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2018 F-150 Lariat 4X4
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Discussion Starter #1
Does anyone launch in 4A (4WD Auto) with a tune? I know not everyone has that, especially XLT’s, & those guys launch in 4WD and then flip back to 2WD. I was wondering if the 4A engages under a (tuned) high power and then disengages after traction gained? Guessing it’s pretty hard on the parts if it does..
 

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4A has its own load factors for sending torque to the front wheels. (I actually don't know what controls the torque split)

If the dashboard display can be believed, you can view an image in real time showing the amount of total torque being shared front to back.

Anytime you are accelerating from a stop it indicates as much as "equal" (50%?) torque front and back. But that's not ordinarily for more than just the first few seconds. And then it tapers off to much less. If you get out of the throttle or settle at a given speed, it quits sending anything to the front.

You probably have already seen this yourself if you have 4A. And although I'm not one to boost-launch my truck, I'd be happy to find me a good spot and roll into a WOT and watch it to see how it behaves.

I don't know if you could say 4A is any harder on the front diff than a non slip diff. But I can tell you that my truck is at about 31,000 miles and almost all of them are in 4A. I absolutely love it and it's night and day when maneuvering aggressively on the back country roads I live in.

Again, I'm not hard on my drivetrain. Try to be smooth. But I have big fat Brembo brakes and a rather dialed in suspension and I like to brake late and roll strong. For a pick up truck anyways.

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Discussion Starter #3
I like how you roll LOL. Sounds like me. The front brakes don’t feel all that great on my 18’. If there is a Brembo setup available, that could be in my future. Especially nice for towing and even add a little bling.
 

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Discussion Starter #4
Is there a MPG hit for the 4A? I am not familiar with Fords. In my 2015 Ram Sport I traded in, I used 4A all winter, but there is a small hit to gas mileage; .5-1 MPG. It was from part of the front end staying loaded so to speak. I miss the LSD it had.

So you have launched in 4A then? Just not power braking?
 

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Not worth the price for the Bling! Lol

But towing the RV they are awesome if/when you suddenly need them. And they can do a full ABS stop on dry pavement. It's very impressive for a truck indeed. You can FREAK OUT a passenger. (and they don't seem to appreciate what they just experienced)

Way overpriced though. Double the normal Brembo price, just because it's for an F150. Small market I guess. The same size Caliper on a supercar would be considerably le$$

While I have no regrets on doing this build with them, I don't think I would do it again. The extra stopping power that requires that huge pad (surface area) doesn't come into play often enough for a street truck. But I admit that when towing it is kinda amazing how great brakes add stopping confidence.

But I could convert the RV to disk brakes cheaper and really have nice stopping power.



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I'm almost always in 4A. So every "launch" is 4A. :)

But no, I'm not a brake-launcher. I'm an old geezer that just loves a truck that is stealthily quite, flat out flies, and has a bit of go-cart DNA in the suspension.

No doubt I would get better gas mileage in 2WD and normal size tires and not being a hooligan. The dash shows just over 17.5(?) mpg average over the last 3000 miles. But I haven't been traveling much so not much highway miles in the mix. It gets a good 19+ on cruise and flatland.

I've had a bunch of trucks in my lifetime. This is by far the most amazing overall package of engineering hands down.

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Discussion Starter #7
Just looked up brakes for an F-150. Definitely not cheap LOL.
 

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Yes there would be an MPG hit. Ford's fully disconnect the front driveline at the hubs and at the transfer case on the F150 so I would think it might be more substantial than your Ram. I believe Ram leaves the front connected to the hubs and only disconnects the t-case.
 
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Discussion Starter #9 (Edited)
Yes there would be an MPG hit. Ford's fully disconnect the front driveline at the hubs and at the transfer case on the F150 so I would think it might be more substantial than your Ram. I believe Ram leaves the front connected to the hubs and only disconnects the t-case.
That's from my understanding as well on the more modern Rams. Reading up on Fords & an actual Ford video I found it looks like Ford does the same. Front hubs locked in 4A and the center diff is clutched based, not gear based.
 

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The impact on 4a and 2wd is small. I did some 'testing' an never saw more than 2/10mpg difference.

Boosted launching in 4a may cause problems due to, from what I understand, the clutch system. I suppose it could wear out or get fubar'd. But I honestly do not know, I always launch in 4h.
 

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What are you trying to achieve by launching in 4A? Also launching in 4H and turning the dial to 2wd will not do anything. Until you let off the gas it will remain in 4H!
 

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Discussion Starter #12
I’m thinking more for around town driving. Having a one wheel wonder sucks. Been so use to LSD’s in the back for years.
 

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I’m thinking more for around town driving. Having a one wheel wonder sucks. Been so use to LSD’s in the back for years.
Than look at a Raptor E- Locker Relay Kit or the SPE Full Locking Diff Kit that I pirchased.....for $50+
Now...when I engage the E-Locker it stays on until I switch it off!


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I broke my transfer case boost launching in my 2012. (4hi) Now I'm scared to death to try with my 2019. Is it uncommon? Did I just have some bad luck? Seems pretty common for guys to do it.
 

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2013 Ford F150 XLT 3.5 Ecobeast SuperCrew 4X4
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I’m thinking more for around town driving. Having a one wheel wonder sucks. Been so use to LSD’s in the back for years.
Help me understand why it matters that your rear isn't locked or LSD while driving in town please. Confused.
 

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2013 Ford F150 XLT 3.5 Ecobeast SuperCrew 4X4
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Personally, I don't like to throw money out the window in the form of rubber.
 

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2013 Ford F150 XLT 3.5 Ecobeast SuperCrew 4X4
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Well you’re no fun.
I like to watch my Son's videos of him destroying bowties in his platinum. He's probly going to jail for street racing soon. :(
 
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