C8.R packs in flat-plane V8
08-12-2018, 04:25 AM
#21
Another thing about these high revving overhead cam motors is that they don't have the low RPM torque Corvette owners are used to. In the Shelby, really need get well into the 3 grand RPM range before "wake up time." Glorious exhaust notes, fun at the higher RPMs, but something small block Corvette owners are not used to, and frankly, much more suited to track than street.
I'm not a big fan of having to feather the throttle to avoid throwing the damn thing in a ditch...
Also, IMHO 5.2 liters just too big for the FPC, massive vibrations issues that Ford had to deal with besides the other problems...
Last edited by sunsalem; 08-12-2018 at 04:25 AM.
08-12-2018, 08:45 AM
#23
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As the guy said in the MT vid, his comment was seemed to be nothing below 3500 rpm and then hold on. That would remind me of some ancient street turbos (not the more modern ones, of course). Still, if Chev can solve the lifespan and low end torque/power, it would be a winner.
I dont believe the base model model will have the FPC.
08-12-2018, 09:05 AM
#24
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This LS7 Passat sounds like nothing else with just custom headers. You would never know its an LS with the hood closed.
https://youtu.be/Qq8zEJHWT7g
Take time to listen to this. Just the new ME exhaust configuration can change a lot of things.
I have one off 180 degree headers on my C7Z and it’s intoxicating exotic. It’s like a big displacement FPC car.
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08-12-2018, 10:26 AM
#26
Burning Brakes
The 6.2L Gen V LT V8 powertrain for the base mid-engine Corvette model.
The right set of headers can make a Subaru sound like an LSX, a 2JZ sound like a Coyote, or an LT1 sound like a Ferrari 430. The headers on the LT1/LT2 powered mid-engine Corvette are certainly unique in the LS/LT family, and they may be able to make the engine sound very different than the C7’s LT1. Using similar headers on a smoother, higher-revving, lower-displacement DOHC V8 could make the setup sound like a FPC engine. I have very little knowledge in exhaust system design, so I could be wrong, but I agree with others who say that the headers (and, potentially, the rest of the exhaust system) are making the C8.R’s CPC V8 sound like a FPC V8.
There’s no way that they would make FPC DOHC V8s just for use in the mid-engine Corvette and the rest of the Corvette lineup(if a front-engine C8 will be built at all). The Corvette has to share some V8’s with the Camaro, and it seems that Cadillac will be using their own V8’s starting in 2020. There’s no way that they would put FPC engines in the Camaro, and there’s absolutely no possibility of GM making engines specifically for the Camaro. Performance cars are losing more and more market share each year, and GM doesn’t want to spend more money on them than they need to.
Last edited by Quinten33; 08-12-2018 at 10:27 AM.
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08-12-2018, 11:21 AM
#27
Le Mans Master
If they are building a FPC engine, it will have to be low displacement. As Ford found out, in order to quell the inherent vibration of a large displacement FPC engine, you have to add a lot of balancing weight to the crank. They ended up adding so much balance weight that the rotational inertia ended being about the same as a cross-plane crank engine. What's the point of all this? To say you have a flat crank engine? It still ended up not being very smooth, and they had to add even more mass to engine parts so they wouldn't shake apart.
I don't get the fascination with flat plane crank engines. They are inherently flawed.
I don't get the fascination with flat plane crank engines. They are inherently flawed.
Last edited by Michael A; 08-12-2018 at 11:23 AM.
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08-12-2018, 12:58 PM
#28
If they are building a FPC engine, it will have to be low displacement. As Ford found out, in order to quell the inherent vibration of a large displacement FPC engine, you have to add a lot of balancing weight to the crank. They ended up adding so much balance weight that the rotational inertia ended being about the same as a cross-plane crank engine. What's the point of all this? To say you have a flat crank engine? It still ended up not being very smooth, and they had to add even more mass to engine parts so they wouldn't shake apart.
I don't get the fascination with flat plane crank engines. They are inherently flawed.
I don't get the fascination with flat plane crank engines. They are inherently flawed.
