Okay, maybe it isn’t some secret-squirrel prototype from deep in the innards of GM’s black ops syndicate, but it is a Corvette and it definitely has a flat-plane crankshaft. The story behind it is just as interesting as the means to make it happen, and folks are chiming in on both sides of the debate.
There are some benefits of flat-plane crankshafts, such that some of the OEM’s have already begun manufacturing performance-minded daily drivers using this technology. There have been rumors that the next-gen, mid-engine Corvette could likely use this technology. If you’d like a good primer on what the differences are between a flat-plane and a traditional cross-plane crankshaft, feel free to click on this video below, where Engineering Explained puts it all into perspective.
For those who are salivating in anticipation of the day when Corvette will become available with its own flat-plane crank, your wait has been shortened immensely. In fact, there is no wait, so long as you’re the lucky bidder on this eBay ad for this 2006 Chevrolet Corvette Z06.
Nothing so clearly points out the differences between a flat-plane and cross-plane crankshaft engine like taking a torquey 7-liter, 505 horsepower Z06 and infusing it with a flat-plane 5.3L engine. The difference in size is just as much a product of the flat-plane’s design as it is the number of axis within the crank’s makeup.
One of the benefits of a flat-plane crankshaft is the need for less counter-balancing, thereby making the crankshaft inherently lighter. To balance the rotating assembly, both rods and pistons are considerably lighter, which aids in higher revs, but doesn’t produce the torque loads one might be used to with their massive LS7.
In this video of the car running, you can tell, even as the car sits idling, that there’s something different going on in the engine’s firing order. But it’s when the loud pedal is depressed that you get a real feel for what a flat-plane crank is capable of producing.
One would do well to note the way the car leaves as it drives away from the camera. While a smooth shoe could start out with a stock 7-litre Z06 without even touching the gas, the smaller, high-winding engine definitely requires some fiddling to get going.
Before you fret that we’ve forgotten all about those high-winding mouse motors back in the day that haunted drag strips, red lights and makeshift ¼-miles for decades, let us explain that we’ve got a soft spot for those engines as well. In fact, we’d point out that they were a LOT of fun, and they housed a more “contemporary” cross-plane crankshaft and even-so, still wound to 8-9,000 rpm frequently.
They had a purpose, and they served it well. Much like the engine in this C6 Z. The post explains that it was designed to be a road race monster with a Ferrari soundtrack. We’re not sure what class this car may have been designed to compete in, but with the long list of high quality parts involved, we’d think that it’s quite capable to carve out some corners and put a smile on anyone’s face.
We do think though, that it would take a little bit of learning to break any habits of relying on the factory 7-litre engine’s torque to carry you away from an apex quickly. Gear selection is key when relying on a usable, but limited rev band to get you to the winner’s circle and the ad doesn’t mention the rear gear ratio, but we’d surmise that it still has the 3.42 gears.
All in all, it’s an interesting proof-of-concept for a flat-plane engine in a Corvette. It’s interesting to see how it changes the dynamics of the car and, it may just be the pre-cursor of things to come in the next-gen Corvette. Either way, you don’t have to wait to get your hands on one, as of this writing, there are only a few hours left, so don’t spend all your time looking at the videos!
- 2006 Corvette C6 Z06
- 5.3L Flat Plane LS V8
- 560HP, 450 Ft-LBS
- 8250 RPM Redline
- 4.165″ Bore, 3.000″ Stroke
- Road Race LG Suspension
- Custom Carrillo H Beam Rods
- Custom Wiseco 12.5:1 Pistons
- Custom Sonny Bryant Flat Plane Crankshaft
- Custom Comp Camshaft
- Dailey Engineering 5 Stage Dry Sump
- LS7 CNC Ported Head
- Jesel Tool Steel Keyway Roller Lifters
- Jesel Pro Stainless Steel Rockers
- Custom Manley Pushrods
- Inconel Exhaust Valves
- Titanium Intake Valves
- Fast LSX Intake Manifold
- ERL Performance Superdeck Sleeved LS Block
- Exedy Hyper Single Disc Clutch
- Fidanza Aluminum Flywheel
- Custom Tuned ATI Crankshaft Balancer
- Holley EFI Dominator ECU
- LG C6 Z06 Super Pro Longtube Headers
- Corsa Z06 Exhaust Mufflers
- LG GT2 Adjustable Coilovers
- LG C6 Drop Spindles
- LG HD Quiet End Links
- LG G1 Swaybars
- SKF Racing Hubs
- StopTech 6 Piston Front Calipers/Rotors
- Road Race Suspension Setup & Corner Balance