Question on 4A vs. 2H

[dixonk]

I don't have the torsen front diff so my steering feels about the same whether it's in 2hi or 4A.

If mine was like that I would keep it in 4A

 

[Russ103]

I don't have the torsen front diff so my steering feels about the same whether it's in 2hi or 4A.

I thought that all Raptors had the exact same drivetrain?

 

[dixonk]

I thought that all Raptors had the exact same drivetrain?

Torsen Front diff is an option.

 

[KAH 24]

4A vs RWD is actually something that I’ve focused on throughout my career in the industry—and as a fellow motorsports enthusiast.

As always, this is my opinion (objective to me/subjective to others) based on professional experience and learning from my fellow professionals. It is not intended to create a debate—as everyone operates their vehicles under different parameters, with different experiences, etc.

As we know:

1. All 4A (AWD) creates more friction drivetrain loss vs. RWD—ie horsepower loss as transmitted from the crankshaft.

2. Drivetrain performance is impacted by every component between the crankshaft and pavement.

3. Friction is present in the drivetrain—but friction between tires and pavement accelerates/decelerates. Friction where we want it is good (tire to pavement). We want to minimize unnecessary drivetrain friction—always.

NOTE1: Due to sheer mass and poor handling dynamics/characteristics For full size/large SUVs—I’m a biased devotee of full-time AWD with 4H/4L options based on the OEM systems I am familiar with.

“Rhinoceros on roller skates” comes to mind when I think of our Raptors and other trucks/SUVs.

NOTE2: If selection is available between 2wd and 4A—indisputably there is more physical wear placed on an AWD/4A system using more moving parts—clutch packs, gears, driveshafts, bearings, etc.

NOTE3: Whether drivetrain wear is significant during the lifetime of an OEM system will vary based on maintenance, usage, and the design of the system. There are intangibles including environmental, infrastructure, etc.—well into heavy duty nerd territory.

NOTE4: Pragmatically, getting power/applied friction to the ground in a controllable manner is more important from a safety/performance standpoint—which is why some AWD vehicles outperform RWD counterparts under any conditions (dry, wet, etc).

NOTE5: The friction/wear/performance impact imparted by 4A vs RWD on the Raptor or any pickup/SUV of similar size/dimensions/physical characteristics—are hidden by other variables (see below):

1. Poor “barn door” aerodynamics: accessories added such as lift kits which make a bad situation far worse in control/center of gravity/control.
2. Tire/wheel choices: larger diameter wheels/tires, low tire pressure, rotating mass weight, etc. Friction and significant stress.
3. Maintenance: Says it all. Not everyone takes care of their vehicles.

In summary, I like AWD in big trucks due to physics (high CG and poor handling characteristics)—but prefer the ability to choose when available. I run 2wd full time and turn the knob to 4A/4H/4L/rear lock—when conditions dictate based on conditions.

If you encounter a big speed bump at the drive thru/mall, encounter a pothole, or need to street race the car next to you—none of this is applicable. You do you.

 

[rtmozingo]

4A is more wear and tear on the 4WD drivetrain and worse mpg, but if you need it then you need it.

Also I found the Torsen front to resist turning when 4A engages.

This is the correct answer. 4A is a great feature on these trucks (took Ford entirely too long to copy Chevy on this), but if you aren't having traction problems on road, run 2H.

 

[Halo Raptor]

We wrestle with this off road all the time. I run in So Cal desert and try both throughout the day. When we are in tight twisty sections, I go to the 4A, it seems to pull through the corners and gets acceleration better out of the turns. When we get to the high speed long sections, I switch to 2WD. Dont need the extra drag on the driveline for high speed stuff. I have wanted the AWD a few times when it got a little squirrely at high speed, I aint gonna lie. I find that unless we get in sand, I prefer 2WD usually, as I like to be able to slide the back end a bit. Now thats just me in the desert.