Towing rpod 192 - Event Date: 28 May 2020 - 30 Jun 2020

The OP may wonder what sort of wasps nest he uncovered!

Just for the record, virtually all class 8 OTR semis that have been made in the last 30 years or so are using a turbo charged 6 cylinder inline diesel engine (various brands) other than the occasional experimental hybrids or electric prime movers...etc....but pretty much all commercial OTR class 8 units hauling freight...more or less. Probably 99.999 percent. Just sayin.

But that is a larger, relatively slower turning turbo with well-proven technology, and equipped with engine braking.

My primary concern with the new generation of gasoline turbo engines in trucks used for towing:

How effective is the engine braking? 

OTR trucks running turbo engines nearly always have some sort of engine brake.

I've not heard of such a thing on gasoline turbo-equipped engines, unless they have some sort of automatic exhaust brake. When coasting down a long downhill grade with a 5,000 or 10,000 pound trailer pushing the entire rig towards the lowest point on the road on a long steep grade, you WANT at least SOME engine braking so your disc brakes and electric trailer brakes dont turn into red-hot smoking pools of useless molten metal. 

Normally aspirated engines always have a good amount of engine braking on tap, available by simply downshifting one or two cogs. Turbos do not. Not unless that engine has some sort of supplemental system for engine braking. I do know that some gasoline turbo equipped engines have variable valve timing, and that may be able to be used as an engine brake. But I have heard no mention of it, nor have I driven a gasoline turbo engine in the mountains with a heavy trailer.

After all, when pulling a trailer in the mountains, GO power is nice, but WHOA power is a necessity.

Or so it seems to me.

(BTW I have about 3 million miles of diesel truck driving experience, including all US mountain ranges...so I know a bit about the topic of pulling heavy trailers in the mountains)

There are no specs yet for the F150 ev but some of the other ev pickups and SUV's have claimed ranges of around 500 miles. Cutting that in half or a bit more than half for towing (which we all see is about right) would still be around 250-300 miles range which would be OK (my Highlander's range is about 260 towing) with sufficient level 3 DC fast chargers, which take around 30-40 minutes. I'm OK to stop and rest for 30-40 minutes after driving 200 miles. That network isn't there yet except maybe Tesla's proprietary one is getting close, but its getting built out pretty fast. Gas fueling has only had about 100 years to get there after all. Will it be there in 2022? Not likely for most RV'ers but probably yes for most drivers who will be getting better range. By 2025? Probably yes for almost everyone, and by then there should be some nice used EV SUV's and pickups available. That's why I don't expect to have to buy another ICE, as long as my 2012 Highlander can go for another 4 or 5 years I should be good. 

Forget in road inductive charging, that is far more expensive infrastructure to build out than a level 3 network. Battery cost is dropping fast so its not like 500 mile range EV's are going to be a lot more expensive than gassers in a few years, 260 mile passenger cars like the Chevy Bolt are already down around 23-25K. I'd buy a Bolt tomorrow if my Prius became a problem, but I'd rather wait till Chevy puts nicer seats in the Bolt next year.....

I own a hybrid drive vehicle, which is a much more advanced drivetrain than any of the alternatives we are discussing here. It is the most efficient gasoline powered vehicle on the planet and has a normally aspirated engine. If Toyota had a hybrid drivetrain better optimized for towing I would have that in my Highlander right now. I will happily purchase an EV as my next passenger car. Both hybrids and evs are compelling in terms of reliability and efficiency. 

OTOH there is nothing inherently more "advanced" or compelling to me about turbocharged engines, they have been around forever. They have their pros and cons. I don't drive at high altitudes so there is no compelling reason for me to have one. I simply prefer normally aspirated engines for the limited time remaining before battery technology reaches the point where internal combustion engines are no longer being sold. 

I'm not in the market for a pickup at this point anyway, my normally aspirated V6 SUV and utility trailer combo serves my needs much better. And I personally hope not to ever have to buy another ICE vehicle. But, the electric F150 is apparently coming in 2022. How about 1 million lbs tow capacity? I might sign up for that..... 

I think it is time to cease this turbo vs normally aspirated debate, it is obviously a sore point with some ecoboost owners and is going nowhere. Enjoy your turbo boost and be happy!

You're right about wind resistance being the biggest horsepower consumer when towing at a steady 60 m/h. I've run the numbers and about 60% of the demand is air drag at 60, flat ground, no wind. The other 40% is rolling resistance which is proportional to rig weight. With my rig I'm at about 44 hp total, 27 aero, and 17 rolling. mpg about 13. 

That's cruising on flat ground. Climb a 10 degree grade at 60 and suddenly there is an additional roughly 150 hp requirement, for a total of close to 200 hp. Accelerating from 50 to 60 in 10 seconds requires a similar additional hp. These numbers are what they are due to weight, not aero drag, you have to convert fuel into energy and store it in the mass of the rig. Then you get to waste all that stored energy heating up your brakes later. 

See where I'm headed with this? It's climbing, passing, and accelerating that demands gobs of power, and that is because of weight. Just cruising along doesn't require that much, even dragging a trailer. Either tolerate slowing down on hills and slower acceleration rates (like semis do), tromp on that right pedal, or get more hp under the hood. There ain't no replacement for displacement (unless you like turbos) 
 

Normally aspirated V8's are proven. They are simple beasts. Those reciprocating parts don't fail much, pressurized engines have much higher stresses. Old tech isn't inherently a bad thing, so I don't take being labelled as 20th century as the insult I expect was intended.  I would choose an old 1950's design normally aspirated Lycoming aircraft engine over a new high rpm blown Rotax too. Why? Because my life depends on it working and giving me fair warning when its getting tired.