You know Truck Trend did a test of 2 86 Chevy trucks both 4x4 both 700R4's both shortbeds, both 3.73 gears the only difference between the two was one was a 4.3 the other was a 5.0. Both trucks got 20+ miles per gallon the 305 got 20.? and the 4.3 got 21.? mpg, these tests were done a 55mph all the time. The 305 won everything but MPG's(I wish they would have put 2 Ford trucks against each other 300I6 vs 302V8). I know people that get 20 MPG with 350 Chevy 4x4's at highway speeds. We really haven't come that far, as far as economy is concerned, sure we have a lot more HP from the factory than we did back then, but thats about it.
I know people that think it's all a conspiracy that oil tycoons don't want you to have fuel efficient gasoline and diesel engines so we don't get them because they dish out to much money to auto manufacturers to keep trucks fuel suckers. I don't know wether to belive that or not, but it could be true. I do however think there are better things out there than ethanol. I think E85 is a conspiracy, there is a grass that would make a better fuel and be cheaper than corn, but corn people want us to spend money on them, so we get screwed all over again.
I think the gasoline, and diesel engines can be taken much further than what they are now, have much more power, and be much more efficient than they ever have been. The 5.4 is a sweet truck engine it only has 300 HP but it has up to 11klb tow rating with a 5.4 liter engine. Toyota has 10klbs with a 5.7 liter engine. The reason Ford's engine is awesome because it has a 4.17 inch stroke, like a truck should be.
All the older 80's truck six cylinders were rated for 20+ highway MPGs, I don't think they really got that kind of mileage but I have heard of Fords with 300's getting 25 MPG with the manual 4 speed overdrive tranny. Here are some Highway numbers of half ton trucks from 1980: Ford 300 six 25 MPG, Chevy 250 six 24 MPG, Dodge 225 /six 20 MPG 23 MPG in 1983, Jeep J-10(4x4 only) 17 MPG in 1980 but 25 MPG in 1983. Maybe if everybody still drove 55MPH we could get 23 MPG or so. I think 4x4 Full size totally decked out trucks should get 19 MPG city and 23 or 24 HWY. The only way you can come close to this with a 4x4 pickup is to get a midsize truck, which any more are just light duty half tons, I think the Dakota will pull 8k pounds or more, and the Jap trucks will pull a little less. I say we should expect a half ton pickup to get 20 MPG easy, even when driving like a maniac. These trucks are a little heavier now than they used to be, but they are more aerodynamic as well. I don't think 30 MPG is out of reach for a 4x2 truck in this day and age.
I get mad when people say we are driving a heavy full size truck, and good gas mileage is out of our reach. Well, whatvever we should be able to get 20 MPG all day long in a heavy full size truck, it's 2007. If people got 20 MPG 20 years ago driving like little old ladies, we should get 20 MPG today driving like maniacs, and 25 MPG driving like old ladies. Don't let the auto companies off the hook on fuel efficient pickups just because they are heavy tanks, we should turn up the pressure on both sides, power and economy, a powerful engine should be an efficient engine. We should get our cake and eat it too, I mean 25 MPG is still a gas hog with prices they way they are.
the reason that engines have more horsepower now than they did is theyre cammed differently and have higher compression. wider lobe separation, longer duration, higher lift, and higher compression mean their power is higher up in the rpm range... usually their rated hp is out of the rpm range most people drive in, so they dont feel much more powerful... its all a marketing numbers game. you can get 20 mpg out of a carb 460 if you are light on the throttle and have light gears in a lighter old 2wd truck... the fuelie 460s got 15 mpg because they were heavier and had lower gears for higher rpms. my old ford fiesta would get 35 mpg in town and 45 highway and it was carbed. you dont get better than that with anything new. if its got a good mix its got a good mix... you cant get out of the laws of physics- it takes so much fuel to make so much hp, and so much hp to move something... the heavier that something is the more fuel it takes to move regardless of how the fuel is put in... if the fuel mix is stoic (14.7-1 a/f) its going to be as efficient as it can be.
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drive trane parts may strand you, but suspension parts can kill you.
if you cant pay cash for it, you cant afford it.
What do you mean you can get 20 mpg out of a 460??????????????
I know alot of people that have them, and get 7-10 mpgs.
Some could use some tuning, and drive slower/smarter, but at best possible tune and a very smart driver, I serriously don't think 15mpg is possible. 12 yes, easily, but not a whole lot more, not unless you gave the truck a serious diet.
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Matt
- Special Forces/Mud Division
79 Bronco 400 C6 NP205 D44 9" 4.56 gears Lockers 6" lift and 37" SS Iroks
77 F-100 302 C4 D44 31" M/Ts
04 F150 Lariat Screw 4x4 2"AS 32x11R17 Hankook M/Ts or 34x10.50-17 SS LTBs
if the fuel mix is stoic (14.7-1 a/f) its going to be as efficient as it can be.
True, but better ways of getting the fuel to burn these days, diesels can run well over lean of that ratio. Direct injection at TDC is a way to get around the traditional problems of fuel mixing of the piston engine, but the fuel systems are more expencive.
