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GM's New 2.7-Liter Turbocharged Truck Engine Rated For Regular Unleaded

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John Goreham
Contributing Writer, GM-Trucks.com
10-11-2018

 

Following our report yesterday on the new GM 2.7-Liter turbocharged gasoline engine, Mike Ofiara from Chevrolet Communications confirmed to GM-Trucks.com that GM will recommend Regular Unleaded fuel for the engine. This will have a major impact on the fuel economy of the vehicle. Many automakers launch new boosted engines with high compression as replacements for larger normally aspirated engines, only to then require premium fuel. Premium fuel has an average cost 16% higher than regular unleaded fuel according to today's average prices. While this may not seem like a big deal at first, do the math on a typical truck with a base engine and you will find the 10-year fuel cost can be around $23,000.  16% of that is around $3,700. 

 

With the new gasoline engine rated for the least expensive fuel in America, the cost comparison to operating a comparable diesel may tip in favor of the new gasoline engine from GM.  

 

The EPA has yet to publish the final official fuel economy numbers for the Silverado 1500 with the new 2.7-Liter engine. Once they are available, we will post them.  

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I don't care what the car manufacturers say, If you have a boosted engine it needs 91 or better octane. I would never run 87 in any boosted engine.  

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On ‎10‎/‎11‎/‎2018 at 8:04 PM, qwank said:

I don't care what the car manufacturers say, If you have a boosted engine it needs 91 or better octane. I would never run 87 in any boosted engine.  

I hear ya but consider thirty years ago we would have said the same thing about running 11:1 motors on 87 octane but today that is as common as dirt. It is a pretty good argument. OEM's have done this for years. Come up with something that has a huge impact on efficiency and then price the thing to keep the difference in their own pocket. I'm thinking about the first Honda Insight. Give the 100K battery life and initial cost the Insight cost more to own/operate than their very own Honda Civic HX that year. Oil burners have the same issue. 15% better mileage but 15% more expensive fuel. :lol: 

 

Just saying if they pull this off and don't price the thing to keep the gains for themselves this time  it might be the first time the consumer got an actual win in the exchange. 

Edited by Grumpy Bear
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I had two F-150s with the 3.5L ecoboost engine (2012 and 2015) and always used regular 87 octane gas.  Never had a problem even when towing.

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The engine also has direct injection, which effectively cools the combustion chamber and allows higher compression. And a pretty efficient (on paper at least) intercooler to chill the compressed air.

According to Automotive News, for RWD models:

2.7L:
20 city / 23 highway / 21 combined

5.3L:
17 city / 23 highway / 19 combined

Since these small turbo gas motors get crappy mpg under boost, I wouldn’t be surprised if real-world mpg is less than the 5.3



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12 hours ago, 71_340 said:

I had two F-150s with the 3.5L ecoboost engine (2012 and 2015) and always used regular 87 octane gas.  Never had a problem even when towing.

The takeaway isn't that you can't run 87 octane in an EcoBoost but that its numbers would be lower for power and fuel economy if Ford had rated it on 87 octane

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The 3.5L ecoboost engine is designed for 87 octane fuel which is the recommended fuel listed in the owner's manual.  There is no benefit in running premium in an engine designed for 87.

 

On the other hand most engines designed for premium will run OK on 87 because the ECM will just derate the engine power by retarding the ignition timing once spark knock is detected.  You will loose efficiency and some power though.

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I think that the 2.7 I4 is a dang joke.. If it got 30MPG Hwy OK maybe it'd be worth considering but. with a 2 mpg difference vs the V8 ? Same argument I have against the old 4.3, for the minor increase in MPG it's not worth giving up the power... Plus I'd be embarrassed to own a 4cyl full size pickup, at least the 6cyl models are respectable but, a 4 banger in a big ole truck like that just seems funny...

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23 hours ago, pronstar said:

The engine also has direct injection, which effectively cools the combustion chamber and allows higher compression. And a pretty efficient (on paper at least) intercooler to chill the compressed air.

According to Automotive News, for RWD models:

2.7L:
20 city / 23 highway / 21 combined

5.3L:
17 city / 23 highway / 19 combined

Since these small turbo gas motors get crappy mpg under boost, I wouldn’t be surprised if real-world mpg is less than the 5.3



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I agree, we have a 1.5 Turbo in our Malibu and it misses the mark by  a couple MPG if you get into the boost much... It sure beats the old 2.5L N/A for performance...

