5.2 FPC - Devil's Advocate

[Trackaholic]

I would agree that the weight of individual components can affect engine performance, i.e. connecting rods, pistons, cam shafts, and anything else that moves, but overall engine weight shouldn't be a factor in engine performance.

It's not a factor in performance, but it is a metric useful in determining how effective the engine design is, especially when looking at different types of engines (rotary compared to OHC compared to OHV for example).

Looking at something like hp/liter makes no sense when comparing those types of engines, because the displacement means different things. However, overall engine weight and packaging size means the same to all engines, and therefore are good ways to rate their effectiveness.

Imagine you are designing a car, and had to pick an engine. You primary considerations are going to be:
1. Will it fit
2. How will it affect my weight distribution
3. What will it feel like to drive
4. How efficient is it
5. How much power does it make

Not necessarily in that order.

You can see that displacement is really only a concern in how it affects those other metrics, and when looking at engines of different architectures, it is not a very good proxy for any of them.

-T

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[DHG1078]

It's not a factor in performance, but it is a metric useful in determining how effective the engine design is, especially when looking at different types of engines (rotary compared to OHC compared to OHV for example).

Looking at something like hp/liter makes no sense when comparing those types of engines, because the displacement means different things. However, overall engine weight and packaging size means the same to all engines, and therefore are good ways to rate their effectiveness.

Imagine you are designing a car, and had to pick an engine. You primary considerations are going to be:
1. Will it fit
2. How will it affect my weight distribution
3. What will it feel like to drive
4. How efficient is it
5. How much power does it make

Not necessarily in that order.

You can see that displacement is really only a concern in how it affects those other metrics, and when looking at engines of different architectures, it is not a very good proxy for any of them.

-T

I understand all of that, but what erne75 said was

There is only one metric that truly matters when it comes to engine performance: Power generated for a given engine weight.

If that was the case, we wouldn't have our big OHC engines we have in our mustangs, trucks, and other cars. OHC engines are more efficient than OHV engines in a lot of ways, but they are bigger and more costly than OHV engines just by nature of the design.

 

[Potrillo]

:doh:
The voodoo won't be affordable... and is limited. That is why the car it is in, is limited.


Ford just made a FPC Coyote bro... it's called Voodoo.

I should have been more specific, a FPC 5.0. I think the 5.2 for me is enough that the Voodoo is a different motor. It is obviously different enough for Ford to give it a special code name.

 

[DHG1078]

I should have been more specific, a FPC 5.0. I think the 5.2 for me is enough that the Voodoo is a different motor. It is obviously different enough for Ford to give it a special code name.

The only thing that's going to make a FPC 5.0 cheaper than a FPC 5.2 based off the coyote is that the 5.0 won't require PTWA coatings to get the extra displacement, which I hear isn't cheap. The 5.0 would still need completely redesigned to make it a FPC. Just like the 5.2 doesn't have any common parts to the 5.0, a FPC 5.0 likely won't share many, if any parts with the current 5.0. I suspect it would still be far to expensive to be in a GT which is supposed to be affordable. (Pure speculation on my part but I don't think i'm far from the mark)

Also, in the interviews they said it was much harder to meet emissions regulations with the FPC. That alone is probably enough to make sure it never ends up in a mass produced GT with ever tightening CAFE requirements.

 

[Wblv17]

I should have been more specific, a FPC 5.0. I think the 5.2 for me is enough that the Voodoo is a different motor. It is obviously different enough for Ford to give it a special code name.

all new ford motors have a nick name, some are just cooler then others.

and Voodoo fits perfect for the 5.2, Ford engineers are just cooler:ford:

 

[w3rkn]

I should have been more specific, a FPC 5.0. I think the 5.2 for me is enough that the Voodoo is a different motor. It is obviously different enough for Ford to give it a special code name.

When u take an engine and make it a FPC, you have to redesign the whole thing, because it requires different engineering. The 5.2 is a Coyote, that has been made into a FPC.


That is what I guess you don't understand.

