Lingfelter Performance Engineering's LS9 Blower Upgrade - Blown AwayLPE’s LS9 blower upgrade unleashes 55 extra horses in a true bolt-on system From the November, 2011 issue of Vette By Barry Kluczyk
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Your first experience with the Corvette ZR1 is sure to be life-altering. It’s a car that changes your perception of performance. It redefines the words “quick” and “fast,” and it most assuredly makes the muscle cars of old seem like rally-striped tractors by comparison. And then you get used to it. It’s a guy thing, mostly. Sure, 638 horsepower is stunning, and the brutal acceleration of the ZR1 will have most passengers wondering whether their will is in order, but even if the car packed 800 horses from the factory, most owners would still inevitably wonder: Could I get 850 out of this thing? The primary elements of adding... The primary elements of adding more than 50 rwhp to the ZR1 include LPE’s front supercharger cover (snout) and a smaller-diamter, 2.60-inch blower pulley that helps pump up the boost by a couple of psi. Satisfying that need to push beyond the regular-production boundaries is the reason the multi-billion-dollar aftermarket industry exists in the first place, and owners of the 205-mph ZR1 are no different. In a previous issue, we showed how Detroit-area engine tuner Thomson Automotive ( www.thomsonautomotive.com) bolts an LS9 supercharger to the 7.0-liter foundation of the LS7 to generate a nearly 800hp combination. That package comes with an approximately $35,000 price tag and requires an entire engine swap, however, while the bolt-on performance upgrade outlined in this story will add a significant 55rwhp bump to an otherwise stock ZR1, pushing its (flywheel) output beyond the 700-horse mark. That’s not to say it’s a cheap proposition. The upgrade in question—Lingenfelter Performance Engineering’s (LPE) 710hp LS9 Supercharger System Upgrade—runs just shy of $5,300, when performed at the company’s Decatur, Indiana, facility. Or, you can order all the parts separately for about $2,500 and do it yourself, but that price doesn’t cover the tuning and chassis-dyno testing that’s included when LPE spins the wrenches. Here’s the LPE snout (right)... Here’s the LPE snout (right) compared with the OEM piece. Besides the obvious differences inside the plenum area, note that the inlet isn’t angled like the stock part. That design feature helps smooth the airflow into the supercharger. The heart of the package is LPE’s unique, cast-aluminum front-supercharger-cover assembly, or “snout,” which serves as the housing for the blower pulley and air inlet (as well as the mounting point for the throttle body). LPE redesigned the inlet with a smoother, more direct airflow path. When matched with the company’s complementing 2.60-inch-diameter supercharger pulley, boost jumps by about 2 pounds—to approximately 12.5 psi—and airflow drawn by the blower increases significantly. The other components of the upgrade system include the following: - A larger, 100mm double-bearing idler assembly that enables the original supercharger belt to be retained.
- One of LPE’s solid supercharger-isolator couplings. It replaces the stock, spring-loaded coupling, which can cause a rattling sound after time or even score the pulley shaft.
- A cold-air induction system that matches the new inlet position of the throttle body.
- A 160-degree thermostat that will kick on the cooling fans sooner to maintain a lower overall engine operating temperature.
Perhaps the most surprising aspect of the project is the relative ease with which the intake swap is made. There are no exotic tools required. The engine doesn’t have to be lifted off its mounts. Heck, apart from a little coolant that’s lost during the thermostat swap, no fluids have to be drained. These close-ups show the inside... These close-ups show the inside of the stock intake and the LPE snout. That’s not to say it isn’t a complex job, however. There are a million lines, hoses, and fasteners that have to be pulled off, unbolted, and/or removed—and then reinstalled exactly in the reverse order. Miss any of them, and the engine flat-out won’t run correctly, and you’ll spend hours chasing down the problem. So, if you don’t have a particularly strong attention to detail, and your mind generally fogs over at the sight of vacuum lines, you’ll probably want to farm out this installation to a professional. We used LPE’s own techs, tuner, and chassis dyno, which made the job look nearly as easy as changing an air filter. They performed the installation in about a day, but give yourself a full weekend if you plan to do it yourself. DIYers will also need to get the tuning upgrade from LPE in order to make sure the higher-boost LS9 runs properly. LPE engineers say they discovered... LPE engineers say they discovered a reduction of about 2.9 psi of air pressure with the stock snout, which indicated a significant airflow restriction and prompted the development of the high-flow unit. And if the proof is in the dyno numbers, those we recorded before and after the test demonstrated the system’s effectiveness in no uncertain terms. On LPE’s Mustang chassis dyno, the test car spat out 549 hp and 528 lb-ft of torque at the wheels in stock form. If you weigh that against the approximately 20 percent drivetrain parasitic loss that’s typically attributed to rear-wheel power, the results put the flywheel output a few horses above the factory’s 638hp rating. After the blower upgrade and tuning, we rolled the ZR1 right back onto the same chassis dyno and recorded an eye-opening 604 rwhp and 589 rwtq, with a maximum boost of nearly 12.9 psi. That’s just about 725 hp and 706 lb-ft at the flywheel, improving the ZR1’s already enviable power-to-weight ratio to about 4.6:1—or one horsepower for every 4.6 pounds of the car’s mass. For the record, the 3,726-lb/612hp (and $330K) Ferrari 599 GTB Fiorano has a power-to-weight ratio of about 6.1:1. That means each one of those 612 prancing horses must lug around an additional 1.5 pounds when compared with the Lingenfelterized ZR1. Kind of makes want to hang out in front of the country club and pick a fight—not that we would advocate such deviant activities.  