This chapter is dedicated to the familiarization with the different manufacturers of turbochargers and turbo systems, their models, flow ranges, part numbers, and flow maps to make selecting the best turbocharger for your project a little easier. While there have been several books written about the subject of turbochargers and how to match them to your engine project, too often obtaining the flow maps and assembly part numbers has been left to the reader, and that can be its own challenge.
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Historically, turbo manufacturers have held flow maps captive and you almost had to know someone to get enough maps to make a good selection. Also, diesels were the real reason so many turbo models existed, and the automotive aftermarket was too small for turbo manufacturers to actively pursue, so they had little motivation to prepare, assemble, and release good information. That has now changed. The following pages contain information about some of the top turbo manufacturers and systems makers in the world and their most popular models, features, and series nomenclature.
While most of these suppliers publish catalogs illustrating even more turbocharger models and their compressor maps, many of the most popularly applied turbo models are consolidated in this chapter. In the case of Holset brand turbochargers, the maps contained here are possibly not found anywhere else. Holset is the only turbocharger manufacturer dedicated exclusively to diesel engine applications, and the folks there have made these maps available specifically for use in this book.
It is entirely possible that more than one turbocharger make and model will match well with your application. However, it’s also possible that there could be only one make and model that looks best for a specific engine. In Chapter 3, I made the recommendation to select a turbo model where several choices of turbine A/R ratios existed, which would allow you to fine-tune your application. This book does not catalog all of these facts. However, the distributors for these various makes and models will give you greater insight into what hardware is available. Many of these manufacturers also have published catalogs and websites that display their full range of products.
Honeywell Turbo Technologies: Garrett Brand Turbochargers
Founded in 1936 by Cliff Garrett, the Garrett Corporation grew to become the world’s largest turbocharger manufacturer. With manufacturing plants located in Europe, Asia, North America, and South America, Garrett—now Honeywell Turbo Technologies—employs more than 6,000 people. Garrett has always been active in all forms of engine boosting and its involvement in racing has proven to be a valuable development test bed for advanced design concepts.
Headquartered in Torrance, California, Honeywell Turbo Technologies has made many turbocharger models and families over the years. The most current state-of-the-art model series is the GT line of turbochargers. Prior to the GT series’ introduction in the 1990s, the T series was the workhorse of the OEM and aftermarket, and served each market well. During the development phase of the GT, it was referred to as New Garrett Technology, or NGT. Over time it was shortened to GT.
The GT series contains 45 percent fewer parts than the previous T series. The GT family also has improved aerodynamics, increased thrust load carrying capabilities, improved journal bearings that reduce shaft motion by 20 percent, come in both traditional journal bearing and ball bearing designs, and contain an expanded line of available trims to more accurately match turbo to engine, which results in optimized engine performance. Today there are GT models that can be applied to engines from 50 to 2,000 hp.
Garrett has been extremely active in both diesel and automotive turbocharger development for many years. However, in recent years Garrett has recognized the growing interest in turbocharger retrofits, and has demonstrated great leadership in the area of turbocharger model development and information, thus allowing the racer and street enthusiast ever more access to specific models designed for street and strip use. The Garrett GT range of turbochargers not only bring the latest design features to OEM engine manufacturers but to performance engine builders, as well. The following pages help to explain the GT nomenclature and flow range of the GT series. The compressor maps and assembly part numbers help the engine builder apply the best match to their project. While not all of the Garrett GT models are represented in the following pages, those listed represent some of the best.
Understanding GT Nomenclature
Let’s take a look at the basic Garrett GT model nomenclature.
Positions “XX” refer to the frame size of the turbine wheel inducer. For example, the “GT28” in “GT2860RS” refers to its turbine wheel frame size. All GT28 turbos use a turbine wheel with 53.85mm inducer diameter, and as a rule of thumb, the larger the number, the larger the turbine wheel.
