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Power Adders: Bolt-On Solutions For Huge Horsepower Gains

Demand for turbochargers, superchargers and nitrous oxide continues to expand beyond traditional race segments to provide a powerful sales boost for racing operations.

By Bill Sessa

A racer who isn’t after more power is about as unlikely as a kid turning down an extra scoop of ice cream on a hot day. Got the picture?

As manufacturers downsize engines to meet fuel economy and environmental standards, and racing organizations turn to lower compression engines to cut costs, the market for devices that boost power is robust—and expanding beyond the traditional road course, oval track or drag strip.

Whether a customer is looking for the rocket-launch power at the push of a button from a nitrous oxide system, or stratospheric horsepower from a supercharger or turbocharger, manufacturers and dealers are finding them in the sand, on the water, and in mud, ice and snow.

“We do a lot of tractor pulling, land speed racing, powersports and boats,” said Erik Radzins of Procharger, Lenexa, Kansas, to emphasize the variety among racers. Drag racing in sand or on ice are both growing segments, he added. “If we can fit a supercharger on it in a class, we will,” added Radzins, who noted that his company works closely with racing organizations to ensure that their applications fall within the rules.

His experience is similar to that of other manufacturers. “Drag race turbocharging is cranking right now, and powersports seems to be slowing down, but diesels are on fire,” noted Marty Staggs of TurbosmartUSA, Rancho Cucamonga, California. “If you look at diesel track sales, they are the biggest.”

“We have numerous applications for tractor pulls, rally cars, drifting and snowmobiles,” said Heather Dorethy of Precision Turbo and Engine, Hebron, Indiana, echoing the experience of fellow manufacturers.

So many applications in a broad racing market raises a dilemma of sorts for dealers and retailers. How to advise a customer who is looking for optimum performance? Like most matters in racing, there is no one simple answer; no magic formula or “rule of thumb” to rely on. Whether it’s a question of which system will work best or how to determine the appropriate size of a nitrous bottle or turbocharger, the most common answer is: It depends.

“If you want to make more horsepower, you need a bigger unit,” noted Reggie Wynn of Turbonetics, Moorpark, California, stating what may seem to be an obvious conclusion. “Once you get a taste of boost, you usually want more,” he added.

To underscore that point, he noted that half of his company’s business is upgrading turbos in models that are factory equipped with them, such as the LS3 and L99 engines from Chevrolet, and the Ford Mustang EcoBoost engine, both of which are certified by air quality officials as street legal. “It’s a simple bolt-on installation that uses the same oil and water fitting,” he said.

Other popular applications for Turbonetics’ units, which range from 100 hp to over 2000 hp, are Pro Mod dragsters, off-road Jeeps, and pro drivers on the drifting tour, he noted, who often refine the turbo response by adding a nitrous system as well.

“Each application is unique,” noted Dorethy. “It is not like opening a catalog” to identify the best combination to meet customers’ needs. When talking with customers, she and other manufacturers stressed the importance of asking questions, and lots of them. “We need to find out what they are doing with the product,” she explained, estimating that more than half of the inquiries her company receives require some form of a customized response.

If the customer is a racer, she asks about sanctioning body rules, engine size and compression ratios, and the amount of horsepower they hope to make, among other factors, before recommending a product that will meet their needs.

Like most manufacturers, Borg Warner of Auburn Hills, Michigan, perhaps most well known for its sponsorship of the Indianapolis 500 championship trophy, has collected an endless stream of data from its experiences on the race track, which it uses to respond to inquiries from customers and dealers.

The company’s “MatchBot” feature on its website ( underscores the many variables that are taken into account when matching a turbocharger to a customer’s performance needs. The website asks for the type of turbocharger the customer is looking for (single or twin), engine size, ambient temperature where the car is being driven, altitude and the type of fuel the race car will run on. The interactive feature then offers choices of up to 33 different turbocharger models, for either enhanced street performance or motorsports quality.

For each turbocharger model the customer selects, the interactive feature produces a mass flow chart, recommendations for compressor and turbine housing sizes, and data such as volume efficiency at various boost and rpm levels, and exhaust gas temperatures.

