Here you can see how the sensor...
Here you can see how the sensor fits against in inside of the wheel. The whitish streak is a silicon-based sealer that HRE applies after the inner- and outer-wheel halves are bolted together to make their wheels airtight.
I had the Yokohama tires and HRE wheels shipped to CWS, and while we were waiting for HRE to manufacture the 549s (having the outer rims chrome plated by CWS added to the time required, and the wait seemed interminable), I ordered a new set of tire pressure monitors-again through CWS. As you may have noticed by tire comparison chart, I violated one of my "prime directives" and selected rear tires that are approximately 0.4 inches smaller diameter than the stock 275/40-18s-not a lot but enough to throw the speedometer and odometer reading slightly off. So I called Granatelli Motorsports and ordered a Predator tunable programmer.
The Predator offers a tremendous range of adjustments and recalibrations, and is a hand-held device that does not require a laptop to perform its many functions. Among the Predator's plethora of programming options are: adjusting or eliminating speed governors in cars so equipped; adjusting/resetting the rev limiter; adjusting shift points and line pressure (for firmer and quicker shifts) with automatic transmissions; diagnostic capabilities (it can scan fault codes, perform live data monitoring, and be used to erase or reset codes); fine-tuning fuel and timing curves (something that should be left to qualified experts with chassis dynos and air/fuel-ratio-reading equipment); and (of most immediate interest to me) the ability to recalibrate the speedometer for tire-size and/or gear-ratio changes. It also has a "performance" flash for essentially stock engines and when you go to download that "flash," it first loads the car's stock program into its memory so the stock tune can be "reflashed" at any time, should it be necessary (like if you need to have warranty work performed on your C5).
Two views of the new sens...
Two views of the new sensor...
Everything else was on hand when the HRE wheels were delivered at CWS, so I arranged to have the tires mounted as soon as possible. Tires and wheels can be high-dollar items for cars like C5, and what looks good (or doesn't appeal) can be a very personal matter. When I first saw the HRE 549s, I was ecstatic. The finish and craftsmanship was impeccable, and the look was almost exactly what I'd visualized many weeks (well, it seemed like it) before. To me, the tire-and-wheel package actually looks better than I'd hoped or expected.
The new tire and wheel package fits the car perfectly; there are no clearance issues whatsoever. Before manufacturing the wheels, HRE obtained engineering drawings from Wilwood so they could be certain that their 18-inch diameter, 540-series wheels would fit with the 14-inch Wilwood front Big Brake kit. Anyone contemplating installing the 14-inch Wilwoods can be assured that they'll have no problems with wheel fit if they go with the 18-inch (or, of course, larger) HRE wheels.
...securely tightened and...
...securely tightened and ready for a tire to be mounted.
Shortly after getting the new tires and wheels installed, I brought the car and Predator programmer into the Primedia Tech Center. We, technician Jason Scudellari and I, were curious to what if any changes could be measured from the performance "flash." Mainly, I wanted to get the speedo and odometer calibrated for the new, slightly shorter diameter tires.
The Predator comes with a comprehensive, 50-plus page instruction manual with a series of step-by-step directions on installing the "performance tune," restoring the "factory/stock tune," modifying parameters, and using the diagnostics capabilities of the controller. Hookup is extremely simple; the Predator plugs into a C5's diagnostic port, which is located under the driver's side of the dash facing the floor. The Predator guides the user through the procedures to make changes in the factory programming via instructions on the unit's screen. Jason probably spent all of 15 minutes loading the "performance tune," then recalibrating the speedometer so we'd have the correct readings with the new tires. The speedo recalibration only took 2-3 minutes.
 With a wheel positioned on...  With a wheel positioned on the mounting machine, our installer lubricates the inner and outer beads with a special soapy solution to help the tire slip onto the wheel easier. |  Then he carefully works what...  Then he carefully works what will be the inner bead of the tire over the outer lip of the wheel, making sure that no metal touches the exposed surface of the wheel. |  Next, he rotates the tire...  Next, he rotates the tire and wheel on the machine and works the outer bead over the lip of the wheel. Neither the plastic wheel nor his pry bar is allowed to contact the lip of the wheel. |