Anybody go from 6.2 to 3.0 diesel?

[truckguy82]

So right now I have a k2xx. I average 10mpg in my 6.2. This is extremely low because I live in the surburbs of philadelphia and 99% of my driving is a stop sign or traffic light every 1/4 mile. On top of that I have a rather heavy right foot. I know I don’t have a problem with my truck because if I gently cruise along the highway at 65mph I’m getting 25-26mpg.

 

This, as you might guess, is extremely expensive. To the point where it I’m about to go hybrid or full electric since they recapture most of their inertia, an ideal situation for my area.

 

is there anybody who lives in a very dense area, that got remotely close to my mpg in a 1500 gasser, and now drives the new baby duramax. What sort of mpg are you getting?

[blckblt]

2020 TB w/ 6.2 to 2021 AT4 with 3.0.  Had 14k miles on 6.2 over 15 months in Maine. Lifetime of 14.9 MPG.  Small city driving, some rural roads and some highway.  I have a ~35 mile trip that I make 3 times week.  The best I got was 21 on trip and typically 19ish.  Mix of all conditions except highway.

 

2021 AT4.  1100 miles.  Lifetime 22.3 and has been climbing.  Same driving as above with the exception of cold winter as I got the truck in mid April.  On the same ~35 mile trip as above I average 25-31.  Depends on traffic, lights etc.  Last night I got 27 and the truck did a regen.  Prior to that I hit 31 on the trip before.

 

Having all the torque at 1500 rpm is awesome.  I loaded the truck with bags of mulch (31 bags) and didn't even notice the weight (truck squatted 3")

Edited May 19, 2021 by blckblt

[bdallas]

I live and drive in a dense area. I have about 1200 miles on my baby duramax and I'm currently averaging just under 24 miles per gallon. This is all suburb/city driving. Stop and go, stop and go. Very little highway time. I also have noticed it getting slightly better over time. 

 

[Ben M]

Same...getting around 26 with 15 miles of stop and go to and from work

[truckguy82]

Wtf? 25 in the city?

 

no way

 

why do i feel like you guys say this but when I get it I’ll get 14-15 lol

Edited May 20, 2021 by truckguy82

[truckguy82]

19 hours ago, blckblt said:

2020 TB w/ 6.2 to 2021 AT4 with 3.0.  Had 14k miles on 6.2 over 15 months in Maine. Lifetime of 14.9 MPG.  Small city driving, some rural roads and some highway.  I have a ~35 mile trip that I make 3 times week.  The best I got was 21 on trip and typically 19ish.  Mix of all conditions except highway.

 

2021 AT4.  1100 miles.  Lifetime 22.3 and has been climbing.  Same driving as above with the exception of cold winter as I got the truck in mid April.  On the same ~35 mile trip as above I average 25-31.  Depends on traffic, lights etc.  Last night I got 27 and the truck did a regen.  Prior to that I hit 31 on the trip before.

 

Having all the torque at 1500 rpm is awesome.  I loaded the truck with bags of mulch (31 bags) and didn't even notice the weight (truck squatted 3")

This seems more realistic. I mean I had a house in Vt and have been to main a lot.

 

the amount of stop signs and traffic lights I hit in NJ is about 10x what it is in vt and maine

 

so if this guy was doing 15 in his 6.2 and I’m doing 10, and now he’s averaging 22-23, it sounds like 14-15mpg seems more realistic

 

Lets be honest guys that say 25mpg, you’re trying get that? That sounds nuts. I mean it’s still 5500lbs of mass propelled by petroleum.

 

[blckblt]

Trim and tires effect this.  Non AT4 and especially non Duratracs would give about 2-3 more mpg.  Those 2 items add a lot of wind drag and rolling weight for the tires.  With that said I am a direct comparison as my TB had duratracs as well.

 

I will add that my lifetime went up to 22.4 yesterday with basically just small town driving yesterday.

 

I will add that I drove my 6.2 like it deserved to be drove at times.  That motor was fun. As the 3.0 is just getting broken in I have started to get on the pedal heavier.

 

Regardless my lifetime right now is slightly more than a 7 mpg gain.  Diesel around here is the same (or cheaper) than premium.  160-170 extra miles per tank.  Roughly saving me $20-25 per tank.

