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bobbin · 06-08-2023, 09:36 PM

I have no rig currently: waiting for 2024 models. Recently I tagged along with the guys on a fishing weekend (aka boozing away from spouses

). Was a passenger to and fro. The journey 1way is about 160 miles, mixed terrain, fair weather. [we brought many jerry cans for extra fuel].

To, the rig was a 2022 Tundra TRD, turbo V6, pulling a TT about 24ft and 5000lbs. Averaging about 65mph, the mpg was about 11.

Fro, the rig was a 2022 Titan Pro4x, pulling a TT about 24ft and 5000lbs. Averaging about 65mph, the mpg was about 10.

wow, ostensibly same mpg between V6 and V8. This got me thinking, why? Best I can fathom is power. Whether a V4, V6, V8, moving a TV+TT requires power. The question is at what point do the engines produce the power needed? The Toyota needed higher rpm and the turbo seemed to be spooled constantly; which equates to more air and more fuel, relative to lower rpm. So, given the power required, both engines consumed equal amounts of fuel, because the fuel mixture itself can create only so much power?

If this ultra simplistic thinking is valid, then the only advantage to a turbo V6 would be running the vehicle with no load, ie a grocery getter. This seems to be the case: the Tundra has better mpg unloaded then the Titan, as grocery getters.

I respect Toyota for its quality: and the V6 is DPI, which is a big factor for me. But the Titan was a much more comfortable ride (zero gravity seats for taller guys) and seemed to work effortlessly pulling the TT; but the V8 is not DPI. The V6 worked much harder, so I do wonder about longevity of the turbo. For the V8, I wonder about carbon on the valves.
Many pros and cons between the two brands.

Well, what do others think about this? Constructive comments are welcome.

Old-Biscuit · 06-08-2023, 09:44 PM

How much does the Tundra & Titan weigh?

What was transmission speed (4,6, OD, Tow/Haul) & rear diff gearing?

What is 'DPI'?

ctechbob · 06-08-2023, 10:40 PM

You're not far off the mark.

Everything else being equal, and having 2 trucks with the same drivetrain but different motors, both tuned to operate near their peak efficiency, you're going to end up with almost the same MPG. You can't fight physics, it takes a certain amount of power to pull one of these things through the air. Diesels mostly give the appearance of being more efficient (higher MPG) because there is greater energy in a gallon of diesel vs a gallon of E10/E15 that us gassers have to use these days. (although their higher compression does give them the edge in the end)

Powertrains these days, with their 8/9/10 speed transmissions are pretty efficient and can operate at the engines peak efficiency, so towing a lot of the time works out to be about the same whether it is a NA V8, Turbo V6/I4, Etc.

I can add one more to your example. Our TT (26DJSE) made it from north GA to FL and back a few weeks back being towed by my Ranger at a 50mpg average, which is pretty much 70mph on the highway with gas stops included. My trip MPG avg? 9.1 MPG. If I slow down to 65, I pick up about a MPG. If we travel country roads instead of interstate, I get about 12.

As for working the turbo motors hard? Better to work them than let them carbon up. Practice an aggressive maintenance schedule and they'll go a long way. Yea, you're putting more fuel through fewer cylinders, but materials and construction these days is pretty advanced and its not something I really think about when we're working our truck.

deserteagle5 · 06-08-2023, 11:16 PM

No experience with either the Turbo Tundra or the Nissan so I can't speak to either of them. But I've had my Ecoboost 3.5 F150 for 7 years now, and towed a lot of miles and I can tell you that compared to the 5.0 V8 F150 my Ecoboost can pull the same load at lower rpms/higher gears. The Ecoboost 3.5 V6 puts out a lot more torque at lower rpms than the V8.

Here's the specs...that little twin-turbo V6 pretty much puts out as much torque as did the early Cummins diesels:

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I would think Toyota would have tuned their twin-turbo V6 to equal the Ford's specs. As far as mileage...I enter all fuel data into Excel spreadsheets for all my vehicles. The spreadsheet tells me that my F150 has averaged 20.5 mpg since new. And it has never been in the shop for any reason - all I've had to do is change the oil/filters and rotate the tires.

MCCOHENS · 06-09-2023, 07:14 AM

ctechbob said it, down to physics. Energy to overcome friction and air resistance. Both engines are gas so the efficiency is about the same. I wonder what the result would be with a diesel, but then we would need an electric truck and have to compare $/mile.

Dave Pelletier · 06-09-2023, 09:12 AM

Quote:

Originally Posted by bobbin

wow, ostensibly same mpg between V6 and V8. This got me thinking, why? Best I can fathom is power. Whether a V4, V6, V8, moving a TV+TT requires power. The question is at what point do the engines produce the power needed? The Toyota needed higher rpm and the turbo seemed to be spooled constantly; which equates to more air and more fuel, relative to lower rpm. So, given the power required, both engines consumed equal amounts of fuel, because the fuel mixture itself can create only so much power?