08-12-2018, 03:21 PM
#29
Burning Brakes
More $$$$
08-12-2018, 03:56 PM
#30
Burning Brakes
According to a spreadsheet put together by one of the members of a forum called Mustang6G, he has logged nearly 60 reports of blown FPC motors - data drawn from probably less than 1000 owners on a couple of different Mustang forums and FB. According to some of them, Ford says the engine replacement cost (just cost of the engine, not labor) is about $30,000. Ford refuses to let any of their dealerships look inside the motor, it must be shipped back to Ford intact. I am sure if GM does a FPC it will have considerable smaller displacement than 5.2 liters. And if they want torque down low, it will need a turbo or a supercharger.
08-12-2018, 08:20 PM
#31
Race Director
Thermal managment advances on GMs four cylinder 2-7liter will make its way to the corvettes v8..
it ll be amazing...
the entire tri power advance is impressive if possibly a little far reaching with its name..
flat plan cranks tend to be under 4liters in displacement due to harmonic imbalance difficulties..
cadillacs 4.2could become 3.9 liters with a flat plan crank...
that i could believe.
5.5 liters could be a difficult challenge
fords gt350 has had some vibration challenges over time i believe.
it ll be amazing...
the entire tri power advance is impressive if possibly a little far reaching with its name..
flat plan cranks tend to be under 4liters in displacement due to harmonic imbalance difficulties..
cadillacs 4.2could become 3.9 liters with a flat plan crank...
that i could believe.
5.5 liters could be a difficult challenge
fords gt350 has had some vibration challenges over time i believe.
08-13-2018, 06:43 AM
#32
Burning Brakes
Thermal managment advances on GMs four cylinder 2-7liter will make its way to the corvettes v8..
it ll be amazing...
the entire tri power advance is impressive if possibly a little far reaching with its name..
flat plan cranks tend to be under 4liters in displacement due to harmonic imbalance difficulties..
cadillacs 4.2could become 3.9 liters with a flat plan crank...
that i could believe.
5.5 liters could be a difficult challenge
fords gt350 has had some vibration challenges over time i believe.
it ll be amazing...
the entire tri power advance is impressive if possibly a little far reaching with its name..
flat plan cranks tend to be under 4liters in displacement due to harmonic imbalance difficulties..
cadillacs 4.2could become 3.9 liters with a flat plan crank...
that i could believe.
5.5 liters could be a difficult challenge
fords gt350 has had some vibration challenges over time i believe.
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08-13-2018, 07:01 AM
#33
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St. Jude Donor '15
"In honor of jpee"
Adding to your point, only two modern FPC V8’s have exceeded 4 liters of displacement. One is obviously the 5.2L Voodoo V8 in the GT350, and the other is a 4.6L V8 in the Porsche 918. According to ZERV, who the forum tends to trust, GM is making a 5.4L V8 and a 4.6L V8 for the C8, and one displacement is likely to have a naturally aspirated variant alongside its turbocharged setup. Unless GM plans on making an engine with the Bore:Stroke ratio of a Ducati Panigale, There’s no way that they’re making a 4.6L or 5.4L FPC V8.
08-13-2018, 07:29 AM
#34
As much I wanna believe it not being a FPC V8. I have not come-up with better reasoning for the engine to sound like that.
1. It is definitely not V6 as the difference between V6 and V8 is clearly audible. That sound is definitely not sounding like V6. It is a V8.
2. Exhaust alone cannot make the CPC V8 sound that smooth. There should be multiple elements causing the engine sound that smooth. If that is true that it is CPC V8 but is sounding smooth like FPC I would like to know how.
3. If firing order is changed it still will be odd-firing engine which will not give you this smooth sound output. That cannot be the cause.
1. It is definitely not V6 as the difference between V6 and V8 is clearly audible. That sound is definitely not sounding like V6. It is a V8.
2. Exhaust alone cannot make the CPC V8 sound that smooth. There should be multiple elements causing the engine sound that smooth. If that is true that it is CPC V8 but is sounding smooth like FPC I would like to know how.
3. If firing order is changed it still will be odd-firing engine which will not give you this smooth sound output. That cannot be the cause.
