Swiss engineer Dr. Alfred Buchi is credited with developing the first exhaust-driven turbocharger, sometime around 1912. By 1915, he published a proposal for employing a turbocharger on a diesel engine, but the idea was mostly ignored for the next few years. The first real world applications were in aviation, where turbochargers helped aircraft engines build power in the thin air of higher altitudes.
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Turbocharged aircraft engines became more prevalent during World War II, but were far from common. General Electric was the big supplier of turbochargers to American aircraft during the war and that’s when J. C. “Cliff” Garrett entered the picture. His company supplied after-cooling systems that were used with General Electric’s turbochargers on B-17 bombers.
After the war, Garrett continued manufacturing gas-turbine engines and experimenting with turbocharging. That led to the formation of a spin-off division of his company called AiResearch Industrial Division. It would later be renamed Garrett Automotive. Proving Dr. Buchi was on to something, but simply a few decades ahead of his time, early automotive-industry uses were targeted at diesel-powered over-theroad trucks, as well as similarly powered industrial engines.
Interestingly, engine-driven supercharging had been used successfully in automobiles since the 1920s, even if it wasn’t a widespread technology. Nonetheless, turbocharging didn’t arrive on the North American automotive market until the early 1960s, when several import-fighting, rear engine compacts were released by GM. They included the Chevrolet Corvair and Oldsmobile Jetfire, but while performance was adequate, durability and reliability were not.
Turbocharging mostly disappeared for the next 15 years or so, when its use became more widespread in large trucks and racing. The technology was also revisited by mainstream auto manufacturers after the fuel crisis of the 1970s as a way to balance performance and fuel economy. Buick, Ford, and Chrysler developed turbocharged powertrains in the late 1970s, but it wasn’t until the advent of modern-style electronic enginecontrol systems, electronically controlled fuel injection, and intercooling systems that turbocharging became a viable, reliable, and consistent method of building horsepower. Volkswagen and Mercedes-Benz also offered turbocharged models at that time. The intercooled turbo engine of the 1986-1987 Buick Grand National was a landmark design, not only in factory force-fed GM vehicles, but in the advancement of mainstream turbocharging. At a time when many V-8 “performance” cars struggled to offer 200 hp, the intercooled Grand National’s 3.8-liter V-6 was offered with 235 hp (rising to 245 hp in 1987). And while Ford’s 2.3-liter turbocharged engine was offered as a performance engine in the 1980s, the Grand National was the first turbocharged production model that offered a distinct advantage over V-8-powered competitors.
The Grand National shares nothing with the modern LS engine, but the basics of its intercooled turbo system are essentially the same as the aftermarket systems employed today.
LS-Powered Production Vehicles
There are a number of turbo kits available for production LS-powered vehicles and knowledgeable tuning shops can custom build them with the necessary components and good tube-bending skills.
With nearly unlimited performance potential, good low- and moderate-speed driving characteristics and the undeniable aura of exoticness, there’s much to like about the prospect of turbocharging a Corvette, Pontiac G8, or TrailBlazer SS. That doesn’t mean, however, that it’s the most practical solution to building a high-powered street car.
As mentioned in Chapter 1, the investment in kit cost and installation labor makes a turbo system typically more expensive when compared with a typical bolt-on supercharger system. There is usually more fabrication required to install a turbo system. I followed the installation of several supercharger and turbocharger systems and found a large gap in the time and special fabrication required between them, ranging from approximately 8 hours for the installation of an intercooled supercharger kit on a Pontiac G8 GT (see Chapter 5) to more than 40 hours for a turbo kit installed on a fourth-generation Trans Am.
At shop labor rates of $60 to $75 or more per hour, the installation time becomes an important and expensive consideration. On the low end of the labor rate scale, the additional time of the Trans Am’s kit versus the G8’s would add up to about $2,000.
With the tuning capability and driveline component strength (transmission, axle, etc.) comparatively equal between supercharged and turbocharged production vehicles, there’s no clear advantage of one over the other. The performance potential with a turbo system is undeniably greater, and for the enthusiast who envisions taking his or her car’s performance to higher levels in the future, a basic turbo system is an excellent foundation. System complexity and consequential installation cost, however, should weigh heavily on the decision to invest in one.
Terms As noted earlier, a turbocharger uses engine exhaust to spin the turbine, which is connected via the center hub shaft to the compressor side of the housing to generate boost. The basic components are defined below.
Turbine: The exhaust-driven wheel. Compressor/Impeller: The wheel spun by the action of the turbine that compresses air and generates boost.
