QuasiMofo (John Brown) said:
Gearheadotaku (Forum Supporter) said:
The HWY fuel rating is only 1 mpg more for the 2wd 4cly 8 speed vs the 5.3 10 speed (8 speed is the same)
Every 2019-22 5.3 owner I know are averaging about 15mpg real world driving, you know between valve train repairs, my best tank is 27 my average is nearly 23. I am certain the PUBLISHED 5.3 number is inflated and the 2.7 number is close to actual.
I was just using the numbers from Fuel economy .gov.
Thanks for chiming in with real world experiences.
87 or 93 octane?
In reply to QuasiMofo (John Brown) :
I do a lot of highway for work and my '16 is pretty close to this website. I just burned a tank the past 2 weeks with it all around town, some 4WD action and a bunch of 0dgF weather driving the kid to work. That tank was 13.8mpg - daughter was shocked.
Driven5 said:
In reply to Pete. (l33t FS) :
While I'm not yet ready to buy-in on dual injection doing nothing to prevent carbon buildup, regardless of its primary purpose, looking a little deeper I am inclined (and pleased) to agree that carbon buildup does not appear to be a significant issue on the 2.7T's so far. Basically all of the "common GM 2.7T problems" lists appear to be based more on assumptions than real world results.
Took me a few read throughs on this.... but what I read Pete say is that intake system deposits is not the reason the PFI injector was added to DI systems, which is correct. I don't think he suggested that it doesn't help, just that it's not the reason.
My experience is like yours- DI intake deposits are very dependent on who designed the motor as opposed to being universal.
The added PFI injector is mostly there for more power and for huge options for cold start emissions. The amount of different things you can do with injections and injection timing is pretty astounding for a PFI-DI system. Although I would not say that NOx is the only thing DI or DI-PFI is for.... Maybe for some engines, just not the ones I worked on.
Gearheadotaku (Forum Supporter) said:
310 hp/430lb of torque out of a 2.7 gas 4cly sounds great in a lab, but in the real world I guess time will tell.
I just imagine very high cyl pressure compared to a standard motor putting excess stress on rings and gaskets. Heat soak from long grades or long idle times. Has anyone seen the cooling system on these? Multiple valves controlled by the ECM to cool different things at different rates. Just sounds like more failure points.
The HWY fuel rating is only 1 mpg more for the 2wd 4cly 8 speed vs the 5.3 10 speed (8 speed is the same)
Lots of LS engines out there with 200K+ miles and very little repairs. Other simple designs have done it too.
Who has a 200k mile gasoline turbo engine on its OE head gasket? OE turbo? OE timing chain?
Do you really think none of that was thought about and heavily tested for? Or even tested until things failed to see what the mileage is? Given how testing and requirements have evolved, I'm pretty confident this new engine had to pass a lot more tests than the LS engines did in the late 90s.
That being said, your worries are what I thought would chase off buyers of the turbo DI v6's put into F150s. Boy, was I very, very wrong about that. It's so popular that it's risked the V8 in the Mustang. There are millions of V6 turbo DI engines out there that have Ford logo on the front of the truck.
Yes, I agree that the 2.7 should have undergone heavy testing. Then again I'm sure many things out there have tested well only to flop and fail in the real world. (and sometimes continue to be produced. CVT Nissan anyone?)
The odds just don't seem to be in it's favor, only time will tell.
In reply to Gearheadotaku (Forum Supporter) :
87 octane under 80°, 93 above.
Also 
The last 20 fill ups. Some loaded with trailer, some sub zero which REALLY affects mileage because I will let the remote start eat!
Even if a 2.7T truck "only" averages 2.5mpg (18.5 vs 16) better than the equivalent-V8 truck, that actually saves more gas per mile than a 40mpg car does over a 30mpg car or a 60mpg car would over a 40mpg car.
QuasiMofo (John Brown) said:
In reply to Gearheadotaku (Forum Supporter) :
87 octane under 80°, 93 above.
I tried some premium on my 2.0l turbo when towing. Didn't notice a change at all. Kinda bummed about that.
I think the real issue here is not turbo 4 vs V8, but losing the 4.3 V6 option in the full size truck (and the smaller V6 in the Colorado). My dad has a 2017 Silverado, 4wd, Extended cab, V6, and over 50,000 miles he's gotten anywhere from 20 to 24 mpg, depending on whether he's hauling landscape stuff around or driving to Florida. He's looking at a new truck, and doesn't want the fuel economy of the 8 or a "science experiment" turbo 4.
He's asking me what to do, and my best advice so far is for him to just keep his '17. If he gets a new truck with the 8, and it eats gas, he's going to be upset, and if he gets a truck with a Turbo 4 and it has problems, he's gonna be pissed.
The fuel economy gains of the turbo 4, compared to the 6, seem to be trivial. Granted, the turbo makes more power and torque than the old six, but that's not a selling point for everyone.
In the news: New 2.7l four makes more power and torque than the old 7.4l V8 from the one ton trucks, and WAY more power and torque than the old Diesel from the one ton trucks.
In the thread: "Seems weak"
QuasiMofo (John Brown) said:
Also
The last 20 fill ups. Some loaded with trailer, some sub zero which REALLY affects mileage because I will let the remote start eat!
That is awesome.
Now only if even the base model trucks didn't weigh 7000lb and require a ladder to get things into the bed and FAA clearance before driving because of how tall they are.
Driven5 said:
Even if a 2.7T truck "only" averages 2.5mpg (18.5 vs 16) better than the equivalent-V8 truck, that actually saves more gas per mile than a 40mpg car does over a 30mpg car or a 60mpg car would over a 40mpg car.
