Big Truck . . . Little Engine

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Putting a four cylinder engine in a full-size truck is kind of like taking the alcohol out of beer.  It can be done.

But why do it?

There’s no obvious advantage to doing it.

The little engine struggles to move the big truck . . . on its own steam. It needs heavy turbocharging to make up for its lack of displacement. Which is like skipping breakfast and then eating a really big lunch and hoping you’ll lose weight. 

Adding the turbo also adds parts for the sake of losing cylinders – which adds to the cost of the truck. You’ll pay more to buy it – and you’ll probably pay more to service it, too.

It also adds pressure – as the little engine is almost constantly under boost to make up for the power it doesn’t have (without the turbo boost) because of its small size. And even with the boost, it hasn’t got the gumption of a V8 and so isn’t as suited for work, such as towing and hauling things.

These are the things a truck is ostensibly designed to do. A truck that isn’t capable of such things (or which is less capable) is a lot like beer without booze.

Yet Chevy is going to put a little four – just 2.7 liters – in the 2019 Silverado. It replaces the currently standard 4.3 liter V6 and is destined (unless the political landscape does a parking brake 180) to be the eventual replacement for the current Silverado’s politically incorrect 5.3 and 6.2 liter V8s.

And Chevy isn’t the only one.

Ford is going down the same Weird Road with the 2019 F-150, which will offer a four in a hybrid configuration.

A whole beauty aisle of lipstick has been devoted to dressing up this particular pig. Chevy touts a “14 percent ” uptick in fuel economy – which translates to 20 city, 23 highway.

It sounds like something momentous or at least significant – until you have a look at the MPG specs of the current Silverado’s 5.3 liter V8. It rates 17 city, 23 highway.

You just saved three miles-per-gallon!

In city driving.

On the highway, it’s a draw vs. the V8. And also (both city and highway) vs. the 4.3 V6, which rates 17 city, 22 highway – and does it without the cost-adding of turbocharging. The outgoing 4.3 V6 may not be as powerful – the turbo four makes 310 hp vs. 285 for the V6 – but the V6 had simplicity on its side, which is synonymous (usually) with lower cost, especially over a vehicle’s lifetime. That matters to a truck buyer, who is often the sort to keep his truck for 20-plus years. Which engine –  the V6 or a turbo’d four – would you bet on to ride out those 20 years largely incident free?

The touted mileage is theoretical best case, too.

Out in the real world, the turbo four-powered Chevy will likely return less-than-best-case mileage because the best-case mileage touted depends heavily on the tiny engine not being turbo-boosted.

The whole point of the smaller engine is fewer cylinders to feed.

In theory, this is the Yellow Brick Road to higher gas mileage. Everyone lock arms now – let’s skip to the music!

Follow, follow follow the Yellow Brick Road!

But when the remaining cylinders are force fed – stuffed with air at 22 PSI by the turbo, to increase the effective size of the engine – in order to get the otherwise inadequate little engine to make enough power to keep the truck moving decently – the theoretical mileage will gains will probably disappear.

Big V8 or small, heavily turbocharged four – it takes “x” horsepower to get a vehicle going. And that takes burning “Y” amount of fuel. In the end, it doesn’t matter whether the engine is a big V8 or a tiny turbo’d four.

Except on the government’s mileage tests. And here’s the scoop you’ve been waiting for – or at least, the explanation for this inanity.

The EPA’s test cycle assumes a certain amount of time not moving at all, or not moving much. Stopped in traffic – or just creeping along

Not pulling – or carrying.

Definitely not hauling any ass.

If you’re just sitting in your four-cylinder truck – engine off or just idling – then sure, you’ll burn a little less gas than you would idling the same truck with a big V8 under its hood.

It’s not much less  . .  but that 3 or so MPG improvement Chevy’s touting is a very big deal to Chevy when it comes time to calculate Corporate Average Fuel Economy (CAFE) numbers, which is the main reason for this engine being put where it doesn’t belong.

