The Chevrolet Silverado HD and GMC Sierra HD may have gained all-new generations for the 2020 model year, but the latest 2021 model year still brings some important changes for both nameplates. On the mechanical side of the equation, the most notable changes to the 2021 Chevrolet Silverado HD and 2021 GMC Sierra HD is the addition of FlexFuel capability.
GM Authority was the first to cover this news, and now, we’re taking a closer look in the following post.
Both the 2021 Chevrolet Silverado HD and 2021 GMC Sierra HD come with E85 FlexFuel capability for the new 6.6L V8 L8T gas engine. Previously, this engine was gasoline only.
Output from the L8T is rated at 401 horsepower and 464 pound-feet of torque, with the GM six-speed automatic handling the transmission duties.
For 2021 GMC Sierra HD models, this option is only available on base models (1SA) and requires the JL1 trailer brake controller. The FlexFuel capability option also requires the Convenience Package on Regular cab models, and is not available with the pickup box delete option.
Meanwhile, the 2021 Chevrolet Silverado HD offers FlexFuel capability exclusively on the Work Truck trim level with the Regular Cab body configuration. It too requires the JL1 trailer brake controller, and is not available with the pickup box delete option.
For those who may be unaware, FlexFuel-capable engines are designed to run on E85 ethanol, gasoline, or any combination thereof. Generally speaking, E85 ethanol fuel is less prone to detonation, and is considered cleaner than regular gasoline in terms of emissions. Additionally, E85 ethanol can be made from sugar cane or corn, which makes it a great alternative to sourcing imported oil.
Back in 2010, General Motors doubled down on its FlexFuel commitment by ramping up the number of vehicles that offered the feature, putting millions of FlexFuel-capable SUVs and trucks on the road. These days, the automaker has shifted its focus to all-electric vehicles, but the addition of FlexFuel capability to the 2021 Chevrolet Silverado HD and 2021 GMC Sierra HD will surely make the workhorses even more attractive for those customers sticking with internal combustion.
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Comments
The front end of the 2021 Silverado is maybe the ugliest I have seen since I can remember. The early 60’s were worse that the late 50’s but this is far and away worse. The picture I seen was like a chrome plated 4×8 sheet of plywood with slots cut into it. I have owned Chevy all my life. I have now a Camaro and a Chev 3/4 ton and a Escalade Platinum.
So having said all that… can you answer this: have you seen one in person?
Wrong, best looking HD yet!!! The L8T is a very well thaught out engine with tons of power. I pull a 7500 pound trailer and the truck dosent even know it’s back there. I have a 2021, all black and it looks mean. i love mine and get many more compliments on the 21 than I ever did on my 2001.
Yeah they’re sooo ugly that they flew off the dealer lots as they came in.GM outsold Fraud in the first quarter despite COVID19 and it was mostly trucks,so your opinion carries no weight.It actually looks like a heavy duty truck, unlike the garbage F(junk) series.
Well josh I opinion dose carry weight as does everyone else’s so when you say that it dosent then your not verry informed. But everyone does deserve to have a comment and opinion.
Michael, you had so many spelling mistakes in that last comment I don’t know how anyone can take you calling someone uninformed seriously.
In person I think they look pretty dang good, especially the ones with LED DRL’s. They have an imposing look.
I wonder if RPO KL5 gaseous fuels prep option will eventually be offered on the L8T.
I didn’t say you can’t have an opinion,just that yours doesn’t carry any weight when compared to the statistics.The fact that they outsold Fraud and the dealer lots are nearly empty now should tell you something.
Some corrections need to be made to your article.
“Meanwhile, the 2021 GMC Sierra HD offers FlexFuel capability exclusively on the Work Truck trim level with the Regular Cab body configuration.”
Sierra base trim is the 1SA. You have Chevy as being a 1SA. The E85 option is not cab specific either. It can be optioned on all 1SA and on regular cab requires PCI Convenience package.
“For 2021 Chevrolet Silverado HD models, this option is only available on base models (1SA) and requires the JL1 trailer brake controller. The FlexFuel capability option also requires the Convenience Package when selected on Regular cab models, and is not available with the pickup box delete option.”
Chevy does not have 1SA, Chevy has the Work Truck 1WT. You’ve strangely got the other part of that quote correct for the Chevy however.
Thanks for calling that out, newdude. We got our wires crossed and put Silverado in place of Sierra and vice versa for those sections. The post has been updated.
The local natural gas companies prefer the option of the E85 fuel option because the valve seats are different than the regular gas engine versions. Previous differences are also the piston rings and the computer timing setup. Since GM tests all engines on CNG, LPG propane and E85, they post the HP and torque figures for each fuel. In other GM engines, the torque increase was 8.5 percent on E85 over regular 87 octane gasoline. This means that with 464 pounds feet of torque on gas, it should be about 503 pounds pounds feet on the 99.5 octane E85 fuel. The HP running on E85 should increase to about 435 HP from the factory rated 401 HP on gasoline. Since the engine won’t ping or knock when the engine is under heavy load on E85, GM can set the shift points on the transmission to be lower, allowing for faster acceleration and a bit better MPG. On E85 fuel, the exhaust valves are cooled by the alcohol and therefore less heat builds up in the engine and transmission oil cooler.
AKA…this thing on E85 makes even more big block power lol. I think its stupid its on Work Truck/Base trims only. It should be an option all the way to High Country.
I still think the lack of 10 speed is a hurting factor for it.
The natural gas companies used to buy the L96 6.0L with RPO KL5, which was a true CNG/LNG prep package consisting of special valves and valve seats. It went a step further than E85 capability as E85 is actually easier on valves than ‘dry’ gaseous fuels like natural gas. The primary ‘special’ components in an E85 engine are higher flow injectors and fuel system components that resist corrosion from ethanol.
Screw China, support US farmers by making E85 fuel for the entire General Motors fleet.
GM, the truck is still hideous looking. Fire the starbucks soy latte drinking millennials who are designing these ugly piles. I’ve bought 2 new 2500hd trucks in the last 3 years. I wanted to like the 2020….I even tried to force myself to like it. When I saw them in person and test drove them…..so unbelievably disappointed.
Is this true?