Gas or Diesel on my new 2025?

[securityguy]

But the 6.6L gas has 401 hp and 464 lb ft of torque while the 6.2L gas has 420 hp and 460 lb ft of torque. Am I missing something? What makes the 6.6L so good? Please educate me....

No lifter issues because no built in DFM components and no auto start stop built in. Much better and more reliable motor.

 

[AXE]

I'll jump on the negative bandwagon for the 6.2
Piece of shit. Lifters and converters in just 5700 miles
Some have bearing issues now
Spent more time in the shop than on the road.
Actually the whole truck is turning into a POS.
I believe the 6.6 doesn't have the DFM and no lifter issues.
22 years it took me to buy a new truck and the ZR2 is the worst decision I have ever made

Check out the Rams right now, they have some huge discounts. You may be able to exit without much loss.

 

[185EZ]

Check out the Rams right now, they have some huge discounts. You may be able to exit without much loss.

Started the chevy buy back process.
Not really sure it will turn into anything positive
Also sitting down with owner of dealer next week.
I see him everyday and he said whatever it takes to make me happy
I like the ZR2 but this one not good. Diesel won't work for my driving. Might consider the HD but really don't need to go big.

 

[DNZR2]

It stays in one piece.

Would you mind posting a dissertation of why that is? I’ll have about an hour I need to kill.

 

[KLA]

Some of you guys are making a joke of this, but i asked a serious question. What makes the 6.6L gas motor so good? I get it that there is no DFM or auto start/stop, and that is a BIG PLUS, but the power is just not there. For a bigger 6.6L motor, I would expect a lot more power than this one puts out.

 

[MrScottly]

Some of you guys are making a joke of this, but i asked a serious question. What makes the 6.6L gas motor so good? I get it that there is no DFM or auto start/stop, and that is a BIG PLUS, but the power is just not there. For a bigger 6.6L motor, I would expect a lot more power than this one puts out.

Without posting a dissertation, maybe it's best to say that it doesn't produce enough power to self-destruct. And keep in mind, horsepower is just a number based on RPM and torque.

 

[AXE]

Some of you guys are making a joke of this, but i asked a serious question. What makes the 6.6L gas motor so good? I get it that there is no DFM or auto start/stop, and that is a BIG PLUS, but the power is just not there. For a bigger 6.6L motor, I would expect a lot more power than this one puts out.

I think it's a just a matter of managing the power output to match the integrity of the block. This motor is primarily in tow rigs and service vehicles (ambulances) and higher torque matters more than higher power. I think if they try to grab more horsepower with minimal torque gains, it would only compromise the integrity of the motor and longevity. If you hooked up 15k lbs and start trying to push higher horsepower, that motor is gonna be screaming trying to tug that load up a 6% grade. Also, your already burning massive amounts of fuel, so more power makes this an undesirable motor if you can't get 6 mpg.

I assume if you bought one and never plan to tow or carry cargo, then you could tune it or supercharge it and get better performance. Maybe it wouldn't compromise the reliability.

 

[AXE]

I'll jump on the negative bandwagon for the 6.2
Piece of shit. Lifters and converters in just 5700 miles
Some have bearing issues now
Spent more time in the shop than on the road.
Actually the whole truck is turning into a POS.
I believe the 6.6 doesn't have the DFM and no lifter issues.
22 years it took me to buy a new truck and the ZR2 is the worst decision I have ever made

I've got two 6.2s and they have been perfect and one of them gets flexed plenty. Oil analysis suggests they are a well oiled machine. I expect they will run about 250k each.

 

[MrScottly]

Some of you guys are making a joke of this, but i asked a serious question. What makes the 6.6L gas motor so good? I get it that there is no DFM or auto start/stop, and that is a BIG PLUS, but the power is just not there. For a bigger 6.6L motor, I would expect a lot more power than this one puts out.

6.2L V-8 L87

• HORSEPOWER: 420 HP @ 5600 RPM.
• TORQUE: 460 LB-FT @ 4100 RPM

See the difference? The 6.2 has to spin faster to create that higher number. The 6.2 has a shorter stroke so it's comfortable spinning faster. But what's more important is the curve....Which I don't have. I'd bet that the 6.6 has higher torque output through out the RPM range, particularly the lower range. This makes USING that power easier. And because you don't have to spin it as fast to create that power, you can theoretically spin it slower to move a given load, resulting in less wear and tear.

 

[KLA]

Without posting a dissertation, maybe it's best to say that it doesn't produce enough power to self-destruct. And keep in mind, horsepower is just a number based on RPM and torque.

I think it's a just a matter of managing the power output to match the integrity of the block. This motor is primarily in tow rigs and service vehicles (ambulances) and higher torque matters more than higher power. I think if they try to grab more horsepower with minimal torque gains, it would only compromise the integrity of the motor and longevity. If you hooked up 15k lbs and start trying to push higher horsepower, that motor is gonna be screaming trying to tug that load up a 6% grade. Also, your already burning massive amounts of fuel, so more power makes this an undesirable motor if you can't get 6 mpg.

I assume if you bought one and never plan to tow or carry cargo, then you could tune it or supercharge it and get better performance. Maybe it wouldn't compromise the reliability.