Positions “YY” designate the compressor wheel exducer (major) diameter in millimeters. For example, the “60” in the GT2860RS example above has a 60mm compressor wheel exducer diameter. Note however, that wheel sizes 100mm and over omit the “1” (hundreds digit), so the “02” in a GT4202 turbo refers to its 102mm compressor wheel exducer diameter.
Positions “ZZ” may be used to describe special features of a particular turbocharger where applicable. For example, the “RS” in “GT2860RS” means this is a ball bearing unit (the “R”), while the “S” is simply used for units which require some differentiation from other turbos in the same family.
Compare a GT2860R to a GT2860RS. While both use ball bearings and are externally similar, the GT2860RS is better suited for higherflow applications than the GT2860R. In this case, the S reflects the higherflowing nature of the GT2860RS. While the turbine wheels are the same, note the compressor maps for each later in this chapter. Find the point on the GT2860RS compressor map where 25 lbs/min flows at a 2:1 pressure ratio, then look at the GT2860R map. That same point is at a completely different place. The primary difference between these two turbos is that the GT2860RS compressor wheel has a 2.7mm larger inducer diameter. The reference point in question shows the GT2860RS right square in the middle of the highest efficiency island at 76 percent, while that same coordinate on the GT2860R reveals only 68 percent efficiency. That’s a big difference.
GT Frame Sizes
Following is a basic reference of frame size to use as a guide to understanding the GT nomenclature and their basic application range of intended usage. A turbocharger frame size or family refers to turbos that typically use the same or similar sized turbine wheel castings trimmed to various configurations and where the same bearing housing, shaft size, and internal parts are common among the various turbo assembly models. The same frame size will typically have the same turbine foot mount as well. As previously discussed, it’s possible that more than one turbocharger model may match well to your application. So, using the frame size reference chart it can be an advantage to select the turbo model where alternative turbos can be slected from the same frame size that will make adapting a different turbo to your application easier.
GT12 – GT15 – GT20 – GT22 This range of modern wastegated turbochargers is ideally suited for small-displacement applications including motorcycles, and more.
GT25 – GT28 – GT30 – GT32 – GT35 Garrett offers a huge selection of housing options, with both journal bearings and the patented ball bearings, in its medium frame turbo family. Horsepower capabilities range from 170 to 550 hp. Large Frame GT37 – GT40 – GT42 – GT45 – GT47 – GT55 – GT60
Large frame turbos are best suited for large-displacement engines, drag racing vehicles, and other applications that require significant airflow. There are wastegated or free-floating units, plus ball-bearing units available.
BorgWarner Turbo Systems / Schwitzer / 3K Brands
Today, BorgWarner Turbo Systems is a combination of two turbocharger manufacturers BorgWarner, Schwitzer and Kuhnle, Kopp & Kausch (3K) , both with a history rich in turbocharger design, development, and applications. BorgWarnerFounded in 1918 by Louis Schwitzer, the Schwitzer Corporation began with cooling system components and pumps. One of Schwitzer’s greatest legacies that remains largely unknown, is that he was the winner of the first race at the Indianapolis Motor Speedway in 1909. No, it wasn’t the Indy 500, but winning the 5-mile race was still an accomplishment. Louis Schwitzer was always involved with the Speedway and his name resides in the Automotive Industry Hall of Fame. Louis Schwitzer was of Austrian- Hungarian decent, and earned master’s degrees in both mechanical and electrical engineering from German universities. Before immigrating to the United States, he developed the first gasoline-powered fire hose pump in Budapest.
When Louis Schwitzer arrived in America, he had just $30 in his pocket with which to begin his success story. But few end up with stories like Louis Schwitzer, who helped shaped both the automotive and heavy-duty industries. Someone once asked Schwitzer why he decided to design and manufacture fan blades for Henry Ford, and Schwitzer responded, “Because, I know more about them than anyone else!”
During the 1960s and ’70s Schwitzer developed a highly successful series of turbochargers for engines in the 200 to 400 hp range.
