Welcome to the world of "MODULAR" designs my friends!

The flexibility and variety that can be offered from this platform is pretty wide open.


Why do you say that?
Just because the bores in the Mod motors are close together doesn't mean you can't add deck height and stroke that puppy!

Seriously, the V10's we have all heard about (both 427 and 351 versions) are derived from the basic modular design behind the everyday 4.6 . These all share common architecture.

There is a similar - yet slightly different - architecture for the truck engines. They are typically designed to allow longer intake runners and longer strokes - both of which yield better torque (good for trucks pulling and hauling). Even though the intakes/exhausts, and some supporting components are different, the basic architecture and even much of the actual tooling are still common between all corporate modular engines.

Not in this thread, but I'm trying to find out more about Coletti getting over 400hp from an N/A 4.6 modular!

 

or a BOSS 400 cu. in. (if they are willing to give it some stroke)
if that every happened, i swear......

 

I don't consider differences in intake runner lengths an architecture difference in an engine. That is more of a packaging change.

Same reason its called the LS1 in a car and a Vortec 5.7 in a truck...exact same block, different intakes and other components.

The modular motors (really a misnomer since there's no more interchangeability than in any other mass produced U.S. V8 in the last 60 yrs) are already huge physically and weight wise. You're going to add deck height to it? I guess in a truck there'd be room to package it but I think you're hitting the limit already with the mod motor squeezed into passenger cars.

Gm's stuff is modular too. you have multiple displacements of the GenIII V8 all with most internals totally interchangeable, and the trailblazer inline 6 sharing some parts too.

 

A similar displacement V10 will actually get worse MPG than a comparable V8 due to the greater internal friction. The extra pair of cylinder would be beneficial in terms of increased valve area, but only in a high performance application.

 

Making a vehicle underpowed doesn't neccessarily save fuel.

Try $3/gal on for size.

 

Not true. The smaller bores are usually more efficient and require less octane since the flame front has less distance to travel. That is, assuming the valves are adequate (unlike a Chevy 305 which suffers from too little valve area vs. bore). And the smaller bores, because they are more efficient, will run cleaner with lower emissions gasses.

Those benefits outweigh the increased friction from an extra set of rings, mains, rod bearing and cam lobes/valvesprings. Besides, with smaller valves & bores than you'd need in an equal displacement V8 you need less spring rate and less ring tension.

I used to see it the same way you do but I read an article a while back that revealed the advantages of more cylinders given the same displacement.

 

Isnt the modular already pretty extreme in terms of being undersquare as a 5.4?

 

The mod motors are at the end of the line. They are maxed out at 5.4 deck height. The stroke on the 5.4 is longer than a 460ci big block! Remember the mod motor was supposed to be a 4.6 FWD V8. That meant unusually short length with tightly spaced bores with NO room to grow.

So how do you bore out a mod V8? You add 2 cylinders. The 5.8L V10 is a physically smaller motor than the 5.4L V8! And it's a good contender to be the top Mustang's powerplant.

This new 6.2 motor is Ford's RETURN to RWD application V8s. It's probably not based off the Jag V8s because I'd bet those were designed too tight on the bore spacing also. I say it's SOHC 3V VCT with big bores on short stroke. The ULTIMATE design.

 

wha? only one cam in a mustang? never!

 

Actually, a V10 has more valves, pushrods, and piston/ring surface area, all of which add reciprocating mass and friction. The problem with larger bores is getting consistent combustion across the cylinder. If you can do that, then the V8 will be more efficient.

GM and Chrysler don't seem to have too much problem with a 4" bore (Chrysler uses dual spark plugs to ensure consistent combustion with their nearly hemispherical cylinder head). With a 4" bore and a 4" stroke, you have 6.6 liters of displacement. So Ford should be able to make a 6.2 liter V8 more efficient than an equivalent V10. If they continue with a V10, I'd expect it to start from the 6.2 V8 (a 7.7l V10).

 

Gee, I didn't know that

Actually, all that is true but the greater efficiencies of a larger valve area to bore ratio overcome all that. If the valves are smaller and lighter you don't need as much valve spring do you? And if the displacement is equal then the rotating mass will not be that much greater.

Otherwise what's the point in making anything but giant 4 cyls other than "smoothness"?

 

Power.

That's different from efficiency (also different from torque, but that's another discussion).

The large valve to bore area is useful for getting lots of air in the cylinder, which helps you make power. However, the extra friction is bad for efficiency. As long as you can get a complete burn, fewer cylinders should always be more efficient than more cylinders. Getting a complete burn in a .75l cylinder seems not to be a problem. If it were, GM would not be building a 6l V8.

Notice that newer 6 cylinder engine designs are almost all greater than 3 liters, and there are several around 4l.

Now maybe GM, Ford, and Chrysler, and Nissan all don't know what they're doing building V8 engines around 6 liters. But I suspect that they do, and that for a 6.2l truck engine, you really want just 8 cylinders.

 

boss 372 has a nice ring to it...(assuming thats the number)