Also.... that does not include wind resistance..... we are in big blocks of metal, not exactly areodynamic..... Long enough stretch of road and enough bravery to hang onto the wheel long enough and you might reach that eventually. Because atleast for the 5.4 I know it is still pulling at 5K rpm.

 

My definition of steep is the same as my definition for low when talking about gears.

4.10 gears are not too low for a 2wd truck. This is really just an opinion.. and mine is that these truck should come from the factory with a MINIMUM of 3.73 gears.. 4.10's preferably. With 33"+ 4.56's.

I guess that is just my opinion though.

 

I guess 2600 rpm at 60 mph isnt to bad to ask of a 2wd vehicle. It'll never happen factory unless they go from a .70:1 (f150's highest overdrive avaialable now) to a .40:1...... gas milage requirements wont let them.... It is my understanding that the Corvette has the steepest OD available and it's only .5:1.

I can understand Low gears for offroad purposes. But I cant understand why anyone would want them on a 2wd for highway.

With my 3.55's I have more than enough power to pull my 4500 lb boat out of the water, infact I still have to use second gear and feather the gas to keep from loosing traction. That's with 29" tires and 3.55, hopefully it wont be as bad this spring with these new 30.5" tires.... I should beable to give it a little more gas and not slip the torqe converter as bad.

 

Ok Matt, I'm being lazy and I'm busy...so with 265/75/16 tires and 3.55 gears in 3rd gear (1:1) at 3,000RPM, what speed am I going?

 

77.97 rounded to the nearest hundredth




or
125.49 kilometer/hour
or
0.102 mach
or
67.77 knot
or
114.356 foot/second


hehe

 

Gear choice shouldnt be determined by whether a vehicle is 2 or 4 wd, if you ask me. If a vehicle is cruising at 60 mph turning 2600 rpms, its not going to hurt it any more if its a 4x4 than it would if its a 2wd.
to me, it just all depends on how the vehicle is going to be used.
If you have something that is going to spend 95% of its life running up and down the highway or interstate, then heck yes, the higher the gears the better. 3.08's and maybe even a little larger tires all the way. But then you also have to consider, does the engine make enough horsepower, at that low of rpm's, to pull the vehicle in overdrive? Or is it going to be hunting back and forth from 3rd to OD, or have to be locked in 3rd running a higher RPM, maybe even getting worse milage.
Heck, my 4.6 with 3.55's and 265/75/16's doesnt even run 1500 rpm at 60 MPH. Much higher gears and I dont think it could pull itself around hardley. Id hate to know the little bit of power a 4.6 makes at 1500 rpm, let alone lower with higher gears (3.08s or something)

He11, I can afford to give up a few RPM's and cruising speed though. Im all for taking off from a stop like a bat out of he11, so I want something like 4.10's, or if it was something like a Lightning that saw dragstrip duty most of the time, maybe a set of 4.30's even, as long as you dont run out of gear at the end of the track.
4.10's in something like the 4.6 would probably bring the RPMs up high enough in the RPM range to actually make some decent power and make the engine work a little less to pull around these tanks; maybe even getting BETTER milage.

Just all depends on what the vehicle is going to be doing.

PSS, math man, lol, with my setup Im running around 1450 RPM's at 60 mph (something like that anyway), if I drop in some 4.10's, what would my RPMs go up to at 60? I did this in a calculator once, but cant remember what it said. I think it only raised it like 300 rpm or something. Do you know?

 

In OD roughly 1825 ish would raise it about 375 rpms

I agree vehicle use decided what gears go in it....

Typically, a 4wd is more likely not to be used on the highway or atleast is expected to spend a portion of it's times off the beaten path, a 2wd is typically choosen to use o nthe highway or drag stip... but who buys a 5K lb hunk of steel shpaed like a block in the wind to use on the drag strip?

edited to add:
Somebody posted on here a couple of years ago what they had calculated the amoount of horsepower it takes just to get these truck through the air.
If anyone knows where that post is I cant remeber.... I just remeber being shocked

 

Thank you!

