The ZR-1’s LT5 V8 is arguably the most over-engineered engine in Corvette history. There is a 100k mile owners club for these cars, reflecting the durability of the LT5. This is astonishing considering the complexity of this motor, which sported many “engineering firsts” at the time of its debut
While Lotus provided the high-RPM 4 valve cylinder heads, Corvette engineers couldn’t just bolt them to a stock 5.7L Corvette block and work from there – computer modeling revealed that this combination would be octane-limited to 350hp after meeting emissions, which was far short of the 400hp goal. Tony Rudd of Lotus insisted that the block be custom designed from the ground up for these special heads, which would allow control of piston cooling, cylinder wall cooling, and head cooling. This was essential for a 400hp output
The Lotus partnership would have been in jeopardy if it weren’t for a client that canceled a project with Lotus to develop an F1 engine for a period 1.5L turbo Formula car (F1 had just changed the rules to require 3.5L N/A motors). This freed up an entire group of engine design and development engineers at Lotus. Without this cancelation (and F1 rule change), Lotus would not have had the resources to meet Chevrolet’s tight time constraints, and the Lotus-Chevrolet partnership could easily have been terminated – especially considering that both Cosworth and Porsche were available as an alternative
In addition to the four-valve heads, Lotus was responsible for designing the highly sophisticated valvetrain and injector setup. The intake ports, valves, fuel injectors, and cam lobes are divided into two systems. The primary system, which engages below 50% throttle (or 3000 RPM), limits engine breathing through the primary ports and fires fuel through 8 injectors. In this mode, the ZR1 makes roughly 250hp
Above 3,000 RPM, the secondary port valves open, allowing air/fuel mixture through the secondary intake valves. These valves are actuated by cam lobes with a larger profile than the primary lobes (similar concept to VTEC). This activates all 16 fuel injectors. With all 32 valves wide open, the driver now experiences the full 375 hp
This unique system required an unusually complex ignition timing map and knock control parameters. Unfortunately, GM had no engine computer large enough that could handle such requirements. It was by sheer luck that Delco Electronics in Indiana was designing a highly advanced computer with the power to handle the job. Without it, the LT5 project could have been killed, if not radically changed to something far less complex
The ZR-1 never came with the problematic Opti-Spark distributor found on base LT1 Corvettes. In fact, the LT5 had no distributor, period. It relied on a modern four-coil “direct-fire” system
Key Model Year Changes:
“ZR-1” emblems are added above the fender vents
First year of traction control (“ASR”) created by Bosch
The switch was made from quad exhaust outlets to dual rectangular outlets (excluding very early ’92 cars, such as this one)
Instrument buttons and faceplates are now all black (vs grey/black)
Weatherstripping is improved to provide a better seal from the elements
Insulation is added to the doors and transmission tunnel to reduce road noise
The speedometer readout now sits above the fuel level readout, rather than underneath it on previous years
Gauge dial graphics are enhanced with notches to help better indicate temperatures/oil pressure/battery voltage
The “upshift” light is now gone
First year of the Goodyear GS-C directional tires
The power delay function now includes the passenger door – when ignition is shut off, power is now disabled when the passenger door is opened (vs. only the driver’s door)
45k original miles
Black on black
Bought in CA in 2018
Dashboard is in impeccable condition and works perfectly
Original factory manual, VHS video, key fob and sales invoice
Small mark (3 cm) on the trunk of the car and on the side
*SAE rated from factory. May not reflect current output.
*Performance numbers pulled from either the factory brochure or reputable automotive road tests.
*Base price when new does not reflect original MSRP of this particular car, nor does it reflect what the original owner paid for it.
*Advertised price at time of posting. Sellers can raise or lower prices on their original ad at any time. Click on the original ad to view current price/availability.
Mileage Disclaimer: NOC has not confirmed if the mileage stated by the seller is true and accurate. It is up to the buyer to verify these claims. Vehicle history reports, service records stating mileage, and even inspections of odometer tampering are recommended.