I’m going to get flamed on this, but I really feel this has to be one the lamest things that Ford have come up with in sometime. Why in the world would you choose a displacement 4.4L in a V8 format? What is the bore and stroke going to be, little and a little less? This is a recipe for a motor that has to be spun up to make any torque. Could they not go with V6 or dare I say an I6?
Most likely they did this so they could engineer one engine in the 6.7L and then scale it down to the 4.4L. A V6 would have been a better design in my mind, but that involves a complete redesign of V angle and engine balancing. Also, probably not enough room in the engine compartment for an I6.
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2003 F250 FX4 Sport, 6.0L Diesel, TorqShift Auto
- 4" Donahoe Racing springs, Bilstein shocks, 35" tires
- Off Road Tech winch bumper, powdercoated white
- SCT Xcal2 with Spartan tunes (ASE)
most people would pry think an I4 sounds too weak for a truck yet it would pull more than a big v8 gasser,and if they made an I6 it would last too long and be much better than the v8
[quote=cartmanea;6488123]Most likely they did this so they could engineer one engine in the 6.7L and then scale it down to the 4.4L. A V6 would have been a better design in my mind, but that involves a complete redesign of V angle and engine balancing. Also, probably not enough room in the engine compartment for an I6.[/quote
I thought this motor was based off of or is the Range Rover design. If so, we could already know what the 6.7 is going to look like. What do you think?
I know we are talking about diesels here, but here is my take on MPG/Torque/HP.
For all of my discussion, I am going to assume the engines are going geared to be useful.
A high torque engine, my example, FE 410 cu/in, in a 1966 F250 PU, four speed, 4.10 rear axle. This engine I would classify as having high torque, for its HP. Driving along a flat freeway, in fourth gear, I need a small part of the over 440 FT/LBS of torque that is available. The engine is throttled down, the manifold vacuum is high. Even with a camper, and a four horse trailer. Reasonable MPG for moving that much crap. Here comes the 6% grade, uphill. To get the extra torque required to move the weight up the hill, move the right foot down. The speed is maintained the same as it was on the flat, and the truck was not downshifted, so the additional HP comes from the additional torque the engine is producing. This truck was capable of a real world 14 MPG empty, at legal speeds. The power reserve was in the throttling back of the engine.
A low torque engine, my example, 1970 Datsun PU with a 97 cu/in OHC, 4.375 rear axle ratio, and much smaller overall diameter tires than the Ford F-250 above. Driving down the freeway, pulling a trailer. Fourth gear, throttle opened up quite a bit, but still not floored. Here comes the 6% upgrade. Throttle goes down to the floor, still not enough to hold speed, a downshift is required. Maybe even two downshifts. Now I have a very high rpm. The torque, multiplied by the reduction gear ratio allows the relativly high HP engine (for its displacempnt) to move the heavy load up the hill. The power reserve was in the rpm of the motor, and required a down shift to get it, rather than just opening the throttle.
Here is where fuel economy comes into the equation. The 410 v8 has a lot of stuff inside the engine to move around. A lot of rings sliding on cylinder walls, 16 valves with 16 heavy lifters, pushrods, and rocker arms to move.
The Datsun 1600 has a lot less stuff to move around, and does not have to move it as far. (shorter stroke)
If you double the speed of anything, it requires four times the amount of power to maintain that speed. You cannot fight, or deny physics.
If you double the speed of an engine, (RPM) you will increase the parasitic losses in that engine by a factor of at least four.
Obviously, the Datsun got better fuel mileage than the Ford did. I was also giving up a lot of HP/Torque. However, I do remember one trip I made with an empty two horse trailer, down the Columbia gorge, when a lot of wind was trying to get up the Columbia gorge, and I had to run the Datsun in second gear, WOT, 5000 RPM, about 36 miles per hour. 11 miles per gallon.
You can also gain a little more MPG, if you are able to run the transmission in a one to one ratio.
So, to sum up. You want an engine that is capable of producing a reserve of torque as the speeds you use it at. This enables you to just open the throttle, or inject more fuel into it to get additional HP when you need it. An engine with a high torque will enable you to do this. A high HP engine might require you to run it at a higher rpm range, to gear it down to be able to multiply the limited torque tourque have from the engine, to do what you want it to do.
So, it does require a lot thought and design to be able to get high mpg, and HP and Torque.
Getting back to physics. The best way to increase the fuel economy on a vehicle on the freeway is to slow down.
Yes, I did pull a two horse trailer with a 1971 Datsun pickup. Mid 1970's, when they were restricting gas sales, using the odd/even system. The trailer did have brakes.
The Datsun PU would hold about 35 miles per hour, with a two horse trailer, and two horses, climbing a six percent grade. I did pass quite a few semis, climbing hills. I also used a 1966 Ford PU with a 428/c6 engine combo, and later my own 1966 with the 410/four speed.