What no one will ever advertise, is the thermal efficiency of their engine, you know, like what home heating systems have. Our home furnace is over 90% efficient, the average gasilone engine cannot be more efficient than 30%, its just the limitation of the design.
What is funny to think about though, is that if you could use the average V8 engine to boil water from the radiator and the exhaust heat, you would get MORE than twice the power than from off the crankshaft it self.
The internal combustion engine is a relic of the industrial revolution, and no amount of bells and whistles will change that.
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1986 F250HD Ex cab Fresh built up 6.9L diesel Lariat AC leather seats power everything w/full cluster, sterling rear 3.08LS gears, E4OD trans, ram intake ATS 088 turbo
1986 F150 Ex cab Lariat rollercam 5.0L on LPG AOD trans 3.55 gears 390 000Ks
What do you mean you can get 20 mpg out of a 460??????????????
I know alot of people that have them, and get 7-10 mpgs.
Some could use some tuning, and drive slower/smarter, but at best possible tune and a very smart driver, I serriously don't think 15mpg is possible. 12 yes, easily, but not a whole lot more, not unless you gave the truck a serious diet.
take a stock body 1970's f100 2wd, with a 2.75 rear, then take a 460, rebuild it to about 9.5-1 compression, run an edelbrock 600 cfm carb, make sure you have the cam timing straight up and not retarded like the factory did from 1972-1987, use the stock cam, stock c-6 and with a light foot you can get 20 mpg highway and about 14 in town. try it it works
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drive trane parts may strand you, but suspension parts can kill you.
if you cant pay cash for it, you cant afford it.
I have a 77 with a 302, and if I baby it, I can get 20 mpgs on the hwy, but it isn't easy. There is only so much mile a big cubic inch egine can get, and I'm telling you 20 mpgs out of a 460 isn't possible.
You are right though. You will get better mileage if you bump up the compression ratio(from the stock 8.5:1), put the timing chain to 0 instead of the 4 degrees retarded like stock(which is stupid), and that 2.75 gear ratio would be good for low RPMs on the hwy, but it'd suck for acceleration(requireing more gas to get moveing, so 14 in town with that gear ratio isn't possible either), but if you put a gear venders overdrive unit behind the C6, then takeing it easy if you have about 3.00-3.50 gears and 29-31" tires then if your lucky 18 mpgs might be possible on the hwy.
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Matt
- Special Forces/Mud Division
79 Bronco 400 C6 NP205 D44 9" 4.56 gears Lockers 6" lift and 37" SS Iroks
77 F-100 302 C4 D44 31" M/Ts
04 F150 Lariat Screw 4x4 2"AS 32x11R17 Hankook M/Ts or 34x10.50-17 SS LTBs
Tom is pretty much correct that the amount of fuel required to drive a vehicle at a given speed is independent of engine displacement. There is one variable here that can make a smaller engine putting out the same power as a larger engine and get better fuel economy. This is called pumping losses. This the power an engine has to produce to pull the required air through the throttle body. I at one time thought this was not a significant amount of power, but I was wrong. When a gas engine is idling most of the power it produces is used to "pump" the air into the engine. This is the reason why diesels get so much better fuel economy at part throttle, the point where we spend most of our time.
Most of the current research that is going on for gas engines is to reduce this pumping loss without increasing emissions. Engines that have direct injection, currently Mazda has one and possibly Nissan for sale in North America. These engines are used in Europe quite a bit. They run the engine so lean that the throttle is wide open and speed is controlled as in a diesel by regulating fuel flow only.
What are the problems with this type of engine? The biggest is that very lean burns produce more NOx which are more tightly controlled in North America than in Europe. If yourun extremely lean than the NOx comes down again but igniting the mixture so that you do not get high hydrocarbon emissions becomes the problem. Particulate emissions also increase so that a gas engine may have as much particulate emissions as diesels. Currently particulate emissions are not measured on gas engines as they do not normally produce particulates.
The current research in engines seems to be merging diesel and spark ignition engine technology and in 10 to 20 years there maybe only internal combustion engines. The difference between gasoline and diesel will be of historical interest only.
Water injection is one way to bring the NOx emissions down while at the same time improving thermal efficiency, but who has time to fill up a seperate "fuel" tank?
I like the sound and feel of a V8, but the more I learn about the "rattle box" the less I want to know about it. But I will admit, I am a proponent of pure electric vehicles, and not parralel hybrids, or fuel cells (blecchh -fuel cells....).
How does $0.04 per mile sound? Or better yet, charging it off your own solar panels. Ooops, maybe I went too far.... .
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1986 F250HD Ex cab Fresh built up 6.9L diesel Lariat AC leather seats power everything w/full cluster, sterling rear 3.08LS gears, E4OD trans, ram intake ATS 088 turbo
1986 F150 Ex cab Lariat rollercam 5.0L on LPG AOD trans 3.55 gears 390 000Ks
I don't know a whole lot about anything mechanical or engineerical(I think I made that word up), but I really don't want to see an end to the "rattle box". I don't know what water injection is, I have never heard of it. I know one thing for sure, I don't want an electric only car!