True, however lots of people dont always think that way. Like around here, everyone just has to have a 4x4, cant live without one, blah blah, tell me their truck is so much better because its a 4x4, and go on about how stupid I am to get a 2 wd, yet, all they do is run up and down the highway to work or school or where ever the heck they go. My 2wd spends more time offroading then a lot of thier 4x4;s would ever think of doing. Granted, some of them do need the 4x4 and do some offroading, but the ones that dont just bother me. Im getting a little off topic, but, just for conversations sake, there are always the people that get opposite of what they need.

I would love to see that post, Im going to try to do a little searching for it...

 

haha
Yea I get the same thing here....

My reply....

When was the last time you had to have your 4wd?

They answer (now), remember that ice strom a month ago?

I reply, Yea, that wasnt nothing, I got around just fine.

They reply... ohhh

then they shut up.

In actuallity, I did get around fine in my truck, but got stuck in wifes 4wd....

 

Once moving, it doesn't take much HP too keep these beasts moving, for a good example of how little HP it requires to maintain a constant highway speed, see GM's and Dodge's similiar "Displacement on Demand" when they run on 4 cylinders...

For me (and probably, most anyone) 4.6L has served me just fine in 4 of the 5 f-series trucks weve owned, I know its probably an illusion, but the 4.6L in my 2000 Expedition (230 HP) felt as swift and powerful as my 5.4L (260 HP) did. I've even towed a 6 x 12' U-haul jam packed with stuff 606 of the 808 miles (previous trip) not to mention a loaded interior.

Last week I drove my old 2000 Expy to LA. 808 mile round trip, and averaged 21 MPG, what worse, I-20 between Dallas and say, Ruston, LA, is nothing but hills, up one, down another... On flat land, she might do 22-23 MPG, but that 2003 5.4L I had only got 14 MPG whether I was in the city, or on the highway. I was disappointed in its MPG and not impressed by its "advantage" over the 4.6L.

I agree on the 4wd stuff too... If you can drive, you won't "need" 4wd. 4wd is more for "play" or excellent if you get stuck, or desire to pull other folks out. I've driven in very bad conditions in Germany, and rarely had to "lock the hubs" and go 4wd....

 

Every review that I have read about the new GM trucks mentions how little the DoD actually gets used. Most testers comment that the only time that it is used is when coasting either to a stop or downhill. Sometimes when going very slow on very flat ground it would also engage. However, with even the slightest use of the throttle all cylinders are required. The system works great under conditions like the EPA fuel mileage test, but fails when a normal driver gets behind the wheel

 

It would fail for me too then, I have the worst habit of gassing it, then letting off, then gassing it again. I'm trying to break the habit, I just noticed it a few weeks ago. If I'm just driving and not thinking about it, I'll do it.

 

If you do long haul driving like I do (occasionally), especially if you live in a flat area (not hill country like North & East Texas, and western Louisiana) then DoD will work well for you while cruising, espcially if you utilize your CC, thereby eliminiating speed fluctuations. For me- it wouldn't work as well, even with cruise control, because of all the hills on I-20 (If you pay attention, you'll notice them). Those hill make the CC downshift (the long climbs anyway).

Nevertheless, the point still stands, it takes only a fraction of peak HP to keep these (or any) vehicle at 60 - 70 MPH. I seem to remember reading the Cadillac Deville only needed 12 HP to maintain 60 MPH. (Long before DoD came back to life).

It goes back to the laws of physics, a body in motion tends to stay in motion. In this case, the kinetic energy used to move the vehicle from standing still, into movement. It's true in space, it's true for a train, it's true for trucks. Once moving, the power required for an F-150 to overcome atmospheric friction and road friction is minimal (Compared to the HP the 4.6L and 5.4L engines are capable of generating).

For me, once I get past Ruston, LA- where I-20 is relatively flat until you get to Georgia, DoD would work well for me. When I drive, I set my cruise-control on 72 or 74, and I get there when I get there.

But yes, if you accellerate or while you are accellerating, all 8 cylinders are firing, and there goes your gas mileage. I don't think DC's system is as touchy as GM's. My AWD in my MDX works in the same manner- only when needed, or under accelleration.