Oddly enough, the Datsun was more reliable than the Fords, towing the trailer. It made more trips without breaking down.
This is the point I was trying to make. A big high torque motor is nice for towing a heavy load. But it is not necessary. How big would an engine need to be to move a semi? So, Ford has decided to make a small displacement probably high RPM diesel.
The new engine will probably pretty fuel efficient in a "consumer" type truck. Sufficient power to move the truck around when it is empty, and when it is loaded down, an ability to be run at higher RPM, and run in lower gears to move a heavier load. You will have to burn more fuel to run the engine at a higher RPM, when it needed to move the heavy load. The advantage is that you are not always having to supply fuel to a large displacement engine, when you only need the large engine for moving a heavy load occasionally.
If you are using the truck for heavy duty hauling on a daily basis, this engine is probably not a good one for you.
I'm a mechanical engineer, and the hp/torque debate is often what causes me to write essays on forums about, explaining to some folks that "torque is what drives you up hills" is a false statement. Your explanation is pretty much bang-on.
At any vehicle speed, your total available driving force, at the wheels, is solely a function of the available hp. Torque is what MAKES hp. Torque is simply a unit force in the angular coordinate. Torque must be coupled with rpm (velocity) to be meaningful.
A 600 hp engine is a 600 hp engine. Whether that engine makes 100 lb-ft of torque or 2500, is irrelavent, provided that you're in an ideal world, with perfect gearing (think perfect CVT). The only benefit of having a high torque engine, such as Cummins ISX, is the ability to make that same 600 hp in an efficient manner. As you mentioned. If you put a 600 hp IRL racecar engine in to the semi, it'll move 80,000 lbs just as fast, just as well, except you're looking at 0.5 mpg and 500 mile rebuild intervals.
Whether or not this new "consumer V8" would use more or less fuel, I personally believe it's hard to say. Yes, you are forced to turn higher rpms, but a smaller displacement engine has, presumably, better thermal efficiency. The smaller bore/stroke also creates less surface area, so while the pistons are moving faster, there's less surface area to create oil shear drag. So I think in the end, the efficiency might not be much different than the large engine, unless you're at WOT and max rpm.
RoyJ, I am not an mechanical engineer, just someone with a little real world experience. Thanks for the validation. I know enough to know that we are not going to know how this engine is going to perform, until is is actually available.
Having driven trucks on both ends of the HP torque equation, I have a few real world experiences on what happens in real life.
I also have ran both the Datsun PU, and the Ford F250 with a 428/C6 on a chassis dyno. The Datsun put out 40 HP at the rear wheels, in fourth gear, about 3600 RPM, holding a speed of 55 MPH. The HP went up to 55, if I remember correctly by shifting down to third gear.
The 428 F-250 put out 140 HP at the rear wheels, at a speed of 55 MPH, engine rpm around 2500.
You may think "what was wrong with the 428?" the short answer was nothing. It just was not running where it was at an advantage in the production of HP.
It was suggested to me when I was young to tow a horse trailer with a Datsun Pickup my a gentelman named Norman Williams. He founded Williams Air Controls here in Portland Oregon. He was your classic stereotype of an inventor, I am pretty sure he was a mechanical engineer, amoung other things.
When I was a teenager, I made a comment around him about a wankle engine developing torque at a higher RPM than a reciprocating engine, and he challenged me, "you do not even know what torque is" I tried to explain my concept of torque to him, and he came to the conclusion that I did have a rudimentary understand what torque was, but he sure did elaborate, and taught me a lot more.
Back to the 4.4 L diesel engine. This could end up being a very good engine for a "consumer" truck. I do not know how it is where you live, but a lot of full sized trucks are being used as commuter vehicles, here in Portland, OR, and run empty most of their time they are used. I see this engine as a possibly very good sized engine to run in a mostly empty truck, at more or less normal engine speeds, and when the truck is loaded down, the ability to be run at higher rpm ranges to develop more horsepower only when it is needed.
This will not end up being a good engine if you want to jack up your truck, to fit the largest sized big lug off road tires you can find. This will not be a good engine if you think you should be able to accellerate from 70 to 85 mph on a six percent grade, with a 30 foot gooseneck RV trailer.
Hmm... well you all sound enthused about this new 4.4L. Where can I see a glimpse of this contraption? This is going to be sweet. But dudes I seen the coolest thing ever the other day, it was a 1986 Ford F250, with a '97 Ford Powerstroke diesel in it. I was going to do the exact same thing with my 96 F150 put an 01 powerstroke in it. That would be kick ass.
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2002 Ford Taurus SES DOHC Duratec 3.0L V6 (200hp)
1996 Ford F-150 XL 5.0, 302, M5R1 5sp, 4x4, 31's, leveling kit on front end.
1988 Ford Mustang LX 5.0 Hatchback, ported E7's, electric fan, 3.55's, smog pump delete. 14.9QM@98mph (Black)