Center Hub Rotating Assembly: The “floating” shaft that links the turbine and compressor/impeller wheels.
Inducer Wheel: The portion of the turbine or compressor wheel where airflow enters it; on a turbine wheel, it is the “major” diameter section, while on the compressor wheel, it is the “minor” diameter section.
Exducer Wheel: The portion of the turbine or compressor wheel where airflow exits it; on a turbine wheel, it is the “minor” diameter section, while on the compressor wheel, it is the “major” diameter section.
For most manufacturers, the general size of the turbocharger is measured in millimeters across either the turbine inducer or the compressor exducer. Racers who must comply with sanctioning rules regarding turbo-charger size should check the rules carefully to determine whether the size of the turbo is measured at the impeller inducer or the compressor exducer.
Like a supercharger, the turbocharger helps increase engine power through increased volumetric efficiency. It does this by compressing the engine’s intake air, making it denser, and forcing it into the engine at greater pressure than normal. When combined with the correct amount of additional fuel to match the denser air charge’s correspondingly greater oxygen content, it is a safe and reliable method for increasing the amount of air the engine can pump at a given RPM level.
The additional air delivered by the turbocharger comes from exhaust gas that exits the engine and blows into a turbine. As the turbine Exducer Inducer Fresh Air Compressor Wheel Exhaust Gas Turbine Wheel Inducer Exducer This illustration shows the internal elements of a turbocharger. When the exhaust gas spins the turbine, it simultaneously spins the compressor that is drawing in the fresh air that is forced into the engine. Exhaust gas is not fed into the engine. TURBOCHARGER TYPES AND SELECTION HOW TO SUPERCHARGE AND TURBOCHARGE GM LS-SERIES ENGINES 37 spins, it spins an air compressor that blows fresh air into the engine’s intake tract. The turbine and air compressor portions of the turbochargers are separate housings bolted together and linked by an interconnecting turbine shaft.
Generally speaking, the size of the turbocharger determines the volume of air it can generate, or the amount of boost it’s capable of blowing into the engine; i.e., the larger the turbo, the greater the boost. That’s a simplification of the theory of building horsepower with a turbocharger, but it’s suitable for this portion of the discussion.
The boost level is carefully tailored in production vehicles to deliver a balance of on-demand performance and fuel efficiency, along with smoothness and quietness that is acceptable to the 99.9 percent of the car-buying public that isn’t interested in running 9-second 1/4-mile ETs. In these factory applications, the size of the turbocharger is carefully selected, along with matched turbine and air-compressor sizes.
Whether a tailored factory system or high-performance aftermarket system for an LS engine, all turbocharger systems are affected by factors that influence overall performance and efficiency, including:
Heat: Turbochargers generate tremendous heat that is radiated through the engine compartment. It can elevate the inlet air temperature, reducing boost and possibly promoting detonation or pre-ignition.
Turbo Lag: The time difference between the application of the throttle and corresponding response in boost-induced power. This is typically due to the “spool-up” time it takes for the turbine to get up to sufficient speed to generate boost with the air compressor. Turbo lag has been a longtime detriment to turbocharging, with its tendency generally increased along with the size of the turbo.
Turbo Size: A larger turbocharger typically makes more power, but it can also induce greater turbo lag, as it takes a larger turbine more time to spool up. Conversely, a smaller turbocharger may spool up quicker, but not deliver the desired power gain or at the desired RPM level.
There is more to turbocharging than can possibly be described and explained in this single chapter. I recommend Jay K. Miller’s recent book, Turbo: Real World High-Performance Turbocharger Systems. It offers a wealth of more-in-depth information on the theory, design, and application of turbo systems (go to www.cartechbooks.com for more information).
Dealing with the Heat
The heat generated by a turbo system is part of the price to pay for performance. It uses the already-hot exhaust gases and, rather than immediately expelling them all through the exhaust system, retains a portion to spool the turbine. The heat radiated by the turbocharger can quickly build up in closed or tightly packed engine compartments, such as the fourth-generation Camaro and Firebird or the C5/C6 Corvettes. That heat is generally absorbed by the air intake system, heating the air charge and reducing its density.
Combating engine-compartment heat can be done with a variety of thermal wraps and thermal barriers placed on or around the affected components; a lower mounting position of the turbo(s) also helps. The innovative system designs from Utah-based Squires Turbo Systems (STS) approaches the problem by locating the turbocharger near the rear axle and removing it (and the heat it generates) from the engine compartment. (See Chapter 6 for installation details.)
