For the 5.3-liter LS engine in our Project Swedish Meatball, selecting the right throttle body was essential for our turbocharged LS engine combination. Fuel Air Spark Technology’s (FAST) 102mm Big Mouth Electronic Throttle Body is the ideal solution for handling high levels of boost for track outings while maintaining highway drivability and reliability. Designed specifically for GM LS engines, this throttle body provides greater airflow, better blade control, and improved safety features. To understand how it benefits our project Project Swedish Meatball and it goals, we’ll explore its key benefits, with insights from Mark Honsowetz, Product Manager for EFI at the Edelbrock Group.
The FAST 102mm Big Mouth throttle body’s larger diameter is crucial for increasing airflow. With a 102mm inlet, it flows significantly more air than the stock 90mm unit. This difference is particularly noticeable in turbocharged engines, where airflow restrictions can limit performance. As Honsowetz explains, “The larger 102mm diameter was engineered to provide increased airflow, supporting the demands of high-performance builds. In a boosted application, this difference is even more noticeable.” By eliminating the bottleneck that a smaller throttle body can cause, the FAST unit allows the turbocharged LS engine to reach its full power potential.
FAST’s design also addresses the inherent challenges of drive-by-wire (DBW) systems, which are common in modern vehicles but can create reliability issues in high-performance environments. The FAST throttle body includes an upgraded motor and dual return springs, which offer improved throttle response and added safety. “The dual return spring design offers additional safety and reliability, especially when dealing with higher loads in forced induction applications,” says Honsowetz. The dual springs ensure that if one spring fails, the other will maintain proper throttle control, making this feature crucial for high-stress applications like turbocharging.
A common issue with stock throttle bodies under high boost levels is throttle blade flutter, where the blade becomes unstable due to the increased pressure. This can lead to erratic performance and cause the ECU to enter limp mode. FAST solved this problem by using a reinforced shaft and rigid butterfly design to eliminate blade instability. “The critical aspect of this throttle body is blade control. Stock LS throttle bodies will flutter under high boost, especially in draw-through setups, causing erratic performance,” Honsowetz explains. By improving blade stability, the FAST throttle body ensures we’ll have smooth operation without performance issues as we rip around the track and take long drives.
The high-torque drive motor in the FAST throttle body is another significant improvement over the stock throttle body. In forced induction setups, throttle response needs to be immediate, especially as the turbo spools up. The stock LS throttle body motor can struggle to keep pace with the rapid changes in airflow required by turbocharged engines, leading to a sluggish throttle response. The upgraded motor in the FAST Big Mouth throttler body provides quicker, more consistent control. As Honsowetz explains, “The high-torque motor, combined with a rigid shaft and butterfly design, ensures consistent and quick throttle response even under the immense pressures seen in turbo setups.”
Despite these high-performance features, the FAST 102mm Big Mouth electronic throttle body remains straightforward to install. Its plug-and-play compatibility with Gen IV LS ECUs means it integrates well with stock or aftermarket systems, including the Edelbrock Pro-Flo 4+. For Project Swedish Meatball, this feature was vital, as it simplified the installation process while ensuring noticeable performance gains from the throttle body without extensive modifications.
The Big Mouth electronic throttle body proved to be the perfect component for Project Swedish Meatball’s turbocharged 5.3-liter LS engine. By delivering significantly more airflow than stock, stabilizing the throttle blade under boost, and providing rapid throttle response, it directly addressed the demands of forced induction. “This throttle body was designed from the ground up to be the best in the industry for boosted LS applications, and it shows in every aspect,” says Honsowetz.
With its durability, focus on safety, and increased performance, the FAST throttle body was a critical component in ensuring the engine in our Volve project could handle the power and demands of turbocharging while maintaining every-day drivability. It addressed the key limitations of stock LS throttle bodies in high-horsepower turbocharged setups. With increased airflow, an upgraded motor, and improved safety features, it’s a reliable, high-performance solution for boosted LS builds like Project Swedish Meatball, providing maximum performance without sacrificing drivability or safety.