The Schwitzer Corporation was sold to Dison-Kisner in 1963, but it went through several more corporate divestures and acquisitions before becoming an integral part of today’s BorgWarner Turbo System division.
Another turbocharger manufacturer, Kuhnle, Kopp & Kausch (3K) of Frankenthal, Germany, was similarly acquired by BorgWarner. This gave BorgWarner the combined strength of both Schwitzer and 3K engineering, manufacturing, and turbocharger model ranges for the world market.
Together with other BorgWarner turbocharger facilities, BorgWarner Turbo Systems maintains operations in Europe, the U.S., Brazil, Japan, and Korea. Headquarters for the turbo systems division is located in Kirchheimbolanden, Germany. The current BorgWarner models are primarily the S-series from Schwitzer decent and the K-series of 3K decent. The S-series turbochargers are a complete redesign of Schwitzer’s earlier 3LM, 4LE, and 4LF turbo models that were so popular in the ’70s and ’80s. The earlier 3L and 4L series turbos referred to a basic frame size where the turbine wheel outside diameter was either 3 or 4 inches. The S-series model families built on the range of 3L and 4L turbos, and also benefit from various performance improvements.
The S-model nomenclature is rather simple, where an S100 refers simply to a turbine wheel diameter of approximately 100mm, while an S200 is 200mm, and so on. While the actual finished wheel diameter will vary from this actual size, this is the basic frame size of reference before the final turbine trim was established.
BorgWarner Turbo Systems established its AirWerks independent aftermarket program, which markets a series of premium turbocharger models specifically designed for the high-performance turbo aftermarket. The following pages contain a complement from some of BorgWarner’s best models from the S-series and K-series models for performance applications.
Cummins Turbo Technologies / Holset Brand
In 1952, Paul Croset and Brian Holmes formed a new company. Brian Holmes thought that the company’s name should derive from the family names of HOLmes and CroSET. So, on March 29, 1952, Holset was incorporated as a limited company and a wholly owned subsidiary of B.H.D. Engineers Ltd. of England.
Holset Engineering was deeply involved in the design and manufacture of various heavy-duty engine components such as vibration dampers and couplings. In 1954, Holset took a license from Dr. Alfred Buchi to manufacture his turbocharger design. Around 1957, Louis Schwitzer’s company in Indianapolis had developed a small, lightweight turbocharger, and a close association and licensee agreement between Holset and Schwitzer followed. Holset designed and manufactured turbochargers for the European market where Schwitzer did not have manufacturing facilities at the time. Holset’s one-millionth turbocharger came off the assembly line in 1973.
Today Holset is known as Cummins Turbo Technologies. While the name is relatively new, Holset has been a part of the Cummins Engine Company family for over 30 years now. Holset is a world leader in turbocharger technology and Holset turbos are an important element in Cummins’ success throughout the world. But Holset turbochargers are applied to many commercial applications beyond Cummins engines, and applications include Volvo, Iveco, Detroit Diesel, and Scania, among others. Holset’s engineers are also very familiar with racing and performance. Their assistance in the turbocharger used on the Banks land-speed-record truck is but one example.
Holset’s current state-of-the-art turbos are the X-Range family. From the HX20, for engines of up to 4 liters in displacement, to the HX83, suitable for engines as large as 25 liters, these turbochargers carry advanced design features that include better aerodynamics, improved durability, map width enhancement, and sound suppression. Holset also boasts a patented variable geometry turbine design they believe will surpass traditional designs in long-term durability. This new variable geometry design is utilized on the 2007 Dodge Cummins turbo diesel pickup.
Cummins Turbo Technologies’ headquarters is in Huddersfield, England, while their U.S.-based headquarters is located in Memphis Tennessee. There are six manufacturing plants located around the world including the USA, Brazil, the United Kingdom, China, and India. The newest plant just opened in 2006 in Charleston, South Carolina, with a manufacturing capacity of 200,000 turbos per year to support the growing demand for turbochargers in North America.
