Mason "Mase" Rowland of B&D...
Mason "Mase" Rowland of B&D Racing finagles a shorter Dayco drive belt (PN 50855) around the 3.25-inch, big-boost supercharger pulley on our Top Car Challenge Shelby GT500. Using a little muscle is necessary for installing the 85.5-inch belt, as well as removing an idler pulley that is used with the "stock" 4.0-inch wheel on Lysholm's twin-screw blower.
As we stated in the first article in our series on the 2010 Castrol Syntec Top Car Challenge ("Dangerous Drop Top," Sept '10, p. 76), we definitely learned a lot last year in the annual performance/endurance shootout that pits a Mustang flying 5.0's colors against five other rides (and their owners) representing Source Interlink Media's importcentric mags-Eurotuner, Super Street, Import Tuner, Modified Magazine and Honda Tuner. We're on a mission to improve on the fourth-place finish that Ron Cooper scored at the '09 Challenge with his supercharged '94 Cobra. To do this, Carlos Cortez and his '07 Shelby GT500 stepped up as our players for 2010.
We're putting Carlos' steed through a battery of buildups to ensure it will be ready to outperform the imports when the Challenge begins. The on-track tests are quarter-mile (e.t.), acceleration (0 to 60 mph), braking (80 to 0 mph), and-a crowd-favorite-the road-course showdown (lap time), and we decided to use a Shelby GT500 for its factory-borne power and improved handling over standard Mustang GTs. However, based on previous research with Mustangs, we know a good 'Stang can always be made better with the proper measures.
For Carlos' ride, a complete suspension makeover was performed using race-proven pieces from Eibach Springs, Maximum Motorsports, and Nitto Tire ("Maxed Out," Oct '10, p. 64). The new pieces replace previously installed hardware that brought the Shelby down some (lowered), but wasn't quite ready for the hard abuse our entry will endure during the contest.
Once our 'Stang's handling was dialed in, it was time for us to step up the Pony's performance program a bit. As we noted in the introductory report, our Top-Car contender is motivated by Ford's mighty Four-Valve, 5.4-liter engine and topped with Lysholm's enormous 3.3-liter Twin Screw supercharger.
With a VP Racing Fuels C-16 tune, the Shelby puts down 694.68 horses at the rear wheels, and 657.64 lb-ft of gut-turning torque, which we feel is plenty enough to place us among the top dogs at Top Car.
The Challenge is an event where contestants lay every ounce of their cars' performance on the line-especially horsepower-which is measured on the SuperFlow chassis dyno at K&N Performance in Riverside, California. While several performance criteria are evaluated in the Top Car Challenge, rear-wheel horsepower (unofficially) is the big deal in this contest.
Be it domestic or import, big steam ranks high when it comes to determining a street car's level of prowess. So with our mindset on big steam, we added a few cool hop-up goodies to Carlos' Shelby GT500.
The showstopper in our new-parts collection is a 3.25-inch supercharger pulley, which replaces the 4.0-inch Lysholm pulley. The reduced diameter increases the big blower's boost output by more than 5 psi, and we hope it will put our entry in front of the others when it's time to tally up its rear-wheel ponies on the dyno.
In the driveline department is the all-new twin-disc Dyad clutch system from Centerforce (PN 04114805). At 10.5 inches in diameter, the Dyad is a big step up from a Shelby's factory clutch package.
We understand the move was made in an effort to make pedal-effort somewhat minimal, but with the cars weighing 4,000-plus pounds and with the huge amount of torque GT500s can potentially create, the small clutch unit really doesn't stand much of a chance. The larger-diameter Centerforce has more surface area, friction coefficient, and a greater clamp-load capacity than the factory piece. These two qualities are keys to Dyad's overall effectiveness at moving as much of the Shelby's power through the drivetrain as possible.
It's show time, fellas! Take a close look at this report, and then look elsewhere in this issue to learn details of how our Shelby GT500 performed at the 2010 Castrol Syntec Top Car Challenge. And, if you haven't already done so, cast your peoples' choice vote for our entry on the website (www.syntectopcarchallenge.com).
Increased fuel volume is required...
Increased fuel volume is required when the Lysholm is turned up for max boost and power.
As such, our first task is...
As such, our first task is to replace the GT500's OEM fuel injectors (left), which are fine for the engine's 4.0-inch pulley/pump-gas tune, with Ford Racing Performance Parts 80-lb/hr squirters (right).
Once the belt is removed,...
Once the belt is removed, the pulley swap on our big twin-screw is super simple. A small dab of Loctite on each Allen-headed fastener helps ensure the pulley will stay put when it reaches full spin.
