Mustang Heaven - 2005 Saleen Mustang Engine

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2005 Saleen Mustang

Saleen has a couple of credos the company lives by. One of them is "Power in the Hands of a Few." "Power" can mean a lot of things, but first and foremost at Saleen it speaks to what lurks under the hood.

A muscular V8 infuses every S281 Mustang with tire-smoking performance. The 2005 4.6-liter V8 has new three-valve heads - two intake valves and one exhaust valve. The additional intake valve measurably improves engine breathing on the intake side.

Innovative Exhaust System

The exhaust system is an innovative "variable design," featuring twin mufflers with vacuum-actuated valves that open above a specified back pressure. When these valves open, a portion of the exhaust gases is routed through a second set of tail pipes pointed at the ground. This design offers numerous advantages. It allows the engine to be calibrated to produce higher torque. Secondly, it provides a free-flowing exhaust system, while still providing the capability for passing mandated pass-by noise regulations in the U.S., Canada, and U.K. Thirdly, it makes for some lovely exhaust sounds at wide-open throttle. The exhaust side of the engine also features a full 2 ½ inch stainless steel exhaust system, running from the exhaust manifold outlet to the tip of the exhaust pipes.

Because of its all-aluminum design, the new engine weighs 75 pounds less than last year's V8, which, along with the increased wheelbase, reduces weight on the nose from 5 percent down to a much more ideal 53 percent for a front-engine/rear-drive performance machine.

Supercharged S281 SC

Saleen has been using supercharging since the mid 1980's and introduced a supercharged version of the S281 in 1999. Once word got around about its performance capabilities, the S281 SC quickly displaced its normally aspirated S281 counterpart as Top Gun on the Saleen sales charts.

The supercharger is an all-new innovative design, so new and so innovative that Saleen has several patents pending on the design.

Saleen started with unconventional wisdom. That meant tossing all current supercharger design theory out the window. When they had finished with their out-of-the-box thinking, Saleen's engine wizards created a design unique in the annals of supercharging; a supercharger that "blows" all others away. A blower charming in its design simplicity and elegant in its compactness, light weight and high efficiency. It's called the Saleen Series VI integrated TwinScrew supercharger with two-stage water-to-air intercooling system.

Essentially, the Saleen design integrates the previously separate intake manifold, blower housing/assembly and intercooler into one compact unit that nestles neatly into the valley between the heads. This allows for a much wider intake manifold.

The blower assembly contains twin screws, which push 2300 cc of air per rotation versus 1600 cc for last year's supercharger. As a result, the supercharger turns slower for equivalent boost, producing lower stress and lower air charger temperatures. The higher supercharger efficiency, along with the lower air charge temperatures allows for an intercooler that is smaller, lighter and more compact and which has virtually zero pressure drop from inlet-to-outlet side.

Where does the "two-stage intercooling" description come from? A second cooler located in the airdam below the engine radiator assists the intercooler integrated into the supercharger assembly.

The shape of the snorkel opening for the intake air tube is designed for maximum flow. To maintain a constant volume of air as the air flows toward the rear of the engine, the housing widens and flattens-out of the engine. Some other significant design features of the Saleen supercharger:

It features an integrated bypass for low-speed running; when you are driving at low speeds and don't require boost, the bypass helps reduce heat buildup in the engine. The Saleen design provides for optimal runner length, resulting in more torque and better low-end drivability.
All bends are opened up to provide smooth airflow.
It features long, beefy downdraft runners with minimal bends for maximizing torque and horsepower. On the previous design, the air had to make two 180-degree bends. The new design provides a straight, direct shot into the cylinders and about 50 percent increase in flow compared to last year's supercharger.
The new design is much more maintenance-friendly. It has only one sealing surface; the previous supercharger had four. In addition, you only have to remove the eight screws that bolt the air tube to the plenum for access to all of the blower components. Previously, you had to remove the supercharger assembly from the engine and then disassemble it.

The overall efficiency gains - in the engine, the supercharger and the intercooler - mean the new supercharged V8 produces more horsepower and torque at a less stressful 6-7 psi boost than last year's supercharged engine at 7-8 psi.

The S281 SC also benefits from a specific Saleen PowerFlash performance computer along with a Saleen free-flowing air filter.

The S281 SC cranks out a neck-snapping 400 horsepower, 25 more than last year's S281 SC, and an eye-popping 420 lb-ft torque, 5 more lb-ft than in 2004. The 400 bhp figure matches that of the 2005 C6 Corvette. Transmission

The S281 SC Mustang is equipped with an improved version of the current 5-speed manual gearbox. The ratios are the same as last year but the gear change mechanism has been revised for smoother shifting. In addition, the S281 SC receives a higher final-drive ration 3.55:1 versus 3.27:1 from last year - for more aggressive acceleration. An electronically-controlled 5-speed automatic transmission is available. It is matched to a 3.31:1 final-drive ratio.