While Holset is proud to say that they are the world’s only turbocharger manufacturer that produces turbochargers exclusively for diesel engines, an aftermarket retrofit of a Holset brand turbocharger could be as successful on a gasoline engine as on a diesel. It just all depends upon the particular engine and its airflow demands. Because of Holset’s range of turbomachinery, and specifically their extremely high-flow models, they are often the choice of extreme performance applications such as tractor pullers that need all the airflow they can get.
The maps displayed in this section outline various flow maps from a portion of the Holset brand line of X-Range turbochargers and others, for application to virtually any project from 100 to 1,000 horsepower. Holset has never before published compressor maps, but has done so specifically for this book. Special thanks goes to the folks at Holset for their recognition of the general performance community’s interest in their products.
Turbonetics & the Roots of the High-Performance Turbo Aftermarket
Bob Keller founded Turbonetics in 1978, but his turbo beginnings precede that by several years. His is a story that’s both interesting and important to the history of turbos and gasoline hot rod engines. Bob is a turbo engineer, certifiable hot rodder, all around good guy, and friend. When Bob began his turbo career in the early ’60s, there were few people who wanted to turbocharge gasoline engines. The major turbocharger manufacturers had little product offering because the total market demand for gasoline engines wasn’t significant enough for the manufacturers to tool and manufacture special turbos for the aftermarket.
Carburetors were the dominant form of fuel management and it was difficult to tackle the associated problems with turbocharging at that time.
The technical problems associated with turbocharging by the average do-it-yourselfer mostly centered on the age-old issue of “pull through” or “blow through” the carburetor. If you used a blowthrough method you would maintain optimum placement of the fuel distribution from the carburetor, through the manifold. But the problems associated with this method were boost enrichment of the fuel flow because a carburetor senses airflow, not air density. The pullthrough method was favored by most, including Keller, because the turbo’s compressor was located down-stream of the carburetor. That meant that the carburetor could sense the increase in volumetric airflow that was feeding the compressor prior to the turbo increasing the air’s density through the development of boost pressure.
Keller’s interest in turbos began in 1962 when the Olds Jetfire was turbocharged by GM using a Garrett T-5 turbocharger. Keller saw the turbo and had to have one. He contacted Wolf Schlegel of Garrett, then called AiResearch Industrial Division, and bought one for about $85. Keller applied the T-5 turbo to a Plymouth Valiant with a slant-6-cylinder engine. It appeared in a few magazine articles that gave Keller some notoriety. Soon after, Chrysler commissioned Keller to do a project car with a turbocharged 426-ci Hemi that made gobs of power, but was rather erratic and not very streetable. In Keller’s words, “That car got more press and publicity than any car that never won a race or set a record.”
Keller’s friendship with Schlegel of Garrett grew and together they formed the original company, Turbonics, in the late ’60s. After a few more project cars, like a mid ’60s Mustang, they began producing performance marine turbo packages and created a new product called the Turboveyor for Fruhauf trailers, used for pneumatic conveying and off-loading of bulk commodities from large commercial truck trailers. This product had its problems for the same reason that turbocharging of gasoline automobiles was problematic during this era. The positive carbon face seal used to seal the turbo’s compressor was not durable.
Keller was involved with a number of turbo companies through the years by way of mergers and acquisitions. He saw an ever-growing interest in turbocharging gasoline engines, but an insufficient number of models available to match most project and competition engines.
As a result, In 1973 the Accel Division of the Echlin Corporation bought out Keller and Schlegel’s interests and formed the new product line called Turbosonic. Turbosonic by Accel division sold a great number of turbo kits for retrofit upon street cars using the unique feature designed by Keller called the “priority valve.” This was a valve body that was installed between the carburetor base and the intake manifold that allowed normal fuel distribution from the carburetor through the intake manifold until sufficient boost pressure was developed by the turbo inside the manifold that actuated a flapper valve to shut off the path leading from the carburetor to the intake manifold, and reroute the air-fuel mixture through the turbo’s compressor. This device allowed many kits to be more easily installed by the average do-it-yourselfer in the performance aftermarket and helped launch the turbocharger automotive retrofit market for gasoline automobiles.