Fighting Turbo Lag
As for turbo lag, it has always been an issue with turbocharger systems and is generally more prevalent on larger turbochargers, as more inertia is required to spool up the larger, heavier turbine when compared with a smaller turbo. Ceramic roller thrust bearings are used in some lightweight turbochargers to reduce inertia, while the aspect ratio of the turbo’s exhaust housing influences lag through the affect its aspect ratio has on spool-up time (see below).
One of the more effective ways to combat turbo lag is with a high-flow exhaust system. Some backpressure is required to help the turbine spool, but a freer-flowing exhaust system minimizes the time required for it to generate boost. On engines where quick spool-up and more low-RPM power are desired, the use of a pair of smaller turbochargers rather than a larger, single unit can help.
Ball Bearing Turbos
The standard, conventional “floating” bearing in a turbocharger is what the turbine wheel rotates on during spool-up. Minimizing friction as the turbine spins on the bearing reduces inertia for quicker spool-up and enables greater maximum turbine speed.
High-performance turbo systems also undergo tremendous thrust load; the greater the boost pressure, the greater the load on the turbo’s internal components. In the quest for greater turbocharger efficiency and durability, the ball-bearing-type turbo was developed by Garrett (currently a division of Honeywell). As its name suggestion, the ball bearing turbo’s center section (also known as the cartridge) on which the turbine shift spins features low-friction ball bearings. The lower friction significantly reduces inertia, delivering a more immediate spool-up of the turbine. The bearings are surrounded by a film of oil that not only lubricates but acts as a vibration damper.
On the heels of the ball bearing turbo came the ceramic roller thrust bearing that was pioneered by Turbonetics. It is commonly known as the ceramic ball bearing turbo, as the bearing is made of a silicone-nitrade ceramic material. With this design, the lightweight, heat-resistant ceramic ball bearing is used on the air compressor side of the turbocharger, while the turbine side uses a conventional floating bearing.
The Garrett-style turbo uses a pair of ball bearings, while the Turbonetics design uses a single bearing. Both enable quicker spool-up through reduced friction—Turbonetics claims only half the exhaust energy is required to drive the turbine—but just as importantly, the capability to withstand substantially greater thrust load. In fact, Turbonetics claims up to 600-percent-greater thrust capacity than a conventional turbo bearing. Turbonetics also claims the builder can step up to a larger turbo size without compromising drivability on the street—thanks to the reduced turbo lag and more immediate delivery of power.
While the quicker spool-up of these low-friction turbochargers is immediately noticeable when compared with a turbo using a conventional floating bearing, the advantage is more useful with vehicles where boost is desired during driving conditions, such as primarily street driving or road racing. On a vehicle designed primarily for drag racing, the difference in spool-up on the starting line doesn’t affect performance when launching under boost, but the greater thrust load capability ultimately means longer turbo life. This is due to the great load on the turbo that comes during staging, as the turbocharger is brought up to high speed in order to launch under boost. The sustained high RPM of the turbo on the starting line generates tremendous heat and load, so a ball bearing turbo pays off with performance longevity.
But, along with greater performance, ball bearing turbos (whether the Garrett-style or Turbonetics design) bring a significant price premium—perhaps up to double the cost of a conventional-bearing turbocharger. The performance and strength virtues of ball-bearing turbochargers are well established, but come at a price. If your budget allows, the ball-bearing turbo is the way to go.
Selecting the Right Size Turbocharger
While larger turbos generate more boost and, generally, more horsepower, there is a limit to their effectiveness. At the other end of the spectrum is the minimum size a turbocharger needs to be in order to effectively boost an engine. That minimum size is determined by the engine’s airflow at its maximum RPM level, measured in cubic feet per minute (cfm).
Arriving at the engine airflow requirement is achieved by multiplying the displacement by the maximum RPM and volumetric efficiency and dividing the product by 3,456. Generally speaking, naturally aspirated engines have a volumetric efficiency of about 85 percent, so the equation would look like this:
Displacement x RPM x .85 / 3456 = Minimum CFM
Let’s use a 6.0-liter LS2 engine as an example; it has a displacement of 364 ci and a 6,000-rpm redline:
364 x 6,000 x .85 / 3,456 = 531.157 cfm
This means that a turbocharger for the LS2 must have a minimum airflow rating of at least 531 cfm. Within reason, a turbo with greater airflow capability is fine, but that’s not the only consideration when selecting a turbocharger. The aspect ratio must also be considered.
