Why Different 2018 F-150 Pickups Can Tow Different Amounts
The smaller EcoBoost V6 and V8 make similar power, but the towing difference rests somewhere else.
The 2018 Ford F-150 is the most capable half-ton truck in America, but that best-in-class towing rating of 13,200 pounds only applies to trucks with the 3.5-liter EcoBoost V6. Trucks with different engines and different gearing all have unique towing capacities, with the 5.0-liter V8 offering 11,100 pounds of trailer-pulling ability while the same truck with the 2.7-liter EcoBoost V6 can “only” tow 8,300 pounds.
The power output of the 5.0-liter V8 and the 2.7-liter V6 aren’t all that far apart, so how can the V8 tow so much more? That is what forum member “dnewton3” wanted to know when he started his thread discussing the towing capacities of the 2018 F-150.
When the OP first posed his 2018 F-150 towing question to the forum, he ran through a collection of numbers, explaining why he was comparing these two engines so closely and offering up some math on the power levels at different engine speeds.
It’s somewhat hard to find a 3.5EB or 5.0L on the lot in my area; most are 2.7EB equipped. And that’s OK with me. But I don’t understand why there is such a disparity in the towing ratings with VERY similar power levels of the three main selling engines (2.7L, 3.5L, 5.0L). I would be willing to consider a 2.7L EB if the towing ratings were higher, closer to the other two.
Example of 2018 listed specs:
2.7L EB in RCLB 4×4 with 3.73 gears has tow rating of 8300 lbs.
5.0L in the RCLB 4×4 with 3.73 gears has tow rating of 11,100 lbs. (2800 more than the 2.7EB).
Towing is about torque. Both the 2.7EB and 5.0L make 400 ft-lb max, but the 5.0 makes more “power” (HP). But if you really analyze it deeper, the disparity is not big at all.
2.7EB makes 400 ft-lb at 2750, and if you convert HP to Tq at rpm, it makes 310 Ft-lb at peak HP rpm (5000 rpm).
5.0L makes 400 ft-lb at 4500, and convert HP to Tq at rpm, it makes 360 Ft-lb at 5750 rpm.
But look at the RANGE of TORQUE application …
The 2.7EB make an AVG of 355 Ft-Lb at 3875 rpm, and it’s torque is spread over 2250 rpm (from peak TQ to peak HP).
The 5.0L makes an AVG of 380 Ft-Lb at 5125 rpm, and it’s spread is much narrower engine speed (1250 rpm peak to peak).
Essentially the 2.7L EB really only gives up about 25 ft-lb as a disadvantage, but it gets a much larger spread of rpm to apply the torque it does have, so it does not fall off the curve nearly as badly. Given that the engines now all have the 10-spd tranny, all of the engines should be able to stay in the “power band” easily, and use the spread of torque through their unique range (peak Tq to peak HP). So in essence, the 2.7L is only a little behind the 5.0L in grunt because it’s torque range, while a bit lower in magnitude, is also almost 2x wider! So if you put the engines all in the same chassis, why is there such a huge disparity in tow rating? In theory, the small EB should tow just about as well as the 5.0L. The 2.7 will grunt it’s way along, whereas the 5.0L will scream along.
And before you start talking about engine stress, let me add this:
The 2.7L will make it’s 400 ft-lb max at 2750 rpm; the 5.0L at 4500 rpm. Plus, the 2.7 has a CGI (compacted graphite iron) block, to take the extra boost stress; the 5.0 is all aluminum. I’m not saying either one is a detriment; I’m just noting that both are each engineered to take the beating in a unique way. I don’t think the small EB is any more prone to a block or crank failure by grunting along under boost, as is the 5.0L screaming along at 5,000 rpm all the way up a hill.
I find it incredibly hard to believe that the 2.7L should not be at least “near” the 5.0 in towing ratings. Perhaps 1000 lbs less? That I could understand. But nearly 3000 lbs less towing rating? If the 5.0L can tow 11,000 pounds, the 2.7L should be able to pull 10,000 in the same chassis with same equipment. The 2.7L EB gives up only 6% average torque loss to the 5.0L, but it gives up 25% tow rating? That’s some wonky math coming from the Big Blue Oval.
Members Toss Out Ideas
After that initial post, is seems that none of the first members to comment knew why there was so much difference between the various 2018 F-150 engines, but they were willing to offer up ideas.
“JKBrad” thought that it may be due to the durability of the engines:
Just from a physics stand point, a V6 crank is less susceptible to the forces placed on it by the rotating mass than a V8. A V8 is much smoother running though, which makes up for much of that.
Remember, towing (or anything else for that matter) isn’t done at a constant wide open throttle. You have to look at the power and torque in the 1800-3800 RPM range, where most of the engine’s work is done. This will give you an idea of why Ford rates them as they do.
“Mark Kovalsky” ran through a quick list of possible reasons for the differences:
Sometimes there are physical limitations the limit the towing capacity. I don’t know many specifics for the F-150 so this is all educated guessing.
Maybe there is a brake difference? Or a cooling system difference? Sometimes it’s all about marketing. If both engines could tow the same, why spend the extra money for the larger engine? I didn’t work on these so I don’t know the reason. But it could be one of these.
Forum moderator “Tom” also questioned the durability of the engines, but he also brought up the aspect of marketing:
I’ve wondered the same question, and my thought was that it had something to do with duty cycle. Perhaps the 2.7L engine could suffer durability concerns if run at high loads for extended lengths? Not sure about that, though…I imagine 8,000 lbs up a steep grade would put significantly more strain on things than 12,000 lbs on flat ground.
I think marketing has something to do with it, but I don’t have anything to back that up.”