 

I believe that the silverado gets slightly better MPG as it is a little more aerodynamic.

 

I will also add that the 10sp transmission is a game changer.  smooth.  always seems to be in the right gear.  definitely helps with the economy.  I have had 6 and 8 sp GM transmissions, tundra 6 sp, ram 8 sp and by far the 10 speed is the best 1/2 ton transmission I have driven.

 

I am curious to see what 14k of mileage looks like on the 3.0 for more accurate comparison.

 

2 minutes ago, truckguy82 said:

This seems more realistic. I mean I had a house in Vt and have been to main a lot.

 

the amount of stop signs and traffic lights I hit in NJ is about 10x what it is in vt and maine

 

so if this guy was doing 15 in his 6.2 and I’m doing 10, and now he’s averaging 22-23, it sounds like 14-15mpg seems more realistic

 

Lets be honest guys that say 25mpg, you’re trying get that? That sounds nuts. I mean it’s still 5500lbs of mass propelled by petroleum.

 

 

[It's Tim]

21 hours ago, truckguy82 said:

This, as you might guess, is extremely expensive. To the point where it I’m about to go hybrid or full electric since they recapture most of their inertia, an ideal situation for my area.

Why bother to drive a truck if one doesn't need a truck?

No one buys a truck for "fuel economy", they buy it because they need a truck.

[truckguy82]

49 minutes ago, It's Tim said:

Why bother to drive a truck if one doesn't need a truck?

No one buys a truck for "fuel economy", they buy it because they need a truck.

I’m just going to pass on penetrating your soul with the giant dick of logic since you and everybody else is well aware how stupid that is.

 

Only morons don’t care about expenses

 

[blckblt]

4 hours ago, truckguy82 said:

I’m just going to pass on penetrating your soul with the giant dick of logic since you and everybody else is well aware how stupid that is.

 

Only morons don’t care about expenses

 

I drive a truck as I like trucks, I am not a car guy.  I like to be in a bigger and higher up vehicle as there are a lot of shitty drivers.  With that said I do use my truck as well for truck stuff so if I can get better economy it is an extra benefit for me.

 

The response of no one drives a truck for fuel economy is not helpful on a thread asking about going from the 6.2 to the 3.0 as fuel economy would be the main reason for doing so......

[truckguy82]

On 5/20/2021 at 2:57 PM, blckblt said:

I drive a truck as I like trucks, I am not a car guy.  I like to be in a bigger and higher up vehicle as there are a lot of shitty drivers.  With that said I do use my truck as well for truck stuff so if I can get better economy it is an extra benefit for me.

 

The response of no one drives a truck for fuel economy is not helpful on a thread asking about going from the 6.2 to the 3.0 as fuel economy would be the main reason for doing so......

Yeah I mean I’m spending $500/month in fuel.

 

All I need is a bed and 4 seats. I haul tools not weight. Spend 4 hours a day in my truck so want it to be luxurious. Also want it to be fun to drive since I’m a sports car nuts and I have to be stuck in a truck all day. Be perfect vehicle would be a 4 door sports car with a bed in the back. Seriously considered highly modifying a subaru baja.

 

I’ve owned diesels before. They are not fast, but the acceleration is “satisfying” and it seems like, from the reviews, the 3.0 has that satisfying acceleration feeling in spades. Literally every review comments on how nice the engine “feels”

 

 

 

 

[johnnymordoc]

Quick question - I take the new diesel 3.0 and the larger ones do not have a fuel management system?

A co-worker has a 2019 and  his gas engine shuts off when he stops? Do the diesels also do this? If so, how is it on wear and tear? In California it cost me almost $100 to fill up my 2014 Sierra 1500 and I am my mileage is steady at about 11-12 mpg. It used to be 20-22 when new. What kind of fuel management is in new trucks - especially with the chip shortages now?

I think the rule of thumb is not to by the first year of a major change to the truck line. Any news on the 3.0 Duramax diesels? They have only been out a year or so and wondering about longevity and maintenance. 

Thanks in advance.