In 1976, Echlin bought RotoMaster, an aftermarket turbocharger manufacturer that primarily reversed engineered turbocharger parts and assemblies for the commercial diesel service market. This meant that the Accel division of Echlin could now manufacture its own turbochargers for the kits it sold in the automotive aftermarket. Hugh MacInnes, a wellknown turbo guru and published author of the book, Turbochargers, was vice president of engineering, and Bob Keller was chief engineer of turbocharger systems. Keller left RotoMaster in 1978 and returned to his entrepreneurial pursuits and founded Turbonetics Incorporated in 1978. Bob saw an ever-growing interest in turbocharging gasoline engines, but an insufficient number of models available that uniquely fit what was needed for most project and competition engines.
At the time, turbochargers were produced for commercial diesel applications, not gasoline. And while a diesel turbo can be applied to a gas engine, the available turbos would typically be sized incorrectly for specific gas engines due to the differences between engine and fuel types. Turbonetics began as a distributorship for most major brands of turbos, but Keller also mixed and matched components to form hybrid turbos optimized for popular hot rod gasoline engines. The company grew gradually, filling niche markets and slowly developing certain key components to augment assemblies from Garrett or Schwitzer, which uniquely positioned Turbonetics in the performance community. The rapid introduction of electronic fuel injection to the gasoline engine in the 1980s was the great enabler allowing turbocharger systems to more easily be installed as a retrofit because most all of the concerns relative to carburetion went away.
There are two ways to throttle an engine: by air or by fuel. A turbocharger is basically happier with an engine throttled by fuel, as is the case in a diesel. With the advent of electronic fuel injection on gasoline engines, the same potential would now hold true. In 1998, Kelly Aerospace purchased Turbonetics from Bob Keller and continued investment in the company that was poised for growth in a rapidly expanding turbo aftermarket. Near the end of 2006, Edgewater Capitol Partners purchased Turbonetics and is still the owner at this time. Tubonetics changed hands a couple times in the past 10 years, and Keller is in semi-retirement but still acts in a consulting capacity as president emeritus.
Today, Turbonetics is a company with a rather unique standing in the turbo world. In most cases, companies with turbocharger expertise are either turbocharger manufacturers, such as those already mentioned in this chapter, or they are turbocharger system specialists who apply turbos and/or manufacture turbo kits specifically to fit popular aftermarket applications. Turbonetics is actually both. They have full application engineering and manufacturing capabilities along with gas stand capabilities for turbo research and development of their product offering. Turbonetics also carries a full range of turbo system components and accessories as well that are helpful to the do-it-yourselfer.
Turbonetics appears in this chapter not only because of their unique position, but also because of Keller’s grassroots involvement in the development of the gasoline turbocharger aftermarket retrofit industry. Bob Keller’s passion and insight birthed a company who today still uses specialized components from the various leading world suppliers while also manufacturing their own components wherever there is an application need, or an opportunity for improvement.
This page highlights some of their complete turbocharger products, while many of the accessories outlined in Chapter 6 on Turbo Systems are from Turbonetics as well.
The GT-K Model Family
The newest line of turbos from Turbonetics is their GTK line-up. Features include their ceramic ball bearing system and map width enhancement, which is evident in the ported slots located in the inducer approach. In addition to their new high-efficiency hipped compressor wheels made from 354 heattreated aluminum, the new F1 turbine wheel is made from Inconel 713. The turbine housings are coated with a high-temperature ceramic to trap turbine heat energy in the turbine housing to do more work.
Written by Jay K. Miller and Posted with Permission of CarTechBooks