With the 5.7L it seems that even a small payload drops the mileage. Wind drops the mileage. Driving a little above 2000rpn drops the mileage. Sure it has some nice power, but increasing the speed above 65mph drops the mileage like crazy. All of those things I could do in the 4.6L and the mileage barely changed. Long story short, the 5.7L feels like it's always pulling an invisible trailer behind it and of course that's easy money for the fuel pumps every week.
I get your overall point to the entire post. I appreciate what you're saying and for the most part agree that realistically, for what most people actually use their truck for, it wouldn't make much difference which size V8 they had.
But the above doesn't make much sense to me.
I agree that with the tow pkg gearing, fuel economy isn't great above 65 mph simply because of the rpm. (Kinda wish they would look into an 8spd option for the Tundra).
But if you took 2 identical trucks, the one with the smaller engine, that's geared more for hwy speeds will naturally get better fuel economy. But when taxed and loaded, the smaller engine will always suffer a higher % of efficiency loss than a larger engine with more torque.
If you took 2 identical trucks (let's say both are a base model 2wd with tow pkg) and towed the same weight with each, added the same payload and drove them on the same course, I highly doubt that the one with the smaller V8 would barely see a change in fuel efficiency.
You said that if you are going to be working your truck regularly, you might be better off with the 5.7. I agree with that.
But the section above contradicts that a bit.
Now, I've never driven a Tundra with a 4.6. I would assume it's a much better V8 than GM's and Ford's smaller V8s.
I know they are capable engines, as I drove a full size Ford van with a 4.6 and we have a small GM shuttle bus at work that's a lot heavier than a van or pickup and it only has a 4.8 V8. No problem doing work or moving. But neither were even close to being impressive with fuel economy. Especially when taxed.
As far as the 5.7 suffering more under any amount of stress,....that's also not exactly accurate. You have to load it up pretty good or drive it like a maniac. Pulling a lighter trailer or your typical load of crap from the hardware store in the bed is not going to kill your average MPG. I've had my 5.7 DCLB for over 3 yrs and for the last year, have heavier tires and the bed and cab have been completely filled with gear and tools 24/7. I've worked the truck harder over the last year and my average MPG went from 14.4 in the first 2 yrs to 14.1 over the last yr.
If I had a 4.6 V8 in my truck, I would have suffered a lot more than a .3 MPG loss under the same conditions.
Also, that sluggish feel in the 5.7 is the throttle response that they dialed back in the 3rd gen. My truck has it too and I hate it. My 2011 CM with the 5.7 was very zippy from a start.