Saul The Surgeon" Gutierrez...
Saul The Surgeon" Gutierrez monitors the flow as your tech editor pours Snow Performance's Boost Juice (the company's premixed 50/50 water-methanol potion) into the 2-quart reservoir included with Snow's Stage 3G Boost Cooler. The water-meth kit was installed in jury-rig fashion (we zip-tied the reservoir to the rollcage) to make the most efficient use of our time on the dyno. A complete and clean final installation was done a few days afterward.
Horse Sense: The steady progress we've made with our project car's rear-wheel horsepower/torque certainly has been amazing. In our quest for more performance, we've gained a greater appreciation for the enthusiasts we've endearingly chastised for racing the dyno instead of racing their 'Stangs on the dragstrip. While blasting 'Stangs down the quarter-mile will always be our favorite performance evaluator, the work we've done on the dyno has given us a better understanding of just how good it feels when an engine in a dyno-tested 'Stang goes to full scream, the rollers spin furiously, and the graph shows more power than originally thought possible.
Although Editor Turner's feature story on our '86 T-top coupe LX (Top This," Jan. '08, p. 102) gives the impression that we've reached a closing point for a wonderful project, the saga of our latest flagship 'Stang continues.
To tell you the truth, we really don't know exactly when we'll stop reporting on our exploits with the project ride, as it seems there are countless modifications that can still be made, including the project we're embarking on in this report. There are other upgrades on the horizon to further solidify our T-top coupe's status as one of the baddest Fox-Rod project Mustangs in history.
Changing the fuel injectors...
Changing the fuel injectors is our first task. After removing the supercharger's discharge tube, the throttle linkage, and all the related hoses and lines, Saul takes off the upper portion of our Holley SysteMAX II intake manifold for better access to the fuel injectors.
One thing we're learning as we continue using the dyno to fine-tune the 'Stang's engine is that there's definitely a mountain of difference between a combination's actual power output and something we call theoretical horsepower. That's horsepower that gearheads believe their Mustang's bullet should make based on its internal components, power adders, and so on.
For example, based on an assessment of its parts, we originally forecasted (hoped) the supercharged 347 stroker in our coupe would throw down 600 to 650 rwhp; all the parts to accomplish this goal were in place. However, we didn't reach the milestone with the original bullet due to its unfortunate early demise (Full-Throttle Meltdown," Jan. '08, p. 68) during a dragstrip test. The best horsepower/torque achieved with the 347 was 473.34 hp/476.51 lb-ft at 5,000 rpm, with the torque converter locked, barely 8 psi of boost (thanks to a slipping blower belt), and 91-octane pump gas.
This is one of eight RC Engineering...
This is one of eight RC Engineering 650cc fuel injectors that we selected for our project car before we had any idea that its blown bullet would produce anywhere near 800 hp at the tires. Our initial goal was to see 600-650 rwhp. This size injector, which is about the same as 65-lb/hr, is more than enough for supporting a small block/power-adder combo making that kind of power.
A freshened 350ci bullet now rests between the fenders of the project 'Stang. With the corrections we've made in the blower department (a larger-diameter main idler pulley and the addition of a second idler pulley for improved belt tension to create 20 psi of boost), the addition of higher-octane fuel (VP Racing Fuel's MS 109E instead of 91-octane pump gas), an Aeromotive A1000 fuel pump, and spot-on FAST XFI tuning by Harv of HMS Performance, the coupe stands high and mighty with 811.28 horses and 700.25 lb-ft of torque available at the back tires.
One interesting but completely unscientific theory on horsepower is that it always seeks and usually finds the weakest link in an engine or drivetrain. While there may be some truth to this idea, the real deal is that a high-performance Mustang should be outfitted with parts that are designed and manufactured to make, or support, a specified amount of power.
This became blatantly clear for us during our last dyno session, when we discovered our original engine's 650cc (approximately 65-lb/hr) fuel injectors are far from capable of supporting the 800-plus horsepower that the rebuilt bullet produces.
While injectors typically run at and should not exceed 80- to 85-percent duty cycle (0.80/0.85) at 60.5 psi of brake specific fuel consumption in a supercharged application, we're now experiencing 100 percent duty cycle at 5,500 rpm (762.33 hp). Duty cycle refers to the amount of time the injectors must remain open and flowing in order to feed the engine its required amount of fuel. With the injectors maxing out so soon, we're asking for serious trouble if we continue trying to eke more performance from our engine. The blown stroker gives every indication that once it has fuel, it will put up even bigger numbers.
 Here's a close look at the...  Here's a close look at the difference in fuel-injector design. The RC injector on the left uses three large spray holes, whereas Ford Racing Performance Parts' 150-lb/hr piece has a single needle-style head through which large volumes of fuel dumps each time it pulses. |  There's really nothing exotic...  There's really nothing exotic about the FRPP 150-lb/hr injectors. They have the same EV1 body style and extra length as most stock (19-lb/hr), 24-, 30-, and 42-lb/hr injectors used in fuel-injected 5.0- and 351W-based engines. However, we must make clear that adding considerably larger squirters doesn't mean we're adding horsepower. Our engine simply goes above and beyond the power capacity of the 650cc pieces, so we're making the move to the 150s to ensure the engine will receive the fuel required for sustaining big horsepower. |  Our engine utilizes a 1-inch...  Our engine utilizes a 1-inch phenolic spacer to create sufficient clearance between the upper intake and the valve covers. |