Turbocharger Aspect Ratio
Another important element to turbocharger design, size and selection is the aspect ratio, which is the ratio of the area of the housing’s cone to radius from the turbine or air compressor’s center. Aspect ratios are measured on both the exhaust side and the air compressor side. On either side, the ratio is determined by dividing the cross section of the turbo by the distance from the center of that section to the center of the turbine wheel.
The aspect ratio should be constant throughout the housing, because the spiral-shaped housing reduces in size the closer it is to the center. The spiral shape is known as the volute; it directs airflow to the turbine. Comparing similar-size turbochargers with different aspect ratios, a greater ratio (identified by a larger number) enhances upper-RPM performance with greater airflow, but requires longer turbine spool-up time. A turbo with a smaller aspect ratio has quicker spool-up, but less upper-RPM airflow.
For turbocharged engines used primarily on the street and for road racing, a smaller aspect ratio on the exhaust side of the turbo delivers the best performance, as it promotes quicker spool-up and, consequently, more immediate power delivery. For drag racing, a larger aspect ratio helps build power at higher RPM, where it is more effective.
The size of the turbo and other factors ultimately determine the maximum airflow capability, but knowing how the aspect ratio affects performance should influence the decision when selecting similarly sized turbochargers.
Pitfalls of Mixing Turbines and Compressors
The turbine and compressor sections of a turbocharger must complement one another in order to produce strong, effective performance. Generally, turbocharger manufacturers and retailers match the exhaust-driven-turbine half of the turbo housing with an appropriate air-compressor half to generate optimal volumetric efficiency.
But in the quest to squeeze more boost from the system and generate more power, some builders experiment with different-size components, such as installing a larger turbine in the exhaust housing or bolting a larger air compressor to a smaller turbine. The changes drastically affect the turbocharger’s performance and should be attempted only if you have extensive knowledge and experience with turbocharging systems. It is very easy to kill the performance advantage of a turbo system with mismatched components that generate heat and noise, but little in the way of effective boost.
If you are experimenting with a custom turbo system for the first time, consult turbo manufacturers and experienced builders prior to purchasing or bolting on a new turbocharger. A defined horsepower goal or application, such as street and/or drag racing, helps the experts size a turbocharger that is the most appropriate for the project.
The complementing engine combination must also be considered in the role of volumetric efficiency, as the cylinder-head airflow characteristics, camshaft specifications, and even the intake manifold can affect performance under boost. In other words, it’s not necessary to experiment with internal turbo modifications if a camshaft swap would be a more logical and effective alternative.
Only after the as-delivered turbo has been tested and its performance parameters thoroughly understood and explored should you consider experimenting with its turbine and air-compressor components. Optimal volumetric efficiency is the goal and messing with the manufacturer’s balanced turbo assembly is a good way to adversely affect it.
Elements of a Turbo System
Of course, a turbocharging system is comprised of more than the turbocharger itself. A number of supporting components go into it, each affecting performance and durability in important ways. They include the following.
Turbo Exhaust Manifolds: They replace the conventional exhaust manifolds and mount the turbochargers, positioning the turbine side within the flow stream of the exhaust.
Turbocharger(s): The exhaust-trim air compressor that generates boost to increase horsepower.
Down Pipe: The exhaust pipe located immediately after the turbocharger, which receives the exhaust after it spins the turbine, as well as the exhaust from the wastegate.
Wastegate: It is essentially a bypass valve for the turbine, whereby a portion of the exhaust gas is diverted around—instead blowing of into— the turbine. It is used to tune or limit boost pressure by limiting the maximum exhaust flow to the turbine. When the maximum boost level is reached, the wastegate opens to bleed off exhaust pressure and prevent the turbo boost level from increasing.
Blow-off Valve (BOV): A device mounted on the air-intake pipe, between the turbo and the throttle body, that bleeds off excessive boost, which builds after the throttle is quickly closed—a condition known as compressor surge.
Bypass Valve: Similar to a blow-off valve, the bypass valve vents excessive boost pressure; but rather than venting it to the atmosphere, as the BOV does, the bypass valve vents it back to the compressor inlet.
Intercooler: The air-charge-cooling device that reduces the inlet temperature of the boosted air charge, which serves to maximize power and reduce the chance for detonation.
Complementing the basic elements of the turbo system, of course, are the corresponding fuel and ignition system upgrades, such as the fuel injectors, fuel pump, spark plugs, etc.