If this ultra simplistic thinking is valid, then the only advantage to a turbo V6 would be running the vehicle with no load, ie a grocery getter. This seems to be the case: the Tundra has better mpg unloaded then the Titan, as grocery getters.

What I think is that you already have a good understanding of the physics involved. ;-) The turbo will get better empty mileage and has a power advantage but it's more complicated and both will get roughly the same mileage towing the same load.....all other things equal.

2 cents,
Dave

David55 · 06-09-2023, 11:21 AM

I'm driving a 2022 Platinum F150 V6 Ecoboost 3.5 liter. As you may know, it is a biturbo. This is my second Ecoboost F150. From the most simplistic standpoint, 6 cylinders in general is less entropy than 8, therefore not towing you have the opportunity to get better mileage that a larger displacement 8 cylinder engine of the same power. That is my experience with this engine. Under heavy load, either engine will have to develop a certain amount of horsepower/torque to handle the additional load. My experience is that under towing conditions, the Ecoboost has about the same MPG as a V8. The Ecoboost engine is now the recommended engine by Ford for towing in that class. It is an impressive engine, but I do not recommend buying a Ford as my service experience with them of recent has been nothing short of abysmal.

The downside of a turbocharged engine is literally more moving parts, more stuff to go wrong. The life span of the the turbos on the Ecoboost engines is 150-200K miles in a well maintained engine. That is also my experience.

Tomahawk · 06-09-2023, 12:12 PM

It's been a long time since I took my thermodynamics courses.
I think it comes down to this, the engines have efficiency curves they follow. The peak efficiency won't be much different from one engine to the next if they are of similar design (Internal Combustion, gas, Vx). The external resistances are independent of the engine as mentioned above. Maximizing fuel efficiency means operating the near peak engine efficiency as much as possible. 10 Speed transmission, means being able to keep the engine at max efficiency more of the time. I want to say the turbo has two efficiency curves, one with turbo engaged and one without the turbo, but as mentioned it has been a long time. For a NA engine the amount of fuel that can be burned is limited by the amount of air (oxidizer) that can be drawn into a cylinder and achieve the correct air fuel mixture. A turbo compresses the air making possible to have more oxidizer in the cylinder and that allows more fuel to be added and maintain the air fuel mixture. More fuel, more power output.

kdauto · 06-09-2023, 01:36 PM

Average MPG for anything weighing as much as the tow vehicle and being 10' tall or more will be very close from one to another. Wind resistance is the greatest factor.

My brother-in-law's Toyota FJ cruiser with the 4.0l and auto trans barely makes better than 24l/100km at normal speeds of 100-105km/h, and he's towing a small 12' or 18' Kodiak Cub that probably weighs 3500-3900lbs loaded, and is only maybe 9' tall.

I tow 13 000lbs, 31' long, one extra axle on the trailer, one extra set of tires on my truck with a 6.0l gas dually and make 26l/100km(best) to 30l/100km(worst). He'll stop for fuel 4x before my one time, but I'll be putting a LOT more fuel in.

David55 · 06-09-2023, 02:52 PM

Quote:

Originally Posted by kdauto

Average MPG for anything weighing as much as the tow vehicle and being 10' tall or more will be very close from one to another. Wind resistance is the greatest factor.

My brother-in-law's Toyota FJ cruiser with the 4.0l and auto trans barely makes better than 24l/100km at normal speeds of 100-105km/h, and he's towing a small 12' or 18' Kodiak Cub that probably weighs 3500-3900lbs loaded, and is only maybe 9' tall.

I tow 13 000lbs, 31' long, one extra axle on the trailer, one extra set of tires on my truck with a 6.0l gas dually and make 26l/100km(best) to 30l/100km(worst). He'll stop for fuel 4x before my one time, but I'll be putting a LOT more fuel in.

For sure, cutting right to the chase, for the real world application stated, wind resistance for sure is biggest factor . . .

Everything else being equal, smaller displacement turbocharged engines give the opportunity for somewhat better fuel mileage for obvious reasons but given the application and nature of usual use, that advantage can easily be negated.

tuffr2 · 06-09-2023, 03:37 PM

Those F-150 Eco-Boost trucks are sure fun to drive. I bet I could get 9mpg driving solo in town - zoom zoom.

ctechbob · 06-09-2023, 06:38 PM

Here's a log of my mileage. I get pretty decent returns when I'm unloaded, but I've seen 2.7EB's and 3.5's return about the same. I tend to have a heavier foot than most people though.