Ford Godzilla on the Ike results

[kdauto]

Originally Posted by Parks

So, someone please explain why a 445cu in V8 gasser with 430/475 stuffed into a 7500# 4x4 truck would get anywhere close to 17mpg? 10 speed or not, how could one expect anything close to that? Please 'splain yourselves.

Gearing! 10 speeds, a few which are all overdrive help fuel mileage immensely. Better fuel management etc. Heck, even if a truck still looks like a brick aerodynamics have improved a lot on the past 20 years.

I'm not surprised a SRW 3500 can get 18-19 MPG unladen. I have gotten a bit over 14 MPG unladen with my dually.

[Parks]

Originally Posted by kdauto

Gearing! 10 speeds, a few which are all overdrive help fuel mileage immensely. Better fuel management etc. Heck, even if a truck still looks like a brick aerodynamics have improved a lot on the past 20 years.

I'm not surprised a SRW 3500 can get 18-19 MPG unladen. I have gotten a bit over 14 MPG unladen with my dually.

Nope! I don't buy it. If you think you are going to take a truly big block V8 motor and get 17-19 mpg just by adding a few gears to the tranny and some engine management hocus pocus your smoking something fun. With real world driving (75-80mph on the interstates) there is nothing you are going to do to any big block to get that kind of mileage, period. If you want to argue fantasy land and tell me you will get that mileage on the interstate because you only drive 62pmh while not towing then OK, but that is not real life for, well, just about zero people.

I really don't give two ***** about gas mileage on big gas trucks. I just think it's funny when people post topics about **shucks, I would have thought this massive gasser would have gotten better mpg**. I have a Ram MegaCab with the 6.4 and I could careless about the mileage I get. I didn't buy the truck for is MPG. Had I cared I would have gone the Cummins route.

[twinboat]

Folks think that RPMs burn gas, but that's not true, HP burns gas and you need the same amount to move the vehicle at any engine RPM.

Import motorcycle engines turn thousands of RPMs and get great mileage.

Big rig engines turn 1800 RPMs and get 6 MPG. That's with 18 speed transmissions.

[kdauto]

Originally Posted by Parks

Nope! I don't buy it. If you think you are going to take a truly big block V8 motor and get 17-19 mpg just by adding a few gears to the tranny and some engine management hocus pocus your smoking something fun. With real world driving (75-80mph on the interstates) there is nothing you are going to do to any big block to get that kind of mileage, period. If you want to argue fantasy land and tell me you will get that mileage on the interstate because you only drive 62pmh while not towing then OK, but that is not real life for, well, just about zero people.

I really don't give two ***** about gas mileage on big gas trucks. I just think it's funny when people post topics about **shucks, I would have thought this massive gasser would have gotten better mpg**. I have a Ram MegaCab with the 6.4 and I could careless about the mileage I get. I didn't buy the truck for is MPG. Had I cared I would have gone the Cummins route.

who was talking about 75-80 MPH speeds? I don't think many trucks will get that MPG at those speeds. I'm even curious as to how many areas allow these speeds anyway? I've crossed the USA via a few routes and only saw 75 MPH speeds in maybe 2-3 states tops. In Canada, most areas are capped at 100 km/h or 62 MPH. I attained 14.1 MPG with my dually but yeah, that was at 60 MPH or so. At 70 mileage dropped substantially.

There really is no need for the big words or insults either, we aren't in grade school, at least, I'm not.

Also, if you "could careless", it would mean you actually cared. If you couldn't care less, that would mean you didn't give a darn.

[kdauto]

Originally Posted by twinboat

Folks think that RPMs burn gas, but that's not true, HP burns gas and you need the same amount to move the vehicle at any engine RPM.

Import motorcycle engines turn thousands of RPMs and get great mileage.

Big rig engines turn 1800 RPMs and get 6 MPG. That's with 18 speed transmissions.

Comparing big rigs to motorcycles is insane. One weighs 500 lbs and the other up to 100x that with 9x as many wheels.

All things being equal as far as displacement the rig that can push it at a lower RPM without lugging will get better MPG. If you don't believe me take whatever vehicle you're driving, get it to 65 MPH and drop down a gear or two to compare fuel consumption over 100 miles or so.

