Vinnie The Hitman
March 1, 2009
Photos By: Frank Cicerale
Our rock-steady '03 Cobra has been pounding out the e.t.'s thanks to some sticky Nitto DRs and newfound power from a ported Eaton blower. Our new best is an 11.59 at 122 mph.

The magical numbers that pour out of Ford's latest supercharged mod motors make us look back and cry at the good ol' days of 5.0 racing. Looking back, you needed not one, but more often, two power adders to make anything over 450 hp at the wheels. Street racers, and even the big guns of Mustang racing used the hot setup of the time, which was to slap on a Vortech supercharger and a 100-shot of nitrous to dip into the 9s. Meanwhile, the most radical of EFI Mustangs sported big-dollar engine combos to get into the 8s, but often that resulted in unstreetable and often unreliable combos.

Fast-forward to 2009 and the early days of horsepower discovery are nothing but a long-distance memory, like cheese grater taillights, a short-belt, Pro-M 77mm mass air meters, and Reef Blue Metallic paint.

So when we say it's easy to make horsepower these days, we mean it. For instance, we've been able to witness this '03 Cobra make over 450 to the tires with nothing more than basic bolt-ons. As a matter of fact, this particular Terminator has already cranked out 453 rwhp and 453 rwtq with nothing more than a few normal bolt-ons, including a simple cold-air system, a cat-back exhaust, an overdriven supercharger pulley, and a quick reflash of the PCM.

Just 15 years ago, we would have given an arm, a leg, and maybe even a reproductive organ to make that much power. But when you can have it in a car that drives like it did when new, starts up every time to take you to work, and gets respectable fuel economy, it makes you happy enough to hug your local gas station attendant.

Even at $4 per gallon for hi-test, I can't think of any Mustang owner who's not looking to find a way to make their ride quicker. Aside from bragging rights at the parking lot of the local Choke `n' Puke (or Internet website), we all want to be slammed back into that seat and hang onto the steering wheel for dear life. We want to be scared and have things happen so fast that we barely have enough time to think. So, as addicted as we are to power, we decided to take a look at doing the normal thing that Cobra owners do next, which is to add boost.

After conferring with Mustang Magic's in-house tuner Joe Lauzardo and proprietor Joe Panciarello, we decided to install a ported supercharger. At our stage of the game, we were maxing out what the factory Eaton M112 can provide.

Even at 12 psi, the stock supercharger is limited by its outlet port size, which is a V-shaped opening that faces downward and dumps pressurized air into the intercooler core and the intake manifold. Total airflow and volume coming out of the stock blower is just about at its limit at 453 rwhp, so going to a ported unit would not only increase airflow and volume, but velocity as well, enabling us to increase boost pressures and ultimately, horsepower and torque. As luck would have it, a good friend of ours was upgrading to an aftermarket blower and we bought this ported unit, which was just sitting on his shelf, never used. He forgot who he bought it from but it looks like a rather professional port job. We figured there was no better way to see how it works than to dyno and drag test it.

With the blower in hand, we called Mustang Magic, where Lauzardo explains, "On a car like this, a ported blower will usually not give you tons of peak power, but rather big gains in torque, especially when driving around town. To make it work, you should put on more aggressive pulleys to get the blower spinning faster so that the power comes in early and it snaps when you hit the gas pedal. You should use a four pound pulley on the crank and leave the 3.0 upper pulley that's on there."

Now, it may appear that Joe was speaking a foreign language, but what he means by a four pound crank pulley is often what Mustang tuners refer to as a larger diameter supercharger drive pulley that is mounted to the crankshaft to provide greater blower overdrive and four more pounds of boost without changing the supercharger's driven pulley, which is on top. This results in increased supercharger speeds in relation to the crankshaft, and more boost earlier in the engine's operating range. However, it should be noted that it seriously overdrives the supercharger beyond the factory-recommended shaft speed, but, what the heck, if all the cool kids are doing it, why can't we?

