2021 Tahoe w/ a diesel

[gregtay]

It will be interesting to see what the tow ratings are on the new Tahoe and how well the 3.0L oil burner performs. With the air suspension it might make for a decent Malibu puller. I think i'd be tempted to still go with the 6.2 just for the fun factor when not towing.

https://www.foxnews.com/auto/chevrolet-tahoe-suburban-debut-2021-diesel

[jjackkrash]

No tow ratings yet, but TFLT thinks the towing numbers are likely going up.   

https://www.tfltruck.com/2019/12/2021-chevy-tahoe-silverado-your-questions-answered-q-a/

Edited December 15, 2019 by jjackkrash

[RyanB]

I'm still far from sold on the front end design of the current Chevy trucks, but it isn't as repulsive to me as when they first came out.

I think that the 3.0 diesel is the perfect engine for these.  Adequate power, and great MPG.  It is something I will look at pretty hard when it comes time to upgrade from my Expedition.

2021 should be a good year for full size SUVs.  That is when the new Jeep Wagoneer and Grand Wagoneer are slated to debut.

[JeffK]

9 hours ago, jjackkrash said:

No tow ratings yet, but TFLT thinks the towing numbers are likely going up.   

https://www.tfltruck.com/2019/12/2021-chevy-tahoe-silverado-your-questions-answered-q-a/

My issue with that is that they talked about reducing weight to increase the tow ratings by going with the aluminum.  This seems counterproductive to me.  As someone who has been dragged down a ramp by a boat before, I want that vehicle to weigh enough that it can keep the tires locked in as I back down the ramp.  If they offer a diesel option, it would be great to offer the 3L and the larger duramax platform.

[jjackkrash]

1 hour ago, JeffK said:

My issue with that is that they talked about reducing weight to increase the tow ratings by going with the aluminum.  This seems counterproductive to me.  As someone who has been dragged down a ramp by a boat before, I want that vehicle to weigh enough that it can keep the tires locked in as I back down the ramp.  If they offer a diesel option, it would be great to offer the 3L and the larger duramax platform.

On the Tahoe at least, they are reportedly going to be 50-200 lbs. heavier overall than the outgoing model.  The suspension is heavier and its almost 7 inches longer and they are using better hi-strength steel in the frame.   I suspect they are just trying to save weight where they can to keep the things from bloating and reducing payload capacity.    We will see, but it looks like they made some pretty nice structural upgrades to these vehicles in addition to adding some cool new tech options like the camera system.  

[BSUBU_Kris]

I had a 2010 Denali towing a 2010 LSV.  I did like the Denali and it did a great job towing the LSV other than the mileage which was terrible both when towing and not towing.  I did not get more than 10 mpg when towing and never saw 20 mph.  I moved to a Range Rover Sport with the 3.0 liter diesel and must saw I prefer it in every way.  Easier to drive around town, more comfortable, better off roading, much smoother pulling the boat, about the same performance wise towing the boat and great milage, over 15 towing the boat and near 30 on the highway without the boat, about 24 combined without the boat.  I do one trip every summer that is about 2,500 miles towing the boat from Northern California to about the Canadian border.  The diesel is such a nice change from the 6.2 V8 gas engine.  It is quieter when towing and also very quiet overall.  I hope the GM diesel ends up being a great engine, it has been too long since they have offered a diesel option in an SUV.

[carnold12]

10 hours ago, BSUBU_Kris said:

I had a 2010 Denali towing a 2010 LSV.  I did like the Denali and it did a great job towing the LSV other than the mileage which was terrible both when towing and not towing.  I did not get more than 10 mpg when towing and never saw 20 mph.  I moved to a Range Rover Sport with the 3.0 liter diesel and must saw I prefer it in every way.  Easier to drive around town, more comfortable, better off roading, much smoother pulling the boat, about the same performance wise towing the boat and great milage, over 15 towing the boat and near 30 on the highway without the boat, about 24 combined without the boat.  I do one trip every summer that is about 2,500 miles towing the boat from Northern California to about the Canadian border.  The diesel is such a nice change from the 6.2 V8 gas engine.  It is quieter when towing and also very quiet overall.  I hope the GM diesel ends up being a great engine, it has been too long since they have offered a diesel option in an SUV.

I get your point for comparison sake, but A LOT has changed with both diesel and gas engine platforms since 2010. The new GM 6.2L gasser is night and day different from what you had, especially when paired with the 10 speed transmission that is currently offered. As has been stated before, torque numbers for the little Duramax are almost identical to the 6.2L and tow tests show them to be on par with one another. This in combination with the cost of diesel fuel and maintenance led me to stray away from the little diesel in my 2020 Sierra. I like the idea of it a lot, but it would've had to be a bit beefier (more displacement & torque) to go that route. Just my $0.02

[RyanB]

Does the 6.2 still require premium fuel?  Or do they now only recommend it?

