Well, the speculation can be put to rest. The 2018 Chevrolet Corvette ZR1 is indeed getting an LT5 engine but it will not have turbochargers as some hoped. According to GM's internal RPO system the LT5 will be supercharged and seems to be a reworked LT4 6.2 liter.

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This is not a bad thing as a larger blower is expected. GM will not admit it but the R1740 TVS supercharger from Eaton is way too small for the LT4 engine. It produces a ton of torque down low and has great response but the top end falls off quickly.

A rumored much larger R2650 would fix that. It likely will also become a popular swap for the LT4 once ZR1's are out in the wild and they show what they are capable of.

We will see what GM does but a turbo V8 is not in the cards for now. The previous reports about a DOHC naturally aspirated LT5 seem to be incorrect or the engine was renamed.

R2650 versus R2300

  • 4% more efficient
  • 15% larger (2300cc vs. 2650 cc)
  • 18% less input power required
  • 25% more air flow at 18,000 RPM and 14 psi boost (2.0 Pressure Ratio)
  • 72% isentropic efficiency vs. 68%


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