http://www.enginelabs.com/engine-tec...n-small-block/

 

That's a nice article summing up what we (think we) know along with the more plausible rumors! If it is a dupe, I hadn't seen it yet, thanks for posting!

 

Interesting - Thanks for posting!

However, I wasn't aware there was a "1967 fuel injected 327"..... Guess that must have been even rarer than the L88........

 

Thanks Runge. I always look forward to reading your informative posts.

 

Great posting. Thank you !

 

Good stuff! Oh, the speculation...

 

Great stuff Runge!

 

Runge: Thank you for finding this and posting the link.

Even though it contained no new Gen V engine "inside info", I suspect that most of us who are more curious about the C7 engine than the C7 tail lights found it very interesting. I for one agree with most of the predictions and %-probability estimates; I assume that these apply to some Gen V engine applications but not necessarily the C7 Gen V engine.

A few observations, questions, and nits:

1. I'm disappointed that Magda didn't speculate about the holes in the exhaust manifold. Are they just test engine probe ports which won't be on production engines (as suggested in other articles and noted in another CF thread), ports for O2 sensors for individual cylinder A/F control (my wild speculation in another CF thread), or something else?

2. I'm guessing that Magda's 90% eAssist and/or start-stop (his wording is a little confusing here) prediction applies to Gen V applications other than Corvette. I'm confident that neither technology would be popular with Corvette buyers.

3. He says AFM (cylinder deactivation) is a "sure bet." What is his % prediction that the C7 Gen V engine will have this?

4. My read is that he is predicting two C7 engine displacements : 5.3 L & 6.2 L. But I'm confused by his 4.3 L (possibly V6) prediction; is he predicting this for Corvette? How do others read this?

5. "...the engine can run leaner mixtures to help fuel economy...". I think Magda might be off base here because my understanding is that 3-way catalysts require a very narrow A/F (or "Lamda") range to operate, I'm confident that all Gen V engines will rely on 3-way catalysts for exhaust emission control, and so any sort of "lean-burn" operation is out of the question. I'm open to corrections and other opinions on this.

6. What is "a radiator shutter for fuel economy" (which is mentioned in the same sentence as the Corvette turbocharger or supercharger possibility)? Somebody please 'splain me.

 

The radiator shutter is an aero device. GM is already using them on their eco line of cars. It's a shutter that closes when cooling air is not needed across the radiator, so that the air hitting the front of the car, flows around the car instead of into the engine compartment. Reduces the car's drag.

 

I had to chuckle when I read the prediction of a 3V engine during a mid-cycle refresh.

The LS3 was appreciated, but it wasn't as significant as a whole new valvetrain design. The LT1 was a big deal, but that didn't come until the eighth model year, right? We don't really want an eighth year C7 much less an eighth year mid-cycle refresh.

But what about seeing a 3V design on a Z06?

.Jinx

 

@235265283

Received your email and thought I would reply for all your friends to read.

1- I don't know the purpose of the exhaust manifold holes. As mentioned, I believe the engine in the photo bears little similarity to the finished product, either for the C7 or the truck line. It's either a ruse designed to get rumors started, or it's a test mule full of data-gathering equipment. Two years ago I interviewed a GM engineer charged with engine-noise reduction, and they were having all kinds of fits controlling DI noise. The valve-cover bulges could be some type of data gathering tool. But my point is: that engine is not close to the final product, and speculating on every feature would likely fulfill some clever PR person's intentions to generate wild rumors.

2 - Unlikely eAssist or other types of mild hybrid technologies will go into the Vette because of battery-pack weight and packaging issues. The trucks need it more.

3 - AFM is a sure bet for the Gen V family but maybe not on all applications. Again, the trucks need it more but all of GM is still being pressured to meet CAFE. If the engineers can get it to work in a performance application, don't be surprised to see in the C7. I was driving down a lonely country road in the late '90s with then chief engineer Dave Hill. He was rather perturbed about having to run DRLs in the C5 because it lowered the overall mpg by 0.1 mpg, or some very small fraction. He charged that the lights made the alternator work that much harder, which became that much more of a parasite to the engine. The engineers are under incredible pressure to improve fuel economy, whether the customer gives a damn or not.

4 - Again, the story is about the entire Gen V lineup. Unlikely the Vette will ever see a V6 unless it's twin turbo or twin charged, which is a distinct possibility in the future. There is a definite trend toward downsizing because you can get real serious with power adders while still reducing gas consumption with smaller displacements. However, I believe there will be a V6 based off the Gen V architecture for the Camaro and truck lines.

5 - An inherent benefit benefit of DI is running leaner mixtures because the spray has a cooling effect in the combustion chamber. I don't know of any specific warranty problems regarding the cats in other GM vehicles with the SIDI engines, but if there are adjustments to be made down pipe with V8 applications, I'm sure the engineers will have that covered.

6 - I've heard of testing a radiator shutter on the C7. That doesn't mean it'll make the final cut but it's one of the tools the engineers can use to adjust the power/fuel economy balance.

@Jinx
If powertrain can make a business case for the 3-valve, then it could come out next year. The technology is probably already where the engineers want it, but there are still issues with parts sourcing, warranty durability, assembly costs, etc. And in the current economic climate at GM, I don't see it happening right away. But 3V would make a great story down the road. Of course, I can always be wrong and we'll see it next month!

 

For any readers of this thread for whom it isn't obvious: "Racemag" is in fact the author of of the excellent (IMHO) OP-linked article.

And, Racemag, thanks for your detailed and informative post responding to mine. I assume a professional automotive journalist wouldn't be making pro bono posts to a forum like this unless he/she really loved the subject matter.

 

I do have a question - if you can Racemag. (Great article BTW)

I understood that cylinder deactivation was a possibility for the LS3 but there were driveline harmonics issues with the rear mounted transmission on the Corvette.

I've got AFM on my 07 Yukon and it's seamless on the 5.3. Have they worked the bugs out for the Corvette?

 

It is sort of a 'dupe' as I'd posted the original article that this one references back in July (and I wasn't even the very first one to do it) ...but it's still worth seeing again.


http://forums.corvetteforum.com/c7-g...-block-v8.html

 

If C7 is a hybrid front/bottom breather like C6, radiator shutters would make a lot of sense. It could help highway mileage quite a bit whenever the weather isn't too hot, couldn't it?

 

Thanks for the info - very interesting read.

 

I wonder two things about the shutters -

1. What will they do to the aftermarket intake world?

2. if you put tinfoil on the inside, will they bounce speed radar to the sky like the old backslanted radiator on the C3s?

 

The majority (70%)of the current C6's are not a hybrid front/bottom breather. The GS, the 427 Convertible, the Z06 and the ZR1 are front ONLY breathers. Maybe Ox can tell us what the C7 will be. Shutters installed behind the grille would help with the car's aerodynamics at speed.

 

Air for the current C6 air breather does not come from behind the radiator. That would kill performance as the IAT would be at the same temp as the coolant. There is a shroud between the radiator/A/C condenser and the air breather.

The radiator in the C5 and the C6 are backslanted just like on the C3's. Hasn't stopped anyone from getting a speeding ticket yet.

 

GM released information in their restructuring plans that indicated HCCI was about to surface, projected for 2015. The sensor bungs in the manifolds may be the biggest indicator that HCCI may make its debut on the Gen V. The autoignition process of HCCI is highly temperature dependent and the monitoring of the combustion health of individual cylinders may be necessary.