[jjackkrash]

On the 5.3l GDI in my boat the dealer told me the computer just derates the power in the engine, if necessary, based on octane, even though higher octane is recommended.  I go back and forth between 87 and 92 and have not been able to tell a difference in normal use.  A local gas station has 87 octane ethanol-free gas and I run that when I can get to it and i'll mix in premium when I can't get to the non-ethanol.  The boat doesn't seem to care either way.    

[carnold12]

21 hours ago, RyanB said:

Does the 6.2 still require premium fuel?  Or do they now only recommend it?

"Premium Fuel Recommended" is the exact wording from GM on new the 6.2L. I'll run 89 most of the time, but try to run 91 when towing. It's more for anti-knock than energy content anyways, so just cheap insurance IMO.

[RyanB]

33 minutes ago, carnold12 said:

"Premium Fuel Recommended" is the exact wording from GM on new the 6.2L. I'll run 89 most of the time, but try to run 91 when towing. It's more for anti-knock than energy content anyways, so just cheap insurance IMO.

Not knocking the 6.2, but the fuel requirements are something future owners should consider. Especially those that don’t want to pay the “extra cost” of diesel fuel. 
 

For the record, I really like the 3.0 diesels.

[carguy79ta]

6 hours ago, carnold12 said:

"Premium Fuel Recommended" is the exact wording from GM on new the 6.2L. I'll run 89 most of the time, but try to run 91 when towing. It's more for anti-knock than energy content anyways, so just cheap insurance IMO.

I was under the impression that the "energy content" from premium vs reg is about the same. The premium burns slower, allowing more timing advance, thus more power/tq.... ? ...

 

Edited December 25, 2019 by carguy79ta

[carnold12]

16 hours ago, carguy79ta said:

I was under the impression that the "energy content" from premium vs reg is about the same. The premium burns slower, allowing more timing advance, thus more power/tq.... ? ...

 

I believe that is spot-on. Sorry if my post implied otherwise. I was just saying that people often think the number is related to energy content and that's not correct. The number is instead your ant-knock index,  with higher AKI fuels allowing for higher compression before ignition. I assume these motors have a higher compression ratio which is why that works?

[shawndoggy]

2 minutes ago, carnold12 said:

I believe that is spot-on. Sorry if my post implied otherwise. I was just saying that people often think the number is related to energy content and that's not correct. The number is instead your ant-knock index,  with higher AKI fuels allowing for higher compression before ignition. I assume these motors have a higher compression ratio which is why that works?

Knock sensors allow the ECM to advance or retard timing. 

[dlb]

My truboed vehicles require premium to deal with the higher compression ratios.

My ‘08 Denali recommends premium, we use it while towing.  I have not compared the compression ratios on that motor with the new motor in the ‘21 Chevy/GMC/Caddy but will.  We will probably replace the ‘08 with a ‘21.  Looking forward to the 10 speed and independent rear giving the fold away rear seats.

[carnold12]

A little coffee-fueled research this morning yields the following:

• The current GM L86 6.2L has a compression ratio of 11.5:1 (premium fuel recommended); this is the same larger displacement V8 motor that will be an option for the 2021 Tahoe (standard on High Country models)
• The previous GM L94 6.2L has a compression ratio of 10.4:1 (premium fuel recommended)
• The current GM L83 5.3L has a compression ratio of 11.0:1 (regular unleaded); base V8 motor for the 2021 Tahoe

Based on 2019 national fuel price averages from AAA:

• the difference between regular and mid-grade fuel looks to be in the range of +$0.30-$0.35 per gallon
• the difference between regular and diesel fuel looks to be in the range of +$0.40-$0.69 per gallon

Back of the napkin math says the 3.0L diesel would have to get something like 4-5 mpg better than the 6.2L to come out even on fuel cost alone. GM touts 24 mpg combined for the 3.0L diesel and 18 mpg combined for the 6.2L on a 2020 4WD Sierra. Not sure that I buy either number based on the 4,500 miles driven in mine, but who knows...

