ZR1 BOMBSHELL PROOF!!! TT 5.5L LT7 it is!!!
10-30-2023, 04:07 PM
#21
Pro
I also am of the opinion that they keep the FPC V8, as at certain points in the latest 'ring video, when coasting or engine braking (and out of boost), the sonic signature is very similar to that of the Z06, but muffled. I listened with my hi-fi headphones. I also recognize that I could be listening for what would amount to my confirmation bias, and I could be very wrong.
I'm also thinking that since Chevy showed they could play in the same FPC league as the exotics used to, albeit with more power, that they want to "beat them at their own turbo game" with the ZR1. Since both McLaren and Ferrari (and AMG on the GT-R Black Series) use Turbo-charged FPC V8 engines, I think Chevy wants to do the same but show power output superiority.
I'm also thinking that since Chevy showed they could play in the same FPC league as the exotics used to, albeit with more power, that they want to "beat them at their own turbo game" with the ZR1. Since both McLaren and Ferrari (and AMG on the GT-R Black Series) use Turbo-charged FPC V8 engines, I think Chevy wants to do the same but show power output superiority.
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10-30-2023, 06:00 PM
#24
Melting Slicks
Thread Starter
I am not aware the CPC makes any more torque than FPC with the same compression and cams etc. if anything it will make slightly less. Torque is typically driven by VE, BMEP and displacement. CPC has a few less points of VE due to adjacent cylinder timing.
As I recall from the North American Engine plan leaked in 2017 target horsepower at the time was 850 hp, 720 lb/ft of torque.
As I recall from the North American Engine plan leaked in 2017 target horsepower at the time was 850 hp, 720 lb/ft of torque.
10-30-2023, 08:27 PM
#25
Le Mans Master
Can't believe what's sitting before us in the GM Parts catalog!!! Interesting to note:
Corvette model designations in the parts catalog
YC = Stringray
YG = E-ray
YH = Z06
YR = ZR1
An obvious oversight by GM to start populating the 2024 Parts Catalog with about a dozen or so LT7 parts so get your screenshots of this before CF is asked to take this down!!! Here is one of those parts, an air inlet adapater...
And OBVIOUSLY just as I reported this weekend, the LT7 will UNFORTUNATELY have AFM (cylinder deacativation). Also note, just as I have suspected, the ZR1 DCT is unque to the TT motor, designated M1K, not M1L like the LT6 DCT due to increased torque capability and likely different gear ratios! Well 6.2L YouTubers...how does that Crow taste now...bwaaahahaha!!!
Corvette model designations in the parts catalog
YC = Stringray
YG = E-ray
YH = Z06
YR = ZR1
An obvious oversight by GM to start populating the 2024 Parts Catalog with about a dozen or so LT7 parts so get your screenshots of this before CF is asked to take this down!!! Here is one of those parts, an air inlet adapater...
And OBVIOUSLY just as I reported this weekend, the LT7 will UNFORTUNATELY have AFM (cylinder deacativation). Also note, just as I have suspected, the ZR1 DCT is unque to the TT motor, designated M1K, not M1L like the LT6 DCT due to increased torque capability and likely different gear ratios! Well 6.2L YouTubers...how does that Crow taste now...bwaaahahaha!!!
In the attachment description it shows SC TURBO. What does the SC stand for?
10-30-2023, 09:00 PM
#26
Melting Slicks
Thread Starter
you're welcome! SC is for Super Charger....for whatever reason, in the Parts Catalog and ECM Calibrations GM doesn't distinguish between "Forced Induction" Turbocharger or Super Charger....they refer simply to SC/Turbo
10-30-2023, 09:31 PM
#27
Instructor
I hope so…. A concern I had with a bespoke engine is parts availability down the road. Although it sounds like the ZR1 will have different pistons, compression, etc I’m sure there will be commonality with many parts ensuring a reasonable supply of parts down the road.
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10-31-2023, 10:10 AM
#28
Nice find... really curious what this ends up being. Seeing all this talk of AFM makes me wonder why? And how it will be executed on a DOHC engine with no lifters.
10-31-2023, 10:12 AM
#29
10-31-2023, 10:16 AM
#30
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10-31-2023, 10:24 AM
#32
Race Director
10-31-2023, 10:25 AM
#33
10-31-2023, 10:35 AM
#34
Melting Slicks
And since it was indicated as having AFM and not DFM this engine could function as a 4 cylinder like the LT2 Stingray engine. DFM (GM's latest fuel management tech) could possibly function as a 2 cylinder but would have further engine vibration risks. And then we still have the potential of the BWI Magneto Rheological Engine Mounts which I always thought would be on the LT6 engine but didn't. It makes sense to have them now. BWI Group launched their latest adaptive engine mount technology a few years ago and has recently partnered up with Boston, Massachusetts based ClearMotion Active Suspension Systems.The only tech left that we haven't discussed but could advance this ZR1 or later ZORA would be rear wheel steering by ZF. I would imagine BWI has looked at this for Corvette since Porsche has used this tech on their GT 911's.
https://www.bwigroup.com/news/bwi-gr...sion-business/
The Gen 2 Magneto-Rheological (MR) Powertrain Mounts also enable the use of CO 2 -reduction strategies such as engine downsizing, cylinder deactivation and stop-start, all of which can introduce NVH challenges for conventional, passive powertrain mounts.
