Rimmer Engineering, Inc.

Rimmer Supercharging System




A supercharger is an air pump.  Its purpose is to provide the engine with more air at a higher density than it could naturally ingest on its own. Under boost (positive manifold pressure), air combined with fuel is packed into the engine’s cylinders, allowing the engine to produce more energy on each power stroke. This results in substantial horsepower and torque increases, beneficial for anyone who wants more power and better driveability as well as for special needs such as high performance driving, towing, or off-road operation. A supercharger also can restore the power losses experienced when operating at high altitudes, where the air is less dense.

Rimmer Supercharging Systems (RSS) utilize two different type of superchargers, depending on the particular vehicle application. The choice of supercharger is based on installation space and access requirements, desired performance characteristics, or both. Generally speaking, a positive-displacement supercharger has a larger physical size which makes it difficult or impossible to install on some vehicles, but is more efficient (and effective) at lower engine speeds than a centrifugal supercharger. On the other hand, a centrifugal supercharger is more efficient at higher RPM and can usually be installed in a much smaller space. Rimmer Engineering’s systems use either the Eaton or Rotrex supercharger.

RSS / EATON eaton_chargers.jpg (8924 bytes)

RSS/Eaton systems include the well-proven Eaton positive-displacement pump as the supercharger component of the system. The Eaton supercharger is a positive-displacement Roots-type supercharger mechanically coupled to the engine’s crankshaft through a reliable belt-drive system. Each RSS is designed and developed for particular vehicle applications, using compressor displacement, drive ratio and fuel and ignition control factors as necessary to configure the system to the vehicle and engine combination.

Eaton superchargers are premium quality, OEM-grade components. They are found as original equipment on models of Buick, Oldsmobile, Pontiac, Ford, Mercury, Mercedes-Benz, Jaguar and Aston Martin. Eaton’s worldwide distribution has earned more customer quality awards than any peer vehicle component supplier. The Eaton supercharger is a modernized and highly-developed successor to the "Jimmy" (GMC) Roots-type superchargers originally designed for heavy-duty diesel engines and made famous by championship fuel dragsters.

Since 1949, Eaton has continued to improve the supercharger, particularly in regard to noise and durability. By changing the pump’s rotor design to a twisted, 3-lobe configuration, radically revising port geometry and inlet configuration, efficiency has been greatly improved and excessive noise eliminated. This has also allowed the size of the supercharger to be reduced, thus enabling installation in the tightly-packed engine compartments of today’s vehicles. Durability issues were solved through development of modern self-contained lubrication, shaft and bearing systems which do not require any outside lubrication source (such as connection to the engine oil system). Eaton superchargers are designed and built to last the life of the engine and typically do not need service or maintenance in normal use. Service life on most vehicles will exceed 100,000 highway miles. The supercharger unit, although "sealed for life," is rebuildable or can be replaced through an exchange program.

drawing.gif (4353 bytes)An important and highly beneficial element of the Eaton-based Rimmer Supercharging System is the automatically-actuated bypass valve which recirculates the supercharger air flow when boost is not required, thus reducing loads and improving fuel economy. During most driving conditions, including idle and steady cruising speeds, the bypass valve will be open. Whenever the engine needs additional air to accelerate, climb or pull, the valve quickly closes and supercharging boost is immediately available. There is no perceptible "throttle lag" as experienced with turbocharger systems; the RSS gives true power-on-demand performance. And because it is directly linked to engine speed, the response is linear allowing smooth and precise control.

Additional information is available from Eaton’s website, www.eaton.com/supercharger/

RSS / ROTREXrotrex3.jpg (13803 bytes)

Continuing the company’s tradition of automotive supercharging system research and product development, Rimmer Engineering, Inc. has taken on the innovative Rotrex supercharger line and launched a program of evaluating and testing vehicle applications suitable for its specific performance characteristics.

This program involves prototype installations for proof of concept and performance improvement appraisal. If accepted, prototyping is followed by comprehensive development, test and production of complete installation packages. Going far beyond the typical "tuner" approach in design and specification of its supercharging systems, Rimmer Engineering evaluates the entire package, including the manufacturing, installation process and everyday practical use of the supercharged vehicle.

Because of its very compact size and technically simple but advanced design, the Rotrex supercharger is able to be fitted into many vehicles where other superchargers are very difficult to install. Its quiet and unobtrusive operational sound level is far superior to that of other centrifugal superchargers currently available, making it much more suitable for normal (non-racing) daily use.

The boost characteristics of its centrifugal compressor configuration mean the Rotrex is best suited to sports, GT and high-performance driving, rather than off-road or heavy-load work where maximum power is needed at lower engine speeds. For those applications, Rimmer Engineering offers supercharging systems utilizing the positive-displacement Eaton compressor. Since the Rotrex, like the Eaton, is a mechanically-driven supercharger, many of the problems associated with turbochargers, including throttle lag and increased under-hood temperatures, are eliminated.

rotrex3d.jpg (15646 bytes)Current development projects include the Porsche 944 (eight-valve engines) and the Subaru 2.5 liter (SOHC) applications. A complete Rimmer Supercharging System (RSS) package for the 944 is expected to be released to market within a few weeks time. Other vehicle applications are being researched.


Additional information is available from Rotrex’s website,

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