[Parks]

Originally Posted by kdauto

who was talking about 75-80 MPH speeds? I don't think many trucks will get that MPG at those speeds. I'm even curious as to how many areas allow these speeds anyway? I've crossed the USA via a few routes and only saw 75 MPH speeds in maybe 2-3 states tops. In Canada, most areas are capped at 100 km/h or 62 MPH. I attained 14.1 MPG with my dually but yeah, that was at 60 MPH or so. At 70 mileage dropped substantially.

There really is no need for the big words or insults either, we aren't in grade school, at least, I'm not.

Also, if you "could careless", it would mean you actually cared. If you couldn't care less, that would mean you didn't give a darn.

Actually, there are many states that have 75mph limits on their interstates. AZ, NM, TX, UT, NV, MT, WY, ID to name a few. And just because a posted speed limit of 65 is the law it doesn't mean that is what people drive. Most drivers will drive between 4-5 MPH over the posted speed limit and still feel safe at that speed while still being close enough to legal limit to not get pulled over. So, at least in America, most drivers traveling in the mid to high 70's mph. These speeds don't accommodate 18mpg from big gas V8 motors.

I don't use big words or insults either. Maybe you just get triggered to easily. That's on you, pal.

[Itchytoe]

Engines, gas or otherwise, get their best fuel economy running at a constant RPM right at their peak torque. That might be 1250 RPM in a big diesel, or 6000 RPM in a little inline 4 sport bike. That's the RPM that will provide the most work for the least amount of fuel because that's where it is most efficient. From a mechanical standpoint, lower RPM doesn't get you better fuel economy. The change in fuel economy due to mechanical efficiency is kinda like a bell curve with the highest at peak torque. Sometimes increasing RPM will get you better efficiency.



People think lower RPM always gets better fuel economy because of aerodynamic drag. Lower speed is what actually gets you better fuel economy in a vehicle. The rate at which fuel economy drops due to aerodynamic drag is exponential, so you notice it much more the faster you go.


At low speeds, engine efficiency is the dominant curve when fuel economy is concerned. At higher speeds, where most people in the US drive, drag is the determining curve. Lowering your speed when the drag curve is dominant is why you get better MPG. It just so happens that lowering your speed makes your engine turn slower, so people think the lower engine speed is what's doing it, but it's not.


As it turns out, adding a few gears can put your engine at peak torque while at highway speeds, which will give you the best fuel economy at that speed. Engine tuning can also make a huge difference. Advancing the timing can produce a more complete burn of the fuel which will allow your engine to extract more energy per unit of fuel, which translates into better fuel economy. Heat generation and cylinder pressure is also changed when you do that, so there are other things to consider when performing "engine management hocus pocus".

[NevadaNick]

Some states have 80mph limits as well. In my work truck, 2018 Ram 2500 with service body and rack and 6.4 gas weighing a bit over 9k lbs i can average 14 mpg at best. In the 80 mph speed zones its around 12. My 2018 GMC dsl when empty on the same roads averages 20 mpg. My GMC weighs just over 8k lbs.

[kdauto]

Originally Posted by Parks

Actually, there are many states that have 75mph limits on their interstates. AZ, NM, TX, UT, NV, MT, WY, ID to name a few. And just because a posted speed limit of 65 is the law it doesn't mean that is what people drive. Most drivers will drive between 4-5 MPH over the posted speed limit and still feel safe at that speed while still being close enough to legal limit to not get pulled over. So, at least in America, most drivers traveling in the mid to high 70's mph. These speeds don't accommodate 18mpg from big gas V8 motors.

I don't use big words or insults either. Maybe you just get triggered to easily. That's on you, pal.

Canada is America too, as are other countries. Maybe we should replace this with USA?

Yeah, I've driven through the first 5 states you mentioned. I can remember the 75 MPH limit in 2 or 3 of them. I'm not making 15 MPG with my empty gasser either at that speed.

I was just referring to your "bleeped out" words, the **********, no big deal.

[tuffr2]

There are areas of US highways where it is a race track...or so it seems. I95 in Georgia and Florida has 3 lanes each direction because it is just two lanes one direction in Virgina, North Carolina and South Carolina.

Speed limit is 70mph but left lane goes 80 - 85, middle lane is 75 - 80, and right lane is 72 - 75 mph. I never see any highway patrol either.

Texas has speed limit at 85mph on a few highways I think.

