How to make a modern Chevrolet LS7 spin to 11,000 rpm
High-revving V-8s are a dream to many hot rodders. You’ve got the generous displacement to allow torque at the bottom of the power curve, and a dyno graph wider than an early ‘60s Chrysler Cross Ram intake manifold makes for a balanced race or street engine. To build an LS engine that can rev to 11,000 takes NASA-grade attention to detail and a whole lot of courage.
Getting an LS7-based engine to turn at stratospheric rpm numbers is no small task, but the students and staff at EFI University put themselves to the challenge for project they dubbed “Spinal Tap.” This project engine is being built for 11,000 rpm (it goes to eleven, get it?) and is ultimately destined for the drag strip. So far it’s been a two-year journey just to sort out the valvetrain and top-end kit.
The valvetrain is centered around a tool steel camshaft with a 60-mm core. The oversized core minimizes deflection and keeps valve lift consistent. The rockers are a one-off set up from Jesel, which the company says is the most stable system it has made for the LS series. The valves themselves are titanium and will see a full inch of lift without spring binding or interference.
The crankshaft and lower rotating assembly are, compared to the lifter setup, more easily engineered to withstand high-rpm operation. The bottom end is highly detailed, but less engineering is required to make it withstand the forces at play, even when those forces include a piston speed approaching 7300 feet per minute at 11,000 rpm.
The team has been working on this project for two years and has hit very impressive numbers on a Spintron machine, which uses an electric motor to cycle the assembled valvetrain at the rpm they expect the engine to run at. EFI University has posted a Facebook video of the engine zinging to over 11,500 rpm, and they talk through a few of the improvements that might be in store down the road.
While the engine has not yet run on its own, it appears that goal is firmly in EFI’s sights. We will surely be keeping a sharp eye for any future updates.