Yes, horsepower is a calculated number and torque is what matters. I understand all of that. But, for a bigger displacement motor, I would expect more torque than just a gain of 4 lb ft. Maybe the 6.6L brings the torque in at a higher number at a lower RPM. That would make a big difference in driveability and be better for towing. Maybe it is a more reliable motor? Just wondered what is so good about the 6.6L?

Edit: @MrScottly, I posted this before I read your last post. Guess we kinda had the same conclusion. The 6.6L brings in higher torque at a lower RPM, which makes a big difference in driveability and better for towing.

 

[185EZ]

I've got two 6.2s and they have been perfect and one of them gets flexed plenty. Oil analysis suggests they are a well oiled machine. I expect they will run about 250k each.

No doubt there are some good ones out there.
I got the bad apple out of the bunch.
If one side the lifters went bad it's only a matter of time the other side goes.
We have a couple off road trips planned and I just don't have any faith in this truck to get us home safely.

 

[AXE]

No doubt there are some good ones out there.
I got the bad apple out of the bunch.
If one side the lifters went bad it's only a matter of time the other side goes.
We have a couple off road trips planned and I just don't have any faith in this truck to get us home safely.

Yeah it seems as though your never out of the woods. I've logged about 35k ish miles between the 2, if I hadn't started doing the oil analysis early on and had repeated good results I may not feel as good.......time will tell.

 

[AXE]

Higher torque is always better at lower RPM, cause you can take advantage of gearing. But honestly the gearing on the current HDs isn't anything to brag about for a tow rig, however the 10 speed transmission does a good job of managing it.

 

[8ball_99]

Some of you guys are making a joke of this, but i asked a serious question. What makes the 6.6L gas motor so good? I get it that there is no DFM or auto start/stop, and that is a BIG PLUS, but the power is just not there. For a bigger 6.6L motor, I would expect a lot more power than this one puts out.

So I had both and 6.2 ZR2 and now have a 6.6 HD ZR2. The 6.6 is just a more reliable, robust engine. The 6.2 is an aluminum block shorter stroke faster revving sport engine. The 6.6 is a iron block long stroke, work engine. It has a lot of torque down low and just has more power. The 6.2 is faster, but needs to rev more to make power.

But all that aside the biggest reason is no DFM or autostop/start on the 6.6. Atleast for now. Lots of lifter failures on 5.3s and 6.2s for years. AFM sucked and so does DFM. It makes them less reliable. Just like how DPFs and DEF makes diesels less reliable. Autostop also effects a ton of systems in a vehicle. If you actually look into how the system works. It's amazing it works at all. Same with DFM. They are very complicated systems.

 

[KLA]

So I had both and 6.2 ZR2 and now have a 6.6 HD ZR2. The 6.6 is just a more reliable, robust engine. The 6.2 is an aluminum block shorter stroke faster revving sport engine. The 6.6 is a iron block long stroke, work engine. It has a lot of torque down low and just has more power. The 6.2 is faster, but needs to rev more to make power.

But all that aside the biggest reason is no DFM or autostop/start on the 6.6. Atleast for now. Lots of lifter failures on 5.3s and 6.2s for years. AFM sucked and so does DFM. It makes them less reliable. Just like how DPFs and DEF makes diesels less reliable. Autostop also effects a ton of systems in a vehicle. If you actually look into how the system works. It's amazing it works at all. Same with DFM. They are very complicated systems.

Thank you! That's the answer I was looking for.

 

[Waterdog]

Really complicated systems that offer little to no real world improvements in fuel savings and compromises reliability.

 

[8ball_99]

Really complicated systems that offer little to no real world improvements in fuel savings and compromises reliability.

Exactly!, that's the really annoying part. They improve fuel economy by a couple of percent. It's not like you are gaining 20-30% for the extra possible headache. It's a very minor difference. But manufacturers have to meet EPAs numbers or it cost them money. It's across their whole production line. So if chevy can improve the numbers on a silverado by a couple percent. It helps their overall average. Which makes them more money. Same time it costs us more. Adds cost to the vehicle price and reduces reliability and longevity at the same time. Just look at Toyota now. Even they struggle to make a reliable vehicle now while meeting emissions, lol.

One of my sons friends has a older Toyota Corolla with over 400k on it. He just changes the oil. He is a 24 year old kid, so it isn't like that car has lived a pampered life lol.

 

[Epsilon Plus]

The L8T makes 400lb/ft @ 1,800RPM. That's pretty substantial. The lack of big power numbers to outshine the 6.2 and others is simply down to fleet use and MPG. They used the increased low end torque over the 6.0 to get rid of the 4.10s in the back and go to 3.73s to try to help it but it still drinks like a fish. The 87 octane tuning and conservative cam numbers....etc. Fleets buy multitudes of these engines and don't need it thumping out 500hp and 8 MPG so Julio and Stan can drive the 4" PVC load to the jobsite.

Let's not kid ourselves. It's a deep skirt forged bottom heavily stroked 6.2 LT foundation. Just the LT2 cam and 93 octane has is jumping up 123HP and 79TQ to 523/543 making the 6.2 look like it's B. If you want to make it breath, it will oblige. Be prepared to tow a fuel trailer with you. With 37s and tighter throttle response (Pulsar) I'm averaging 10.5MPG city with 0 lead foot, all grandpa. I'd be getting LS-6 Chevelle MPG with a cam and tune.