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Callaway Of the Month Nov & Dec '04

Welcome! The Callaway Owners Group is dedicated to the preservation of the world's most powerful Corvette.

 Callaway's 2003 Z06

For November and December, we are pleased to bring you the two-part story about the recently introduced Callaway Power Groups for the C5 Corvettes. As exciting as this car has been to follow through its evolutionary process of designing, building, testing, and more testing, Callaway Cars gained a lot of knowledge about the LS series of engines from the project – ideas and products that will be adapted for use on the upcoming Callaway C6 SuperNatural™ project and beyond!

Callaway Z06 – The Technically Correct Solution

            Callaway Cars, a company that has been at the leading edge of the Corvette performance field for almost two decades has recently written a new chapter in Vette performance.  Officially introducing their new C5 product line at the Bloomington Gold Corvette show, they showcased their packages and designs in the silver Z06 sitting out on the Ballroom floor within the Special Collection XX.

            The first thing noticeable, once the door of the Callaway Cars Z06 test bed is opened, is the scent of rich leather.  Slipping into the sculpted leather sport seats, you will find them extremely supportive; yet still retain the ease of entry that regular C5 Corvettes have been known for.  Exquisitely stitched, the leather doesn’t stop there. Callaway has also covered the airbag panel and steering wheel in those hides and embossed them with the Callaway logo.  Once seated, with a quick turn of the key, the car burbles to life, introducing you to the next generation of Callaway Cars legendary performance.

            Developed using many of the techniques honed while constructing the Callaway C12, this latest round of performance is called “Power Groups”.  These engineered packages were designed to work as a system when installed, with each level building upon the next.

            I recently spent the day with the car featured here, a 2003 Corvette Z06, fitted with Callaway Power Groups I and II and driving the car was a blast!  While the car itself, rides as smooth as a rail, the power delivery is broad and useable throughout the rpm bands, it was explained to me, that is the results of the new Power Groups.

The Power Group method allows a customer to build upon a car in a logical fashion, adding parts proven to work together in what Callaway Cars Managing Director and Chief Engineer, Mike Zoner calls, “the technically correct solution to greater power”.

            The First Power Group consists of the Callaway Honker™ Air Inlet and the Callaway designed cat-back exhaust system. This package gave the car a 20 horsepower gain over the 350-rear wheel horsepower baseline, and recently received E.O. D319-6, making it legal for road use in all states, including California. Part of that group of upgrades, Callaway’s Honker™ is a piece unique in a market filled with products of good intentions. Flow bench proven to out-flow all popular designs compared, this design was originally developed for use on the big cube Callaway 6.8L engines.  Precision design elements such as smooth interior bellow walls, make this a signature piece with other highlights including the relocation the mass airflow sensor for a truer reading while allowing for a smoother transition of the inlet over the radiator shroud. These are features, which will be adapted on the upcoming Corvette C6 by G.M.; the General must have been taking notes…

Fitted with Power Group II, the car is taken to the next level. Building upon the components listed in the first group, a big bore throttle body and tubular exhaust headers are included in this package and produce an additional 10 hp, bringing the horsepower level to 380 at the rear wheels.

The first two Power Groups boosted the performance the Z06, an already stellar performer by all accounts.  Tested by Callaway cars when stock, it had initially run the quarter mile in 12.4 @ 116 mph. With the first two groups in place, the car ran 12.0@ 118.7 mph in the quarter mile.  Performance like this was previously obtained through increased displacement or positive manifold pressure.

Driving the enhanced Z06 was effortless, like any of the other C5’s I have previously driven. Docile while cruising, with a pleasant exhaust note that while distinguished, it still allows a conversation to be held inside the car at speed. Hit the gas pedal and let the engine rev, you will be delighted by the tremendous power curve, all the way to redline. With an authoritative growl, the car leapt forward when called upon, and called we did!

Taking the car on the back roads of Old Lyme, Connecticut, Mike Zoner accompanied me for the ride.  While sharing the details on the development of the new packages, he also encouraged me to open the car up to its maximum potential on a rapid tour of the scenic area. It was during this drive, Zoner mentioned the car would soon be fitted with the next Power Group in time for the Bloomington Gold Corvette event.

Introduced to the public at Bloomington, I sampled the car again complete with more power. Power Group III, which increases power to 410 rear wheel horsepower, adds a “top end” package, including CNC ported cylinder heads, camshaft, and high ratio rocker arms which are emission compliant in 49 states with California certification on the way. Track proven, the car in this form runs the quarter mile at 11.7@ 120 mph with all three Power Groups in place, working together to achieve this impressive level of performance.