And now that fuel economy is being conflated with exhaust emissions – “climate changing carbon dioxiiiiiiiiiiiiiiide” – Chevy and Ford (and everyone else skipping down the Yellow Brick Road) can claim a reduction in “greenhouse gas emissions,” too.

It’s all pretty silly – and very disingenuous.

It’s also the canary in the coal mine.

Chevy – and everyone else making big trucks – can’t go much smaller under the hood. Turbos can only compensate for so much lost displacement.

Yet buyers still want large trucks – with big capability.

These are irreconcilable differences.

Meanwhile, the mileage mandates go up or threaten to – and the political pressure to downsize the “carbon footprint” of vehicles increases.

At some point, not too far distant, something’s going to have to give.

Either it will be acceptance of downsized, down-powered trucks that can’t do the things people need and want their trucks to be capable of doing… or enough people will decide they’ve finally had enough nudging and throw open their windows and scream that they’re not going to take it anymore.

It’s been a long time coming.

. . .

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  1. It’ll be interesting to see the real world fuel economy numbers of the Wrangler with the 2.0 turbo 4. It’s no lightweight at around 4400# for a 4 for Rubicon.

    That said, Jeep is NOT planning to offer the turbo 4 in the Wrangler based, mid sized truck due out next year. Just the current V6 and the Ecodiesel. Performance in truck roles might have something to do with that.

  2. My company fleet vehicle is a 2015 Ford f150 with a tiny twin turbo v6 . I think 2.7 liter(auto tranny) . From a dead stop it has a very lazy acceleration , I hate the motor in the city. At 40 mph and up , like a freeway entrance ramp , it pulls hard and doesn’t run out of breath. The motor is fast at high speeds , but low torque. Just the opposite of what I want in a truck motor. The people buying these trucks are ignorant.

  3. How about a V8 with a turbo or supercharger. That’s what I want.

    Vehicles are getting all ridiculous. Uncle wants more mileage, but safety–supposed, not actually–trumps everything. Therefore, no more compact trucks. Instead we get fat assed “midsize” trucks. What a fu**ing waste. The first generation Tacoma’s were awesome. Compact but useful. Ditto for S-10’s and frontier’s. Now they are just fat pigs that are only about 10% cheaper than a fullsize pickup instead of around 30-40% less. Compact pickups had small, inexpensive parts. They are easy to replace and can be done by an average mechanical knowledge individual……I could go on but there’s no use. It’s all so aggravating.

    • Amen, Ancap –

      It’s why I love my ’02 Frontier. It’s not afflicted by Cod Piece Fever and you know what? Even though it’s “compact,” the bed is at least as functionally useful as the stubby/short beds they’re installing on most mid-sized trucks (which are almost as large as full-size trucks used to be) with the Quad Cab layout, which is dominant because so many people are using their trucks as cars, for commuting and family hauling.

      I have thought about using my Dark Connections to acquire a VW TDI engine and convert it to RWD and install in my truck. Given these engines are capable of 50-plus MPG in a Jetta, I bet I could get 40 in my truck.

      Just wish I had time… and money… to do projects again.

      • Speaking of diesel’s, what kind of mileage do the Toyota Hilux’s with the DD4 that every country in the world has–except for the U.S.–get?

    • The compact truck was largely killed by the so called Chicken Tax, and the physical growth of mid sized trucks like the Taco are driven by CAFE footprint formulas.

      • The quad cab layout is also preferred by manufacturers because it increases wheelbase, and thus footprint, making it easier to fit into less strict CAFE categories.

  4. Ram is coming out with a 7 liter (426 cu in) HEMI in 19 or 20. 520 HP, 525 pound feet of torque! They are calling it the Banshee and putting it in the TR and TRX versions of the Rebel. I want one!

  5. The solution here is really diesel.

    As been discussed on this page, the US is in some sort of bizarro dimension where diesels are vilified. I had a Chevy diesel back in the 80s, the kind with the crappy engine, and it still pulled about 20-25 MPG. It was 4×4, and I swear would climb a tree. My only complaint was acceleration. Day to day driving, it was great.

