JerryU

^^

Hmm, thinking the LT was much more, I condensed a two page description of the differences to these:·

Oil-Spray Piston Cooling: Oil-spray piston cooling, in which eight oil-spraying jets in the engine block drench the underside of each piston and the surrounding cylinder wall with an extra layer of cooling, friction-reducing oil. ·
Rotating assembly and windage tray: The “bowl” and shape of the top of the piston head is designed to promote thorough mixing of the air and fuel …The crankshaft in the Gen V small block is located with new nodular main bearing caps – over more conventional grey iron main and are stronger and can better absorb vibrations and other harmonics to help produce smoother, quieter performance. A redesigned windage tray is also used with the Gen V engine, which features a new oil scraper design. This enhances performance and efficiency by improving oil flow control and bay-to-bay crankcase breathing. The cylinder block an main bearing caps maintain the optimal cranksase “windows” that were perfected on the Gen IV engine.·
PCV-Integrated Rocker Covers: One of the most distinctive features of the Gen V family is its domed rocker covers, which house a patent-pending, integrated positive crankcase ventilation (PCV) system that enhances oil economy and oil life, while reducing oil consumption and contributing to low emissions.– about three times the oil/air separation capability of previous engines.·
Dual-Equal Cam Phasing: All Gen V engines feature dual-equal camshaft phasing (variable valve timing), ·
Cylinder Head Design: (in addition to what you said was a bit the11.5:1 compression ratio it has) . Large, lightweight intake and exhaust valves … hollow intake and hollow sodium exhaust valves ( sodium cooled exhaust was only on LS6.) The lightweight valves enable the engine to rev quickly and capably to greater than 6,000 rpm. …stiffer, larger-diameter pushrods 8.7mm that provide greater stiffness than the previous 7.9mm design. ·
Direct Injection: Direct injection allows the mixture to be leaner (less fuel and more air), so less fuel is required to produce the equivalent horsepower of a conventional, port injection fuel system. ·
Active Fuel Management: Active Fuel Management temporarily deactivates four of the cylinders and seamlessly reactivates them when the driver demands full power. ·
Exhaust Manifolds: The LT1 engine uses a similar yet cast version of the “four-into-one” short-header exhaust manifold design used on the Gen IV LS7 engine. The cast header passages enable consistent exhaust flow into the “wide mouth” collector at the converter.·
Cooling System: The Gen V’s cooling system is redesigned, compared to the Gen IV engine .·
58X Ignition System: the Gen V has an advanced 58X crankshaft position encoder to ensure that ignition timing is accurate throughout its operating range.

NOT SURE ABOUT THE EXTENT OF THE DELAY OF THE C8 AND EXTENSION OF THE C7
I saw my first C7 in Mid January 2013. Although I put a small amount down to hold my C7 a short time later the prices and part numbers did not come out until May as I recall when I placed my order, I was #9 at Hendreick in Cary and my car was not built until September 2013, not long after Rick Hendrick got his firsrt built (for wheich he paid $1,100,000!)

Athough the "Introduction of the C8 is delayed," I expect vendors have already redcued parts for the C7 close to what had been planned. Same with producing most parts for the C8. The first C8 production may not be delayed from what was planned as much as the delayed "Introduction.".

We'll See!

PS: Not planning to buy my C8 like I did my 2014 Z51 C7. If Lutz is right and it will have an LT1 engine (which it did not sound like that in the cars in Germany) I'll wait for a version of the Blackwing double overhead cam, twin turbo! My 2017 Grand Sport is just fine until that is available but don't believe it will be years away- may be there day 1!

84 4+3

That oiling system was one of my complaints. It self drains and causes dry starts...

mountie55

Oh, I agree.... the current Corvette Racing has been awesome!!! ( How many Corvette TV commercials have you seen, compared to the Lexus LC 500 )

skank

I remember reading a few articles on the new LT1 engine on the C7 Corvette. Jordan Lee made a comment at that time that the new LT1 was vastly different than the previous generation LS series engines. In fact, very few carryover parts between the two generations of engines. The video below is excellent in describing the differences between the two being discussed by GM Powertrain engineer John Rydzewski. Also two interesting articles on the LT4 and LT5 engines. The new LT2 will upstage the LT1 further. Can't wait to read about the new advancements of the LT2 over the LT1 as the new base engine. It is unimagineable that Bob Lutz was not on top of the differences between the two which is huge.


https://www.enginelabs.com/news/lt4-...wer-is-coming/

https://www.hotrod.com/articles/grit...t5-powerhouse/

Telepierre

Good stuff.
Adding more numbers just for historical perspective and using the past to try to predict the future... experts correct/edit as needed..

