>MotorHeads >Peer inside the Corvette Z06's monster 650-hp V8 <
#1
06-15-2014, 06:25 AM
>MotorHeads >Peer inside the Corvette Z06's monster 650-hp V8 <
Peer inside the Corvette Z06's monster 650-hp V8
The LT4 gets the cutaway treatment.
By Alex Kierstein June 15, 2014 / Photos by GM
This is the new American face of shock-and-awe horsepower tactics: a pushrod engine whose power density and output make the European exotics look foolish for all their overhead-cam trickery. It's such a typically American engineering tour de force that I'm surprised the valves don't have little flags stamped into them. As you can see by this cutaway, they don't. Maybe in the next ZR1?
Let's explain what you're looking at when you peer inside the LT4.
First, the displacement is the same 6.2 liters as the LT1 V8 it's based on. In case you missed the total output figures, they're an even 650 hp at 6400 rpm and 650 lb-ft at 3600 rpm. A completely insane 457 lb-ft is available just off idle. The torque curve has a lot to do with the 1.7-liter supercharger screwed on top of the engine—it can rotate as fast as 20,000 rpm thanks to smaller rotors, which produce boost at lower rpm.
The valves? Titanium. The compression ratio is 10:1, quite high for a forced-induction engine thanks to direct-injection technology. And as you can see, at the center of the engine, it's still cam-in-block—a technology most companies abandoned decades ago.
And here it is, the most powerful GM production motor ever, putting the fear of cheap torque into the Italians and Germans.
If you thought the horsepower wars were drawing to a close, think again.
Click the image below to view the LT4 in hi-res.
GM
The LT4 gets the cutaway treatment.
By Alex Kierstein June 15, 2014 / Photos by GM
This is the new American face of shock-and-awe horsepower tactics: a pushrod engine whose power density and output make the European exotics look foolish for all their overhead-cam trickery. It's such a typically American engineering tour de force that I'm surprised the valves don't have little flags stamped into them. As you can see by this cutaway, they don't. Maybe in the next ZR1?
Let's explain what you're looking at when you peer inside the LT4.
First, the displacement is the same 6.2 liters as the LT1 V8 it's based on. In case you missed the total output figures, they're an even 650 hp at 6400 rpm and 650 lb-ft at 3600 rpm. A completely insane 457 lb-ft is available just off idle. The torque curve has a lot to do with the 1.7-liter supercharger screwed on top of the engine—it can rotate as fast as 20,000 rpm thanks to smaller rotors, which produce boost at lower rpm.
The valves? Titanium. The compression ratio is 10:1, quite high for a forced-induction engine thanks to direct-injection technology. And as you can see, at the center of the engine, it's still cam-in-block—a technology most companies abandoned decades ago.
And here it is, the most powerful GM production motor ever, putting the fear of cheap torque into the Italians and Germans.
If you thought the horsepower wars were drawing to a close, think again.
Click the image below to view the LT4 in hi-res.
GM
#2
06-15-2014, 06:29 AM
>2 dare 2 `Dream<>It's still `free<
In-Depth with the 2015 Chevrolet Corvette Z06 *Note >HP Increased (Check above post)
The Name Game: With looks inspired by the new Corvette race car and a power target inspired by the old ZR1, this thing really ought to be called something else.
From the March 2014 Issue of Car and Driver
What car are we describing? It’s a wedge-shaped, two-seat Chevrolet with a rear transaxle, a front-mounted pushrod 6.2-liter V-8 with an Eaton TVS supercharger nestled in its valley, and some carbon-fiber body pieces. It makes more than 600 horsepower, wears shocks filled with magnetorheological fluid, and is offered with carbon-ceramic brakes nearly as large as those fitted to the Bugatti Veyron 16.4.
If you guessed the dearly departed Corvette ZR1, you are correct. If, however, you guessed the 2015 Corvette Z06, you are also correct. If you guessed anything else, you’re reading the wrong magazine. Because of the upcomingZ06’s striking similarities to the ZR1, we’ve taken to thinking of the new car as the “ZR06.”
Yes, the rip-roaring, high-revving, naturally aspirated, 505-hp 7.0-liter LS7 of the previous Z06 is gone (though it lives on in the upcoming Camaro Z/28). That the new Z06 has a blown engine shouldn’t come as a surprise. We noted about a year ago that the standard Corvette Stingray’s instrument panel includes a digital boost-pressure gauge buried in the driver-information menus. Menus it no doubt shares with the new Z06.
Note flat-bottomed steering wheel.
The Z06's supercharged V-8 will make at least 625 horsepower.
The Name Game: With looks inspired by the new Corvette race car and a power target inspired by the old ZR1, this thing really ought to be called something else.
From the March 2014 Issue of Car and DriverWhat car are we describing? It’s a wedge-shaped, two-seat Chevrolet with a rear transaxle, a front-mounted pushrod 6.2-liter V-8 with an Eaton TVS supercharger nestled in its valley, and some carbon-fiber body pieces. It makes more than 600 horsepower, wears shocks filled with magnetorheological fluid, and is offered with carbon-ceramic brakes nearly as large as those fitted to the Bugatti Veyron 16.4.