    I know this push to turbos in pickups has zero to do with logic and reason, at least from the consumer standpoint. But even then, you don’t buy a pickup for MPG. I had a friend that bought a full size chevy, with a 5.7L back in the 90s. I asked why he bought that as opposed to a smaller truck (a rodeo is what he traded, if memory serves). He said at the end of the day, it was a way safer vehicle, and his net cost in gas was maybe $20/month. Well worth the tradeoff for him.

    I have something similar happening now. I had a 2008 Honda CR-V, which I bought when my 4runner was totaled. Perfectly fine car, of which the 4 Cyl motor got what I would calculate as worse mileage than my 4runner. The problem being my driving style, and the amount of gear I haul every week. I traded it for a ’05 Sequoia with the 4.7L v8.

    This truck is a dream to drive, seems like for my normal driving seems to do between no worse or slightly worse than the CRV but is big, heavy, and safe. The difference in cost is nominal when compared to the utility and safety of the bigger truck.

    • As I’ve said before, other than turbo diesel, no replacement for displacement

      Sorry to hear about the 4runner btw, those are nice suv’s, but at least you got a Sequoia

      • The tale of the ‘totaled’ 4runner is a truly sad and disturbing story of more abject stupidity than anything. What totaled it was hail, greed, and laziness.

        We had a hail storm, which dinged the body (not all that bad) and broke the driver side rear window. I fixed it with sheet metal, and ordered new glass from RockAuto.

        Then I realized that I had comprehensive on it, and why not have someone else fix it? I screwed up the removal of the busted glass anyhow. But, at 12 years old, and 230K on the clock, the insurance company totaled it. Instead of taking the lower price, and keeping it, I took the payout – a little over 9K, and went shopping.

        What I wound up with was a 2013 Versa 1.8L. I reasoned that since I worked at home, all I’d use it for was tootling around town, and to the airport. Then my side business took off and I found myself loading tools, parts, and ladders on my versa and hitting the highways here in TX. The Versa is astonishingly ill equipped for TX highways, and really doesn’t get that great mileage for a small car.

        The good wife had to drive it while her car was in the shop. Took two days for her to get sick of it, rock up to our used car dealer buddie and swap it out for an older CRV. I’m sure newer ones are nicer. This one was a little worn and neglected.

        So it’s gone, and I have an even older sequoia. It’s a very nice truck. I find the 4runner to be a bit more robust.

  6. Someone posted a similar comment about a potential future car ad (I forgot who it was), but anyway, here’s my version:

    “Introducing the brand new 2025 Chevrolet Silverado. Now comes standard with FWD for the first time in Silverado history! The all-new 600cc (that’s a whopping 0.6 liters!) delivers the same reliability and excellent fuel economy well known to the Japanese as it’s the same engine that they use in their “Kei” cars. Oh, you want to use the truck to actually haul something? Well then I’m afraid you’re going to have to upgrade to our “Z71” package, which features AWD and a more powerful 500cc engine with 5 turbochargers and 2 superchargers to give it that “VEE-AYTE POWAH” that you’ve come to expect from a big American brand, without the political incorrectness of a real one. All trucks come with a 2-hour/50 mile warranty, whichever comes first.”

    I could add more, but I’m too tired.

  7. 3 MPG more doesn’t mean jack if you’re talking about a 50 MPG Prius. It’s a lot bigger deal going from 17 MPG to 20 MPG, around 900 gallons of gas over 100,000 miles, say 450 gallons if drive 50% in the city.

    And that city mileage difference might be real – when you’re getting 0 MPGs at a stoplight, a V8 loping at idle will play havoc with your overall MPGs.