In similar fashion, Radzins noted, “We have so much data that we have logged on every car over the last 20 years, even including information on the intake manifolds that were used and tire sizes.” Computer-crunched data has produced formulas, available on Procharger’s website (, that guides customers to a potential combination that will work for them. “Most of our dealers are installers and have chassis dynos, noted Radzins. “They already have our recipes, and most of us can rattle a formula off the top of our heads that we used three years ago,” he added, highlighting the value of long-term experience.

Even though there is no simple answer for which form of boost or size of system to use, Radzins added, “Each application has its pros and cons.” For some customers, it may not be an “either-or” choice, but a combination of systems, such as nitrous oxide added to a supercharger or turbocharger, that will meet their needs

Straight Line Power

A supercharger is ideal for enhanced street performance, Radzins believes. Unlike a turbocharger, which relies on the build-up of exhaust gases to provide boost, a supercharger provides immediate power because it is connected to the engine’s crankshaft. “When the rpm’s go up, the boost goes up,” said Radzins. “It gives the best performance from stoplight to stoplight.” He added that the street performance market “is our bread and butter.”

The widespread use of superchargers on street machines is reflected, at least in part, by the popularity of the Street Outlaws television show, he noted. “Two million people watch that show, and there are blowers on three of the top 10 cars,” said Radzins. “It’s a heads-up, winner-take-all format with everyday cars. It relates more to the average guy sitting at home who believes he can emulate that but not a stock car.” He noted how many track promoters are copying that format, attracting young viewers who may not have known that their city had a drag strip before watching the show on TV.

“A big portion of our growth is in emissions-legal systems, especially in California,” said Radzins, reflecting the dual-purpose, street-and-strip performance many customers are looking for. Procharger’s “VO” series supercharger kits, and similar products from other manufacturers, are specifically designed to be street legal by meeting certification standards set by the US Environmental Protection Agency and California’s Air Resources Board, which documents that they do not increase emissions.

Manufacturers stress that any power-boosting devices, including nitrous oxide, superchargers or turbochargers, that have been certified as street legal are clearly marked in catalogs and on websites to avoid creating regulatory problems for customers after the parts are installed.

Procharger’s VO kits, as well as similar street-legal models from other manufacturers, can add up to 700 horsepower and still keep customers within the bounds of the law. “They are designed to meet emission standards, because not everybody who thinks they are an engine tuner can get a car to pass smog standards,” noted Radzins.

Smitty Smith of Edelbrock in Torrance, California, noted that “without a doubt, superchargers are definitely overtaking the market, and typically all of our Stage I supercharger kits are 50-state legal.” Like most manufacturers, Edelbrock offers superchargers with rotor sizes matched to engine size. Kits for a six-cylinder engine, for example, use a 1320 series compressor rotor from Eaton, while those for a V8 may use a larger 2300 or a 2650 model. The rule of thumb here is “the larger the rotor group, the more horsepower it makes.”

Many street-legal superchargers can easily add anywhere from 300 up to 1000 horsepower, and are easily adaptable to most modern new engines. “We do a lot of stroked 6.4-liter and 7.0-liter Chryslers, and we just released a new model for the new Chevy and Mustang,” noted Smith.

That explosive power can send powerful shock waves through an engine. And most manufacturers recommend using forged rather than cast internal engine pieces to withstand the load and ensure reliability of power generated by a supercharger spinning at up to 8000 rpm.

Edelbrock even offers an LS3 engine, rated at 785 hp when it is outfitted with a Stage I supercharger. “They already have forged pistons, rods and cranks,” noted Smith, referring to what seems like a standard list of engine modifications for all power-adding applications. “We make them bulletproof because we put a two-year warranty on them.”

Larger superchargers, such as Edelbrock’s Stage II and Stage III models, or Procharger’s F series, are designed for pure racing applications, and generate much more power. While a street-legal system can add as much as 11 pounds per square inch of pressure in a cylinder, those used in racing applications, such as in Pro Mod dragsters, can add at least 10 times more pressure and generate up to 3000 horsepower, effectively turning a drag car into a rocket on wheels, and making the need for stronger forged internal parts even more critical.

