THE SHOP

November '15

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68 The Shop November 2015 Keeping Up the Pressure performance alternate between the scrolls. So on a four- cylinder engine with a firing order of 1-3- 4-2, one of the scrolls should be fed from cylinders 1 and 4, and the other from cyl- inders 2 and 3. That keeps the alternating exhaust pressure pulsations separate, which results in improved throttle response." It's a lot easier to do that on an inline engine—or with twin turbochargers on a V-engine, with one turbine fed by each bank of cylinders. "This is why Borg- Warner offers dif- ferent product lines for different cus- tomers," Nor ton continues. Harut Stepanyan, aftermarket appli- cation engineer for Garrett by Honeywell, agrees that many of the latest developments in turbocharger technology include the aerodynamics of the compressor stage. "Aerodynamics of the wheels is ver y important, as it is the main driver for the flow, the pressure ratio (boost) and the effi- ciency of the turbocharger," says Stepanyan. "The latest example in our product line is the GTW turbochargers, which contain an advanced aerodynamic compressor wheel made from forged aluminum. The advance- ment gives the customers options from the turbos that can make from 700 to 950 hp. The turbo not only performs well, but the price point for them is lower than the GT turbochargers. As manufacturers, we are developing new ways to squeeze higher efficiencies and bigger boost numbers out of turbos than have ever been seen before." APPLICATION-SPECIFIC Many of the newest OE turbochargers, according to Norton, use "application- specific housings with unique connection points, which then require application- specific upgrade kits. So BorgWarner offers Super-Cores, which are similar to complete turbos, but without the turbine housing. This allows kit designers and engine builders to mount the core of a BorgWarner turbo in an OE housing, or in one of their own design." As with so many other per- formance upgrades, "knowing a customer's realistic end-goal is crucial to making an appropriate recom- mendation for a turbo, intercooler, or complete kit," says Jacobs. Customers often arrive with only a vague idea of what they want, "so it's necessary to 'interview' them a bit, to ensure that they don't wind up with parts that will later leave them unhappy, or worse, angry at the shop that sold the parts and/or performed the install. Ask the customer what they intend to do with the vehicle— (Street driving? Drag racing? Road racing? Drifting? Or something else entirely?)— and their desired horsepower level. It's also wise to discuss the customer's budget: They may want 1,500 horsepower, but not the cost that goes along with it." Wynn agrees that "one of the first ques- tions to ask is how much horsepower the end user would like to make. Most of the time their response is, 'as much as I can,' which, by the way, is the wrong answer. So then we follow up with the intended use of the vehicle. If it's a street-driven car, for example, we'd recommend the smallest turbo possible to achieve the desired power with the least amount of lag. On the flip side, for a drag racer, you don't need to worry about the lag that is associated with a larger turbo that maximizes horsepower. And if they're looking for a street/strip, autocross or Pro-Touring setup, you would want to suggest something in the middle." Turbonetics, Wynn adds, is "excited about our next-generation TNX Series." Completely new from the ground up, the series features all-new compressor and tur- bine designs, patent-pending dual ceramic ball bearings, and dual oil seals at either end of the shaft. "That makes TNX ideal for low-mount or any tricky mounting situation, with no oil getting past the seals." Initially the TNX series will be offered in the popular T3 and T4 industry-standard turbine inlet sizes; but the line will expand "to our larger mid-frame, Y2K, and Thumper sizes in mid-to-late 2016." Also on the way are a bolt-on intercooler upgrade for the Porsche 996, and both turbo intercooler bolt-on upgrades for the EcoBoost Mustang. Meanwhile, PTE's Gen2 CEA designs "have raised the bar in turbocharger aero- dynamics," Jacobs believes, "with wheels that produce substantially more power-per- mm in testing than other similarly sized wheel designs." PTE offers "a full line of replacement, upgrade and custom turbochargers of all Demand for turbocharg- ers that are appropri- ately matched, in wheel size and spool capa- bility, to smaller- displacement engines has been steadily on the rise. (Photo courtesy Precision Turbo & Engine) Advanced efficiencies in air-to-air and liquid-to-air intercoolers have led to better overall turbo performance. (Photo courtesy Precision Turbo & Engine)

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