication the spark was blowing out, and Rick just runs plain, old Motorcraft copper plugs. The Plasma Booster helped, though, just as it had in our previous testing experience, and any power from an ignition is impressive. It boosted the peaks by 3 hp and 2.2 lb-ft, but it picked up power across the board.
Rick likes to maintain consistency by beginning each dyno pull with the intake temperature within 2 degrees of the ambient temperature. This takes into account weather changes, and it makes sure there are no broad swings in temperature between pulls, as the modular engines are acutely affected by temperature. This was one of the things Rick learned during the many dyno pulls on this car. It seemed the second pull was always better, and it turned out that was because the thermostat was open. If he made a pull before it opened, the EEC V would pull timing and kill power. Another quirk he found was the EEC took time to adapt to new parts, so he would take the car out and take it to wide-open throttle four times after each change, then bring it back, cool it, and make a pull.
So, Rick made a lot of pulls, tested a lot of parts, and kept things consistent. Along the way, he learned what the 4.6 modular engine likes and where he can work on parts to improve it even further. With any luck you'll learn something here too. Just keep in mind that when it comes to dyno testing, there are many factors that can influence results. Something as simple as changing the order of the parts you test can impact how things show up. If Rick had installed the ported heads first, then added the exhaust, the heads wouldn't have looked as good, and the exhaust would have looked like a world-beater. We think he followed a logical progression, so check the captions and sidebars for the latest word in natural 4.6 performance.
|5.0 TECH SPECS|
|RICK ANDERSON'S '00 GT|
|ENGINE AND DRIVETRAIN|
|Block||D.S.S. Super Mod w/flat-tops|
|Cylinder Heads||Stock w/AFM Stage|
|Intake Manifold||Stock intake w/Accufab elbow|
|Camshafts||AFM 15h10 Stage II|
|off-road X-pipe, and Mid-Length headers|
|Engine Management||Stock EEC V|
|SUSPENSION AND CHASSIS|
|Wheels||Bogart SS 15x4|
|Rear Suspension||HPM adjustable|
|uppers and HPM Mega-Bite lowers|
|Traction Device||HPM antiroll bar|
|Wheels||Bogart SS 15x10|
|Tires||26x11.5 Mickey Thompson ET Street|
4.6 Vs. 5.0
Part of Rick's desire to test all these 4.6 parts was to see how the newer engines compared with the tried-and-true 5.0 powerplants. Naturally, one of the criticisms of the modular engines is that they are more expensive. While this is true, it's not by as much as you might think. And, have you ever tried to make 300 hp with a stock 5.0 intake and ported stock heads? It's not likely, but you probably have decided to play with a 4.6 or 5.0 based on how much it might cost you to modify one or the other.
To illustrate how close the combinations really are in cost, Rick chose our Plasma Booster pull, which has all the bolt-ons tried to that point, including the ported heads and Stage I cams, but it retains the factory intake manifold. That combination would set you back $5,462 in parts and yield 316.4 hp and 321.2 lb-ft of torque. To that, Rick compared it to a customer's 5.0 com-bination that produced 316 hp and 328.4 lb-ft of torque with $4,554 in parts. It's a little cheaper, but this stock-block 5.0 combination used a lot of parts to get there, including Auto Specialties underdrive pulleys ($79.95), a Bx after-cat ($425), a Bx off-road X-pipe ($239), AFM/Bassani 131/44-inch headers ($449), a 75mm throttle body and spacer ($289), an Edelbrock Performer RPM intake ($555), an AFM Power Pipe ($232), a Pro-M 80mm mass air ($299), an ignition box ($249), Trick Flow Twisted Wedge heads ($1,099), FRPP roller rockers ($279), Trick Flow push rods ($80), and an AFM N-41 camshaft ($279).
So the 5.0 combination makes a bit more power and torque for about $900 less, but it's a lot closer in price than we would have ever imagined.
|Baseline||Air Filter||No Silencer|
|Baseline||Air Filter||No Silencer|
|Mass Air||Power Pipe||Throttle Body|
|Intake Elbow||Headers||New Baseline**|
|Modified Intake||Bullitt Intake||Reichard Intake|
|Stage III Heads***||Ignition||Reichard Intake|
|Stage II Cams***||D.S.S. Short-Block****|
- Averages are taken from 4,000 to 6,000 rpm and 4,000 to 6,500 where applicable
- Established a new baseline after the car was away for three months for PMS development
- With stock intake manifold and Accufab throttle body and elbow
- With stock intake manifold, Accufab throttle body and elbow, 30-lb/hr injectors, and recalibrated Pro-M