When it came time to install...  When it came time to install the upgrade kit, the first thing to remove was the lightweight, carbon-fiber hood, since all the work occurs at the front of the engine.  Next to be removed was the...  Next to be removed was the stock air cleaner/intake system. The mass airflow sensor (mounted aside) must be disconnected, removed, and set aside to be reused with the LPE system.  After the air intake, the...  After the air intake, the next item to go was the throttle body. It’s held on with four fasteners, but it also requires the disconnection of several electrical connectors/sensors.  The intercooler lid is unbolted...  The intercooler lid is unbolted and removed, too, in preparation for the removal of the entire supercharger assembly. Some of the fasteners are located under the lip of the cowl, requiring some slim wrenches and great dexterity. It can be removed and set aside with the coolant lines still attached.  A number of vacuum lines,...  A number of vacuum lines, coolant hoses, sensors, and electrical harnesses must be disconnected during the project. First-timers should consider shooting a number of digital photos before and during the disassembly, to help ensure proper replacement and routing during the reassembly phase.  The fuel line must also be...  The fuel line must also be disconnected. Simple disconnection tools are available at most auto-parts stores, but extreme care must be taken to relieve fuel-line pressure. Start by opening the fuel-fill cap and slowly disconnect the line at the engine. If the engine has been run within the previous few hours, it’s very likely you will experience some high-pressure spray, so be prepared with towels and even a fire extinguisher.  With the fuel line disconnected,...  With the fuel line disconnected, the supercharger can be unbolted and lifted off the engine. It’s not too heavy, but the awkward angle at which you have to bend in order to reach it means the recruitment of an assistant is recommended.  With the supercharger on a...  With the supercharger on a bench, the various vacuum lines and diaphragms on the snout are removed and retained for installation on the LPE part.  In addition to the attachment...  In addition to the attachment hardware, the snout is affixed to the supercharger with a healthy application of sealant. Pulling it off requires some muscle and patience. Also note the blower’s spring-loaded isolator coupling (arrow), which will simply be pulled off and replaced with LPE solid coupling. It reduces the tendency for rattling and won’t score the pulley shaft.  Prior to installing the LPE...  Prior to installing the LPE snout on the supercharger, the pulley is secured to the shaft. At 2.60 inches in diameter, it provides an 18 percent overdrive over the factory pulley, for about 2 additional psi of boost (with the stock crankshaft balancer). That keeps things safe for use with high-octane pump gas, but LPE also offers a 2.35-inch pulley and overdrive balancers as well. That all adds up to more boost, but race gas may be required.  To retain the stock supercharger...  To retain the stock supercharger drive belt, the smaller blower pulley must be used with this larger-than-stock, 100mm idler pulley. It’s a simple swap for the stock unit.  The new snout easily bolts...  The new snout easily bolts up to the supercharger, and all the hardware from the stock part is transferred to the new one, including the throttle-body gasket.  With the new snout/pulley...  With the new snout/pulley assembly installed, the supercharger is lowered back onto the engine. The reassembly procedure is essentially the reverse of the removal steps.  For proper sealing, the intercooler...  For proper sealing, the intercooler lid is torqued to 18 lb-ft.  And, of course, care must...  And, of course, care must be taken to reconnect the myriad sensors, electrical harnesses, hoses, and vacuum lines.  The throttle body and new,...  The throttle body and new, LPE- supplied air intake come next. The new intake is required because the LPE snout repositions the air inlet behind the throttle body when compared with the stock system. It’s also a freer-breathing system with a reusable filter.  The stock mass airflow sensor...  The stock mass airflow sensor is inserted into the mounting boss built into the LPE intake.  Swapping out the original...  Swapping out the original thermostat for this “colder,” 160-degree unit is the final step in the installation stage of the project.  Here’s the underhood view...  Here’s the underhood view of the completed installation. There’s a “Lingenfelter” tag on the snout, but apart from that you’d be hard-pressed to guess there’s anything more than a cold-air intake system feeding the engine. Stealthy.  Because the supercharger changes...  Because the supercharger changes the airflow characteristics of the engine—particularly with the additional boost of the smaller blower pulley—the engine controller must be reprogrammed. Here, that new “tune” is shown being uploaded.  With the new blower snout,...  With the new blower snout, smaller pulley, and fresh programming, our ZR1 test car put down 604 hp and 589 lb-ft at the wheels, or 55 horses and 61 lb-ft more than the baseline test. Not bad for bolt-on parts. vette
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