    Still doesn’t justify the feds meddling in something that, constitutionally, is literally none of their fucking bidness. Be interesting to see if this ironically increases overall fuel useage, when people who would have been fine with the V6 opt in droves to go with the thirstier V8 rather than the 4 banger, because the people driving trucks tend to not be ecowarrior SJWs.

    • Hi Jim,

      I can shed some real-world light on all of this. I’ve been test driving cars for 25 years and have driven literally thousands of new cars of every type imaginable. I can personally attest that the actual mileage delivered by these turbo’d-to make-up-for-their-smallness engines is no better and often worse than a bigger engine would return. The little engines are on boost almost always and this kills the mileage – or at least, brings it down to negligible difference vs. the bigger engine without the turbo it replaced.

      Ford’s EcoBoost twin turbo V6 is a good example. The mileage difference vs. the V8 is a non sequitur – and then one must take into account the higher cost of an engine with two turbos and all the peripherals.

      The whole thing is like security theater at the airport…

      • Theres a website here in the UK called honest john, and they do a survey of real vs stated MPG – look it up (honest john real MPG). Constantly the top performers are non turbo engines – one of the top performers consistently – the good old Land Rover Defender, which by the mainstream press is constantly criticised for being outdated, un green and unsafe….

        • I believe that

          To me, turbos are always for performance, you get a turbo model when you’re into tuning, cause Lord knows a 3.2 V6 in an A4 doesn’t have much in terms of aftermarket support (which is why I drive a 2.0t)

    • Hi Bostwick,

      Yup, another concern. That 2.7 engine will be operating at higher RPM than a 5.3 or 6.2 liter V8 – in addition to being pressurized. It’ll probably be fine for as long as the warranty is good…

      • Thanks for the response Eric.

        Sort of defeats the purpose of a truck.

        It really is planned obsolescence for a truck buyer who buys his rig for the long term.

  8. Wanted to add something that i didnt see commented on…

    Turbos require high octane gas! That fact alone causes your fuel costs and therfore cost of ownership to jump by 10-15%!

    • To be fair, these turbo engines being used for fuel economy purposes are generally okay with 87. They are just designed to run optimally on higher octane. Good example is the 2.0 turbo in the new Wrangler. It can take 87, but the advertised hp/torque and optimal performance is for 91.

  9. Dont think most people will ever realise thats happening to them to go out and scream… they are way too programmed to believe what they are fed…. i think what will eventually happen is eventually those who need to do real work with these trucks will go out and buy 250 or 350 trucks ( or whatever they are called in the US, which are i think out of the CAFE regs)…. and once the showoff young money types realise their 150 isnt the biggest on the road they will also go out and buy 250 and 350 trucks…. in effect the average car will get bigger and consume more gas…. exactly the opposite impact of what the government intended…. just like when they pushed people from station wagons into SUVs in the first place….

    • Only reason I’d ever get a 2500 is if I wanted a manual but needed something bigger than a Tacoma, since you can only find said transmission in a Ram

      Otherwise, dead on

  10. My 2011 F-150, V8 with towing package, consistently gets 19 MPG highway. With a somewhat heavy topper on the bed and often a bunch of equipment being carted from one part of the world to another.

    GM’s new slogan should be “F***ing ants.”

  11. Turbo 4’s make sense when it’s designed for the chassis (wrx, Evo, a3/tt/golf, ect.)

    In big trucks, unless it’s a turbo diesel, no replacement for displacement

  12. Bravo GM!

    For all you chevvy drivers who want a full sized truck for your long, daily commutes through stop & go traffic….your dream has come true! 🙂

    • Hi Mike,

      Part of the reason for this is exactly what you imply – the people who buy trucks to use as cars, for commuting.It also explains the Quad Cab/short bed layout that is very popular among suburbanites.

      All fine, I suppose – in the sense of if that’s what they want.

      But, it is really an outgrowth of these CAFE regs, which effectively outlawed big sedans and big wagons – which were the big and “safe” vehicles preferred by women for carting kids around. Now they drive big trucks and huge SUVs.

