Volume Increase

[MontyMoose]

You can't remove the exhaust back pressure valve or it throws a def code and goes into limp mode.

So they'd have to make something that would require cutting the system after the BPV, which would add to the cost and/or be a more complicated install? Got it. This will be my 1st diesel, so I'm still trying to learn some of the bigger differences before I take delivery.

 

AT4 Forum Fav 👍

The Original Short Rubber Replacement Antenna - Grab one through Amazon!

[LateOnTheBrakes]

So they'd have to make something that would require cutting the system after the BPV, which would add to the cost and/or be a more complicated install? Got it. This will be my 1st diesel, so I'm still trying to learn some of the bigger differences before I take delivery.

Correct. Based on the size of the muffler/resonator I'm guessing you could chop it off after the valve and straight pipe it and it would still be whisper quiet.

 

[LateOnTheBrakes]

So they'd have to make something that would require cutting the system after the BPV, which would add to the cost and/or be a more complicated install? Got it. This will be my 1st diesel, so I'm still trying to learn some of the bigger differences before I take delivery.

This is the one I've found after the valve. I watched a few videos on youtube and heard no difference.

Exhaust - 23-24 Duramax 3.0L LZ0 - Silverado/Sierra 1500 - GM - Diesel Trucks | aFe POWER

afepower.com

https://afepower.com/media/catalog/product/file/49-34146-B_Ins.pdf

 

[LateOnTheBrakes]

Yeah. That's what I was afraid of. I bought it for the fuel economy and 100k mile warranty. But I wish I had the sound and fury of the 6.2L.

 

[pigpen23]

Without a delete, you won't be able to noticeably increase the sound/volume of the exhaust on these 3.0 trucks. That said, I'm not sure you can delete that resonator without throwing codes. Adding a CAI adds some intake/turbo noise, but not like it did on my 6.2L.

 

[Teegunn]

Yeah. That's what I was afraid of. I bought it for the fuel economy and 100k mile warranty. But I wish I had the sound and fury of the 6.2L.

I've had an AT4 with the 3.0. I didn't want a loud diesel, so was fine with the low volume.

I now have a 23 AT4X with the 6.2. At first, it was very quiet. Way too quiet. I almost sprung for a magnaflow or similar, but after several months the exhaust volume got better. More growl. At this point, it sounds a lot better. Then only thing I have done is c-clipped the flapper valve open.

I also got the 3.0 for the MPG and torque. Loved the engine, actually. But then it threw a "service emissions code" late Nov of 22. A month at the dealership, and they could never fix it, with no fix in sight, and I was working 1000 miles from home out of state, and couldn't afford to be stranded any longer.. It was still under warranty. So I traded it for my 23 AT4X (got a high trade value for my 2020 AT4 3.0) with the 6.2. I am happy with it overall.

 

[LateOnTheBrakes]

I've had an AT4 with the 3.0. I didn't want a loud diesel, so was fine with the low volume.

I now have a 23 AT4X with the 6.2. At first, it was very quiet. Way too quiet. I almost sprung for a magnaflow or similar, but after several months the exhaust volume got better. More growl. At this point, it sounds a lot better. Then only thing I have done is c-clipped the flapper valve open.

I also got the 3.0 for the MPG and torque. Loved the engine, actually. But then it threw a "service emissions code" late Nov of 22. A month at the dealership, and they could never fix it, with no fix in sight, and I was working 1000 miles from home out of state, and couldn't afford to be stranded any longer.. It was still under warranty. So I traded it for my 23 AT4X (got a high trade value for my 2020 AT4 3.0) with the 6.2. I am happy with it overall.

Yeah, service of the 3.0L makes me nervous. None of the mechanics seem to be familiar with it. At least I know how to work on the 6.2L. I've rebuilt LS engines before.

 

[Teegunn]

Yeah, service of the 3.0L makes me nervous. None of the mechanics seem to be familiar with it. At least I know how to work on the 6.2L. I've rebuilt LS engines before.

It's really the modern diesel emissions systems that are so complicated. So many sensors and misc, it can be hard to diagnose what the problem is.

Also, the 3.0 is really stuffed into the truck. Not an easy engine to work on. At 150K miles the timing belt (I believe) is recommended to be swapped for new. That means pulling a ton of the truck apart to do so.

I loved the engine. I had to trade it because the dealership could never find out what was causing the "service emissions system" code, which put the truck into severe limp mode. I won't likely be buying another 3.0 again.

This 2023 AT4X 6.2, I plan to keep longer than most trucks. As a contractor, I usually trade about every 3 or 4 years, because by that time, mechanically, it is time to move on. Also live in the mountains, on rough roads and 8+ months of winter weather, which is tough on a truck, suspension, etc. But this one, at least right now, I plan on keeping longer. Ultimately, I want a hybrid truck that is totally driven by electric, but has a smaller ICE engine as the onboard generator. That, to me, makes the most sense for a hybrid. And if they become mainstream or more common, then maybe we won't have to get goofy looking trucks that are electric powered. I also still want an onboard ICE engine to be able to recharge the batteries, and add range.

At some point, battery tech will improve (Samsung says they have a solid state battery that holds more charge and charges much faster). When that happens, it will be a game changer. But for now, I am happy enough with my 6.2 AT4X.

 

[RebelDS]

It's really the modern diesel emissions systems that are so complicated. So many sensors and misc, it can be hard to diagnose what the problem is.

Also, the 3.0 is really stuffed into the truck. Not an easy engine to work on. At 150K miles the timing belt (I believe) is recommended to be swapped for new. That means pulling a ton of the truck apart to do so.

I loved the engine. I had to trade it because the dealership could never find out what was causing the "service emissions system" code, which put the truck into severe limp mode. I won't likely be buying another 3.0 again.

This 2023 AT4X 6.2, I plan to keep longer than most trucks. As a contractor, I usually trade about every 3 or 4 years, because by that time, mechanically, it is time to move on. Also live in the mountains, on rough roads and 8+ months of winter weather, which is tough on a truck, suspension, etc. But this one, at least right now, I plan on keeping longer. Ultimately, I want a hybrid truck that is totally driven by electric, but has a smaller ICE engine as the onboard generator. That, to me, makes the most sense for a hybrid. And if they become mainstream or more common, then maybe we won't have to get goofy looking trucks that are electric powered. I also still want an onboard ICE engine to be able to recharge the batteries, and add range.

At some point, battery tech will improve (Samsung says they have a solid state battery that holds more charge and charges much faster). When that happens, it will be a game changer. But for now, I am happy enough with my 6.2 AT4X.

Sounds like you had the LM2. It’s the oil pump belt and it’s 150K miles for the LM2 but the LZ0 is the upgraded motor with lots of improvements including a good bit more HP and torque. With the LZ0, the oil pump has a change interval of 200K

 

[Teegunn]

Sounds like you had the LM2. It’s the oil pump belt and it’s 150K miles for the LM2 but the LZ0 is the upgraded motor with lots of improvements including a good bit more HP and torque. With the LZ0, the oil pump has a change interval of 200K

Yeah, my 3.0 was a 2020 AT4. I didn't know they changed the mileage recommendation on changing the hard to get at belt or whatever it is that needs to be changed for new.

I liked the engine. I didn't like the complicated emissions system, which is the biggest area of issues for modern vehicle diesels.