acdii

Interesting that a 164" WB 4x4 has only one frame while the 4x2 has 2. This pretty much firms it up regarding frames, so the underlying difference between 2.7 and 3.5 is the engine itself that limits towing capacity.

Ddurham

You guys seem a lot more knowledgeable than me. A couple follow up questions. Mine is a regular cab 141 whelbase. The chart says the thicker frame is "HD and HDPP. So I wonder if mine (which is the maxed out 2.7) is what they are referring to as "HD". If that's right, then pretty much everything is the same except the springs and the tires. (I think the tires may be different. Mine are 110 load rating and I wonder if the HDPP is 118 that have about 500 more pounds rating per tire.)
I'm wondering if the 8500 tow rating for the 2.7 is a marketing thing with ford. To have a gap to the larger engines. They could have put in stronger springs and tires and rated it at close to re 5.0 and 3.5. Again, the 2.7 is muxh more powerful than my 2010 5.4 HDPP and it was rated to tow 11,300.

Great white

iTrader: (1)

It's actually quite simple, although this won't tell you the mechanical differences in the extact trucks you are looking at.

The 3.5 met the criteria for SAE J2807 (http://standards.sae.org/j2807_201602/) at the 12,000-ish weight (varies a little depending on truck configuration; supercab, crew, RWD, 4x4, etc) and the 2.7 met the criteria at 8500.

There's no big mystery to it. It met the criteria or it didn't. Hence the rating.

As to the mechanical differences, you'd need the engineering team at ford to spell it out for you.

Anything else is just a guess at what the total differences are between trucks at different ratings. It can be something big like a different rear axle, or it can be the sum of a lot of small changes like different flow through the transmission cooler combined with other small changes. It's all about getting it to the SAE J2807 criteria.

There's no way to change the stated ratings either. It's not that you can't give the truck more actual capacity, it's that you can't change the factory rating. The factory rating is a "legal" thing, if you want to think of it that way. You can't change that. The problem is that the rating is an accepted capacity given by the OEM under specific testing criteria. You'd basically have to re-engineer that truck to be able to meet the SAE criteria and then prove it by running the test to someone who could "officially" change the ratings for the truck. I would assume that would be DMV, but I doubt they would have any interest in that, or even know what to do about it.

It would be cheaper to probably just buy a larger capacity truck. It sounds like you're more into 250-350 range with your stated usages.

Ddurham

Thanks. I understand. The interesting thing though is that I think it's clear that Ford made a marketing decision to reduce the rating of the 2,7 so it wouldn't step on the toes of the 3.5, not by reducing the performance, but by reducing the capacity of the springs and tires. Because it's starting to look more and more like everything is identical between the trucks except for those things. And there's no way that much difference is caused by the engine. Towing 7000 pounds the 2.7 absolutely eats a chevy 5.3 for breakfast. (There are tests on line pulling those loads up into the Eisenhower tunnel) and the Chevy is rated a lot higher. It's sort of an academic thing for me know but I'd still like to kn ow if I'm Sright or not.
Do you all think that the way to solve this is to get the VIN of a HDPP with max towing 3.5 and a 2.7 with the payload and tow packages, and then look out all the parts for these on line at the Ford parts site?

Ddurham

Following up on that does anyone have a vin of a 2017 HPP +max tow 3.5 truck? I tried to do it using the check inventory feature of ford.com but I couldn't locate such a truck. The search feature is crude and these trucks are pretty rare.

TommyShwa

Look through the "post your payload" thread. Lots of images of Payload stickers that have the VIN on them.

Gale Hawkins

Look at the torque rating @ 2000 RPM for the 2.7 and 5.4 you mentioned.

jp360cj

Old thread, but what appears to have been overlooked is the 2.7 payload package essentially gets you the specs of a regular 3.5EB truck (bumps up the GVWR to whatever the regular 3.5EBs are, 9.75" rear, etc). Comparing the 2.7PP to the HDPP isn't really any different than comparing a regular 3.5EB truck to a HDPP other than the engine.

Gene K

9.75HD is supposed to have a larger differential housing (increased fluid capacity) and some references have stated thicker axle tubes (for increased axle rating) but I have not physically confirmed either.

​​​​​The 2015 2.7 Payload description said it came with the "Heavy Duty 9.75" Rear Axle" whether this referred to the 9.75HD used in the HDPP or the standard 9.75 used in the 3.5 EB, 3.0 PS and 5.0 3.73 I can't say. If it's the standard 9.75 I will say it's a poor choice of wording on Ford's part.

5.0GN tow

Everyone is overlooking the fact that a 2.7 being pushed hard enough to pull the weight a 3.5 is rated to pull, would generate a tremendous amount of heat. Heck 3.5TTs overheat at max load under certain conditions from posts seen here. Push a 2.7 to do that and turbo induced heat would be off the chart.