: V3 Engine



JFJr
08-19-12, 02:02 PM
I know a lot of us have speculated about the next generation CTS-V engine. Anyone have good intelligence on the C7 engines? That could provide clues as to what we might expect. I hope it will still be a V-8.

Jud

RippyPartsDept
08-19-12, 02:24 PM
i heard one of the other forum members mention that it would still be the LSA (maybe modified from current setup) but the new alpha platform will also bring a lot of weight loss so not much hp gain coupled with less weight will bring some significant gains in performance

larry arizona
08-19-12, 03:48 PM
The C7 will be a NA 5.5L probably in the 430 to 460HP range. The LSA will likely stay as is in the V3 and LS9 in the ZR1 ans LS7 in the Z06. Not likely that GM will be doing the investment in a new FI engine.

Jinx
08-19-12, 04:28 PM
The 5.5L figure gets repeated often, but this may be nothing more than Internet echoes of the 5.5L displacement limit in the ALMS race engine. Story goes "C6R will be first to use the new GenV block, and C6R is 5.5L, therefore..." But when C6R first entered its new class it used a modified LS7 reduced to 5.5L; and regardless, the production cars don't have to use the same displacement...

But if you believe that C7 and trucks want to be modest in their power increase and be as efficient as possible, a reduced displacement makes sense in concert with the introduction of direct injection. If direct injection gets you 15% more power, a 6.2L GenV would hit 495hp; reduce displacement to 5.5L and you're looking at 440hp. If rumors of more sophisticated valve timing also bear fruit, you could have a 5.5L engine of 450-460hp. Some Corvette fans are "OMG GT500 we need moar or epic fail!" but considering CAFE and where everything besides the lunatic-fringe ponycars sit in the $70K space today, a 3100lb 450hp C7 could be competitive.

But really we don't know.

So what about CTS-V? I really don't see any carryover engines across generational lines. Look to history; once Corvette gets a new-generation V8, it soon after shows up everywhere else. In 98 the F-bodies got LS1; in V1, LS6 was replaced by LS2. I expect LSA to die with the current CTS-V and ZL1 and LS9 to die with 2013's ZR1. Why not just carry over these small-volume engines? Because they use large-volume parts that won't be large-volume anymore; because they're old, and part of the appeal of cars like ZR1 and CTS-V is that they're latest and greatest; and because fuel efficiency could be much better and that matters even on beasts like these.

Rumors have it that the next ZR1 engine will be turbocharged instead of supercharged. I believe the desire for efficiency will win out and they'll figure out how to package the twin-turbo plumbing under C7's hood. And I bet the next CTS-V gets a version of that engine, probably one with more mainstream internals and less boost, much like LSA compared to LS9. Maybe smaller turbos that spin up faster, or maybe ZR1 gets dual-scroll turbos and CTS-V doesn't.

Of course this is 99% speculation.

A news blurb went out a little while back about GenV truck engine production starting; there was a photo of that engine, and it had funny-looking valve covers....

JFJr
08-19-12, 07:45 PM
The 5.5L figure gets repeated often, but this may be nothing more than Internet echoes of the 5.5L displacement limit in the ALMS race engine. Story goes "C6R will be first to use the new GenV block, and C6R is 5.5L, therefore..." But when C6R first entered its new class it used a modified LS7 reduced to 5.5L; and regardless, the production cars don't have to use the same displacement...

But if you believe that C7 and trucks want to be modest in their power increase and be as efficient as possible, a reduced displacement makes sense in concert with the introduction of direct injection. If direct injection gets you 15% more power, a 6.2L GenV would hit 495hp; reduce displacement to 5.5L and you're looking at 440hp. If rumors of more sophisticated valve timing also bear fruit, you could have a 5.5L engine of 450-460hp. Some Corvette fans are "OMG GT500 we need moar or epic fail!" but considering CAFE and where everything besides the lunatic-fringe ponycars sit in the $70K space today, a 3100lb 450hp C7 could be competitive.

But really we don't know.

So what about CTS-V? I really don't see any carryover engines across generational lines. Look to history; once Corvette gets a new-generation V8, it soon after shows up everywhere else. In 98 the F-bodies got LS1; in V1, LS6 was replaced by LS2. I expect LSA to die with the current CTS-V and ZL1 and LS9 to die with 2013's ZR1. Why not just carry over these small-volume engines? Because they use large-volume parts that won't be large-volume anymore; because they're old, and part of the appeal of cars like ZR1 and CTS-V is that they're latest and greatest; and because fuel efficiency could be much better and that matters even on beasts like these.

Rumors have it that the next ZR1 engine will be turbocharged instead of supercharged. I believe the desire for efficiency will win out and they'll figure out how to package the twin-turbo plumbing under C7's hood. And I bet the next CTS-V gets a version of that engine, probably one with more mainstream internals and less boost, much like LSA compared to LS9. Maybe smaller turbos that spin up faster, or maybe ZR1 gets dual-scroll turbos and CTS-V doesn't.

Of course this is 99% speculation.

A news blurb went out a little while back about GenV truck engine production starting; there was a photo of that engine, and it had funny-looking valve covers....Great thoughts. Certainly, an engine that takes high rpm's to develop a lot of torque is not the answer for the American market. So some sort of reduced displacement, but blown, is probably in the cards. Would turbo charging be preferable to supercharging to best a turbo-charged M5? And I agree that weight reduction is important, but this is a luxury car designed for a particular price point, and given the expectations for more and more luxury features, is that realistic? I guess that the ultimate goal is to compete on a $ - by - $ basis, and Cadillac has closed the gap. Who would have thought that Cadillac would be poised to accept the challenge. It's all good!

Jud

Jinx
08-19-12, 10:24 PM
For the base C7 engine, I don't think they'll reduce displacement beyond the ability of the new tech to compensate, i.e. the power curve won't be lower than LS3 at any point. I expect similar from V3's forced-induction variant relative to LSA. GM isn't going to rev higher for the same power; that's not efficient.

And maybe they won't reduce displacement at all.

And I think we all expect the next CTS to be lighter by at least 300 pounds. The current CTS platform is solid but heavy and somewhat costly; Alpha is supposed to be cheaper and lighter. And I doubt that the luxury features CTS lacks and needs will add a lot more weight. Well, I guess the back seat has to grow a skosh...