The phrase "engine redline" refers to the maximum speed or RPM (rotations per minute) that an engine can handle without causing damage. It's like a boundary set to prevent the engine from working too hard and breaking. Full definition
Those batteries deliver an emissions - free range of 30 miles and make the 1.6 - litre V6 F1 engine redlined at 11,000 rpm much more driveable by beefing up low - end torque. (carmagazine.co.uk)
Few will really need to track their car's engine redline when shifting. (businessinsider.com)
The 2008 - ’09 model featured a stiffer and lower suspension, cold - air intake, revised exhaust, shorter and heavier rear axle, and even a higher engine redline. (fordauthority.com)