Flexibility In Turbochargers

Unlike superchargers, which are used almost exclusively in straight-line, full-throttle situations, turbochargers are used in a greater variety of racing situations because they can be adapted to a wider rpm range. “What we see, especially in Europe, are customers looking to enhance the performance of smaller displacement engines,” noted Brian Rhinehart of Borg Warner, as car makers downsize engines to meet increasingly stringent fuel economy standards, both in Europe and stateside.

“We’re seeing more import cars, as young kids try to get more efficiency out of their daily drivers, like the Audi A4 or the Honda Civic, and more classes of racing, such as snowmobiles,” noted Precision Turbo’s Dorethy.

In addition to boosting horsepower, turbochargers can be an inexpensive method of increasing fuel economy. “For every $1 you spend on fuel, only 30 percent results in power, and the rest is lost in heat and exhaust,” Rhinehart explained. “With turbocharging, you can capture another 17 percent of that heat energy and send it to the crankshaft, and the gains are even bigger on the diesel side.”

In addition to drag racing, the power gains from turbocharging are also becoming more important in road racing, ovals and drifting as engine manufacturers have reduced compression ratios in production engines to meet fuel economy and emission levels. “Compression ratios of 8:1, 9:1 or 10:1 are the sweet spot for turbochargers,” Rhinehart explained, noting that every Indy car, for example, which is outfitted with a pair of Borg Warner turbochargers, has a compression ratio of 8.5:1.

Adding 20 or 30 pounds of boost to an engine with higher compression ratios causes detonation, or “engine knock,” which results in misfires that can damage pistons and other internal parts.

In full-throttle applications, such as drag racing, determining the appropriate size of the turbo may be answered by the age-old racers’ question: How fast do you want to go? “If you want big power, you need a big turbo, no doubt,” noted Turbosmart’s Staggs.

As a general rule, however, the larger the turbo, the longer it takes to get to full power as it ramps up to speed. Manufacturers report a number of ways to manage airflow to minimize “turbo lag” and get maximum performance in a wide range of rpm’s.

Staggs noted that many drag racers mistakenly believe that big horsepower needs a big wastegate to control boost. The opposite is actually true, he explained, since that would increase (not decrease) turbo lag. The size of a wastegate is in inverse proportion to boost levels. In other words, more boost requires a smaller wastegate, forcing more air into the turbo to launch the car off the line.

In road and oval track racing, a compound turbo arrangement can widen the engine’s power band. A smaller turbo can spool up quickly to provide more torque off the corner during acceleration, combined with a larger turbo for more top-end performance. “You have a turbo on the low pressure side and on the high pressure side, which is boosting ‘boosted’ air, so you have optimum performance at both ends,” said Rhinehart, which can allow a car with a smaller engine to get off the corner as competitively as a car with a bigger displacement engine that produces more torque.

Most manufacturers offer boosting units to control the power of a turbo with more precision. Inexpensive manual units can be used to set a boost level to prevent overspinning the turbine, but Staggs noted that programmable units that increase boost at more than one pre-set interval offer more performance. “To be competitive today, you have to be able to map your boost,” he said.

Drag racers, for example, can program the unit to ramp up the boost based on throttle or clutch position, or at specific timed intervals during their run down the strip, Staggs explained. Road racers can program specific boost levels to coincide with wheel speeds or gear changes.

To increase turbo response, models designed for motorsports that can generate up to 1000 horsepower, such as Borg Warner’s “EFR” series or Precision Turbo’s “Gen 2” series, are made with lightweight material. Most construct the compressor wheel with a titanium/aluminum alloy coupled with ceramic bearings that reduce weight and increase response time by 50 percent.

One of the most heavy-duty applications for turbocharging is tractor pulls and other forms of diesel competition, according to Jerry Lagod of Hypermax in Gilberts, Illinois, who offered a reminder for all turbocharging applications. “If you need more air, then you need more fuel,” he noted. A diesel generating up to 4000 horsepower may need up to 10 times more fuel than that of a non-boosted truck or tractor. “You also need to do something to cool the air before you compress it,” he added, to generate optimum horsepower.

“You can use an air to air cooler, but in diesel competition everybody strictly uses water injection,” continued Lagod, to tame the intense heat generated by such stratospheric levels of horsepower. “Some guys can melt 100 pounds of ice in a single run.”