C7: First sightings (google search) Oct 2011 (C7 on C6 GS shell) – Official launch Jan 2013: 14 months gap..
C6 run: June 2004–February 28, 2013 = 116 Months (last year production/sales 13000)

ME: First sightings (google search) Jan 2015 – Official launch: ? 48 months gap and counting..
C7 run: September 2013–July 2017 (due to temporary shutdown of plant) November 2017–present = 60 months (current rate of 20K cars/yr)

With the ME in the baking for quite a while (see above) could it be its launch is really C7 sales dependent and is Chevrolet really killing a C7 at historical mid run?

JerryU

Not true! There is enough oil left in the system that it is available for the engine oil pump at the start. Just that much of what is in Dry Sump Tank is in the pan after it sits. BUT it quickly is pumped into the dry sump tank before any aggressive maneuvers where it might be needed.

PS: Loved the Doug Nash 4 speed with electrically controlled overdrive in 2nd, 3rd, and 4th in my first Vette- a 1988! It was my 2nd 7 speed! My first, which I sold when I bought the Vette, was a Dodge Colt Turbo I had put plus 1 Pirelli P7s, suspension upgrades etc! It had a twin stick 4 speed and two sped overdrive that could be activated in all gears. Would have been an 8 speed but two ratio's were identical! It was similar to my twin stick CJ5 but that was only a 3 speed. However in the time of gas shortage when we could only buy gas every other day. my CJ5 with V8, headers etc could not go from Danbury CT where I worked to LaGuardia and back on one tank of gas! Many a day I stayed out of town IF my scheduled day to return was one where I could not buy gas! Bought the Colt!

Since every DD I have owned for 60 years has been a standard shift was no choice but the Doug Nash "7 speed." In '88 it was the same cost as an automatic! Occasionally would use all 7 speeds by pushing the button on top of the shift **** to engage/disengage overdrive. But most times just pressed the button after 4th.

JerryU

Excellent video! Note he mentions the variable cam timing can vary up to 62 degrees! MUCH more than the offset cam keys used to adjust for more torque or more power at higher rpm! That is one reason the 535 hp wet sump LT1 crate motor can't "just be used" in a production car! The increased cam lift and duration would cause the valves to hit the pistons so it DOESN"T have variable cam timing! Also that engine does NOT have much more torque that a standard LT1!

They use a common old hot rod techique to get more hp at higher rpm at the expense of low end torque. They did not go as far as a race engine cam that gets even more very high rpm power but is a very poor performer off the line. No fun driving on the street!

jefnvk

Eh, I was talking more a luxury prestige aspect than a race results aspect.

I can make a handbag that is functionally and aesthetically better than a Gucci or Louis Vutton, and sell it for a fraction of the price, but people that buy those bags aren't going to buy it. Why? They are buying because of brand cache. Others, who can't afford those bags, might well flock to it, but I'd never really be competing with the luxury brands. That is what the Corvette is, and always has been. Ferrari, Lambo, McLaren, etc are very much luxury brands, purchased for the same reasons that people buy Gucci bags and Cartier watches. THAT is the aspect that nothing with a Chevy badge will ever be able to replicate. It is not a diss on the brand, it is simply a reality of the situation. Maybe you'll peel a few folks away who actually are buying on a pure performance scale when you are beating the other cars on the track, maybe you'll pick up some who really want one of those cars but only can afford Corvette money, but you aren't picking up their sales in any appreciable number, or competing in their market segment. Even the Ford GT falls into that same category as the Corvette, they are selling because of scarcity. Ferrari can crank out 10k quarter million dollar plus cars a year and know every one will sell and they will still have a waitlist, If the GT tried that it would fall flat on its face.

Shaka

Thanks man. I trust that vid will appear on your 'list'? That vari cam idea has been in the works for some time now. There was also a 2 came in block prototype. This is American engineering at it's best. This is the GM we grew up with. Corvette making America great again.