So with Joe's recommendation made, we turned to Metco Motorsports, which specializes in crankshaft pulleys for the '03-'04 Cobra. Metco's supercharger crankshaft pulley kit is modular in design and allows you to change the pulley size based on the boost increase you want. For instance, if you wanted two more pounds of boost, you'd simply use a two pound pulley ring, four more pounds of boost, you'd add the four pound ring, and for six more pounds of boost ... well, you get the picture. The best part about the Metco kit is how the design of the pulley does away with the factory 'cage setup that is bulkier and takes more horsepower to operate. By switching over to the easy-to-install Metco setup we saved about five pounds right off the nose and added some nice bling to the underhood area as the crank pulley's hub is fabricated from billet aluminum and the interchangeable pulley rings from black-anodized billet steel. Because the supercharger drive system also drives the alternator, you will have to replace the alternator pulley with a larger one to slow it down whenever you use a four pound-or-larger crank pulley.

With our new ported Eaton installed and pulleyed up with the blingus maximus Metco components, we headed to the dyno bay at Mustang Magic and rolled our Cobra onto the Dynojet 248c, as Joe plugged in his SCT Tuner to reprogram the PCM. By pulling some timing out down low and trimming the fuel curve to match, he was able to prevent any potential detonation from the big gains in boost that we were about to see.

On our first pull, we were able to notice a louder shrill from the blower. With nothing else, we were quickly rewarded with an incredible 471 rwhp and 506 lb-ft of torque. This was with a boost increase of four pounds (as advertised by Metco) from 12 psi to 16 psi. Horsepower-wise, we were looking at a modest 18 rwhp gain, but as Lauzardo mentioned, the peak horsepower gain wasn't going to be strong because at around 5,000 rpm, the stock Eaton started to lose in boost, going back down to about 12 psi all the way to redline. The primary issue here is the combination of the restrictive factory throttle body and inlet, as well as excessive supercharger speed, caused by internal turbulence that capitates the air. Much of the gains were throughout the bottom part of the power curve starting at a mere 2,500 rpm as we were seeing the gains from idle to the 4,000 rpm boost peak with a peak torque gain of 53 lb-ft over our previous best. With a relatively safe 11.8:1 air-fuel ratio at peak horsepower, we left it alone as the use of pump gas was important to us.

The only way to find out how extra horsepower translates in the real world was to head down to Old Bridge Township Raceway Park and line our car up on the dragstrip. With an aggressive slip-clutch launch at 2,250 rpm on the 17-inch Nitto Drag Radials, we were able to better our previous best of 11.925 at 118.92 with a new best of 11.59/122.5 mph. Granted, the track temperature was about 25 degrees Fahrenheit cooler, but there was no arguing how the car responded with its newfound power.

So with a ported factory blower, we're again getting more power than expected. As Lauzardo mentioned, there have been several instances where other people have made over 500 rwhp from the identical setup, but with the stock exhaust manifolds, throttle body, and inlet pipe, we would not see the big five-double-0. In reality, it doesn't bother us because the car is just plain nasty on the street with First gear being literally useless with so much torque and traction being a huge issue in Second. Hooray for neck-snapping grunt. The problem is, now it has us wanting more.

Pulleyed For Max Grip
On all '03-'04 Cobras, adding an underdrive supercharger pulley increases boost. That's fine and dandy, and yes you get more power. However, one of the biggest issues with this simple mod is the lack of adequate belt wrap with the reduced diameter pulley. It can cause slippage, especially when you're powershifting. The best way to tackle this is to use an auxiliary idler pulley right next to the supercharger's snout to provide the additional belt wrap. What does this do? Well, it makes the belt have more contact area with the pulley and it greatly prevents slippage to make sure that you get the most amount of boost possible with your setup.

For our car, we went with Steeda's billet aluminum setup, which not only looks the part, but also plays the part with a 100mm idler pulley diameter. It bolts right to the factory supercharger "bridge" and installs in mere minutes. Because the belt now has a new route, it will require a longer belt, typically one-half to a full inch longer. If you are using a stock crank pulley and a 3.0 upper, you'll need a Gates PN K080745. If you are going to a four-pound pulley like we did with the ported Eaton, then you will need Gates PN K080850. With your belt tensioner nice and tight, before you know it, you'll be rewarded with slip-free fun.