      • How true. My kids were born in the late 90’s. No big sedans around so I put my wife in tahoes and suburbans. no way I was going to let her drive around a metro area in a small car.
        lately, with the cell phone problem, there have been more and more head-on collisions (many deaths) than I have ever seen, and it’s growing to about one a month, or more, just in my county.
        almost happened to me too, differential speed was over 100mph. the ‘other’ car just drifts over so it’s hard to catch. i got lucky i spotted it just in time but almost hit the pole to my right. she would have been dead in her compact car vs my truck and my son and i would have been in the hospital for sure or worse. i’ve also been lucky that my young son (at the time) witnessed a head on right in front of him leaving school. it was one of his friends too. his friend survived but it scared the crap out of my son.

  13. “The EPA’s test cycle assumes a certain amount of time not moving at all, or not moving much. Stopped in traffic – or just creeping along”

    Hopefully, someone with massive intelligence and testicles will successfully cheat their precious “test cycle” and deliver a better vehicle.

    Just don’t get caught.

  14. Physics doesn’t apply in Congress, Example? They consume vast quantities of energy (food, electricity, transportation fuel, etc) and, aside from moving their fat asses from point A to point B, accomplish no work whatsoever. Now, you may say that that is just a waste of energy, which it is, but I’d be willing to bet that they are so inefficient, they are actually destroying energy and matter in the process. That would at least explain why all our tax dollars keep “disappearing”!

  15. Wow. Your right the car business has gone completely batty. But they’ve done it to themselves, by welcoming and accepting CAFE, which simply limits competition from Asia. And why they were for it.
    I’ve been a GM coolaid drinker for 30 years, well over 30 cars and trucks of all models. I’m finally done with them. It started in ’07 when they started ‘tuning’ their engines/trans for mpg only. My ’07 and ’10 and ’11 trucks were the worst example of truck engine/trans combo’s I ever owned. To be fair, my ’14 6.2 was a lot better, but only because they did direct injection which ‘allowed’ the engineers to dial in a little more drivability.
    I’m going to Dodge this time (’19 or ’20), cause it’s t he oldest school v8 on the market. That’s the only reason.
    And I like how FCA is doing it (CAFE), with an ‘optional’ e-torque thingy, only if you care. I don’t.

  16. Eric,
    You may already know but journey over to the forums and see the million complaints about GM’s AFM/DOD fuel system. Precursor environmental virtue signaling in the NNBS trucks. A) it burns oil and B) once turned off and tuned every silverado owner has seen an uptick in mileage. So what’s the point of it? I follow the Xterra/Frontier forums as well, though I do zero offroading, and drivers there that have put VK56 or LS-swaps in their X and Fronty’s see mileage jump to 26-28MPG! And that is even without headers and a tune. Pray to god these new turbos aren’t flex fuel or their ‘real world’ mileage will be even worse if they try to run on 85-Corn Law gas.

    On another note, the reason they had to downsize the volume to 2.7L is if they left it at 4.0L or even 5.3L it would produce WAAAAY too much power so they had to gimp it into a pathetic drive train with bells and whistles.

    • Hi Brazos,


      I’d much rather have a mid-late ’90s-era 5.7 (350) with a TBI system, paired with a five-speed manual. I have driven these trucks and they are capable of close to 30 on the highway if driven reasonably and have ample V8 power for the sort of work a truck is useful for.

      The car business has gone batty…

      • Yeah, 1988-1995 were the golden years of TBI small block.

        I’ve never got close to 30 mpg but then I pretty much never drive on the highway except for 15 miles or so (out of 25!) to get to town to get gas. As it is I go several months just putting around the neighborhood and getting firewood on a half tank of gas.

    • Government is the first customer of all new vehicles now. The real world and a government test usually don’t match. But automakers have to care about the government test first. That’s why a system that is for fuel economy can actually harm it in real world use. It helps on the tests, just not for the end user.