As for an engine capable of standing up to that kind of horsepower, Lagod remanufactures International Harvester’s most popular engine, the 670-cubic-inch “466,” with forged pistons, rods and crankshaft, which he claims is nearly impossible to break. “It’s a very robust engine that is almost indestructible as it came from the factory,” he said. “Each cylinder normally has about 2200 psi of cylinder pressure, but you can run up to 8000 psi for a short period of time before you hurt them.”

Adrenaline Boost

Athletes run faster or jump higher when their adrenaline levels rise. And, nitrous oxide does the same thing for engines, providing an instantaneous jolt by adding oxygen to wring more power out of the fuel. Manufacturers offer nitrous systems small enough to add 40 horsepower to a four-cylinder grocery-getter or 500 horsepower to a mean street machine.

In the most extreme levels of motorsports, nitrous oxide can be part of a power-adding package that is capable of producing thousands of horsepower. Due to its simplicity and versatility, “nitrous is a low-cost entry into the power-adding market,” when compared to turbocharging or supercharging, noted Smith of Edelbrock.

Because it provides power in short bursts, mainly during hard acceleration, “drag racing is ideal for using nitrous,” observed Matt Patrick of Zex Nitrous, Memphis, Tennessee. He noted that nitrous can also improve the performance of other power boosters. “It’s very popular to help spool up large, laggy turbochargers. Nothing beats the instant exhaust volume it provides.”

A project engine from Speedmaster in Rialto, California, illustrates how much muscle nitrous can add, especially when it’s coupled with a supercharger. The 540-inch Chevy big block put out a respectable 649 horsepower straight from the crate. But with a supercharger tuned for max boost and a nitrous injection, the Chevy put out more than 30 percent more power, measured at 939 horsepower on the dyno.

It’s an engine that would easily find a home in various drag racing organizations, such as the NHRA’s X275 class, where cars can be found with various combinations of superchargers or turbochargers complemented by nitrous oxide. “Racing organizations have done an excellent job of writing rules that encourage racers to use various types of power adders, and all of the combinations are competitive,” noted Precision Turbo’s Krivickas.

Another class that features nitrous oxide is Pro Mod, which appears in both NHRA and PDRA competition. Smith of Edelbrock noted that a new record for the class set in mid-May by Lizzy Musi, whose father Pat is an eight-time nitrous drag racing champion, illustrates how much punch nitrous can pack. The new record is 3.631 ET at 205. 88 mph in a one-eighth mile, set in a PDRA-sanctioned event.

But while there is no question nitrous delivers the goods, a common question centers around how much is too much (and how much is just right)? Patrick noted there is no strict formula to determine the size of a nitrous system. “A good guideline for street applications in an engine with stock internal parts is a kit that increases horsepower no more than 35 percent,” he explained.

Most manufacturers have pre-sized, universal nitrous kits matched to engine types with stock parts. As a general rule, a typical four-cylinder engine, for example, is expected to handle up to 60 added horsepower, while a small block V8 can typically handle up to a 120- horsepower boost, and a big block can accept a kit that hikes power from 125 to 200 horsepower.

By comparison, Patrick added, “purpose- built nitrous race engines with good fuel can easily exceed 70 percent gain if the tuning is done properly,” referring to engines with various grades of forged rather than cast pistons, rods and crankshafts.

Patrick went on to tell us the most common mistake nitrous users make is not retarding ignition timing far enough, which can produce premature ignition and detonation in the combustion cycle. As a result, an extreme case can cause real detonation, with engine pieces littering the path of a car as it moves down the drag strip.

Patrick continued, “We always recommend that a nitrous racer upgrade their fuel system to match the higher fuel requirements needed when using a nitrous system.”

Nitrous oxide is just as popular in street performance as it is on the drag strip, and growth in the market is influenced by the increasing production of electronically controlled, fuel-injected production cars. “The market for nitrous systems has been stable for the past several years,” Patrick added. “but certain markets have shown growth—in particular, the street EFI market.”

Power Adders: Bolt-On Solutions For Huge Horsepower Gains

Whereas superchargers are used almost exclusively in straight-line, full-throttle situations such as drag racing, turbochargers are utilized in a variety of racing disciplines—drag racing, road racing, ovals and drifting, for example—primarily because they can be adapted to a wider rpm range.

Performance Racing Industry