Cars now have areodynamic drag co-efficients of .26 (2019 Altima, Camry and Accord) and even as low as .23 on the 2020 Sonota. These cars can cruise at 80mph all day comfortably.

I think the Ram 1500 is the most aerodynamic truck at around .55 drag co-efficient.

One big advantage of an electric truck is they can be made much more areodynamic because they do not need a big front sucking in air to cool the engine.
My 2017 F-250 looks like Ford tried to make it areodynamic with the duck tail on the tailgate and a chin spoiler on the front but it still looks like a brick.

[laj]

Originally Posted by kdauto

Canada is America too, as are other countries. Maybe we should replace this with USA?



Yeah, I've driven through the first 5 states you mentioned. I can remember the 75 MPH limit in 2 or 3 of them. I'm not making 15 MPG with my empty gasser either at that speed.



I was just referring to your "bleeped out" words, the **********, no big deal.

No, canada is NOT America. Yes, there are foreign, and other 3rd world countries that comprise The North American Continent, not the country America.
Just as there are foreign, and third world countries that comprise South America, another continent.

[4x4ord]

Originally Posted by Itchytoe

Engines, gas or otherwise, get their best fuel economy running at a constant RPM right at their peak torque.
.

This statement is not true. It is true that an engine running a the rpm where peak torque can be achieved is running at the rpm where it can produce the most work per unit of fuel, however, when this engine is being used to power a truck down the highway it is very likely not going to get its best fuel economy running at the rpm where peak torque is made because it will producing far less than maximum torque. If you consider a Cummins diesel which makes its peak torque of 1000 lbft at 1800 rpm you can calculate that this engine is capable of making 343 hp @ 1800 rpm. A typical truck driving down the highway at 65 mph might use about 65 hp. The Cummins engine is able to produce 65 hp at a much lower speed than 1800 rpm. You would have to look at a brake specific fuel consumption graph to see exactly what rpm this engine can most efficiently make 65 hp but it is definitely going to be at a lower speed than 1800 rpm.

[Itchytoe]

Originally Posted by 4x4ord

This statement is not true. It is true that an engine running a the rpm where peak torque can be achieved is running at the rpm where it can produce the most work per unit of fuel, however, when this engine is being used to power a truck down the highway it is very likely not going to get its best fuel economy running at the rpm where peak torque is made because it will producing far less than maximum torque. If you consider a Cummins diesel which makes its peak torque of 1000 lbft at 1800 rpm you can calculate that this engine is capable of making 343 hp @ 1800 rpm. A typical truck driving down the highway at 65 mph might use about 65 hp. The Cummins engine is able to produce 65 hp at a much lower speed than 1800 rpm. You would have to look at a brake specific fuel consumption graph to see exactly what rpm this engine can most efficiently make 65 hp but it is definitely going to be at a lower speed than 1800 rpm.

You're doing exactly what I said most people do. You're confusing the engine with the vehicle. The engine is most efficient at peak torque. Putting it in a vehicle and driving down the road means you've got to take other factors into account. I pointed that out in the post you quoted. There's a difference between the engine and the vehicle. Also, at 65 mph, you're well into the point where aerodynamic drag becomes the dominant curve. That aerodynamic drag is what kills your fuel economy at that speed. You'll get better fuel economy at 55 mph because your engine is doing significantly less work at 55 than 65, not because the engine is more efficient at the lower RPM.

[4x4ord]

Originally Posted by Itchytoe

You're doing exactly what I said most people do. You're confusing the engine with the vehicle. The engine is most efficient at peak torque. Putting it in a vehicle and driving down the road means you've got to take other factors into account. I pointed that out in the post you quoted. There's a difference between the engine and the vehicle. Also, at 65 mph, you're well into the point where aerodynamic drag becomes the dominant curve. That aerodynamic drag is what kills your fuel economy at that speed. You'll get better fuel economy at 55 mph because your engine is doing significantly less work at 55 than 65, not because the engine is more efficient at the lower RPM.

You need to look at a brake specific fuel consumption graph. If 75 hp is required of a 400 HP engine capable of 1000 lbft of torque at 1800 rpm, it will not produce 75 HP most efficiently at 1800 rpm. The most efficient rpm will be something significantly less.

But, if 343 HP is required of that engine it will produce 343 HP most efficiently at 1800 rpm and it will be running at its peak efficiency.