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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!!!
Well, it sucks that it's going to have AFM. There's going to be enough complexity with this rig to potentially put a dent in reliability, and GM's track record with AFM reliability is pretty shitty.
Great find. Many of us believed it will be a cpc dohc engine. As they always said that the LT6 will be unique to the Z06 i took that to mean no fpc in other variants. But the displacement with dohc no need to go larger displacement given the power they can reach with the dohc setup.
Was about to ask if anything in that description confirms FPC vs CPC, I take it the answer is no?
Yeah nothing in the screenshot confirms FPC or CPC, but just knowing FPC motors like to vibrate, I can't imagine having an FPC V8 run on 4 cylinders will make that issue any easier to deal with vs CPC.
Well, it sucks that it's going to have AFM. There's going to be enough complexity with this rig to potentially put a dent in reliability, and GM's track record with AFM reliability is pretty shitty.
Hopefully it'll be a decent set-up on the LT7.
Is it not possible that "AFM" in this engine design is more about variable control and reduction of FI, and not cylinder management like it is in the OHV engines? I don't know if it's possible as an "AFM" to reduce Turbo FI to little/no boost...but regardless of whether or not it is FPC or CPC, a 5.5L V8 can do just fine, power-wise and without FI, to power the car while cruising.
Feel free to poke holes in my thoughts here - I'm just operating under the premise that I do not definitively know what the "AFM" technology actually is in this LT7 application.
Is it not possible that "AFM" in this engine design is more about variable control and reduction of FI, and not cylinder management like it is in the OHV engines? I don't know if it's possible as an "AFM" to reduce Turbo FI to little/no boost...but regardless of whether or not it is FPC or CPC, a 5.5L V8 can do just fine, power-wise and without FI, to power the car while cruising.
Feel free to poke holes in my thoughts here - I'm just operating under the premise that I do not definitively know what the "AFM" technology actually is in this LT7 application.
the other forum is reporting that a birdie indicated AFM in the parts catalog for the LT7 description is a mistake. I could see that being possible given the part description for the carbon flash aero package has the word “visible” in it when that is not accurate.
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.
the other forum is reporting that a birdie indicated AFM in the parts catalog for the LT7 description is a mistake. I could see that being possible given the part description for the carbon flash aero package has the word “visible” in it when that is not accurate.
This would be a good thing!!! We certainly don't need AFM on the Zentih of C8's!!!
The above screenshot release was clearly just a "readily available public information" release, I have no "insider" info but my opimion is that the LT6 was designed around the FPC...therefore, the LT7 by extension is an FPC Motor and because a 5.5L FPC motor with say, 20 PSI of boost (which the LMA 4.2L TT Caddy did) at 8500 RPM would likely make 1200+ HP or more is WAY beyond the spec intended for the RWD ZR1! How can I make such an outrageous suppostion? Simple, just look at the McLaren Senna 4.0L TT FPC motor, 789 hp at 7,250 rpm and 590 lb⋅ft of torque at 5,500 rpm with a FPC, there is NO NEED for 8500RPM in the LT7, I'm thinking it will redline at ~6500/7000 RPM range..
Clearly EVERYONE can agree that the camo ZR1 at the 'Ring NEVER sounded like it was "screaming" at 8500 RPM! Given it's 5.5L size, I think GM created more of a TT Torque Monster to come "barreling" out of the corners and left the high RPM singing to the NA LT6.
Oooops, I think sombody got called into the boss's office lol, time for DAMAGE CONTROL...the first top screenshot was an hour ago, bottom pic is just now!!! Sorry....
Oooops, I think sombody got called into the boss's office lol, time for DAMAGE CONTROL...the first top screenshot was an hour ago, bottom pic is just now!!! Sorry....
Try part number 12728437. GM has those in stock, and any dealer can order it currently.
-Greg
The above screenshot release was clearly just a "readily available public information" release, I have no "insider" info but my opimion is that the LT6 was designed around the FPC...therefore, the LT7 by extension is an FPC Motor and because a 5.5L FPC motor with say, 20 PSI of boost (which the LMA 4.2L TT Caddy did) at 8500 RPM would likely make 1200+ HP or more is WAY beyond the spec intended for the RWD ZR1! How can I make such an outrageous suppostion? Simple, just look at the McLaren Senna 4.0L TT FPC motor, 789 hp at 7,250 rpm and 590 lb⋅ft of torque at 5,500 rpm with a FPC, there is NO NEED for 8500RPM in the LT7, I'm thinking it will redline at ~6500/7000 RPM range..
Clearly EVERYONE can agree that the camo ZR1 at the 'Ring NEVER sounded like it was "screaming" at 8500 RPM! Given it's 5.5L size, I think GM created more of a TT Torque Monster to come "barreling" out of the corners and left the high RPM singing to the NA LT6.
Think about it, if GM used a CPC in the 5.5L motor AND TT, the motor would have too much power AND torque any ANY RPM!
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.
10-30-2023, 11:39 AM
ZR1 BOMBSHELL PROOF!!! TT 5.5L LT7 it is!!!