More on DFM from GM on their current truck and SUV engines. There could be some tech transfer to a newer advanced AFM system that would be derived from their DFM tech described below. The possibility of a newer advanced AFM system on this 850 plus HP engine would certainly help in their EPA fuel numbers.
Dynamic Fuel Management is powered by a sophisticated controller that continuously monitors every movement of the vehicle’s accelerator pedal and runs a complex sequence of calculations to determine how many cylinders are required to meet the driver’s requested torque. The Dynamic Fuel Management computer can make this determination 80 times per second.
An electromechanical system deactivates and reactivates all 16 of the engine’s hydraulic valve lifters, controlling valve actuation. The system uses solenoids to deliver oil pressure to control ports in the lifters, which activate and deactivate the lifters’ latching mechanisms.
When a cylinder is deactivated, the two-piece lifters effectively collapse on themselves to prevent them from opening the valves. When the cylinder is reactivated, solenoids send an oil pressure signal to the control ports on the lifters and the latching mechanism restores normal function, allowing the valves to open and close.
This industry-first cylinder deactivation technology enables the engines to operate in 17 different cylinder patterns to optimize power delivery and efficiency.
“The increased variability of Dynamic Fuel Management means the engine will operate more often with a reduced number of cylinders, which saves fuel across the board,” said Jordan Lee, chief engineer of GM Small Block engines. “Better yet, the transitions are transparent, and because the system is torque-based, you’ve always got that satisfying feeling of power on demand that comes from GM’s Gen V Small Block V-8 engines.”
https://www.bwigroup.com/news/bwi-gr...sion-business/
The Gen 2 Magneto-Rheological (MR) Powertrain Mounts also enable the use of CO 2 -reduction strategies such as engine downsizing, cylinder deactivation and stop-start, all of which can introduce NVH challenges for conventional, passive powertrain mounts.
More on DFM from GM on their current truck and SUV engines. There could be some tech transfer to a newer advanced AFM system that would be derived from their DFM tech described below. The possibility of a newer advanced AFM system on this 850 plus HP engine would certainly help in their EPA fuel numbers.
Dynamic Fuel Management is powered by a sophisticated controller that continuously monitors every movement of the vehicle’s accelerator pedal and runs a complex sequence of calculations to determine how many cylinders are required to meet the driver’s requested torque. The Dynamic Fuel Management computer can make this determination 80 times per second.
An electromechanical system deactivates and reactivates all 16 of the engine’s hydraulic valve lifters, controlling valve actuation. The system uses solenoids to deliver oil pressure to control ports in the lifters, which activate and deactivate the lifters’ latching mechanisms.
When a cylinder is deactivated, the two-piece lifters effectively collapse on themselves to prevent them from opening the valves. When the cylinder is reactivated, solenoids send an oil pressure signal to the control ports on the lifters and the latching mechanism restores normal function, allowing the valves to open and close.
This industry-first cylinder deactivation technology enables the engines to operate in 17 different cylinder patterns to optimize power delivery and efficiency.
“The increased variability of Dynamic Fuel Management means the engine will operate more often with a reduced number of cylinders, which saves fuel across the board,” said Jordan Lee, chief engineer of GM Small Block engines. “Better yet, the transitions are transparent, and because the system is torque-based, you’ve always got that satisfying feeling of power on demand that comes from GM’s Gen V Small Block V-8 engines.”
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10-31-2023, 10:56 AM
#35
Race Director
Or its a cpc with dohc heads and afm lifters. KISS in this situation.
How is the fpc going to cut half the cylinders off and not vibrate to death? It has a tremendous amount of nvh as it is.
I just don't see it working out (durability or acceptance by customer wise).
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LE MANSZ (10-31-2023)
10-31-2023, 11:07 AM
#36
If it's DOHC it won't have lifters regardless of CPC v. FPC. Every ring video seems to lean toward a muted FPC sound w/ lower peak RPMs.
10-31-2023, 11:49 AM
#37
Drifting
SC Turbos ?!?!
SC Turbos ?!?!
https://www.garrettmotion.com/turboc...argers/sc-vnt/
Split Compression VNT (SC-VNT) Turbo
https://www.garrettmotion.com/turboc...argers/sc-vnt/
10-31-2023, 11:50 AM
#38
Pro
What if the head had "shoes"? 
What if the "shoes" added zero reciprocating weight?
What if all 8 cylinders had "shoes" and the computer could shut down any cylinder or numbers of random cylinders at a time to keep heat more even in the engine?
What if the "shoes" added zero reciprocating weight?
What if all 8 cylinders had "shoes" and the computer could shut down any cylinder or numbers of random cylinders at a time to keep heat more even in the engine?
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10-31-2023, 12:27 PM
#39
Drifting
That would be Dynamic Skip Fire, I'm surprised they haven't adapted it to the Vette yet. It also solves a number of vibration issues by spreading the vibration power away from one frequency and around the rpm spectrum. But we'll see. Shoes are a great concept if they can implement.
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10-31-2023, 12:57 PM
#40
Safety Car
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