Boost Controller and Turbo Timer
In addition to the basic system elements described above, a couple of accessories that optimize longevity and performance are the boost controller and turbo timer. Neither are required to enable a turbo system’s operation, but they work to prevent damage and extend the operating range of the system.
The boost controller, as its name implies, is a device that controls the boost level of a turbo system, either limiting its maximum boost level or helping ensure a desired boost level at different RPM levels or throttle positions, as maximum boost can still be achieved with some systems without WOT. The boost controller works by bleeding off air pressure at the wastegate back into the intake system or venting it to the atmosphere.
Manual boost controllers are available and relatively simple to install and operate, but electronic boost controllers are better suited to an electronically controlled LS engine. They can be “dialed in” to deliver prescribed boost pressure at different RPM levels for finely tuned performance. You should check with the turbocharger manufacturer for recommendations of either the most appropriate boost controller or possible hardware changes suggested for the turbocharger itself. The spring in the waste gate, as well as other turbo system components, can be very sensitive and affected adversely with an aggressive controller.
A turbo timer is an electronically controlled device that keeps the engine running for a length of time to allow adequate cooling of the turbocharger after extended driving under high load. With it, the engine idles for a predetermined period, which allows the turbine to cool from extremely high exhaust temperature, with oil continuing to circulate through the system. This is a more important feature for vehicles that are routinely raced, such as drag cars, which benefit from the cooldown period in the pit area. With a street-driven vehicle, the cool-down period can be performed simply by keeping the engine’s RPM low and out of boost for several minutes before turning off the engine.
Single- vs. Twin-Turbo Systems
One of the methods of generating more turbocharged power is employing a pair of smaller, parallel turbo-chargers (one turbo for each bank of cylinders) rather than a single, larger turbo. This approach generally benefits chassis and engine compartments that are mostly stock and have limited room for a large single turbo, but many builders use twin turbos for aesthetic reasons, too.
A belief that a pair of smaller turbos spool faster and deliver more power at lower RPM isn’t entirely true. Although small turbos typically spool quicker than large turbos, when they’re used in a twin-turbo system, each is receiving only half the exhaust pressure as a single-turbo system. So in practical terms, the advantage of a twin-turbo system on a street car lies in the ability to package it within a tight engine compartment.
One of the most dramatic and effective examples of twin turbochargers is the Callaway Twin Turbo Corvette offered between 1987 and 1990. It used a pair of compact turbos to produce a little more than 12 pounds of boost and very little lag within the confines of the standard C4 Corvette engine compartment.
When it comes to racing engines, it is generally true that a pair of turbochargers enables more horsepower than a single-turbo system. However, the design and tuning of a twin-turbo racing engine is different from a singleturbo system to make direct comparisons not entirely accurate. Suffice it to say that, in a racing engine, more power can be had when more than one turbocharger is employed.
Bolt-On Turbo Kits and Tuner Systems
Time has proven bolt-on turbo kits to be tough to design, manufacture, and market successfully. The investment in development time, numerous special parts required for each vehicle model, and the razorthin line those manufacturers must balance between recouping their costs and selling kits at a reasonable price often sinks them after only a few years. Consequently, the number of bolt-on kits is considerably fewer than supercharger systems.
When it comes to turbocharged LS vehicles, Australia-based APS Performance has emerged as the preeminent manufacturer. If offers kits for the C5 and C6 Corvettes; the Pontiac GTO and G8, the Holden Monaro and Commodore; and the 1998-2002 Camaro/Firebird. In North America, the kits are available through a number of affiliated dealers, such as Stenod Performance. APS Performance’s kits have proven to be very well engineered, with inclusive kits packed with all the hardware required to install them, as well as detailed instruction manuals.
The other main turbo kit manufacturer for LS vehicles is Tacoma, Washington–based Turbo Technology. It offers a variety of intercooled kits for C5/C6 Corvettes and fourthgeneration F-bodies, including:
- C6 (including Z06) street/race twin-turbo system
- C5 (including Z06) street/race twin-turbo system
- F-body street single-turbo system
- F-body race single-turbo system
Although the systems above from both APS Performance and Turbo Technology are designed specifically for various vehicles and include the correctly sized and routed mounting hardware, the term bolt-on is somewhat of a misnomer. Unlike, say, an Eaton-based supercharger kit for a Pontiac G8 that can be installed in a single working day at a tuning shop (see Chapter 5), some of the turbo kits described here require up to four times the labor time.