RapidC84B

As a 4X C5 owner and current C7 owner who has built a couple LS motors, I have to chime in that the LT1 is very different than the LS motor. It's the "same" in that it's a OHV V8, but many things are revised/improved as mentioned above. Also, the intake/exhaust ports are flipped. The LS1/2/3/6/7 could share many parts. Nothing shares on the LT series from the LS.

Telepierre

I would agree brand has it's weight but I would also submit that the automotive world is highly competitive and name alone and exclusivity it's not enough.
Ferrari former CEO Montezemolo got fired for the infamous 7000 max (closed numbers) Ferraris a year and now they sell more cheaper cars (see Portofino).
In short they are diluting their luxury brand to keep Walt Street happy and Ferrari's clientele has noticed too and it's not as pretty as it seems..

Corvette has gotten good at the "wait list game" too... There is a wait list for the ZR1.

84 4+3

This is on the full sized trucks but the tsb states the scream in the pump is it starting dry. That's why the lifters tick until the whine goes away... the dry sump isn't as big of an issue in that respect. Hasn't blown yet but sounds like a bad powersteering pump pretty much everytime you start it.

Telepierre

I stand corrected then.

jefnvk

Exclusivity alone? Nah. I'll point back to the GT for that, even the folks that wound up with one seemed to be more high profile car folks, not the truly wealthy that are buying up the half million dollar exotics as a matter of habit. There will always be a small segment that cares about performance and would defect to Corvette over it, but far more overwhelming of a concern is that brand name, the prestige with telling people you own a Ferrari, a Lamborghini, etc. if you are trying to compete in that market.

And no, even with a wait list, the ZR1 is not an exclusive or exotic car.

Foosh

I've not heard there is a ZR1 wait list per se, but, of course, there are customers still waiting for their orders to be built. They're working them into the manufacturing schedule with all the other models, and there are more orders for those.

Telepierre

I suppose I was commenting on the marketing use of "waiting lists" to portray false exclusivity. I actually digged into this marketing practice in some detail when the GT2RS was announced in June 2017: production set at 1000 units already sold out!!.. to find out it was all made up by autobild without any porsche direct source. Fast forward June 2018 to renn list and PFF forums and they are still at about 600ish scheduling batch builds..which externally looks like over demand but which in reality is simply delayed manufacturing on orders.
Same thing for Ferraris, especially the portofinos.. I can buy one tomorrow if I like and the fact I get it in 6/8 months is not because of a "waiting list" but because of slow manufacturing.

So basically I see the waiting for a ZR1 the same as waiting for a Portofino. The semantics around it is just exlusivity marketing(again see Montezemolo and the 7000 max fiasco...).

Bob Paris

We have a winner! Well thought out & explained - the point about the C7 at only 6 model years old and too new to abandon is right-on

Foosh

Exactly, when I ordered a 2018 C7 convertible Z51 in Sebring Orange (SO) in late October 17, I had to wait until mid-January 18 for it to be built because they didn't start painting SO in batches until then. So, I guess I was on a "waiting list" for what most would consider to be far from an exclusive car.

However as a funny aside, it turns out to be very exclusive. Only 2 SO Stingray convertibles were built in 2018, and mine is a 1 of 1. It is the only manual and only Z51 convertible built that year in SO.

They do build and paint in batches. When my car was delivered to Criswell, every single C7 on the completely full truck was SO.

jefnvk

Interesting, never realized that. Seems to me that there would have been a way to do a more on-demand painting in 2019, but always intriguing to learn more about the industry processes!

Foosh

As I understand it, they batch paint a few different colors at the same time, but not all colors. I think it's more efficient that way, because it involves less cleaning of the spray equipment required when changing colors. Pictures of the assembly line with cars lined up usually only show a few colors at a time.

There was a huge omission not considered in the rationale you're praising. Building fewer of each drives up the price of parts for 2 different platforms, thus the overall cost for both FE and ME models. There's a limited market for 2 seaters, and building fewer of each blows up economy of scale in volume production.

A low volume ME would dramatically extend the time it would take for GM to recoup it's considerable development costs, if ever, and declare a profit unless the ME is only sold at high-end Porsche and Ferrari prices, which isn't likely. This needs to be a mass-produced car at C6 and C7 numbers to be profitable.