I agree. Once a car crosses 30mpg diminishing returns stack up fast. Its hard to get people to understand this.
In reply to QuasiMofo (John Brown) :
That's really impressive record keeping. How much oil does it consume and how often do you change it?
Imagine the fuel economy if you could get this in a stick shift regular cab that weighed 1500lbs less!
Gearheadotaku (Forum Supporter) said:
Imagine the fuel economy if you could get this in a stick shift regular cab that weighed 1500lbs less!
A new Colorado is about the same size as an old full size, just missing the manual option.
Pete. (l33t FS) said:
In the news: New 2.7l four makes more power and torque than the old 7.4l V8 from the one ton trucks, and WAY more power and torque than the old Diesel from the one ton trucks.
In the thread: "Seems weak"
So the 2.7T is a suitable replacement for a L29 454 in a 1 ton pickup because it makes a little more power? The V8 made 290hp and 410lbs.
Here's an article form GM authority: https://gmauthority.com/blog/gm/gm-engines/l3b/
Yes its an interesting bunch of tech, but it still feels "fragile".
Gearheadotaku (Forum Supporter) said:
In reply to QuasiMofo (John Brown) :
That's really impressive record keeping. How much oil does it consume and how often do you change it?
Imagine the fuel economy if you could get this in a stick shift regular cab that weighed 1500lbs less!
Given the requirements, probably less than 10k/qt. Modern emissions require very little oil consumption.
Also, modern emissions requirements means that the engine has to meet the rules at 150k miles, which means that it operates better than a engine 20 years ago- by a considerable margin, at 150k. Durability matters for emissions, too.
I've posted it here before, but one of the major drivers for engine durability and reliability have been the emissions requirements.
In reply to Gearheadotaku (Forum Supporter) :
How does it feel fragile?
In reply to alfadriver :
Did not know about the 150k miles requirement. That's fascinating.
Thanks for your effort on this while working for FMC, alfa
Gearheadotaku (Forum Supporter) said:
Pete. (l33t FS) said:
In the news: New 2.7l four makes more power and torque than the old 7.4l V8 from the one ton trucks, and WAY more power and torque than the old Diesel from the one ton trucks.
In the thread: "Seems weak"
So the 2.7T is a suitable replacement for a L29 454 in a 1 ton pickup because it makes a little more power? The V8 made 290hp and 410lbs.
Here's an article form GM authority: https://gmauthority.com/blog/gm/gm-engines/l3b/
Yes its an interesting bunch of tech, but it still feels "fragile".
I mean yeah, if you're constantly working at vehicle capacity and using all the torque available the whole time, it'll be more fragile than a giant n/a engine chugging along at 40% of the output it's capable of. But that's not remotely how 99.99999% of the vehicles with this engine in them are going to be used so it's not really relevant. I wouldn't want this engine in our 20k lb RV despite basically the same power and torque output, but there's no way I'd want the rv's giant V10 in a daily use light truck.
dps214 said:
Gearheadotaku (Forum Supporter) said:
Pete. (l33t FS) said:
In the news: New 2.7l four makes more power and torque than the old 7.4l V8 from the one ton trucks, and WAY more power and torque than the old Diesel from the one ton trucks.
In the thread: "Seems weak"
So the 2.7T is a suitable replacement for a L29 454 in a 1 ton pickup because it makes a little more power? The V8 made 290hp and 410lbs.
Here's an article form GM authority: https://gmauthority.com/blog/gm/gm-engines/l3b/
Yes its an interesting bunch of tech, but it still feels "fragile".
I mean yeah, if you're constantly working at vehicle capacity and using all the torque available the whole time, it'll be more fragile than a giant n/a engine chugging along at 40% of the output it's capable of. But that's not remotely how 99.99999% of the vehicles with this engine in them are going to be used so it's not really relevant. I wouldn't want this engine in our 20k lb RV despite basically the same power and torque output, but there's no way I'd want the rv's giant V10 in a daily use light truck.
To meet that math, the larger engine has to be considerably more powerful than the smaller one. So if one is running at 200hp which is max, and the other that's only 40%, then the larger engine would be 500hp. One is hardly a replacement for the other.
The reality is that the "larger v8" is working just as relatively hard as the "small I4". Worse, since the I4 probably has more torque, the V8 will be spinning faster so that the power output is the same.
So all of these "working harder", "loafing along" is so incredibly relative that the comparison makes no sense.
Don't these also have some new kind of dual-volute turbocharger?
yupididit said:
In reply to Gearheadotaku (Forum Supporter) :
How does it feel fragile?
He caveman-ed it, tore it still running out of the front and hefted it like a trophy skull.
Grugtaku no think engine strong
In reply to GIRTHQUAKE :
Twin scroll (although I don't know if it has it or not- that's what it would be called). For those cyls 1-4 go to one scroll area, 2-3 go to another. So it should spin up faster- allows for a bigger turbo that has less lag.
Variable scroll is also coming back- as it does a better job of that (and applies to 3 cylinders).
All of them have to have a well designed bypass to let the catalyst light off really quickly.
In reply to Gearheadotaku (Forum Supporter) :
Change the oil at "10%" (about 6500mi) at the dealer with whatever Dexos spec they use, two intervals have used 3/4 qt one used 1 qt all before 24k since then no extra oil used.
yupididit said:
In reply to Gearheadotaku (Forum Supporter) :
How does it feel fragile?
A whole lot of small moving parts and (even more) computer controls. Variable oil pump, multiple cooling valves, etc. The simple cast iron pushrod engine has proven its durability over and over. Ford went back to pushrods for their new 7.3 V8.
I've been looking for the GCVW on the 4 cly, but no luck yet.