The tools (including a vehicle lift) and experience required to facilitate the typical installation of a bolt-on turbo kit makes professional help very advised. Assuming a professional shop handles the installation, the cost of the system increases by the number of hours the shop takes to do it. And with 20 to 40 hours of labor at typical shop rates, that could add $1,000 to $2,000 to the final cost of the system.
Currently, additional bolt-on and/or tuner shop kits were either just introduced or planned for release by a number of other companies for the fifth-generation Camaro SS. They include:
- 2010+ Camaro SS turbo system by turbo component manufacturer Turbonetics.
- 2010+ Camaro SS turbo system by Fastlane, Inc.
- 2010+ Camaro SS turbo system by Ultimate Performance and Racing.
Many turbo systems are designed and installed on an individual basis by performance tuning shops (see Chapter 6). This is typically done on vehicles that can’t take advantage of a pre-engineered, bolt-on kit from an aftermarket vendor. An experienced shop can engineer a low-to-moderateboost single- or twin-turbo system that essentially bolts onto a stock engine.
One of the tuning shops that has been particularly adept at designing and building turbo systems is Fastlane, Inc., in Houston, Texas. Proprietor Nick Field says the system complexity is what generally makes it difficult to package a bolt-on kit. “Often, the oiling systems and necessary fabrication would make a kit very complicated, especially for someone trying to install the kit in his home garage—that’s why you don’t see very many bolt-on turbo kits. Our kit for the 2010 Camaro is a lot more straightforward, with no fabrication required, so we’re confident it will make a good bolt-on kit.”
Perhaps the most unique and, in many ways, the most innovative bolt-on turbo systems are those from Utah-based Squires Turbo Systems (STS). The company has streamlined the installation process and removed the turbo-generated heat under the hood by moving the turbochargers to the rear of the vehicle chassis, near the rear axle.
In a nutshell, an STS system takes exhaust from the stock manifolds and runs it beneath the vehicle (much like a conventional exhaust system), where it meets the turbo (very close to the exhaust outlet). The traditional turbo system blows into the turbo directly from the exhaust manifold. STS claims this lowers the overall temperature of the turbo system, reducing underhood heat, as well as lowering the intakeair charge temperature.
The use of the original exhaust manifolds helps lower the cost of STS kits, relative to other turbo systems. They’re still more expensive than most bolt-on supercharger systems, but the comparatively quick installation and lower component content makes them much more competitive with a blower, when installation labor is factored into the equation.
The comparative ease at which STS systems are packaged has allowed the company to offer kits for a greater number of LS-powered vehicles, including:
- C5 Corvette
- C6 Corvette
- 2010+ Camaro SS
- 1998–2002 Camaro and Firebird
- Cadillac CTS-V (2004-2007)
- Pontiac GTO/Holden Monaro (5.7-liter and 6.0-liter)
- Pontiac G8 GT/Holden Commodore
- Chevy TrailBlazer SS
- Chevy Silverado/GMC Sierra
- Chevy Tahoe/Suburban and GMC Yukon/Yukon XL
- Hummer H2
Chapter 6 illustrates the basic installation procedures of an STS kit, as well as a more conventional turbo kit.
Long regarded for exemplary engineering and extreme performance results, Indiana-based Lingenfelter Performance Engineering takes turbo systems to a unique level for LS-powered vehicles. The company offers a number of turbocharging systems, but rather than bolt-on kits, they involve completely rebuilt engines engineered to support forced induction. Its 800-hp LS7 twin-turbo system for the Corvette Z06 is the ultimate example. It uses all-new rotating parts, modified cylinder heads and a revised fuel system in conjunction with carefully tuned turbo components that include:
- Two Garrett oil-lubricated and liquid-cooled ball bearing turbochargers
- Lingenfelter-designed turbo compressor housings and exhaust housings with integral wastegates
- Air-to-air charge-cooling system
- Lingenfelter-designed stainless steel exhaust manifolds/turbo outlets
- Belt-driven turbocharger scavenge pump and turbo oil-drain reservoir
Obviously, the Lingenfelter system is more than a bolt-on kit and its cost reflects that. The base price for the system is more than $45,000— but that includes an essentially brand-new engine engineered for the heat and stress of a high-boost turbo system. It may not be the least-expensive option, but with a three-year/36,000-mile warranty backing it, it should prove to be one of the most durable. Lingenfelter offers similar turbo packages for other LS-powered vehicles.
Written by Barry Kluczyk and Posted with Permission of CarTechBooks