If you guessed the dearly departed Corvette ZR1, you are correct. If, however, you guessed the 2015 Corvette Z06, you are also correct. If you guessed anything else, you’re reading the wrong magazine. Because of the upcomingZ06’s striking similarities to the ZR1, we’ve taken to thinking of the new car as the “ZR06.”
Yes, the rip-roaring, high-revving, naturally aspirated, 505-hp 7.0-liter LS7 of the previous Z06 is gone (though it lives on in the upcoming Camaro Z/28). That the new Z06 has a blown engine shouldn’t come as a surprise. We noted about a year ago that the standard Corvette Stingray’s instrument panel includes a digital boost-pressure gauge buried in the driver-information menus. Menus it no doubt shares with the new Z06.
Note flat-bottomed steering wheel.
If it helps you get over the loss of the nasty-wonderful LS7 engine, know that Chevrolet is trying to deliver as much output with the Z06’s new LT4 V-8 as it did with the old ZR1. In other words, a staggering 638 horsepower. But because the Z06 won’t go on sale until early next year, Chevrolet hasn’t settled on a final figure. The company estimates, no doubt conservatively, that the dry-sump LT4 will put out about 625 horsepower. Corvette engineering Grand Pooh-Bah Tadge Juechter says: “It is our aspiration to get to ZR1 power levels. If we can get there, we certainly will.”
He cautions, however, that because the LT4 will use a smaller supercharger than the LS9 engine in the ZR1 (1.7 liters-per-revolution versus 2.3), running about 9.5 psi of boost, it’ll be a stretch. But do not be surprised if it comes very, very close. Know, too, that the company promises the new engine will make at least 625 pound-feet of torque, or 21 more than the former king-of-the-hill Corvette.
That supercharger is mounted atop an engine that uses the standard Corvette’s aluminum block. To handle the increased power, the LT4 uses forged pistons; strong-er, custom-machined steel connecting rods; and titanium intake valves fitted to cylinder heads that are rotocast of A356T6 aluminum for greater strength and heat resistance. It runs a 10.0:1 compression ratio, relatively high for a supercharged engine, thanks in part to the direct-injection system shared with the Stingray’s V-8. The LT4 also uses the same variable-valve-timing and cylinder-deactivation systems as the Stingray’s LT1.
He cautions, however, that because the LT4 will use a smaller supercharger than the LS9 engine in the ZR1 (1.7 liters-per-revolution versus 2.3), running about 9.5 psi of boost, it’ll be a stretch. But do not be surprised if it comes very, very close. Know, too, that the company promises the new engine will make at least 625 pound-feet of torque, or 21 more than the former king-of-the-hill Corvette.
That supercharger is mounted atop an engine that uses the standard Corvette’s aluminum block. To handle the increased power, the LT4 uses forged pistons; strong-er, custom-machined steel connecting rods; and titanium intake valves fitted to cylinder heads that are rotocast of A356T6 aluminum for greater strength and heat resistance. It runs a 10.0:1 compression ratio, relatively high for a supercharged engine, thanks in part to the direct-injection system shared with the Stingray’s V-8. The LT4 also uses the same variable-valve-timing and cylinder-deactivation systems as the Stingray’s LT1.
The Z06's supercharged V-8 will make at least 625 horsepower.
It’s the cylinder-deactivation system, which GM calls Active Fuel Management, along with emissions concerns that prevented the Corvette team from using an updated version of the big-displacement, naturally aspirated LS7. According to Juechter, Active Fuel Management’s collapsing valve lifters cannot reliably handle the high revs that a new version of the LS7 would generate. And if the company had governed revs to spare those parts, the engine wouldn’t make the sort of shock-and-awe power befitting a Z06.
The Z06 will be offered for the first time in the sub-model’s history with an automatic transmission, in this case a new conventional torque-converter unit with eight forward gears. The Hydra-Matic 8L90 is GM’s own design and will reside right next to the standard Stingray’s seven-speed manual on the Z06 order sheet. And yes, before you ask, Chevrolet considered a dual-clutch automatic, similar to the PDK in the Porsche 911. Juechter claims that the company couldn’t find a dual-clutch that could both fit into the Corvette’s hindquarters and handle the engine’s plentiful torque. Instead, the team sought to match the shift speed of the 911’s PDK, something Chevy claims to have achieved with the paddle-shifted automatic in most circumstances. Either transaxle will be firmly connected to the engine with a Z06-specific carbon-fiber torque tube that’s three times stiffer than the old Z06’s aluminum one.Continued...
PHOTOS (18)
The Z06 will be offered for the first time in the sub-model’s history with an automatic transmission, in this case a new conventional torque-converter unit with eight forward gears. The Hydra-Matic 8L90 is GM’s own design and will reside right next to the standard Stingray’s seven-speed manual on the Z06 order sheet. And yes, before you ask, Chevrolet considered a dual-clutch automatic, similar to the PDK in the Porsche 911. Juechter claims that the company couldn’t find a dual-clutch that could both fit into the Corvette’s hindquarters and handle the engine’s plentiful torque. Instead, the team sought to match the shift speed of the 911’s PDK, something Chevy claims to have achieved with the paddle-shifted automatic in most circumstances. Either transaxle will be firmly connected to the engine with a Z06-specific carbon-fiber torque tube that’s three times stiffer than the old Z06’s aluminum one.Continued...
Last edited by BeachBumMike; 06-15-2014 at 06:31 AM.
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