Chevy first revealed that it was developing an exotic flat-plane crank motor via its C8R race car. We’ve discovered that the race car’s 5.5-liter V8 is very similar to the Z06 production engine. They share the same cylinder block, heads and valvetrain. We all know the old saying, “Win on Sunday, Sell on Monday.” GM has taken this maxim to heart, as engineers have been able to improve the street car engine through the racing program. Perhaps even more interesting is the fact that Z06 street car engineers helped the racing team improve the Gemini.
The primary benefit for the production car team was the validation data that they were able glean from race teams running the engine over thousands or thousands of miles. Engineers were able to access data about wear surfaces, heat management, operating parameters, and many other things. Sometimes, the race and production car teams shared parts. They swapped between each other when they wanted to try something new. The two teams continue to collaborate to determine what will end up in the buyers’ driveways.
The Ferrari 458 lessons will be interesting to you. GM purchased a wrecked Ferrari 458 from Europe $25,000 years ago. They then tore it apart to discover what makes the Ferrari flat-plane crank work so well, and applied that knowledge to their own V8. This American supercar has a lot of Italian flair. The modern 458, anyone?
Cooling and oiling
You may recall that the C7 Z06 had cooling problems with Chevy’s vehicle at-track. Engineers worked hard to prevent that with the C8 Z06 because its cooling capacity seems over-engineered. It has five radiators, which are supplemented by stronger fans. The cooling capacity of the C8 Z06 is 50% higher than the standard Stingray. Chevy recommends that you remove the removable aero panel from the front bumper for track use. Chevy managed to add all this cooling without having to reduce storage in any part of the vehicle, even the trunk.
The Z06 features a unique dry-sump oiling system. Track rats will love it. The system features an engine-mounted, plastic oil tank and provides 85% more cooling power than the C7 Z06. It has six scavenge pumps and a bottom-mounted oil cooler. This system is capable of excellent scavenging, even at high lateral g’s. Chevy claims that the Z06 equipped with the Z07 package can achieve 1.22 g of lateral acceleration from a skidpad.
A mechanical valvetrain that uses high-tech materials and has a hydraulic pump
The Z06’s engine features a mechanical, not hydraulic, valvetrain. GM claims that it will not need maintenance or adjustments throughout its life. It is lashed at the plant and its clearances are measured three more times during the engine’s life. However, it should never require service. GM claims this is possible because of the modern materials used today. The finger followers, made from hardened steel and highly polished with a carbon coating that looks like diamonds, are high-polished. The intake valves and exhaust valves are hollow-cavity sodium-filled nitrided stainless steel valves. All parts are designed to resist extreme wear. Engineers say everything is in spec even in GM’s high mileage validation runs.
All this goes to show that, while the Z06’s engine may be unusual in design, GM claims it will not require an extravagant level of maintenance or short service intervals. The engine has been put through all the same GM validations as the Stingray, so you can expect it to perform in extreme conditions.
It’s a flat plane crank design, of course.
The flat-plane crankshaft design is what makes this Corvette sound exotic. This allows for a different firing order, balanced air and exhaust flows, and allows you to adjust the engine’s revs. Chevy claims that the crankshaft is 33% lighter than the one in the Stingray’s LT2 engines.
Each engine is built by one technician
Each Z06 engine receives a plaque signed by the technician who assembled it. Chevy claims that it takes 3 hours to build one engine. All engines will be assembled at the Performance Build Center, Bowling Green, KY.
Every LT6 is shipped once it has been built. The engine undergoes a 20-minute procedure which runs the engine at full load and high speed. The break-in period for LT6s is similar to that of the Corvette. It takes 500 miles. During this period, torque in the first and second gears is automatically reduced.
The air conditioner system is track-rated
GM had set a goal for the Z06’s air conditioning system to allow proper cabin cooling in track conditions with an ambient temperature at 100 degrees Fahrenheit. We don’t know of any other American supercar goal to reach. Chevy needed to design a new air conditioning system, which was different than the C8 Stingray. Chevy used a lower pulley to run the compressor at 8,600 rpm. This slowed down the pulley at low speeds and idle so the team had the compressor size increased. This switchup has led to the Z06’s air conditioning being slightly more efficient than the Stingray’s. You can still run in extreme conditions on the track, but it’s nice and cool.
GM’s first adjustable valving exhaust system is here
The Z06’s exhaust is so important to enjoy the car that GM didn’t forget it. The exhaust system has a highly adjustable valving that can be adjusted through many settings. Instead of the standard adjustable exhaust, where the valve has only two settings (loud or quiet), it is highly adjustable. The engine ECU uses patented software to control the valves in the middle pipes. This allows GM 2 degree increments of tuning. Outboard pipes, which are Corvette’s “low flow” pipes, do not have valves. GM allows you to choose from three preset positions for your valves. These can be selected by the drive mode: Track, Sport, and Tour. Track is the loudest setting. However, GM states that it is loud enough to be heard on tracks with strict noise regulations.
GM claims that the new exhaust architecture reduces exhaust pressure by 21% compared to the C7 Z06 and that the muffler is 20% lighter than the C8 Stingray. It has a center exit, which GM claims was a last-minute modification to dramatically improve the sound.
Each LT6 engine contains 54 Gemini rockets
Chevy’s internal title for the LT6 project, Gemini, was a reference to NASA’s Gemini satellite program. This engine is a moonshot, so the team wanted to pay tributes to space. You’ll find 54 Gemini rockets in every engine if you look closely enough. Have fun hunting!
It is still called a Small Block by Chevy
This one is a little strange. The only thing that the LT6 shares with the Chevy Small Block V8 traditional is its 4.4 inch bore centerline spacing. It was also designed and engineered by the same team that created the Small Block V8. This engine is also completely new and clean-sheet. Although it is officially a “Gemini Small Block,” in practice there is almost nothing that’s similar to the DOHC engine design found in the Corvette Stingray. You can leave your opinion in the comments section.