Some detailed engine specs are rolling in:
The engine is rated at 670 horsepower and 460 pound-feet of torque, with the horsepower peaking at 8400 rpm, right near the 8600-rpm fuel cut. That Ferrari V-8s also make peak power right at redline is no coincidence. In the LT6, more revs mean more power, and the engineering team will use every last rpm it can.
In an automotive world obsessed with electrification and efficiency, it's bold for GM to develop a new engine with a short stroke and a fat bore. Cylinder dimensions are 104.25 millimeters by 80.0, netting a displacement of 5.5 liters. The compression ratio is 12.5:1. And for the engine nerds: The brake mean effective pressure is in excess of 1400 kilopascals.
The C8 team could have easily installed a pushrod V-8 with a blower on top, but a supercharged engine doesn't have the character of a flat-plane-crank V-8. During development, GM traded its Ferrari 458 for the turbocharged 488, and the team agreed with our assessment that some magic was lost. So they bought another 458.
Flat-plane cranks aren't a perfect solution, however. (Owners of Ford's Mustang Shelby GT350, with its high-revving 5.2-liter V-8, will relate.) They shake—a lot. So much that during LT6 development, an oil filter backed itself off on a test stand. Engineers suspected a tech hadn't tightened it, but video evidence uncovered no wrongdoing. The solution was to switch from a screw-on to a cartridge filter.
To keep those forces at bay, titanium connecting rods and intake valves hold reciprocating mass to a minimum. Exhaust valves are filled with sodium. All 32 valves are fitted with two springs each to prevent valve float at high rpm. Direct-acting finger followers have a diamond-like coating and are shimmed during assembly. "Lash for life," says Jordan Lee, GM global chief engineer for small-block engines.
The CNC-machined DOHC heads make the engine bigger than its pushrod siblings. In the C7 engine, height and width had tighter limitations because increasing either wasn't possible without affecting the hood height and footwell width. With the engine behind the cabin, those dimensions are less of a concern. And considering that the C8 was designed around an engine of a specific length, we understand why engineers kept the small-block's bore spacing.
The block has what GM calls a dedicated lower crankcase. It's similar to how Ferrari does dry sumps, with each crank journal residing in a sealed bay. There are six oil scavenge pumps: one in each bay and one in each head.
The intake features two plenums, two 87-mm throttle bodies, three valves that connect the plenums, and eight beautiful trumpets. Those crossover valves tune the intake to optimize both high- and low-rpm operation.
Direct fuel injection is the obvious choice. But instead of injectors squirting fuel on the intake side of the heads near the valley of the vee, the injectors are located between the exhaust valves, a design cribbed from Chevy's Indy V-6. Squirting fuel toward the incoming intake air promotes tumble (the motion and mix of air and fuel). More tumble improves burn.
Flat-plane-crank V-8s are a visceral thing. The intake sound reminds us of the sounds of our youth and draws in our adult selves like a siren song. The first time you hear a C8 Z06 start, your head will snap around like a kid getting called in to dinner on a warm summer night. —K.C. Colwell
the LT6 and LT2 for that matter have a dry sump oil system, with the LT6 having a much better version of it. that should help with the oiling issues FPC's have.anybody else think this car is already outdated and ugly? they copied a ferrari 458/mclaren12c design from over 10 years ago it would seem.
i hope the zr1 is wayyy more aggressive looking...having women test driving it in the video and giggling the entire time doesnt help either. i'd rather see randy pobst beating on it and giving us real data.
impressed with the NA design but wondering how reliability will be. the problem with the gt350 is too shallow of an oil pan and at high revs the oil is tossed up to the top of the motor and starved at the bottom...this car will need 10-12 quarts to prevent that.
Lastly, the clowns wearing masks in the videos was BRUTAL!!!!
GT350?? lmao
Yes, 58k OTD +tax +doc +adm58k OTD right?
I like how they're selling the coupe and convertible at the same time. Kudos to GM for thinking of all the perspective buyers. IMO the vert looks better because of those humps behind the driver/passenger headrest.
Super long intake runners. Must be nice not having to worry about hood clearance.
4.1 x 3.18Did some more digging, and it seems that its a big overboare. Big bore, short stroke, to keep piston speed down. Ford block doesn't have the bore spacing to pull that off.
FTFYPlaid owns the drag strip and C8 owns the race track.
Mustang owns the Cuck-E.
That's not a very high mark...They run 10.40.But will it beat a Demon???
rofl. Sick car. Can't wait to see what they can do.