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Wow, no 91?  I'm honestly surprised as many OEM's are pushing for higher octane as they can get better fuel economy numbers if they optimize them for 91+up on these low displacement high boost engines. 

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If a 4door full sized trucks could get 30 miles per gallon at 72 MPH and be priced between 25-30K that would end the mid sized car market. The only thing I would do to it would be to put a 2-4 lowering kit on it. And a bed cover.


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Wow, no 91?  I'm honestly surprised as many OEM's are pushing for higher octane as they can get better fuel economy numbers if they optimize them for 91+up on these low displacement high boost engines. 


The folks this engine is designed for are looking to save costs, requiring premium fuel could turn them off to the engine.




If a 4door full sized trucks could get 30 miles per gallon at 72 MPH and be priced between 25-30K that would end the mid sized car market. The only thing I would do to it would be to put a 2-4 lowering kit on it. And a bed cover.


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Sedan market is dying regardless, SUVs and crossovers are killing it globally.


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Sedan market is dying regardless, SUVs and crossovers are killing it globally.


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I was a pickup driver all my life. 8 years ago my wife bought a full sized sport sedan. It’s fast, gets great mileage, more comfortable on trips and much cheaper than a comparable equipped truck. I keep a pickup around just in case,my daily and trip vehicle is a car now. I think with the Asians making sports sedans affordable we may see a leveling out with fun four doors. I see a stinger in my future.


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I think alot of people simply are stuck in the era of wet intake manifolds (fuel wet, not coolant wet) and traditional ignition systems.  There was a camshaft company back in the late 70s/early 80s that was pushing a kit that consisted of 12:1 pistons and a special camshaft grind that allowed engines to use regular fuel on a high compression engine.  For the life of me I cannot recall which company it was. They used the camshaft profile to allow it to work. 

 

There is no sense in being stuck in the era of port injection.  Direct njection was a huge improvement that most people simply either don't believe it, or don't understand it.  Direct injection can allow regular fuel to be used with high compression, including the cylinder pressures under 14psi boost conditions. I can understand the doubt, but, don't really get the idea of writing this engine off without ever seeing it this engine is not shown on the Silverado or the Sierra website.  GM is showing the 5.3 as the standard engine, with no indication the 2.7 will even be in the 2019 truck. 

 

Ford put the V6 Ecoboost engine in their 150 series of pickups 8 years ago and the pundits declared that engine would never work in a pickup truck, and who would ever tow with a lowly V6.  You have to admit Ford accomplished what they set out to do.  

 

Engine power has nothing to do with the number of pistons it has.  It does however have everything to do with the effective displacement.  A 2.7 litre engine running under 14psi of boost is now effectively a 5.4 litre engine.  It has half the rotating mass of a V8 5.4 litre engine, and that frees up some power that gets transferred to output.  The addition of direct injection has changed how engines are tuned.  And it is not just a simple single change, it changes the pressure of injection, the timing of the injection, how the fuel is injected, even the number of times the fuel is injected in one compression stroke. 

 

Ford is so sold on the ecoboost engine that they are putting a 450 horsepower and 510 pound-feet of torque ecoboost into the 2019 F150 pickup truck.  A v6 in a pickup truck. Don't know how far back this website has threads available, it would be interesting to see how many predicted that a V6 would never be able to tow reliably.  I simply prefer to wait to see this technological wonder of an engine.  I have already called my GM salesman to have him call me when the first 2.7 sales lot truck comes in so I can take it for a weekend test drive. 

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18 hours ago, 71_340 said:

The 3.5L ecoboost engine is designed for 87 octane fuel which is the recommended fuel listed in the owner's manual.  There is no benefit in running premium in an engine designed for 87.

 

On the other hand most engines designed for premium will run OK on 87 because the ECM will just derate the engine power by retarding the ignition timing once spark knock is detected.  You will loose efficiency and some power though.

This is what Ford wants you to think.  

 

Yes it will run on 87, but it's power rating and mpg ratings were established using 93 octane.  This is a fact.  They do this to trick the average buyer.  

 

Their literature states the figures are using 93 octane.  So yes, it runs on 87 just fine. But it makes less power and gets worse mileage.  

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