I agree with what some of you are saying, give me as much MPG as you can. Even if they only match the HP and torque of the current 5.4L if they can get 27-30+MPG it will be a big hit. The F150 is called the "most capable" as it is so why not try to push the milage as far as it can be. I am a big guy and love the room inside of trucks and I hate drivng my focus back and forth to work, but at $4 a gallon I can't afford not to. I would like to see something that would make a really nice daily driver.

I guess thats the hard part of making any vehicle a million people have a million different uses for it and its hard to make something that meets them all.

 

Torque determines how fast you can get upto speed, and HP is how fast you can hold speed at.

That is way over simplified, but that is the general idea on how it works

 

Short on-ramps? Semis appearing from around a blind turn after you pull out? I could think of lots of reasons.

As far as holding speed, that's great, until you get to a grade. Then you need more horsepower to hold a given speed. The high torque numbers don't mean anything if the engine is not capable of producing high power.

 

well however you want to discribe it torque is much more important than horspower when towing, i had an chevy silverado with a 350 made simular horspower to my 7.3 but much less toruqe and it would not hold speed towing up hill like my 7.3 will not even close.

 

that is very much true

 

I'm sorry bout torque will NOT hold speed. You can have a 8000 ft-lbs of torque, but if you only had 50HP, it wouldn't be able to hold speed.

 

Then you must not have had the gearing to get the Chevy onto its HP peak. Or, it wasn't truly making the power you thought it was.

Lead Head is right. Torque is only part of the picture. The only thing the high torque numbers of diesels do is to get the HP peak down to an RPM where it's comfortable to tow with. So your perception is that you have a more powerful truck, because it doesn't sound or feel like it's working very hard.

Here's the science: Given the right gearing for each, a 250 HP gasser will move the same load up the same hill at the same speed as a 250 HP diesel, you just might not like the RPM you have to run it at in order to do so. And it most likely won't be as efficient.

My 330HP 400 ft. lb. GMC will tow circles around my 250HP 525 ft. lb. 7.3 PSD, but it's not nearly as pleasant to drive, because I have to run it up to around 3500 RPM to do so.

 

well look at it this way what if you had 8000hp and 50 ibls of torque? you do need both tho, to tow easily

 

You need both in proportion. It's just like everything else, you can't have too much of one thing and not enough of the other or things just don't work.

Mike

 

That would move a HUGE load, if the gearing was right. It's simple. The more HP you have, the more the vehicle will be able to tow. In your example, the RPMs would have to be very high.

Here's the formula: HP = (TQ x RPM)/5252

You don't NEED high torque numbers to tow, it just makes the experience more pleasant, because the higher your torque number is, the lower the RPM that will be required for a given amount of HP.

But that does NOT mean that any engine with 600 ft. lbs. will out-tow any engine with 400 ft. lbs. Horsepower is the best indicator of actual towing capacity.

 

Here's the science: Given the right gearing for each, a 250 HP gasser will move the same load up the same hill at the same speed as a 250 HP diesel, you just might not like the RPM you have to run it at in order to do so. And it most likely won't be as efficient.

Okay then as per your science.. How come my 460 with 4.10 pulling a 8000llbs trailer up a 8 % grade will only hold 60kmh. Engine rated at 230 hp. Take my 7.3 which is rated at 235hp 4.10 axle same grade and same trailer same conditions. The 7.3 will hold the hill at 80kmh. Both trucks are the same. Big difference! I have tried to runn the gasser as hard as i can it still does the same..

 

Okay then as per your science.. How come my 460 with 4.10 pulling a 8000llbs trailer up a 8 % grade will only hold 60kmh. Engine rated at 230 hp. Take my 7.3 which is rated at 235hp 4.10 axle same grade and same trailer same conditions. The 7.3 will hold the hill at 80kmh. Both trucks are the same. Big difference! I have tried to runn the gasser as hard as i can it still does the same..

 

I think the science has to include torque and hp, not just hp. The torque makes a huge difference as big350 stated. When we had a ready mix business the trucks only had 280 hp motors, but the torque made the difference. We went down the road at 78k lbs running 65 mph. Granted it took a while to get to speed and we slowed down a bit on the hills, but I would like to see a gasser pull 78k only making 280 hp.

 

All that really matters is rear-wheel torque, and rear-wheel speed. And if you multiply the two, you get the rear-wheel HP. The rear-wheel HP is a little bit less than the engine HP, due to drivetrain losses. You can never get more HP at the rear wheels than you can from the engine. Even if the engine produces 1,000 ft.lbs. of torque. That would be getting something for nothing.

So the truck holding the grade at 80kmh is by definition producing more rear-wheel HP than the one holding 60kmh, for the same load. There is no way around that math. So if drivetrain losses are the same, that means that the 7.3 is making more HP than the 460.

Torque is already included in the HP calculation

78,000 lbs moving down the road at 65 mph takes a certain amount of horsepower, and if your numbers are right, that horsepower is 280 or less. It doesn't matter HOW you make that 280HP. 280HP is 280HP, whether it's made by a diesel, a gasser, or a gas turbine. As long as you get the gearing right, it will move the same load up the same hill at the same speed.

Think of riding a mountain bike up a hill. Let's say you are short stocky guy that weighs 200 lbs. You're stronger than most, so you can use the taller gears and still climb the hill at 10 mph. Because you are using the tall gear and pedaling slowly, you are making a large amount of torque at the crank.

Then some tall skinny guy who also weighs 200 lbs gets on the bike, and rides it up the same hill at the same speed. But he's weaker, so he has to use the lower gears, and pedal faster. Consequently, he is producing less torque at the crank.

However, both of these guys are generating the exact same amount of power, whether you measure it at the crank or at the rear wheel of the bike. The rear-wheel torque and speed are the same on both bikes, so therefore the rear-wheel power is the same on both bikes. But, the two guys are both producing the same power in different ways, one with high torque and low speed, the other with low torque and high speed.

 

I guess what you are saying is with gearing you can make torque equal between two motors that have the same hp. It is all how you word it. I see what you are saying and everything, but I guess the question should be how much hp is needed. The real answer is much lower than most would think. Even if you dont want monster low gears, that is as long as your make some good torque #s. I think a 200 hp/400lb tq in a 1/2 ton would be great. I dont know the #s they are looking at, but I know the early psd is a great motor pulling heavy loads even with 3.55 rearends, so if a 1/2 ton had similar #s it would be a great little runner.