Edited May 24, 2021 by johnnymordoc

[tommyxc]

Just traded a 19 power wagon for a 3.0 at4. I use my truck like a truck I tow and haul. I was averaging 12mpg with the pw so far with duramax i am averaging 23.2. it only has 2300 mile .IF you don't care about gas mileage then you can pay for mine also 

[redwngr]

On 5/24/2021 at 10:52 AM, johnnymordoc said:

Quick question - I take the new diesel 3.0 and the larger ones do not have a fuel management system?

A co-worker has a 2019 and  his gas engine shuts off when he stops? Do the diesels also do this? If so, how is it on wear and tear? In California it cost me almost $100 to fill up my 2014 Sierra 1500 and I am my mileage is steady at about 11-12 mpg. It used to be 20-22 when new. What kind of fuel management is in new trucks - especially with the chip shortages now?

I think the rule of thumb is not to by the first year of a major change to the truck line. Any news on the 3.0 Duramax diesels? They have only been out a year or so and wondering about longevity and maintenance. 

Thanks in advance.

 

 

3.0 was available on 2020 model.

2022 is approaching.

 

3.0L does have the auto stop/start.  There is a list of conditions when it doesn't run (same as gassers). 

Does not have a 'displacement on demand' type system.  

 

 

https://gm-techlink.com/?p=12050

New Duramax Diesel 3.0L 6-Cylinder Engine Powers Up Silverado 1500, Sierra 1500

September 13, 2019

The all-new Duramax^® Diesel 3.0L inline 6-cylinder turbocharged engine (RPO LM2) delivers plenty of power — producing 282 horsepower and 450 lb.-ft. of torque — along with impressive fuel economy — an estimated 30 mpg (7.8L/100km) highway on 2WD models — in an efficient package. (Fig. 1) Available on 2020 Silverado 1500 and Sierra 1500 models, it’s paired with the 10L80 10-speed automatic transmission (RPO MQB).

 

Fig. 1

 

Turbocharged Performance

The dual overhead camshaft (DOHC) engine uses an aluminum block with six pressed-in iron sleeves and a high pressure diesel fuel injection system. The lower oil pan is made of dual-layer stamped aluminum. (Fig. 2)

The 3.0L diesel engine uses SAE 0W-20 dexosD diesel engine oil. Do not add anything to the oil.

 

Fig. 2

 

The turbocharger is a variable nozzle design with an electric vane actuator attached to the exhaust manifold. The Variable Geometry Turbine (VGT) body assembly contains a contact-less inductive VGT position sensing element that is managed by a customized integrated circuit. The VGT position sensor provides a signal voltage that changes relative to the VGT vanes angle. The customized integrated circuit translates the voltage based position information into serial data using Single Edge Nibble Transmission (SENT) protocol. The VGT position sensor information is transmitted between the VGT body and the Engine Control Module (ECM) on the signal/serial data circuit. The ECM decodes the serial data signal and is used as voltages for the VGT position sensor.

The intake manifold houses the integrated intercooler. The intercooler system includes an air cooler/heat exchanger built into the intake, a charge air cooler (CAC) radiator assembled in the front fascia, and an electric coolant pump. The CAC coolant pump provides operational and diagnostic feedback to the ECM. (Fig. 3)

 

Fig. 3

 

The fuel system features a 3-phase electric fuel pump in the fuel tank that is controlled by the fuel pump driver control module and the ECM. Fuel is pumped from the fuel tank to the fuel filter assembly, which consists of a fuel filter/water separator, fuel heater, fuel temperature sensor, and a water in fuel sensor.

The ECM controls the fuel injection timing and has the ability to learn injector timing performance. Under the correct operating conditions, the ECM will pulse each injector individually and measure the changes in rotational speed of the crankshaft using the input from the crankshaft position sensor. The ECM will run this diagnostic at one fuel rail pressure operating point for each injector. The ECM stores the injector timing value.

 

Active Thermal Management

The Active Thermal Management (ATM) system on the 3.0L diesel engine distributes coolant through the engine in a targeted manner, sending heat where it’s needed to warm up the engine and reduce friction. It also promotes quicker heating of the passenger compartment and enhanced engine cooling during high power operation. The system uses a conventional engine-driven coolant pump while the ECM controls the ATM system using feedback from various coolant temperature sensors.

