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After the dyno test was over, we realized there was another simple trick up our sleeves for the Caprice that should have been tested. The throttle body used on LT1s (like the Tuned-Port engines before them) has a small passage inside for coolant, which is fed via a small hose that taps into the cooling system. The purpose of this arrangement is to prevent ice from accumulating on the throttle blades during cold-climate startups, but the rest of the time it just adds heat to the incoming air. By simply bypassing the coolant connections on the throttle body (connect hose A to hose B), the heat is eliminated--a change reputed to be worth around 3-5 hp in many cases. We'll try this out next time we hit the rollers.
Injector Detector
One of the latest additions to the ever-expanding arsenal of automotive test equipment at Westech Performance Group is the ASNU fuel-injector analyzer. The ASNU rig is intended to provide automotive service centers a means of determining the performance of each injector, allowing technicians to pinpoint defective components by testing them individually under a number of conditions. The rig can test up to eight injectors at a time and provides the ability to vary fuel pressure and injector pulse width, meanwhile allowing the technician to visually observe the injector's spray pattern and compare delivery rates between the injectors in a set. Injectors can be tested for static performance (held open) or dynamic performance (pulsed). There are also programs to simulate typical driving operation, and the rig is capable of simulating engine operation up to 10,000 rpm if so desired. Once the injectors have been tested, the ASNU can also be used to clean them using its patented ultrasonic treatment process. As the name implies, most used injectors can be returned to "as-new" performance using this apparatus.
Although the ASNU was developed for service work, it is obviously an excellent tool for performance tuning and diagnostic work. Our Caprice had fairly new injectors, so we observed a set of Mustang injectors going through the process.
The ASNU rig can mount up to eight injectors at a time for flow-testing. The rig doesn't actually use fuel, but a non-flammable fluid that was specially developed to mimic the properties of gasoline for accurate testing. | 
During the test, the "fuel" pressure can be varied along with pulse width, or the injectors can simply be held open and flowed for a specific time period. The technician can observe spray quality during the test and delivery rate afterward by comparing the amount of fluid in the graduated cylinders. |
The ASNU rig also includes an injector cleaning station, which uses ultrasonic waves to loosen deposits while the injector is rapidly pulsed and partially submerged in a cleaning solution. The rig includes special tools to remove the end caps and tiny screens from the injectors to allow more thorough cleaning; ASNU recommends that these items be replaced when reconditioning injectors. Once the cleaning process is complete and the injectors are fitted with new screens, they can be retested to verify the improvement in performance. | |