Editor's Note: Last month, we covered the build of Project Unfair's rollcage. Truth be told, the installment you are about to read could have run before the rollcage install. Regardless, here is the latest on our 200-mph, 8-second quarter-mile, '69 Camaro build and it contains the kind of information you've probably never seen before. -- Jim Campisano
Project Unfair has entered the period of car building where many things become co-dependent, and it isn't often clear what should be done next. The tasks are easy to list: wiring, engine building, cage fabrication, paint and body, interior, glass and assembly. In practice, though, there are lots of decisions to be made that affect many of these components, and this month's article is about three of them: rollcage design, interior fabrication and wiring.
One pre-requisite your author insists on is to be able to service cars after they are built. That means all the interior panels have to be easily removable. Tim Christ at Coast Chassis Design insisted that the cage tubes be permanently welded (no removable tubes) in place to qualify as a certified cage, especially when the car is chasing an 8-second time slip. Plus, I and Frank Serafine (owner of Prodigy Customs) have decided to put all the wiring components (Holley ECU, AAW harness box, ididit button start, etc.) behind the front seats. This will move even more weight to the back of the car, get the components off the hot firewall, and allow more room for the Vintage Air evaporator and its plumbing.
All those decisions and assumptions have made designing the interior a challenge, and it needs to be broken into several parts. This month's article is about the basic prototyping and how getting all the associated component fabricators together early can save headaches later. The crew at 1Off Rides showed us how they rough in a basic interior that will be used to guide where tube placement for the rollcage will go. And letting the cage guys have a look at the raw interior prototype lets them provide feedback for the interior design and allows changes to be made before they get expensive.
The interior panels also have to be designed to hide the wiring runs, and the wiring runs need to separate the high-current wires (headlights, brakes, A/C, clutch, fans, etc.) from signal wires (sensors, EFI control, speakers, etc.). With the battery located behind the passenger seat, the best place to route the high-current wires is along the wiring trough in the passenger rocker panel. We decided to run the signal wires under the center console. Those paths will allow an easy, non-crossing route to the various bulkhead connectors that will be located on the passenger firewall.
Turning to the panel fabrication itself, and in the spirit of Project Unfair, Guillermo (William) Fonseca of 1Off Rides is using a special material for the panels. Normally custom panels are fabricated using vinyl-wrapped medium-density fiberboard (MDF) and flexible wood-based "bendy board." Those materials can be easily shaped, glued and wrapped, and they work great in most applications. But that's not good enough for Project Unfair, as MDF is also heavy, brittle and not durable in high-humidity Florida.
One alternative is to make the panels from MDF and then transfer the design to fiberglass via custom molds. But William has a better alternative up his sleeve: He is using Airex structural foam for the panels. It's the same material used to make those 80-mph offshore powerboats. Airex structural foam is a closed-cell, cross-linked polymer foam that combines high stiffness and strength-to-weight ratios with superior toughness. It's very light, very strong, and can be constructed and shaped using woodworking tools and techniques.
Fastening the panels to the body is a two-step process: William uses self-tapping sheetmetal screws, which work great on the Airex foam along with providing perfect centering holes to allow us to install his thread inserts. Final assembly will be done with stainless steel machine screws, which will provide durable and repeated removal and replacement of the panels in the car.
Let's follow along and see how William and his crew at 1Off Rides build the raw panels.
Stack It Up
The choice of Stack instruments for Unfair may seem unusual, especially in a muscle car, but we have legitimate reasons. From a styling point of view, the Stack "look" is what 1Off Rides is using for the design approach of the interior panels. But the styling isn't the main reason for its use: We chose Stack because it offers several advantages, especially as they tune the car.
Stack's philosophy is that the driver shouldn't be distracted by a lot of gauges, especially during motorsports activities. Nobody should be looking at their water temp gauge as they apex a turn or wait for the starting-line tree to hit yellow. Instead, Stack's display is programmable, allowing the driver to decide what he needs to know about. The Stack display can be programmed to turn on a light and display the value when one of the sensors reaches a pre-programmed limit. Low oil pressure, high oil temperature, high water temperature and low fuel pressure are all things that can be programmed into the display, allowing the driver to watch the racetrack with confidence. And finally, the display can easily be centered on the dash so that the display is visible through the steering wheel: no more peek-a-boo with that one gauge that happens to be behind the wheel.
In addition to sensor alarms, the Stack display supports a shift light, recording of all the displayed data via CAN connection to the MFR (multi-function recorder), and many different displays in the LCD screen with simple driver input, like lap times, current speed and peak values of all the sensors.
Along with the main display, Unfair will also have a Lambda gauge (air/fuel ratio), and a boost gauge. They will be useful for tuning, and their sensor data can be recorded by the MFR. The MFR can record anything on the display, along with other sensor input, and has its own 3-axis accelerometer. By adding ride-height sensors to each of the coilovers and brake line pressure sensors, it will be possible to tune Unfair's suspension and brakes for the best possible performance. The MFR can also be interfaced to the Holley Dominator ECU (via CAN) so that engine parameters can be overlaid on the suspension data, allowing post-race analysis of how the chassis responded to throttle input and gear changes. -- John Parsons