08-13-2018, 07:32 AM
#35
Race Director
Turbo 4engines makes sense with todays power density.
where did the idea that the new dohc twin turbo corvette engine would be both a flat plan crank and greater than 4liters come from?
the cadillac engine is 4.2 liters with a hot vee design...
gm has stated its a cadillac only engine.
reducing the displacement slightly and putting in a flat plane crank does make some sense....
of course the ability and low cost to share that engine with the pickup truck lineup would seem to fall by the wayside..
id rather have a simplier design thats shared with silverados..
the cost savings is huge to consumers..
im happy with a five hundred hp lt1derivative dct rear mid engine z51c8 starting in the mid sixties
where did the idea that the new dohc twin turbo corvette engine would be both a flat plan crank and greater than 4liters come from?
the cadillac engine is 4.2 liters with a hot vee design...
gm has stated its a cadillac only engine.
reducing the displacement slightly and putting in a flat plane crank does make some sense....
of course the ability and low cost to share that engine with the pickup truck lineup would seem to fall by the wayside..
id rather have a simplier design thats shared with silverados..
the cost savings is huge to consumers..
im happy with a five hundred hp lt1derivative dct rear mid engine z51c8 starting in the mid sixties
08-13-2018, 09:13 AM
#36
Le Mans Master
Originally Posted by AORoads
As the guy said in the MT vid, his comment was seemed to be nothing below 3500 rpm and then hold on. That would remind me of some ancient street turbos (not the more modern ones, of course). Still, if Chev can solve the lifespan and low end torque/power, it would be a winner.
08-13-2018, 10:22 AM
#37
Burning Brakes
If GM stays with a sub 4L flat plane, the fears of "omg, not enough grunt," are overblown. With the obligatory set of turbos, Ferrari has shown you can have a small displacement V8 putz around town at 1500 rpm, and yet still mash the gas and move out with authority. Your not left wanting for more torque even at 2K rpm in that car. Squirting around in traffic is never an issue even in 7th.
Like you, I dont got an addiction to needing 500 ft lbs off idle to have it peter out by 4K. I'd much prefer 90% of torque from 1500 to 7000 or something of the like.
Like you, I dont got an addiction to needing 500 ft lbs off idle to have it peter out by 4K. I'd much prefer 90% of torque from 1500 to 7000 or something of the like.
08-13-2018, 10:26 AM
#38
Instructor
I had three GT350s (long story) but the first one did not have any excessive oil usage while the other two required about a quart between the 5000 mile oil change intervals. What did concern me was the rate of bone stock engines grenading. I do miss the 8250 redline and sweet exchaust note though...
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08-13-2018, 12:10 PM
#39
As much I wanna believe it not being a FPC V8. I have not come-up with better reasoning for the engine to sound like that.
1. It is definitely not V6 as the difference between V6 and V8 is clearly audible. That sound is definitely not sounding like V6. It is a V8.
2. Exhaust alone cannot make the CPC V8 sound that smooth. There should be multiple elements causing the engine sound that smooth. If that is true that it is CPC V8 but is sounding smooth like FPC I would like to know how.
3. If firing order is changed it still will be odd-firing engine which will not give you this smooth sound output. That cannot be the cause.
1. It is definitely not V6 as the difference between V6 and V8 is clearly audible. That sound is definitely not sounding like V6. It is a V8.
2. Exhaust alone cannot make the CPC V8 sound that smooth. There should be multiple elements causing the engine sound that smooth. If that is true that it is CPC V8 but is sounding smooth like FPC I would like to know how.
3. If firing order is changed it still will be odd-firing engine which will not give you this smooth sound output. That cannot be the cause.
08-13-2018, 01:03 PM
#40
Instructor
I find it very telling that Ford decided to go back to CPC for the 5.2L Supercharged V8 in the new GT500. Even they didn't have confidence in the 5.2L FPC to continue use in forced induction applications. Making the GT350 a potential true collectible down the road as Ford's only FPC offering.
Last edited by likeaboss; 08-13-2018 at 01:45 PM.