HPE's Z Series Camshaft and Power Packages
Camshaft Packages:
The HPE C6Z series of camshaft packages retails for $999.95 and consists of cam, dual valvesprings, titanium retainers, Super 7 locks, locators, seals, custom length pushrods, and new crankshaft balancer bolt. The custom-ground COMP Cams are offered in Stage I, II and III varieties. The Stage II cam specs as used in our test car, come out at 230/242 at .050 on a 114 LSA with a .607/.620 lift on 1.8 rockers. The Stage III cam specs are under lock and key somewhere in the Dominican Republic and would require 32 members of the Mafia and one very loud 300-pound opera singer to get them past Chuck's lips.
COMP also supplies the custom length Hi-Tech 3/8-inch pushrods. The pushrods are a one-piece design constructed of 4130 seamless chromoly with an outstanding wall thickness of .080 in. The pushrods are heat treated to a "60" hardness on the Rockwell "C" scale and finished in a black oxide.
Patriot Performance "Gold" dual valvesprings (PN 8401) are capable of up to .650 lift and include titanium re-tainers, machined bases, Super 7 locks and Viton rubber intake and exhaust seals. The Patriot Gold springs feature an open spring pressure of 380 pounds, with 135 pounds closing pressure as compared to approximately 310 and 110 pounds for the factory springs.
Power Packages:
In addition to the camshaft packages, HPE offers the following components to make up a Power Package. Key to the power packages is intake and exhaust changes designed to maximize flow.
The Kooks headers ($909.95) are constructed of mandrel bent T-304 stainless steel and feature 1 7/8-inch primaries and heavy-duty 3/8-inch flanges. The D-Port equal length headers feature 3-inch collectors with integral scavenger spikes. All pipes are TIG-welded with the inlets and collectors hand ported to ensure maximum flow.
The Kooks 3-inch mid-pipe ($703.95) features an aluminized center section with a built-in X crossover and two hi-flow MagnaFlow stainless steel catalytic converters. The 3-inch version bolts onto the 3-inch collectors of the Kooks headers and exits at 3 inches, accommodating the Z06 cat-back. The X crossover is positioned as far forward as possible to help scavenge additional exhaust from the engine. An off-road X-pipe is also available. Both systems require the Kooks four-piece O2 sensor extensions to take care of the revised O2 sensor placement on the header and mid-pipe.
HPE's custom throttle body porting service ($125.00) reworks the GM 90mm casting to remove the machined in leading edge to allow for a smoother transition of air into and out of the throttle body. The porting service is available for all LS series throttle bodies and typical gains are 7-10 rwhp. All work is done in-house.
Options:
The Halltech Z06 High Flow PowerCore air filter (pictured on right) retails for $199.95, and the company claims the filter features 19 percent lower restriction at 850-cfm than the stock Delphi OEM PowerCore filter supplied by the factory.
After completing the exhaust, install the crankshaft balancer and the remaining components that were removed to facilitate the transformation. Fill the engine with eight quarts of factory fill Mobil 1 and replace the Dexcool with fresh coolant. After checking the car over several times, Josh fires up the willing LS7 and allows it to idle, while carefully checking for any fluid or exhaust leaks. Once verified, the car is allowed to cool before being strapped onto the dyno where Chuck Anders refines the idle, air-fuel and timing tables until the LS7 is ready to be unleashed.
Recommended Tools:
Metric Socket set7/8-inch wrench
Metric wrenches
5/8-inch plug socket
3/8-inch socket wrench
Pry bar or large screwdriver
Recommended Parts and Supplies:
LS series valve tool
Anti-seize compound
Wire wheel or wire brush
Conclusion:
When the HPE Z06 camshaft and power packages were installed and the final tuning tweaks were made, the LS7 responded to this mild camshaft upgrade by picking up a total of 48 hp and 44 lb-ft of torque at the wheels. The addition of the Halltech high flow air cleaner boosted the gains up to 51 and 46 hp and torque, respectfully. Just as important as the peak numbers are the phenomenal increases across the entire power band. It's one thing to desire a radical idle and stratospheric peak numbers, but this engine makes gobs of power without sacrificing anything in the way of drivability. The idle has just the slightest hint of a lope and until the driver cracks open the throttle to allow the dual-mode muffler to vent exhaust without baffling, nobody would be the wiser that over 500 rear-wheel horsepower lurks in the car.
