Sometimes something sounds good on paper, but in reality, it begins to lose its luster.
Such was the proposition of using the one-year-only LT5 engine in the imminent 2022 Cadillac CT5-V Blackwing luxury sedan, according to an exclusive interview by GM Authority executive editor Alex Luft with the car’s top engineer.
The LT5 engine, of course, is the most powerful engine ever created by GM for a passenger vehicle and provided the “oomph” for the legendary 2019 Corvette ZR1.
With that setup being one and done in the last of the front-engine Corvettes, it might make sense financially for GM to get some more use out of that impressive engine and stuff it under the hood of the forthcoming Cadillac ultra-high-performance luxury sedan, right?
Wrong, according to V-Series Blackwing Chief Engineer Mirza Grebovic.
“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 told GM Authority.
But instead, Cadillac decided to go with a similar engine, the supercharged 6.2-liter LT4 V8 engine out of the Z06 that now produces 668 horsepower and propels the CT-5 from 0 to 60 in 3.7 seconds with a top speed of approximately 200 mph.
Using the LT5 just wouldn’t have been the right thing to do for any number of reasons, including the fact that it would require the use of a shaker hood on the Cadillac as was fitted on the ZR1. “We couldn’t put a shaker hood on the CT5,” Grebovic said. “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.”
A solution to that problem would have been to lower the engine through the use of a dry sump oil system used on most C7 Corvettes, but converting the Caddy Alpha platform to such a system would have required expensive and complex engineering.
Another problem was simply putting that much power to the road. While the ZR1 handled that by using 335/25/20 rear tires, the CT5 was limited to 305s on the back, not wide enough to withstand the torque of the engine.
“So yes, we considered the LT5, but aside of just engineering issues, let’s say this car did make 760 horsepower,” Grebovic said. “We wouldn’t have the right chassis for it. It would have been a powerful car, but it probably wouldn’t be any faster at the track or the quarter mile, because 305 [rear] tires with that much power would be very tough to manage.”
Going to an all-wheel-drive system might have solved that issue, but again the complexity and expense of engineering such a system rendered that idea impractical, not to mention that GM policy was the use of rear-wheel-drive only with the CT5 and CT4.
Will the LT5 be used by GM again? What’s your opinion?
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