Two hairdryers, no waiting
Reaching the 1,000-horsepower threshold for the Toronado’s engine was achieved with an intercooled twin-turbocharger system pumping 19 pounds of boost into a GM Performance Parts prototype 425-cubic-inch small-block crate engine. Developed in conjunction with GM Performance Division, the engine uses a modified aluminum block and cylinder heads from the Cadillac CTS-V racing program. They’ve been reconfigured to work as a high-performance street engine – a must for Leno, as he intends to use the Toronado as a daily driver.
Although not currently offered for sale by GM Performance Parts, the high-performance 425 engine serves as a real-world evaluator for potential new products.
“All the basic elements of this engine will soon be available in either the GM Performance Parts catalog or elsewhere in the GM parts system,” said Will Handzel, group manager, GM Performance Parts. “Participating in projects such as Jay’s Toronado gives GMPP the opportunity to ‘clinic’ high-performance combinations and evaluate ideas we might not otherwise would have considered. This engine made 1,000 horses without too much trouble, and it already has us thinking of future crate engine possibilities.”
A GM Performance-spec’d forged steel crankshaft and connecting rods are used on the bottom end of the 425 engine, along with custom forged aluminum pistons. When pushing up toward the CNC-ported aluminum cylinder heads, the pistons deliver an 8.3:1 compression ratio – a relatively low compression ratio required to ward off detonation in a turbocharged engine. The cavernous heads channel the huge volume of air generated by a pair of ball bearing-type turbochargers to the combustion chambers. High-flow GM Racing fuel injectors are used to match the airflow and a GM prototype camshaft actuates the valves – the camshaft is a high-performance item that may just reach production sooner than later.
High, prominent mounting of the turbochargers makes them impossible to miss when the Toronado’s hood is raised. They generate airflow that passes through a pair of intercoolers (mounted behind the radiator) and through a pair of GM mass air meters, where the pressurized air supply merges and enters the engine through a GM Gen IV V-8 90-mm electronically-controlled throttle body and composite intake manifold. A custom exhaust system was fabricated from scratch-built, stainless steel headers and is routed through a custom-fabricated stainless steel exhaust system.