With XFI, users have the ability to run two injectors per cylinder on a typical V-8. Although this isn't necessary in even the wildest of street/strip combinations, it does allow for some extreme possibilities. "Sometimes it's simply a matter of fuel volume, and some motors need so much fuel that two injectors per cylinder is a must. On a V-8, our dual-injector setups can support close to 5,000 hp," David explains. "In other scenarios, having multiple injectors helps optimize the fuel charge going into the port. Sometimes, it's better to run two 36 lb/hr injectors per cylinder instead of one 72 lb/hr unit. Placing one injector up high in the manifold and the other down low by the port improves the atomization process. Engine builders can also experiment with injector positioning. Some like to have the injectors spray horizontally along the roof of the port for improved charge density."
Learning to Tune
Advanced aftermarket EFI systems like XFI are perceived by the average enthusiast to be very difficult to tune. Truth be told, pecking away at a keyboard isn't as intuitive as turning screws on a carburetor. To help novice tuners get acclimated with all the different parameters that can be changed with XFI, FAST offers several resources. "Anyone who's willing to invest the time can learn how to tune a motor with EFI. We include a 2 1/2-hour instructional DVD with our XFI system that tells you how to modify each and every table in the software," David says. "While that alone won't make you an expert tuner, it's a great learning tool. Also, the XFI software is available as a free download on our website, so you can try it out before you buy it. Our tech line is always happy to provide assistance, and there's lots of great information available on online forums as well. Furthermore, based on customer feedback, we are in the process of putting together an XFI training course in the near future, so stay tuned for details."
Let's say you want to run an electronically controlled late-model GM overdrive transmission in your carbureted street machine, but don't know how to get its electronics to work. FAST has developed a solution to this common problem with its stand-alone transmission controller. "This is another instance when being part of the Comp Cams family was really beneficial to product development. By working closely with TCI, we came up with a stand-alone trans controller that can be used with carbureted motors, EFI motors using the stock PCM, or with our EZ-EFI and XFI systems," says David. "The controller interfaces with factory transmissions using application-specific FAST wiring harnesses. By hooking up the controller to a laptop, users have full control over setting shift points, shift firmness, and torque converter lockup. Depending on the needs of the vehicle, tuning can be accomplished based on rpm, speed, gear ratio, or load."
"FAST was one of the first companies to develop an aftermarket intake manifold for GM LS-series motors, and they're available with both 92- and 102mm throttle-body openings. All FAST manifolds feature a composite, three-piece construction that can be easily taken apart for additional porting, and keeps heat absorption to a minimum. The 92mm intake works best with 350-383ci motors, while the 102mm unit is designed for larger 408-421ci combos. We have also recently introduced our LSXR intakes, designed for rectangle-port L92, LS3, and LS7 cylinder heads. This has proven to be a huge hit for engine builders installing these innovative new heads on older short-blocks. On a 500ci LS-based engine, we made near 800 hp with this intake."
"FAST is always working hard to stay at the forefront of the market. Our EZ-EFI system and new LS3 intake manifolds are just a few examples of what's currently in the works. For cathedral-port 4.8-, 5.3-, and 6.0L LS-series truck motors where tight hood clearance isn't an issue, we've just introduced a new 102mm LSXRT intake manifold. It features the same modular construction of our other composite manifolds, but with a few key distinctions. This new truck intake boasts more plenum volume, and its runners are angled more steeply to provide a more gradual transition into the intake ports. Also in the works is our new XIM stand-alone ignition control system. This unit is designed to control the spark in LS-motors that are running a carburetor."