Driving the car at this level of performance gets to be addictive. Running out of breath never became an issue, running right up to 6,500 rpm’s; it pulled like a freight train all day long, delivering eye-popping performance.

Your eyes are also rewarded outside the car. Tasteful design elements were added to this car.  Painted side ducts and a smoothed look were subtle touches; however, the most noticeable element was the new wheels. Custom made for Callaway by Fikse, these lightweight aluminum wheels measure 9.5” x18” up front and 10.5” x 18” in the rear and are fitted with Pirelli PZero Rosso tires, 265/35/R18 and 295/35/R18 respectively. In addition to the unique wheels, Callaway has added an exclusive exhaust surround panel, giving this C5 a finished look.

Designed by longtime Callaway Cars Stylist, Paul Deutschman, the panel surrounds the signature “Double D” exhaust tips and it finished with the same screening that the Z06 wears up front in the nose and in the side ducts. While the panel is optional on the exhaust, I think you will agree it is a “must have”, as something so simple has changed the entire look of the back of this car.

Parts such as the ones included in the various Power Groups were developed and brought to reality by the engineers at Callaway, using a tool called PTC Pro Engineer, the industry standard for solid modeling.  A Program Partner, Callaway Cars uses PTC’s programs to design and bring to life their various idea’s, everything from the new Double D exhaust, to the body panels of the C12 have been developed using this tool.

Callaway Engineer, Pat Hodgins explained how the development process works in relation to development of products.  He demonstrated how an idea can be imputed into the computer and then duplicated side to side for a symmetrical balance. It was also shown how the engineers can look inside and out at various surfaces in a 3D view. One of the benefits of this was, in addition to making the product design itself, the new exhaust for example, had its jig mocked up here first, based upon clearances of a production car in relation to the final product. In addition to the exhaust, I also witnessed the design process for the HonkerŌ, and the air filter designed for it.  Quality in design of something often taken for granted, Pro Engineer, at the skillful hands of the Callaway Craftsmen, were able to control the design and allow for precision molding of the oiled cloth filter panel. The rubber element surround, as I was shown on other designs, tends to creep into the filter surface are, therefore causing a restriction. Callaway’s precise design kept the rubber at a constant thickness without that “bleed” into the cloth area – these folks live in the details!

All of this translates into what I felt while driving, consistent delivery of power. Whether it was cruising to lunch, or flat out exiting of a corner to a long straight, this car demonstrated what all Callaway products have in the past – they do what they are supposed to do, every time you ask.

The Callaway Power Groups are currently available for all C5 models directly through Callaway Cars website or by mail order. The folks at Callaway cars will also handle installations at their Old Lyme, Connecticut shop, and are also in the process of establishing a preferred dealer network for both sales and authorized installations.

Looking forward into this chapter of Callaway performance, I can hardly wait for the test car to be fitted with Power Group IV, hopefully that will happen right about the time they introduce their offerings for the new C6, stay tuned…


Callaway Z06

Following up on the Technically Correct Solution

            Having left off at Power Group III the last time we sampled this car (Nov. 2004 Corvette Enthusiast), it was recently fitted with the fourth & final power enhancement that Callaway Cars offers for the C5’s, Power Group IV.

            While the first three Power Groups shaved almost a second off the silver Z06’s quarter mile times, Power Group IV furthers performance gains by delivering a blistering 10.91 @ 126.85 mph, courtesy of increased displacement.

            Power Groups I through III focus was on getting the air in and out more efficiently through full exhaust options, Callaways signature Honker™ air inlet with larger throttle body, and their “top end” package. However, this next gain begins right at the foundation.

            Starting with a Corvette C5R block, Callaway selects a crank and rods along with new pistons that increase the displacement to 6.8 Liters.  The aluminum heads previously installed as part of Power Group III are up-fitted with larger diameter valves to help take advantage of the gulps of air this machine breathes in and out.

            Callaway Cars has certainly done their homework on the drivability of this package.  While I have driven other “big cube” stroker cars over time, I honestly cannot recall one with smoother idle characteristics. While running around town in rush hour traffic, this machine did not seem to miss a beat. Obviously something so powerful needs the means to translate that energy into motion. Pleasantly surprised, the clutch that was selected was not at all overbearing and in the blasts between traffic, it held the power and put it to the ground.

            Callaway’s Z06 reminded me of an old instant camera ad, “just point & shoot”. With 550 horsepower on tap that really sums it up – power on demand yet refined enough to drive every day if one chooses.

            The Callaway Cars website has comprehensive information about all of their packages and products. For more information about them, visit and be sure to check out the various milestones that laid the foundation for what we just sampled.

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