When is more not always better? Cadillac may have case for that when it comes to the engine used in its CT5-V Blackwing.
For those who missed its unveiling last month, the 2022 Cadillac CT5-V Blackwing uses the LT4 engine, a 6.2L supercharged V-8 that generates 668 horsepower, 659 pounds-feet of torque and drives the rear wheels. Sixty miles per hour comes up in 3.7 seconds and the car will top out around 200 mph.
Other than asking why the 4.2L Blackwing V-8 was omitted, people may wonder why GM skipped out on using the LT5, another 6.2L supercharged V-8 found in the seventh-generation Chevrolet Corvette ZR1, especially since the LT5 puts out more power – 755 hp and 715 lbs-ft.
According to Alex Luft, executive editor with Cadillac Society, dropping the LT5 in would have cause several unintentional issues, beginning with visibility. Luft interviewed V-Series Blackwing Chief Engineer Mirza Grebovic about the engine selection.
“When we initially started working on this project, obviously, we were super excited to shove any engine in there and make as much power as possible,” Grebovic said. “But in the end, what we have to balance is a driver’s car.”
In the ZR1, the LT5 used a dry sump oiling system and allowed the engine a lower mounting in its bay but it also wore a shaker hood. Such a hood on the CT5 would have been impractical.
“You would have to make it so high that you can’t see out of the car and we wouldn’t have met regulatory requirements for vision,” Grebovic explained. The Alpha platform that underpins the CT5 is different from the C7’s architecture. Converting the Cadillac to accept the LT5 would have been a complex and expensive proposition. Going to all-wheel drive to solve the power issue would have added another layer of complexity.
The CT5-V also runs different tires than a ZR1 and generates less cornering forces, making a dry sump set-up irrelevant.
Why does tire selection matter? The ZR1 used 335/25-20 rear tires; the widest gumballs on the CT5 are 305mm. That 30mm difference may not sound like much but it is a huge change in footprint and how much friction is on hand to bear the engine’s torque.
“So yes, we considered the LT5, but aside of just engineering issues, let’s say this car did make 760 horsepower. We wouldn’t have the right chassis for it,” Grebovic said. “It would have been a powerful car, but it probably wouldn’t be any faster at the track or the quarter mile, because 305-section [rear] tires with that much power would be very tough to manage.”