  17. You said:
    Big V8 or small, heavily turbocharged four – it takes “x” horsepower to get a vehicle going. And that takes burning “Y” amount of fuel. In the end, it doesn’t matter whether the engine is a big V8 or a tiny turbo’d four.

    It’s actually even worse. The four cylinder turbo is going to burn more gas outputting the same amount of power for one simple reason – it has to compress air. The V8 doesn’t have to compress any air, so it ends up doing a smaller amount of work. This whole story the car press spreads that turbos capture “waste heat” or “waste pressure” is bs, there’s no such thing. Turbo boost comes via increased back pressure, so the exhaust stroke requires more work. This means the power stroke must produce that extra work, which means burning more gas.

    • It absolutely does increase back pressure. But the efficiency gains more than make up for it- and the back pressure is a function of using that otherwise wasted heat energy to stuff more fuel and air into your engine. As for me, I tend to prefer big displacement slow turning engines, like truck diesels and Caddy 500’s.

      Where the smaller engine generally loses ground vs my big slow moving one is friction loss as RPM’s increase, as well as the acceleration losses as you start stop and reverse your pistons faster. Big and slow are the way to go, just the opposite of what the current fad is.

      • What efficiency gains? When you have a naturally aspirated engine, timing and compression are set to maximize efficiency at atmospheric pressure. In a turbo, you have to have lower compression in order not to detonate on boost, that’s less efficient off-boost, more efficient on-boost due to higher net pressure. It’s a wash.

        Turbos are more efficient when not under load because they avoid the boost. They’re less efficient than an equivalent naturally aspirated engine off boost at the same power due to lower compression.

        • And when you have a computer controlled engine, timing and compression are adjusted to optimize engine efficiency under varying conditions. Stoichiometric ratios, combustion temps, etc all can be optimized to get as much useful work as possible out of a given amount of fuel. But I do take your point.

          The thing is, an engine is an air pump, and giving the incoming air a bit of squeeze will make its breathing in much easier, while as you correctly note it make breathing out a bit harder. Since our atmosphere is so thin, increasing the density of that charge allows us to get work out of the same physical displacement. So while the engine efficiency has an optimum, the space, weight, etc, constituting practical measures of efficiency of your car, seen as a system, can be higher.

          Whether it is worth it or not is a value judgement. I tend to agree with Eric, the gains in the real world are probably trivial if not negative.

          • Hi Ernie,

            In re all this:

            As you and other regulars here already know, I have a 1976 Trans-Am with a huge (7.5 liter) naturally aspirated (carbureted) V8 and no computer anything. Merely by swapping in a transmission with deep overdrive gearing (.67 if I remember correctly) and a righteous tune, I can get high teens out of it on the highway. . .very comparable the MPGs of a new Camaro SS.

            Part of the reason (aside from the OD tranny) is that the car is relatively light – about 3,800 pounds – and also rides on relatively small (15×7) wheels.

            Most modern vehicles are appallingly overweight and ride on idiotic 18, 19 and 20-inch “rims” (gnomesayin’)… and that’s why they get shitty mileage, even with all the technical Band Aids!

          • re weight compare say a 1997 Porsche 911 to today’s version. Ot Ferraris from 1978 to 2018. Modern exotics are almost too wide to drive safely and at least 50% heavier. Bloat bloat bloat. And much less nice to look at.

            • Amen, Mark.

              And the bloat is almost entirely due to …. saaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaafety mandates. Consider that almost all new performance cars (and cars generally) have aluminum engines. I can pick up and carry a current Camaro SS’s short block from the bed of a truck to inside the garage. I need an engine hoist to move the cast iron short block in my TA.

              If my TA had an aluminum engine, aluminum 15×7 wheels and aluminum suspension pieces – as well as the paper thin hood/fenders most new cars have – the thing would weigh just over 3,000 lbs.

              Yet the modern analogs, which have all those weight-saving advantages, are as heavy – or heavier – than my TA with all of its cast iron parts and heavy stamped steel panels.


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