 

[Potrillo]

When u take an engine and make it a FPC, you have to redesign the whole thing, because it requires different engineering. The 5.2 is a Coyote, that has been made into a FPC.


That is what I guess you don't understand.

I did get it. I said I want a 5.0 Voodoo. Perhaps that is what you don't understand.

 

[w3rkn]

I did get it. I said I want a 5.0 Voodoo. Perhaps that is what you don't understand.

Are you trying to imply the .2 liters difference in your argument, does what..?


Ford did exactly what you are asking, but added slighter larger diameter pistons, for greater breathing and TQ. Because converting over to a FPC, you tend to lose it. As the GT 5.0 will have more tq than the GT350.. so piston size determines burn and engine response, some alteration were needed to make it work.

What would a 5.0 FPC do for you, that a 5.2 will not..?



Sounds to me like you are waffling. Myself, I would like to see a 4.2 liter FPC w/FI.

 

[Falc'man]

The LS7 is (IMO) GM's best engine. Better than the LSA, LT4, or the TT-V6.
I feel the same way about the Voodoo.

Both use state of the art technology within the limits of their architectures to achieve excellent performance.

Both will probably be similarly fuel efficient.

Both will put similar torque to the wheels after drivetrain gearing is taken into account (due to making similar power). Although it is possible the Voodoo may make much more than the 500 initially disclosed, due to the RPM and peak torque numbers. Torque would have to drop drastically to make only slightly above 500 HP @ 8000 RPM.

Both will probably have similar weight.

The main difference will be in how they feel. The Voodoo will rev higher and more freely due to the lower inertia. The LS7 will have more low-end punch.

Hopefully the Voodoo ends up with less issues than the LS7 has had (thinking of the valve guide issues).

-T

All good points.

Speaking of VE @ peak power, if it is the same as S550's 5.0's VE at peak power then hello 535hp.

I'm a closet fan of LS7.

 

[Grimace427]

...but added slighter larger diameter pistons, for greater breathing and TQ. Because converting over to a FPC, you tend to lose it. As the GT 5.0 will have more tq than the GT350..

Why are people saying this? XPC vs FPC doesn't affect torque output. The GT350 is rated at 400+ lbs-ft which is at least as much as the regular GT.

 

[w3rkn]

Why are people saying this? XPC vs FPC doesn't affect torque output. The GT350 is rated at 400+ lbs-ft which is at least as much as the regular GT.

It is inherent in the design, because the pistons fire at 180.

 

[osu13]

wouldn't 180 degree firing be for a boxer engine?

 

[Grimace427]

It is inherent in the design, because the pistons fire at 180.

I have found nothing to support the idea that flat-plane crank V8 engines produce less torque because of their crank design. The only reasons for a current FPC engine to produce less torque would be from their shorter strokes and smaller displacements.

wouldn't 180 degree firing be for a boxer engine?

Boxer engines(aka horizontally-opposed) orient their cylinders flat across from each other. This FPC engine in the GT350 is still a V-shape.

 

[Potrillo]

Are you trying to imply the .2 liters difference in your argument, does what..?


Ford did exactly what you are asking, but added slighter larger diameter pistons, for greater breathing and TQ. Because converting over to a FPC, you tend to lose it. As the GT 5.0 will have more tq than the GT350.. so piston size determines burn and engine response, some alteration were needed to make it work.

What would a 5.0 FPC do for you, that a 5.2 will not..?



Sounds to me like you are waffling. Myself, I would like to see a 4.2 liter FPC w/FI.

It would stay with the storied 5.0 lineage.

 

[Potrillo]

I have never in my life ever heard of anyone use that metric. That's ricer math at best. Sounds like fanboys grasping at straws. Why is engine weight so important, but the cars total weight isn't? Last I checked the mustang is lighter than the camaro with a heavier/bigger smaller displacement engine.

Um, car designers take it into account. The smaller packaging of the OHV motor is one reason Chevrolet uses it in the Corvette.

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