4.6L / 5.4L 2-Valve Supercharging

Though superchargers certainly predated the fuel-injected 5.0L Mustang, it wasn’t until Ford

replaced the carburetor in 1986 with a long-runner fuel-injection manifold that Mustang

supercharging came of age. Modern 4.6L enthusiasts have the 5.0L to thank for the current crop of

superchargers available for the modular motors. Those of us with a few years under our belts

remember when the Paxton planetary drive blowers were the only game in town and actually

running across one on the street was a real surprise. Those early planetary drive Paxton blowers

have since given way to such impressive offerings as the gear-driven Novi 1000, 1200, and (my

favorite) the ever-impressive Novi 2000. Where the early Paxton blowers were hard pressed to

support 500 hp, the modern Novi 2000 is capable of more than doubling that number. In this

chapter, we’ll test systems from Ford Racing, Kenne Bell, and Vortech, not to mention supercharger

offerings directly from Ford.

This 4.6L 2-valve mod motor

cranked out 800 flywheel hp

running a Vortech YS-Trim

supercharger and a custom

dual-core air-to-water aftercooler.

While Ford offered Paxton supercharged motors back when Carroll Shelby was putting the hurt on

Ferrari, the modern era probably started with the Eaton M62 supercharger in the Ford Thunderbird

Super Coupe. The 3.8L V-6 was equipped not only with modern fuel injection, but also a positive

displacement roots supercharger and intercooler gave it 5.0L performance. Ford supplied truck

owners with an impressive gift in the form of the supercharged 5.4L Lightning truck. An easy 14-

second machine right off the showroom floor (13s if driven well), the 5.4L Lightning mill

demonstrated that the 2-valve mod motors really responded to boost (what motor doesn’t?). Ford

would later add an Eaton M112 roots supercharger to the 4.6L 4-valve Cobra in 2003, and then

apply an even more impressive 2.3L twin-screw blower to the all-aluminum 5.4L 4-valve mod motor

used in the Ford GT. To date, this is the ultimate Ford modular motor, and quite possibly the most

impressive (if not most powerful) motor Ford has ever offered in a production car. Rated at 550 hp,

the supercharged 5.4L 4-valve motor has been tested to produce that 550-hp power rating at the

wheels. I’d pit this supercharged mod motor against any stock 427 Cammer (though not technically

a production motor), 428 Cobra Jet, or Boss 429 any day.

Want to make your 281-ci mod motor

feel like it just gained another 100

cubic inches? This roots blower kit

from the Ford Racing catalog will

provide big-block-like torque from your

4.6L.

Though the 5.0L can be credited with introducing the modern performance world to supercharging,

the 4.6L has continued to expand the popularity of forced induction. Currently there are a minimum

of 10 different supercharger manufacturers that offer kits directly for the 4.6L Ford family. The

number of manufacturers involved (and their success) should give you an idea about the popularity

of the supercharged mod motors. In the end, it’s the enthusiast that benefits from the proliferation

of available kits, as competition improves the product line and decreases the cost to the consumer.

Having 10 different manufacturers also provides variety. This is an important fact and contrary to

some of the propaganda you read on some of the Web sites there is not one ideal form of

supercharging for the 4.6L 2-valve motor. Were there one form that excelled above all others and

provided the very best of every comparison variable, no other form would continue to exist.

Fortunately for us, this is simply not the case. Variety allows you to pick and choose the best

combination to meet your particular needs. Centrifugal superchargers perform a certain way, as do

roots and twin-screw blowers. Which one is right for you depends on what you want.

Even on a mild 4.6L, a centrifugal

supercharger like this T-Trim unit from

Vortech will add an easy 100 hp. The

air-to-water aftercooler provides the

necessary cooling to allow you to run

elevated boost levels on pump gas.

If you are looking for maximum (peak) power production from your (hopefully suitably built) 4.6L

2-valve motor, then you will probably be best served by a centrifugal blower. If instantaneous boost

response is more important, then you should be leaning toward either of the positive displacement

designs (roots or twin-screw). There are obviously positive and negative attributes offered by each

type of supercharger, but in the end, the choice will likely come down to more variables than just

peak power; things like cost, kit completeness, ease of installation, availability, customer service,

and (very important) tuning. Does the supercharger kit come with an ECU program designed to

provide maximum safe performance on pump gas? Does the kit include the necessary injector

upgrade, fuel pump upgrade, or ignition amplifier? Once installed, how difficult is it to further

increase the power output? Is it more involved than a simple pulley change (it almost always is)? I

have just scratched the surface in terms of considerations when choosing a supercharger for your

4.6L Mustang, but know that all superchargers offer a significant power gain, just be sure that the

tune (air/fuel and especially timing) are spot on before putting your foot in it.



While not quite on par with the 4-valve 4.6L, the 4.6L and 5.4L 2-valve motors respond very well to

supercharging. Whether the blower kit is a simple M90 from Ford Racing or an intercooled YS trim

from Vortech, adding a blower kit to your mod motor will yield impressive dividends. One convenient

way to calculate the power potential offered by any supercharger is to take the power output of the

naturally aspirated motor and multiply it by the boost pressure as a function of atmospheric

pressure. Since a naturally aspirated motor runs at an atmospheric pressure of 14.7 psi (or 1 BAR),

all we have to do to double the power output of the motor (in theory) is to double the pressure to

the motor. By this I mean that if the naturally aspirated 4.6L 2-valve motor produced 300 hp, all we

have to do to reach 600 hp is to double the pressure or supply 14.7 psi using a supercharger. If we

supply only 7.35 psi, we should see a corresponding power gain of roughly 50 percent, since 7.35

psi is 50 percent of 14.7 psi. Using 10 psi, we see that the power gain will be 68 percent, since 10

psi is 68 percent of 14.7 psi, while 20 psi should provide a gain of 136 percent. The simple math

formula is as follows: Supercharged HP = NA hp x (Boost pressure/14.7 +1).