I don't know if this is feasable or not but couldn't they make a internal combustion engine with like a giant electric supercharger or something. I think thats what I mean, or maybe I mean like a secondary electric engine that has tons of power on it's own so the gas or diesel engine doesn't do much work, just kind of feeding the electric motor, with a giant alternator, that way you wouldn't have to worry about plugging it in it would be just as easy as a regular car is now, just jump in and drive not worrying about plugging it in, or any other annoyance, and it will still make a rumble.
I guess to give an example of what I mean is say they put a very small diesel in the Super Duty like a 2.5 inline 4 cylinder putting out like 130 HP and 275 TQ on it's own, but it has a secondary(or primary depending on how you look at it) electric motor(or multiple motors) that put out 350 HP and 550 TQ, thats a total peak out put of 480 HP and 820 TQ not to shabby. I think I would want the diesel to just be barely above idle while cruising down the road, just giving the electric motor enough power to keep the truck going. I don't know if this is really a good idea but it sounds cool to me, as long as the electric motor isn't in the wheels or anywhere else but the engine bay or cab or something.
This would mean you could have a lawn mower, or motorcycle engine in a smaller car and have enough power to get up and go, I think that would be cool. Gasoline and diesel engines could shrink by a lot, which should also increase economy, could you imagine a V8 in a pickup truck that is the size of a 4 cylinder is now like a 2.5 or a 3.0.
Like I said this is probably just a stupid idea, and I am just talking out of my rear.
I just realized that my post above is some what describing a vehicle with an electric engine, and it's own internal combustion genorator, that also happens to put power to the wheels, yeah that sounds cool to me.
dwrestle, what you are describing is a diesel-electric hybrid, a very old idea, but a very good one just the same.
It looks like I opened a can of worms again, oh well, here goes....
There are two basic types hybrid -electric vehicles.
The most comon that you are likely to find is the parrallel hybrid, I don't like them because they do not take full advantage of the electric powertrain, but they are usually cheaper to build.
Parallel hybrids take an existing powertrain, and add a motor/generator and a small battery pack to it. The electric motor is used to "help" the vehicle accellerate and doubles as a generator while braking, so your brakes last much longer, and you can increace the fuel economy by recycling the braking energy in urban traffic.
Series hybrids are my personal favorite, because they can offer a wide range of powertrain configurations, and can run on battery power alone.
In a series hybrid, it is possible to almost eliminate the drivetrain completely, no transmission, no drive shaft(s) no Ujoints, no differentials and so on. Basicly you take an engine (rattle box) and bolt it to a generator to match its output and operating range (power curve), bolt the genset to the frame and hook it up.
Now you connect that generator to a battery pack that is in the vehicle and start charging it.
Now hook that battery pack to a controller that can manage the motors in each wheel, now you're cruising. All the hard accelleration is handled by the battery pack, while the piston engine runs consistently at its most efficient output to charge the batteries.
When the battrey is fully charged, the engine cuts out automatically, when the battery state of charge drops below a preset level, it restarts and throttles back up to its optimum range.
The advantage of the series hybrid, is that you can scale up or down any part of the powertrain, if you do a lot of long, heavy towing, you can use a bigger engine, if you just do a lot of commuting, you can get away with less than half the size of engine and scale up the battery for lower operating costs because now you can go to and from work without burning fuel.
What I should also mention here, is that the conventional drivetrain with clutches, shafts and gears is usually eating up a good 30% of the power that comes from the crankshaft, with a parallel hybrid, this problem is still there, with a series hybrid, the losses can max out at less than 10%, so more of the power is actually reaching the wheels.
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1986 F250HD Ex cab Fresh built up 6.9L diesel Lariat AC leather seats power everything w/full cluster, sterling rear 3.08LS gears, E4OD trans, ram intake ATS 088 turbo
1986 F150 Ex cab Lariat rollercam 5.0L on LPG AOD trans 3.55 gears 390 000Ks
What you are describing is Diesel-Electric. These systems are used on very large machines like trains and some the biggest off-road equipment. The advantage to them is that they avoid a transmission and the basically become a constantly variable transmission. This is the electric motor is the transmission. This allows the engine to run at very nearly constant speed so the engine stays at its "sweet spot".
For smaller systems there is the efficiency loss of converting from engine power to electric power through the generator. There are no generators that are as efficient as a good gear system.
To get that extra HP you were talking about there has to be a place to store power from the engine. This is what hybrids do. For larger higher power vehicles the electric systems have problems mostly involving the batteries. Ford and others are looking into hydraulic hybrids which to me seems to be a good way to go. Unlike the battery hybrids the system that Ford and EPA are working on is a series hybrid where there is only one drive system, the hydraulic motor. The internal combustion engine drives a pump which drives the hydraulic motor as a variable transmission. When the engine produces more energy than required to move the vehicle it pumps up a hydraulic accumulator. This is the equivalent of an electric battery.
The neat thing about this system is that it reduces the parts count. Something that electric hybrids most definitely do not.
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