johnglenntwo

(oversimplified proportions!)

403/>450 HP (6.2 Liter DPI)
= 436/>487 HP (6.2 Liter DPI)
= 505/>564 HP (7.0 Liter DPI)
= 638/>712 HP (SC 6.2 Liter DPI)

http://www.gminsidenews.com/forums/f...uto-com-54138/

OnPoint

John,

First of all, nice find.

Secondly, three things stand out in this.

First, the power enhancements noted and which have been discussed on this forum are very likely there - and 10-15% is a big deal when you're starting with a decent baseline. How it translates across a displacement change will be the key.

Second, this was from 5 years ago, which means the engineers have had time to fiddle with this - and hopefully - perfect its application for the Gen V without the valve coking issues encountered in other platforms (and given the importance, and broad application of the Gen V, one would think they'd "get it right" on that front).

Thirdly, it appears from the note you found John, that the trip through bankruptcy likely delayed GM's new pickups and C7 by at least a couple years from what they had planned.

Interesting read.

SanDiegoBert

Interesting article. I can DIG it . . . Thanks for posting it.

OnPoint

Stop being so serious all the time. . .

JLinCA

A 480 HP 6.2 for a base engine would be outstanding.

SanDiegoBert

. . . Yes, dear . . .

johnglenntwo

My guess continues to be that the base motor would end up with less displacement(5.5?) with the closer ratio gearing. They would be trading for efficiency. 480 HP is too much for that gearing on skinnier street tires. That's about what my C5 turbo makes on low boost with that gearing and I can be smoking them all day long off the line.

johnglenntwo

The pumps are louder, more expensive, and maybe a bit of a problem as they go bigger. And perhaps they have just been practicing for the C7:

http://www.worldcarfans.com/10605187...rect-injection

LS1LT1

I can deal with that.





That's what the modern era/high tech launch control/traction control systems are for.

JWell

I'm expecting a 5.7L 350 cu. in. with DI, that should get them 450hp and with the shorter stroke may be able to rev to 7000 reliably. Although I'm hoping for 475 or more in the base.

johnglenntwo

7000 RPM has been associated with titanium rods. Seeing them in the base model?

Basically the lighter C5 Z51 updated and add: DI and the 7-spd(tweaked for traction)!

JWell

This article suggests that DI, an increase in compression, and probably variable cam timing will be incorporated. I remember a few years ago reading that GM had developed or was working on a twin cam in block engine. I have also heard about a cam-in-cam setup.

http://www.insideline.com/chevrolet/...all-block.html

SanDiegoBert

Although for durability reasons, GM will probably set the rev limiter, 500 lower, or more.

LS1LT1

True, there was also a 3 valve per cylinder (but still OHV) head design being shown as well at some point years ago so any of these concepts are potential candidates for the new Corvette/Gen V engine.

johnglenntwo

If they do something substantial with the cams workings they will really be able to dink down the motor and improve on MPG. A 5.3ltr in a 3100lb car? The smaller it ends up the better the MPG! They can get the torque back by reducing the gear spacing.

GrampZ

From Jason, in the ZR1 Forum, 7-15-11:

"If I was a betting man I would put money on a 700hp C7 ZR1 or equivalent in 2015-2016. I'm just speculating though."

I'll bet he's right. (Anyone want to bet against him?)

Also, FWIW, since the C7 is evolutionary, and it doesn't make sense for it to underperform compared to the C6, here's my .02:

Light weight and weight distribution are where it's at. Weight affects inertia, which translates into launch (from a dead stop or roll), change of direction (i.e., through the esses), and energy dissipation (braking). I suspect they've looked everywhere, and traded performance against cost. A smaller engine is lighter, which also helps weight distribution. The spy pics, to me, make the driver's position look farther aft, which also helps weight distribution. I'll also go a little out on a limb and guess the engine is farther aft than the C6's, and so is the cabin. They probably took a bit of a weight penalty to get a better interior (?), but it's farther aft so it shouldn't hurt balance much, if at all.

They've probably also optimized PTMS about as far as they can for RWD. (But look at 911 and GTR for good examples of how AWD and computer aided stability can be leveraged over RWD.)

I wouldn't be worried about a "smaller engine" or not enough hp. Power to weight, and the ability to put it down, are what matter. And weight is in the denominator.

All that said, I'm still worried Corvette is chasing rather than leading (i.e., GTR, 911, etc). By the time C8 is in conceptual and preliminary design, hybrid, or electric power may be starting to mainstream (?), and next gen braking systems (magnetic, etc) will probably be too.

It's tough to lead in high performance vehicles (which are marketed to discretionary dollars) unless your product and management philosophy have long been committed to constant R&D - like P, F, L, etc. That's tough to do when shareholder value is driving the boat, and has been for decades.

Since the C6 Z06 was introduced, I have a new respect for Corvette. I truly loved mine. I'm looking forward to the C7, especially the ZR1. I hope I like it better than the as yet unannounced ACR, or any other would be contender. But as far as emerging as a leader in high performance cars, as opposed to iteratively one-upping the competitors, I'm not sure Corvette can, at least not how I would like to see it lead - though Hope's spring is eternal.

LS1LT1

True.
I hear what you're saying and on the surface it makes total sense. But let's not forget that 'highway' gearing and a sweet torque curve is part of what makes the current base car's fuel economy so stellar (stellar for a 430+hp, 190mph car at least ).
If that turns into a higher winding, more steeply geared combination it might not improve fuel economy as much as one might think.
Think in terms of a Honda S2000 or Civic Si, small little fuel efficient engines but they needed to be revved so high (to really get going) and had to be geared in such a way that their fuel efficiency, though good, was still not exactly what one might call 'great'. For such lightweight cars with little 1.8L to 2.2L 4 cylinder engines at least.

LS1LT1

I have few doubts that if the C7 ZR1 ever comes to be (in these fuel conscious/cost cutting times there's always a chance that it won't, unfortunately), that it will have at least 675hp and likely be lighter than the current ZR1 as well.

johnglenntwo

I am speaking from known facts. My 5.7ltr 3118lb 405hp400ltq C5 z06 got 28/19MPG. If it had all this stuff on it I'm sure it would still make 450hp in a 5.3ltr displacement with better MPG, but, yes it wouldn't really have the torque under the curve of a 6.2ltr. Did you see how they handled the 6.2 liters extra torque. My cars gears(the C6 Z51),: 48(52), 68(74), 98 (108)...
This thing still wouldn't be hurting for power like a 4 banger!

johnglenntwo

[QUOTE=GrampZ;1581055826]From Jason, in the ZR1 Forum, 7-15-11:

"If I was a betting man I would put money on a 700hp C7 ZR1 or equivalent in 2015-2016. I'm just speculating though."

Hmmm! GM is working hard on efficiency and with all the stuff we are talking about they are going turbo in their V6:

Although you wouldn’t get instantaneous acceleration as the V8 engine, but with a lighter weight and more fuel efficient V6 engine, the twin-turbo V6 Camaro is more nimble and easier on the wallet at the pump.

http://carguideblog.com/25128/chevro...-lenos-garage/

With the good cam phazing and direct injection(low end torque) wouldn't they be better off with a midrange power adder and a more normal 1st gear? If they really want to make people excited they will turbo the small block too. 700HP, but, maybe not a SC ZR1!