The twin-screw supercharger from

Kenne Bell combines the immediate

response of the positive-displacement

blower with improved efficiency (and

power potential) over a typical roots

blower.

Now that I have extolled the virtues of the boost/power formula, I can tell you why motors usually do

not reach the stated power outputs. The first problem is that the formula does not take into account

the parasitic losses associated with driving the supercharger. In the case of a high-horsepower

application, the supercharger may consume 50 to 100 hp (or more) and this power is subtracted

directly from the output. If the boost pressure of 10 psi were to supply a mass flow gain able to

support a 68-percent increase, then you would still have to subtract the parasitic losses associated

with driving the blower. Due to the increase in heat associated with the increase in compression (to

10 psi), the number of oxygen molecules per volume is less than it would be at atmospheric

pressure. Therefore, the increase in pressure of 68 percent (to 10 psi) will not likely yield a

commensurate gain in power, though intercooling can improve the air density (number of molecules

per volume). Despite these seemingly insurmountable odds, we often reach the power suggested

by the power/boost formula on 4.6L 2-valve motors by combining a healthy (and powerful) naturally

aspirated combination with an efficient supercharger.

Naturally Aspirated vs. With Ford

Racing Supercharger

PI 2-Valve GT:

298 hp @ 4,900 rpm



With Ford Racing Supercharger:

383 hp @ 5,700 rpm

Largest Gain: 117 hp @ 5,900 rpm

PI 2-Valve GT: NA vs. Ford Racing Supercharger (Horsepower)

When you’re trying to add power to your 2-valve modular motor there’s nothing quite like forced

induction. In this case, the boost in power came from a Ford Racing supercharger kit. The Ford

Racing supercharger system utilizes an M90 Eaton blower and dedicated intake casting that

features long intake runners to maximize the power production below 6,000 rpm. Unlike most other

supercharger systems, the Ford Racing blower doesn’t include an intercooler, but you don’t need

one at the reduced boost. Adding the blower to the SHM 2-valve 4.6L upped the peak power to 383

hp and the torque to 395 ft-lbs. The peak-to-peak power gain was 85 hp, but the largest gain was

117 hp at 5,900 rpm.

PI 2-Valve GT:

345 ft-lbs @ 4,100 rpm



With Ford Racing Supercharger:

395 ft-lbs @ 3,800 rpm

Largest Gain: 95 ft-lbs @ 5,900 rpm

PI 2-Valve GT: NA vs. Ford Racing Supercharger (Torque)

As expected, the roots supercharger provided instantaneous boost and torque, adding 60 ft-lbs at

just 2,500 rpm. In fact, the Ford Racing blower added a solid 50 ft-lbs throughout the rev range. An

extra 50 ft-lbs is always a welcomed addition to any 2-valve 4.6L Mustang. The boost pressure

reached a peak of 6.8 psi, but was just 4.5 to 5 psi for most of the RPM range.

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This has been a sample page from



Building 4.6/5.4L Ford

Horsepower on the Dyno

by Richard Holdener

The 4.6- and 5.4-liter modular Ford engines are finally

catching up with the legendary 5.0L in terms of aftermarket

support and performance parts availability. Having a lot of

parts to choose from is great for the enthusiast, but it can

also make it harder to figure out what parts and modifications

will work best. Building 4.6/5.4L Ford Horsepower on the

Dyno takes the guesswork out of modification and parts

selection by showing you the types of horsepower and torque

gains expected by each modification.



Author Richard Holdener uses over 340 photos and 185

back-to-back dyno graphs to show you which parts increase

horsepower and torque, and which parts don’t deliver on

their promises. Unlike sources that only give you peak

numbers and gains, Building 4.6/5.4L Ford Horsepower on

the Dyno includes complete before-and-after dyno graphs,

so you can see where in the RPM range these parts make

(or lose) the most horsepower and torque. Holdener covers

upgrades for 2-, 3-, and 4-valve modular engines, with

chapters on throttle bodies and inlet elbows, intake

manifolds, cylinder heads, camshafts, nitrous oxide,

supercharging, turbocharging, headers, exhaust systems,

and complete engine buildups.

Click below to view sample pages

Chap. 1 - Throttle Bodies

Chap. 2 - Intake Manifold

Chap. 3 - Cylinder Heads

Chap. 4 - Camshafts

Chap. 5 - Nitrous Oxide

Chap. 6 - SOHC Supercharging

Chap. 7 - DOHC Supercharging

Chap. 8 - Turbocharging

Chap. 9 - Engine Headers

Chap. 10 - 4.6 Engine Buildups

8-1/2 x 11"

Sftbd.

208 pgs.

340+ b/w photos

Item # SA115P

Price: $

This is a great book and a

must have for anyone

considering modifying a 4.6 or

5.4 Ford for more power!

Click here to buy now!









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