For this vacuum/boost source,...
For this vacuum/boost source, Matt T'd into a vacuum line off the throttle body. To do this, he simply replaced an existing single T fitting with this double T.
But before he even drove our GT after its ignition and fuel upgrades, he went underhood, unplugged the SPOUT connector, and set initial timing on the distributor to about 29 degrees BTDC. Unplugging the SPOUT interrupts the timing control signal from the EEC IV, so spark timing remains at initial no matter the engine speed, load, or temperature. This means we now have 29 degrees of spark advance continuously until the 6-BTM starts seeing boost and retards it at (in our case) the rate of 1.3 degrees per pound of boost.
Why does Lidio use this method on blown pushrods, rather than specifying a desired spark curve through the chip as many tuners do? Mainly because he feels some of the EEC IV's basic, unalterable spark strategies can be destructive under boost conditions. "We found a few years ago," Lidio explains, "that we couldn't trust [the EEC]. What would happen is when we left the timing to the EEC, while we were ripping through the gears on a car, as we let off the throttle to push the clutch in, and then refloored it again in the next gear, it would spark knock for an instant." Lidio surmises the EEC adds a bunch of timing as soon as the throttle is lifted and engine load drops. It then takes some time to retard all that advance again once back under full throttle, causing the momentary knock. Spark knock and boost don't coexist peaceably. "We found that by locking the timing," Lidio says, "the problems went away."
So he fixes total timing and leaves it, but any number of other functions, such as the fuel curve, he can adjust, real-time, using Autologic's ChipMaster software on his laptop as he drives. With Chip-Master, the laptop plugs into the EEC's service port-like a chip-and in fact acts like a chip, replacing the EEC's data lookup tables with its own. Changes made on the laptop-such as altering target air/fuel ratios at a given rpm, for instance-take effect immediately. If they don't have the desired result, another adjustment can be made on the fly, and its results observed immediately.
The MSD adapter harness plugs...
The MSD adapter harness plugs in line between the factory coil harness and the plug on the TFI coil, which bolts in place of the factory coil. The four color-coded wires from the 6-BTM then plug into the corresponding connectors provided on the adapter harness. It's a no-brainer. The 6-BTM's final connection is to full-time battery power, for which Matt uses the SN-95's power distribution post near the battery. Needless to say, the battery ground cable should always be disconnected before making any electrical connections.
This real-time tuning ability is one of the things that attracted Lidio to the Autologic system. Instead of waiting to download a file, he can just tune as he drives. Once he has everything the way he wants it, he can burn a chip right off the laptop, and he's done. Lidio also believes he can adjust more parameters using the Autologic stuff.
Specifically, some of the things he did in our case were to raise warm idle speed and mess with injector slopes to eliminate our hot stalling problem; raise the rev limit by 200 rpm; lower the low- and high-speed electric fan engagement points; and reduce the throttle angle at which the EEC switches from closed-loop (correcting air/fuel ratios to Stoichiometric, based on O2 sensor feedback) to open-loop (setting A/F based on lookup tables) operation. The '94-'95 EEC IVs also have a timed delay for going into open-loop, which Lidio virtually eliminated.
Air/fuel ratios are absolutely critical with a supercharger. Whereas a naturally aspirated engine might normally have a wide-open-throttle ratio of 12.5:1 at higher rpm, Lidio likes to run as rich as 11.8:1 to 12:1 with a blower. Prior to installing our T-Rex pump, we could sustain that mixture only up to about 5,500 rpm, after which fuel pressure suddenly plummeted, meaning we were running out of volume. With the supplementary pump, pressure rose steadily all the way up to 6,400 rpm, where the chip started shutting down cylinders.
After a day with Lidio, our spark, fuel, and tuning issues were history. Though we haven't since visited a dyno (yet!), our little 5.0's power is now utterly tire shredding, yet driveability is good enough to make a factory calibrations engineer happy. And the porky old ragtop still delivers better than 20 mpg cruising down the highway. Who says you can't have your cake and eat it too?
 The pump is then clamped to...  The pump is then clamped to rubber mounts bolted through the trunk floor, with its outlet side (the 90-degree fitting) toward the fuel filter. These rubber feet help isolate vibrations of the pump. In the old days, the T-Rex had a reputation of being fairly audible, but ours seems to operate in near silence, an impression no doubt helped by the fact that we usually drive with the top down. |  Using supplied peel-and-stick...  Using supplied peel-and-stick clamps, the relay's two red power wires are routed around the perimeter of the spare-tire well. The wire from relay terminal No. 87 goes down through the floor (cut a hole in the plastic trunk plug) to connect to the positive terminal on the pump. The wire from the No. 30 terminal is routed through the back-seat area and under the rocker scuff plate to the fuse box. It also has its own 20-amp, inline fuse. |  The T-Rex is plumbed inline...  The T-Rex is plumbed inline between the supply line from the gas tank and the fuel filter. The kit has an excel-lent schematic detailing line routing and connections, and as with all things Vortech, it is inclusive right down to the last tie-wrap. |
 Inside the trunk, the pump's...  Inside the trunk, the pump's relay is bolted and grounded (relay terminal No. 86) to the trunk floor in a position shown on the paper template. From relay terminal No. 85, its yellow wire is tapped into the purple wire in the stock fuel-pump harness, as shown. |  As noted, the pump's positive...  As noted, the pump's positive terminal is connected to the wire from the No. 87 relay terminal. The negative terminal is grounded to the trunk floor, as shown, and that's it for the fuel pump. With all electrical and fuel line connections made, take the time to turn on the key and check for leaks. |  Lidio's method of timing a...  Lidio's method of timing a blown 5.0 such as ours involves pulling the factory SPOUT connector and cranking the distributor to between 28 and 30 degrees BTDC. With the SPOUT out, the EEC cannot alter timing at all-the MSD 6-BTM simply steps in to provide necessary retard under boost. We never would have guessed that running a constant 29 degrees of advance could provide good driveability and response, but it does. |
 Lidio believes the EEC may...  Lidio believes the EEC may do strange things during tuning if it doesn't read both factory O2 sensors. For that reason, he likes to drill for a second bung on the driver-side header so that both that side's OEM oxygen sensor as well as his wide-band sensor can be fitted. The wide-band feeds an air/fuel analyzer placed in the cockpit, providing real-time readout of mixture. |  Lidio hasn't wrecked any cars...  Lidio hasn't wrecked any cars yet doing this. With the large digital readout of the air/fuel analyzer directly in front of him, he can quickly monitor the effects of programming changes he makes using one of his faithful little Toshiba Libretto 70CT laptops. Connected to the EEC IV's service port, the laptop's Autologic ChipMaster software takes over the duties of the EEC's ROM memory-the same as a chip would. Since our ragtop currently lacks gauges, yours truly sat in the passenger seat holding and eyeballing a temporarily installed fuel-pressure gauge, acting as a blood-pressure nurse to Lidio's doctoring. We drove around this way for lengthy periods, with Lidio making fine adjustments to many parameters, for all driving conditions, from idle to part-throttle cruise to full-throttle pulls. |  Once satisfied with all phases...  Once satisfied with all phases of a car's performance and manners, Lidio simply saves the program with a unique filename, unplugs the laptop from the EEC, and then downloads the file to a chip, using the Autologic burning hardware. With the chip installed back on the EEC, he then goes for one last, quick test drive, just to be sure. |