According to Z06 owner, Sanjay Mehta, "In stock form, the Z06 was a screamer from the day I drove it off the Bowling Green assembly line, but didn't quite have the power of my LPE 415 ZR1 or Procharged C5. Although the camshaft package was small, it fit my needs. The car runs beautifully, and these mild mods really bring out the personality of the LS7. It will now run neck-and-neck with my LPE 415 ZR-1, and it feels quicker below 4,000 rpm on the street than the Procharged C5. The effortless power at any RPM is intoxicating ... it really roars above 4,000, but I can pass smoothly at 1,800 rpm in Sixth. The cam has a very mild lope ... enough to know something is going on, but not enough to be annoying in traffic. I wanted to retain the stock drivability and reliability, while unleashing some of the potential of the LS7. During before-and-after quarter-mile drag testing at Houston Raceway Park, the best stock run was an 11.8 at 123.5mph on a 2.1 60-ft time with the stock Goodyear F1 tires. After the power package installation, the Z06 turned an 11.35 at 130 mph with a 2.05 60-ft time. Of course, I was promptly booted off the track for running below 11.50 without a roll bar, so I switched on the A/C and XM radio for the cruise home. No detonation, no clutch issues, no Check Engine lights, just stock like drivability, with more power and a crisper, more authoritative sound." According to Chuck Anders, owner of HPE, "I was happy to see that the Z06 responded as well as it did to the mild camshaft and exhaust changes. The extremely refined nature of the LS7's heads and the excellent factory exhaust make it more difficult to achieve the type of results we see on LS1 and LS2 engines. Even with the mild Stage II cam, the engine is putting out right at 575 horsepower at the crankshaft. Not bad for a motor that will pass any emissions test in the country and propel a Z06 to very low 11-second time slips. Additional power gains can be coaxed out of the LS7. We have several customers who have put down over 550 rear-wheel horsepower by going with our Stage III Power Package, even a couple have made over 560, with the only changes being the use of the off-road Kooks mid-pipe and an electric water pump. Mild or wild with an LS7 and the results are the same--phenomenal street power!"
Dyno Chart:
Testing of the 2006 C6 Z06 Corvette was performed at Horsepower Engineering in Houston, Texas. HPE has both Dynojet Model 248 and Mustang MD-1750 in-ground dynos. An in-car monitor is used to collect real time air fuel ratio (A/F) data on the load-simulating Mustang Dyno, while the Dynojet is used for final dyno results. The Z06 required both part and full throttle dyno runs to dial-in the computer program using LS7 Edit.
All testing was done in Fourth gear with traction control off. The barometric pressure, air intake temperature and SAE correction factors for the run are listed here. Correction factors use a standardized SAE calculation, which include reference temperatures of 77* Fahrenheit, and a barometric pressure of 29.23 inches of mercury.
Test Number 1--Stock Z06, Test parameters: Inlet Air temperature 64.1* Fahrenheit, barometric pressure 30.14, Humidity 6%, correction factor .95
Test Number 2--Z06 with Camshaft, Power Pack and Tuning, Test parameters: Inlet Air temperature 89.5* Fahrenheit, barometric pressure 30.08, Humidity 26%, correction factor .99
Test Number 3--Z06 with Camshaft, Power Pack, tuning and Halltech air filter, Test parameters: Inlet Air temperature 90.3* Fahrenheit, barometric pressure 30.11, Humidity 24%, correction factor .99