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Callaway Of the Month April '05

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Carlisle Callaway Corvette C6 – C36

Part II

At the end of our first installment, we had left off with the Carlisle Callaway C36 project car delivered to Callaway Cars in Old Lyme, Connecticut, to allow their team of engineers to begin transforming the car from stock C6 to SuperNatural® level.

Working feverishly to have the car ready in time for Funfest at Mid America Motorworks, the team had to jump in with both feet, designing and fabricating the new components to be displayed at the show. The Callaway crew had only ten days.

Right on time, the C36 was driven to the Funfest and displayed beside the awesome 6.8L Callaway Z06 (Corvette Enthusiast, Nov. 2004) in a huge Callaway Cars tent in front of Mid America’s headquarters building. To gain a better view of all the newly installed components, the cars were parked on Callaway’s new aluminum diamond plate “Show Car Ramps”, allowing one to see every side of the car, from top to bottom.

I was amazed at how quickly this car had changed. When I first saw and drove the car at the end of the summer, it was simply a new six-speed, Z51-equipped C6. Now, equipped with a dozen new components, Callaway Cars was covering all the bases right from the get-go, improving many of the C6’s systems, just like they’ve done with the products currently offered for C5’s.

The first thing I noticed, walking towards the car, is the C36’s lower stance. Sitting on a set of Callaway-specific, lightweight forged wheels measuring 9.5” x 18” up front and 10.5” x 18” in back, complete with Pirelli P Zero Rosso tires measuring 275/35ZR18 and 305/30ZR18 respectively. Hiding behind those huge wheels, resides a massive set of brakes. Fourteen inches in diameter, the Callaway/Alcon rotors were gigantic, even when compared to the heavy-duty Z51 units. Callaway’s rotors feature c-shaped relief pockets cast in for greater resistance to fade and more consistent stopping during hard use. Callaway claims that the reliefs don’t propagate cracks like cross-drilled rotors. Clamping force is applied through a set of six piston front and four piston rear calipers, grabbing the rotors for plenty of stopping power – these brakes are HUGE!

Getting even closer revealed more clues that this car was no longer a production-line C6 Corvette. The signature Callaway “Double-D” exhaust tips protrude through the rear valance and when the engine was started, it produced a throaty “burble” – a far cry from the sewing machine sound the car made when stock. The exhaust was one of the new C6 products that are continuing to be refined. Scott Rawling, Callaway’s Engineering Manager, told me, “Reducing back pressure for more power was relatively easy, but we’ll need more than ten days to find that ‘Callaway’ exhaust note”. Eliminating all in-car resonance is also paramount for Callaway, according to Scott.

In the process of checking out the exhaust design, I quickly noticed the blue Callaway sway bars and coil-over suspension. Surprisingly, the new design retains the use of the OEM transverse leaf springs and, in fact, did provide for a truer and more individual feel of the road - I would get to sample this refinement during my drive later that weekend.

Also noticed while out back, a new Callaway Corvette emblem is in place of the original on the tail. Matching emblems are installed on the nose and steering wheel center as well, for the cars that get the full Callaway SuperNatural® treatment.

Moving towards the front of the car, I was looking forward to lifting the hood and seeing what was new in the motivation department. The uniquely designed Callaway Honker™ high flow induction system was installed in place of the factory system, allowing this C6 to breathe deeply, as much as 1500 cfm, or 32% more than the stock system.  Rawling explained to me that, when engineering the Honker™, it was discovered that there was much more room available in the under-hood area in the C6, compared to the C5. “That made it possible to develop a duct configuration with very high flow,” Rawling smiled.

In order to better expel exhaust gasses, Callaway’s new C6 headers were put in place of the factory manifolds. Made with T304 stainless steel tubing and thick billet flanges, these headers leave the catalytic converters in the factory locations while flowing much better than the stock cast iron manifolds. Leaving the converters in the original locations is a must in order to be compliant with federal and state regulatory agencies, like CARB and the EPA; a practice adhered to by Callaway Cars.

Other changes made under the hood, were a very handsome, yet industrial looking, set of injector covers complete with the Callaway name, set atop in a finish similar to the machined silver found inside the car, surrounding the radio and navigational display.

Speaking of inside, changes were made there as well. Stepping over a set of Callaway sill plates and sinking into the leather drivers seat, one will notice the shifter knob has been changed to the traditional Callaway spherical design, with a short throw shifter in place beneath. Under foot, a set of floor mats were installed, stitched with the Callaway logo and perfectly fit without any trace of sliding.

Driving the C36 in its latest form was true Corvette pleasure. I had really thought highly of the car before, as the stock LS2 engine seems to be a great powerplant with lots of torque across the rpm band, straight from Bowling Green. However, this car now benefits from better breathing on both ends. Let’s drive!

            Selecting first gear, I departed Effingham late in the day, pointing the sleek black Corvette towards the east in a caravan with the Callaway Z06. Rowing the gears certainly is more precise with the new shifter, and the feel of the spherical Callaway knob, while unique, is familiar to me from driving other Callaway Corvettes over the years.

Noticeable gains are felt across the power band. The Callaway C36 is now packing an extra 51 horsepower and 25 lb-ft of torque, yet it retains its civility and ease of driving. My wife, who accompanied me for the trip, fell fast asleep within an hour of departure. To see her fall asleep so quickly and soundly illustrated the comfort level built into this very fast sports car. We continued on, swapping lead position with the Z06 from time to time. As darkness fell, we neared our drop-off point for the C36: Indianapolis, Indiana.

With poorly marked roads and exits, I called upon the Corvette navigation system to locate the airport in Indy. With the nice young lady in the instrument panel telling me: “turn left and then . . . turn left” (we call that a u-turn where I come from), we headed back the way we came and followed her directions. Within five minutes, we were at the airport. Checking in at the rental car agency, behind the counter was an enthusiastic twenty-something fella. I say enthusiastic, because as soon as he saw the Callaway logo shirts, he excitedly yelled out “Callaway Corvette, those are the fastest Corvettes ever made – 254 mph Sledgehammer!!!” Clearly, he was an enthusiast.

As the young man went on about his passion for the Callaways, he quoted specifications, special editions, and milestones like he wrote the book. We were so impressed with his knowledge; we offered him rides in the two Callaways out in the lot. Unfortunately for him, he could not break away from work but he did manage to sneak away from the counter long enough to see what was out in the lot. While outside, the generous folks from Callaway gave him a couple of race team posters and a lapel pin and, certainly, another Corvette experience to add to his memories.

Before I parted ways with the C36, I learned what was in store for the project in the near future. The prototype parts on the development car would be thoroughly tested and evaluated during the coming weeks. Product validation would continue both on the engine dynamometer, chassis dynamometer, dragstrip, skid pad, and emissions lab, maximizing performance while retaining OEM-level refinement and durability. Our next installment of the C36 project takes us to Old Bridge Raceway in Englishtown, New Jersey for more dragstrip testing and then back to Connecticut for more development work at the Callaway factory. Until then, if you have not had a chance to get into a C6 and drive one, I highly recommend that you do so; it’s a Corvette like no other!

© 2004 Christopher Chessnoe

© 2004 C.C. and reprinted with permission by the

All rights reserved.

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