The engine coolant flow control valve assembly that is part of the ATM system uses two chambers to control coolant flow. (Fig. 4) The first chamber controls the coolant flow rate across the radiator and bypass. The second chamber controls the flow to the transmission and engine oil cooler as needed, providing heated coolant from the EGR/turbocharger return circuit or cold coolant directly from the pump outlet.

 

Fig. 4

 

Exhaust Aftertreatment System

The exhaust aftertreatment system is designed to reduce the levels of hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), and particulate matter (PM) pollutants remaining in the engine’s exhaust gases before they exit via the vehicle’s exhaust tailpipe. NOx is controlled by a Selective Catalytic Reduction (SCR) converter combined with precise injections of Diesel Exhaust Fluid (DEF), while PM is controlled by a diesel particulate filter (DPF). To reduce packaging volume and manufacturing cost, the SCR catalyst on the DPF is coated to form an SCR-coated DPF, or a Selective Catalytic Reduction on Filter (SCRoF). The close coupled DOC along with the SCR on Filter are integrated into one assembly.

In the DPF, particulate matter consisting of extremely small particles of carbon remaining after combustion are removed from the exhaust gas by the large surface area of the DPF. DEF is injected into the exhaust gases prior to entering the SCRoF stage. Within the SCRoF, NOx is converted to nitrogen (N2), carbon dioxide (CO2), and water vapor (H20) through a catalytic reduction fueled by the injected DEF.

The exhaust aftertreatment system components (Fig. 5) include:

1. Exhaust temperature sensor
2. DEF injector mounting flange
3. Exhaust pressure differential sensor pipe
4. Exhaust pressure differential sensor pipe
5. EGR flange
6. NOx catalytic converter assembly
7. Particulate matter boss
8. Exhaust back pressure valve

 

Fig. 5

 

The DEF fill, identified by a blue cap, is located behind the fuel fill door. (Fig. 6) After filling the DEF tank, unless the DEF tank was empty, there may be a short delay before the increased fluid level is detected and the DEF level indicated on the Driver Information Center is updated.

 

Fig. 6

 

Automatic Engine Stop/Start System

Designed to help conserve fuel, the Automatic Engine Stop/Start system may turn off the engine when the brakes are applied and the vehicle is at a complete stop, if the required operating conditions are met. The tachometer will read Auto Stop.

The Stop/Start system can be disabled and enabled by pressing the Stop/Start switch on the center of the instrument panel. (Fig. 07) The system is enabled each time the vehicle is started.

 

Fig. 7

 

An auxiliary electric engine coolant pump motor (Fig. continually circulates engine coolant through the heater core while the Stop/Start system has shut down the engine and the ambient temperature is colder than 59°F (15°C) to maintain the passenger compartment temperature.

 

Fig. 8

 

The 3.0L diesel engine also features an active engine mount system to enable an optimal balance between vehicle Noise Vibration and Harshness (NVH) performance and vehicle dynamics, including during Automatic Engine Stop/Start events. There is a single solenoid on each active engine mount that is energized during an ignition event and switched on for idle and driving events. The solenoid valves are supplied with battery voltage through a single fuse and are controlled by the ECM.

 

Normal Sounds After Engine Shut-Off

After the 3.0L diesel engine has been shut off, several sounds may be heard in the engine bay. These sounds may be caused by the following components performing a cleaning cycle:

• Turbocharger linkage (Fig. 9)
• Exhaust throttle valve
• Intake manifold swirl valve

 

Fig. 9

 

The sounds are normal operating characteristics of the vehicle and do not impact the designed performance or reliability of the vehicle.

Refer to Bulletin 19-NA-188 for additional information.

[johnnymordoc]

Thanks redwngr!  

 

This helps a lot - as for maintenance  - I know this is a bit forward thinking, but does it have a chain driven crank or is it belt?

I recall the Japanese cars had that notorious drive belt that had to be changed around 100K for fear of breaking and wreaking havoc on the top end of your vehicle.

 

As for towing - it appears that the transmission cooler is incorporated into the engine cooling system also?

 

What is a service - what is it going to cost me vs. a gas powered vehicle?

 

Is the everything programable as far as fuel management - are they able to do software updates to tweak things?

I have a friend that has a Dodge EcoDiesel that got a software update and I cannot recall if it made gas mileage better or worse for his CA driving - is this something to be concerned about with CA emissions?

 

Thanks.