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
engines 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
Engineerings systems use either the Eaton or Rotrex supercharger.
RSS / EATON
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 engines 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. Eatons 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 pumps 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 todays 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.
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
Additional information is available from Eatons
RSS / ROTREX
Continuing the companys 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
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.
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
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