[RyanB]

On 12/26/2019 at 8:41 AM, carnold12 said:

A little coffee-fueled research this morning yields the following:

• The current GM L86 6.2L has a compression ratio of 11.5:1 (premium fuel recommended); this is the same larger displacement V8 motor that will be an option for the 2021 Tahoe (standard on High Country models)
• The previous GM L94 6.2L has a compression ratio of 10.4:1 (premium fuel recommended)
• The current GM L83 5.3L has a compression ratio of 11.0:1 (regular unleaded); base V8 motor for the 2021 Tahoe

Based on 2019 national fuel price averages from AAA:

• the difference between regular and mid-grade fuel looks to be in the range of +$0.30-$0.35 per gallon
• the difference between regular and diesel fuel looks to be in the range of +$0.40-$0.69 per gallon

Back of the napkin math says the 3.0L diesel would have to get something like 4-5 mpg better than the 6.2L to come out even on fuel cost alone. GM touts 24 mpg combined for the 3.0L diesel and 18 mpg combined for the 6.2L on a 2020 4WD Sierra. Not sure that I buy either number based on the 4,500 miles driven in mine, but who knows...

Why are you quoting the difference between regular and mid grade when the recommendation is premium?  And I'm not sure where you are getting your fuel prices from.  I travel 10 states for work.  Diesel for the last year has been at or below mid grade prices.  I've had a diesel vehicle since 1998 (as well as vehicles that require premium for most of that time), and I don't ever remember it being above premium in price.  But maybe my diesel colored glasses are on.

I also think you need to look at more than just cost for fuel.  I have a 3.0 EcoDiesel in my Grand Cherokee.  This may very well be my favorite car that I have owned.  Love driving it.  And a lot of that has to do with the low end torque of the diesel.  Same would apply here.

[Sparky450]

2 hours ago, RyanB said:

And a lot of that has to do with the low end torque of the diesel.  Same would apply here.

And this goes back to what I said. Once you have driven a diesel, it is hard to go back😎

[Nitrousbird]

On 12/26/2019 at 10:41 AM, carnold12 said:

A little coffee-fueled research this morning yields the following:

• The current GM L86 6.2L has a compression ratio of 11.5:1 (premium fuel recommended); this is the same larger displacement V8 motor that will be an option for the 2021 Tahoe (standard on High Country models)
• The previous GM L94 6.2L has a compression ratio of 10.4:1 (premium fuel recommended)
• The current GM L83 5.3L has a compression ratio of 11.0:1 (regular unleaded); base V8 motor for the 2021 Tahoe

You need more coffee.

L86 and L83 are the "current" motors for models that haven't been updated.  Both were replaced by the L87 and L84, which have dynamic fuel management instead of AFM, along with engine start/stop.  The L83/L86 will NOT be in the 2021 SUV's.  

 

[Arctic Slalom]

i think the 3.0 diesel in a suburban would be awfully nice. 

great interstate cruiser, for sure. 

the 3.0 diesel in a surfboat would be pretty sweet, too!  

[jjackkrash]

On 1/21/2020 at 8:49 AM, Arctic Slalom said:

the 3.0 diesel in a surfboat would be pretty sweet, too!  

https://www.yanmar.com/us/about/ymedia/product/8lv_engine.html

A little bird told me this Yanmar is a $40K upcharge over the standard gasser in a 2020 G23.   I think a diesel would be awesome, but man oh man.  

 

[carguy79ta]

I would never do a diesel in a surfboat. Diesel fuel is able to get everywhere. Side of theboat, crew tracks it into boat,gatorstep, vinyl, etc. Gas evaporates. Abig boat like @TenTwentyOne 's might be different, bu IMO, diesels belong on engine rooms, not bays.🙂

[TenTwentyOne]

On ‎1‎/‎22‎/‎2020 at 11:39 PM, jjackkrash said:

https://www.yanmar.com/us/about/ymedia/product/8lv_engine.html

A little bird told me this Yanmar is a $40K upcharge over the standard gasser in a 2020 G23.   I think a diesel would be awesome, but man oh man.  

 

You want to know the funny thing about that? 

I am doing a repower on the 300, and I considered swapping it to diesels. Ultimately, I stuck with gas, mostly because it is easier to get fuel on the lakes and waterways that I will be on most the time...…. But I priced diesel repower packages anyway.

That 8LV is $31,480 for a full drop in package WITH the transmission. That is the full package. Manifolds, starter, alternator, wiring harnesses, all sensors, etc. It is complete, and is plug and play. 

$7K more than a 6.2 repower package from Ilmor,  and $8k more than a H6 from PCM. The 40k upcharge is pretty funny once you compare the numbers.

[abovewater]

I like the diesel, but another thing to note is you'll be able to buy the 6.2 in a Suburban, which I'm gathering means it will be an option on some of the lower trim lines. We wanted a '15 Suburban with the 6.2, but had to bypass all the Suburban trims and almost all the Yukon ones. I love the bells and whistles of my Denali, but buying a mid trim Suburban vs. the Denali will save a lot of money. Also; any trip to the gas station feels good when I don't have to put 80 gallons in the boat.

I'd probably stick with the 6.2. I really do love that motor. I have the 10 speed transmission and compared to my previous Suburban(5.3) is excellent.