Tom Wilson
September 1, 2009
Filling a gap in Vortech's supercharger line, the Vortech twin-screw blower is a 3.3-liter Lysholm unit. It's designed as a replacement supercharger for Mustangs supercharged by Ford and is not intended for naturally aspirated engines, such as garden-variety Mustang GTs.

Vortech, as any kid who's mastered the 1-2 shift can tell you, is synonymous with centrifugal superchargers. From Vortech's first day in 1991, the company offered one class of product-superchargers-and every last one of them has had a belt-driven whiz wheel whirring away inside. That's because Vortech owner Jim Middlebrook is an engineer who is passionate about efficiency, and nothing is more efficient than a centrifugal blower. Just ask Jim.

But last fall Vortech showed a Lysholm screw supercharger in its SEMA booth. Details were sparse, but the official word was Vortech would soon offer the foreign technology on Mustang applications. Well, soon is approaching, and Vortech just hosted us at its Camarillo, California, headquarters for an exclusive, detailed inspection of its screw supercharger program.

Frankly, we weren't quite sure what to expect. Vortech's screw blower could have been anything from a supplement to its existing supercharger line to a replacement technology involving massive retooling and design. As it turns out, the former is the case.

Make no mistake-Jim Middlebrook remains completely committed to the centrifugal supercharger due to its superior adiabatic (heat) efficiency, but he sees a viable market for those wanting to upgrade their Roots-type superchargers on those Fords supercharged by the factory. That means '03-'04 Cobras, '07-'10 GT500s, and Lightning pickups. Not that it concerns us, but Vortech also sees a ready market for the Lysholm on GM pickup trucks.

With its low-profile and rear entry, the VTS should prove an easy bolt-in replacement for Roots blowers on '03-'04 Cobras and GT500s. The VTS is designed to accept all stock hardware, such as EGR valves, throttle bodies, and so on.

The Fords just mentioned are all equipped with modestly efficient, Eaton-built Roots blowers with limited hot-rodding potential. In a perfect world, Vortech would prefer moving these owners to a big centrifugal supercharger, but that exchange would involve far too much hardware. Such a swap is too expensive and time-consuming to make sense, hence the booming replacement market using screw-type superchargers.

Vortech is also definitely in favor of twin-screw superchargers rather than any version of a Roots blower. Its testing shows a major advantage to the twin-screw compressor, including the latest twin-vortices variations. Furthermore, Vortech sees no sense in cannibalizing its centrifugal blower sales with a screw supercharger. Therefore Vortech won't offer a screw blower where it already offers a centrifugal-or wherever a centrifugal makes sense. For example, Vortech will not offer its screw blower for a Mustang GT.

While Vortech has long been blessed with excellent CNC machining capabilities, it has chosen to purchase its screw superchargers direct from the originator and patent-holder of the twin-screw: Lysholm. The Swedish company is selling its 2.3- and 3.3-liter screw blowers as finished rotor and case assemblies to Vortech. In turn, Vortech has developed its own mounting and support hardware, calling the finished product the Vortech Twin Screw.

We've talked a lot about SLA rapid prototyping lately; here's a great example of it. This is the prototype VTS rear inlet casting in nylon.

Vortech sees the screw-replacement supercharger market as a tuner's market. By that we mean Vortech is kitting its screw blowers for professional installations, not weekend installs by car owners. So the VTS kits are all Tuner Kits, in Vortech-speak.

A Tuner Kit is a supercharger kit optimized for pro installation. Because the pros have their own ideas on how to dress a blower, the Tuner Kit omits much of the hardware common in typical consumer supercharger kits. Tuners, as you'd guess, like to do their own electronic tunes, so Vortech Tuner Kits do not include any electronic tuning. There's no handheld in this carton. Likewise the fuel injectors, throttle body, induction, and such are all left to the tuner, as these items are custom selected by tuners anyway.

Turned upside down, the inlet shows the round bypass passage. Hidden below the intake when installed, the bypass allows air to flow in a closed circuit between the intake manifold and supercharger. This hugely reduces drag losses during part- and closed-throttle operation.

A side benefit to the tuner kits is a low advertised price. With so many accessory parts left to the tuner, the retail price of a Vortech Tuner Kit is understandably affordable. We'd like to quote a price for the new VLS blower, but pricing was not set during our visit. Vortech can only say the kits "must be competitive." And they no doubt will be as Vortech has always offered fair pricing.

So, those new parts designed and built at Vortech are the supercharger mounting plate, the inlet elbow, and small parts such as the bypass valve actuator. Of these bits, the main piece is the inlet elbow. This is the large aluminum casting directing airflow from the throttle body to the blower's inlet at the rear of the supercharger. Our visit coincided with the arrival of Vortech's first prototype inlet, shown in the photos. It's a nice bit of stereo lithography, so the prototype shown is made of nylon. Production pieces will be cast aluminum.

Tuners will also find a touch of work in the bypass valve. The stock Ford bypass valve is disassembled so it can be reassembled in the Vortech installation. Vortech is reusing the blower drive too. So the stock Ford 10-rib drive is retained, but a new belt is supplied to accommodate the different size blower pulley (a size yet to be precisely determined). Other than that, installation is essentially removing the stock Eaton supercharger and bolting on the VTS. It's pretty much like swapping an intake manifold.

Vortech calls for reuse of much of the car's existing bypass valve. The valve's throttle blade is removed so the shaft can be extracted from the Eaton blower and reinstalled in the VTS. Two new throttle-plate screws are provided, which are peened after installation to ensure they don't fall out

Vortech had not run a VTS on a car or test engine when we visited, so boost and power figures have not been set. We'll forecast boost in the 12-pound range with power in the mid-500 range, with optional smaller blower pulleys offering increased power, of course. And that's the point: The VTS blower takes over where the stock Roots blower gives up. We've seen this blower, or similar ones, make power into the 800hp range given a small enough pulley and supporting hardware-think large fuel system and custom tuning.

Vortech seems truly committed to the VTS, as it definitely fills a gap in its blower lineup and can produce the big power numbers routinely associated with Vortech. Look for some electronic tuning support from Vortech as the program develops, along with first sales this summer. Naturally we'll be back to test one as soon as we can, so stay tuned.