B&D Racing of Van Nuys, California, is well versed in power improving Shelby GT500s, S197 GTs, and all-other late-model Mustangs. The shop's lead technician, Mason "Mase" Rowland, took care of the adding the upgrade pieces on Carlos' ride and the following photos detail these key components.
On The Dyno
▼No, our Top Car Shelby GT500...
▼No, our Top Car Shelby GT500 doesn’t make nearly 700 hp at the feet on 91-octane fuel. While that would be cool, we’re playing it safe by using VP Racing Fuel’s C-16 race fuel.
We didn't think it was wise to immediately jump on the new clutch. Centerforce recommends putting 250 miles of shifting-intense (street) driving on the Dyad twin-disc before making WOT blasts. The numbers in the chart are results from a previous dyno test (on a Dynojet chassis dyno), in which our Challenge 'Stang still had its stock clutch and driveshaft, but was set up with the same 3.25-inch blower pulley, C-16 fuel, and Lysholm/SCT tune that were in place for the event.
Here's a look at the difference...
Here's a look at the difference in pulley size. The Lysholm 3.3 is set up with a 4.0-inch wheel from the factory (left). The new 3.25-inch pulley spins faster and increases max-boost by 5.6 psi (from 16 psi to 21.6 psi).
With the boost tasks handled,...
With the boost tasks handled, installing Centerforce's new Dyad dual-disc clutch system is the next upgrade for our Top Car Challenge entry. Removing the passenger-side long-tube header makes extracting the transmission a bit easier, as does slightly raising the engine.
Ford installed this 8-inch,...
Ford installed this 8-inch, twin-disc clutch in Shelby GT500s. The discs are ceramic; they have a tendency to hiss when the clutch is released and shudder/grab a bit, typically at startup.
Centerforce's Dyad clutch...
Centerforce's Dyad clutch system measures 10.5 inches; it features a pair of discs that are made with high-temperature organic material on one side and a metallic-ceramic alloy on the opposite face. Using the two materials facilitates increased holding power and maintains smoothness, which is critical for street-driven cars with big power.
This look at the disassembled...
This look at the disassembled Dyad details its hub-and-pin drive setup, which links the two disc plates. This innovative design eliminates the need to add springs on disc #2 (on the left in this photo), which keeps the unit fairly lightweight, as well as noise/chatter free. Drilled holes around the perimeter of the steel flywheel is another cool feature of this system. Lightening the outer region of the flywheel helps improve acceleration, which will be a big benefit to our heavy 'Stang.
The Dyad dual-disc clutch...
The Dyad dual-disc clutch is designed to fit snugly on the transmission input shaft for positive clutch engagement, and to reduce wear and potential damage to the shaft. Centerforce makes its Dyad clutches with hubs that actually are softer than a tranny's input shaft to ensure the hub will wear before the shaft does. Notice the thick drive lugs, which connect the primary clutch disc with the secondary disc.
Fasteners receive an upgrade,...
Fasteners receive an upgrade, too. Centerforce uses ARP fasteners (flywheel bolt shown on the left) throughout the Dyad clutch system.
Prior to actually installing...
Prior to actually installing the new clutch, there was some talk concerning "tricks" or special tools required for putting the Centerforce twin-disc in a Shelby GT500. The reality is that the swap is no different than bolting one in any other S197 (the drive lugs actually make it a bit easier). Removing and replacing the tranny is the only heavy lifting required with this job.
Returning the Shelby's transmission...
Returning the Shelby's transmission and headers to their proper places closes the clutch-swap deal.
However, before everything...
However, before everything was buttoned up, Mason exchanged the stock shifter with a short-throw unit from Ford Racing Performance Parts.
While we believe replacing...
While we believe replacing the factory two-piece driveshaft is a "must-do" upgrade for all S197s, we definitely encourage the mod for Shelby GT500s that put more than 500 hp on the ground. This lightweight piece comes from Coast Driveline and Gear of Ventura, California (www.coastdriveline.com).
Lysholm created an SCT race-gas/small-pulley...
Lysholm created an SCT race-gas/small-pulley PCM calibration for its Shelby GT500 3.3 twin-screw supercharger system, when Carlos's car served as the guinea pig for the blower's development. Making the plug-and-play file transfer via an XCalibrator 3 unit the last task in this upgrade effort. A full set of Nitto's ultra-sticky NT01 road-race boots were added just as this story deadlined. Details and pictures of the new tire-and-wheel package are included in Tom Wilson's report on the Castrol Syntec Top Car Challenge, which you'll find on page 90 of this issue.