New 2011 GM Duramax Diesel Engine Certified for B20 Biodiesel Fuel

New GM Duramax Diesel Certified for B20 Biodiesel for 2011

GM's new 6.6-liter "LML" Duramax V-8 turbodiesel for its 2011 Chevrolet Silverado and GMC Sierra Heavy Duty pickups will be capable of burning B20 biodiesel fuel, according to a GM press release issued early Monday.

B20 is a blend of 80 percent conventional ultra-low-sulfur diesel and 20 percent biodiesel.

“The 2007 federal energy bill mandates increased biodiesel production and more states and municipalities are requiring it,” said Mike Robinson, vice president, Environment, Energy and Safety Policy. “Biodiesel production is growing and GM is excited and ready to satisfy demand with our new B20 capable Duramax 6.6-liter engine.”

We first reported about the B20 capability of the LML Duramax in August last year. That's up from a B5 biodiesel rating in the current "LMM" Duramax.

Both the 2011 Ford Super Duty (with all-new 6.7-liter Power Stroke V-8) and 2010 Ram Heavy Duty (with 6.7-liter Cummins inline-six cylinder) are also able to burn up to B20 biodiesel, though Cummins approves the use of B20 in Ram trucks for municipal, government, and commercial fleets only.

“We made a lot of enhancements to make sure the new Duramax is robust with biodiesel,” Duramax chief engineer Gary Arvan said. “The engine uses our latest-generation fuel filter that includes a coalescing filter to trap any water that could be present in the fuel. The downstream injector [behind the exhaust] for diesel particulate filter regeneration means we also won’t have a worry of oil dilution with B20 fuel from in-engine post injection [like is used on the LMM diesel]. There’s also additional heating to the fuel circuit so the filter won’t get plugged from old [B20] fuel gelling or waxing.”

We'll have lots more news and information about the new 2011 Chevrolet Silverado HD pickup and its updated Duramax diesel on Wednesday, February 10 at 12:01 am Eastern. Be sure to check back then!


Ok, good to know. I avoid the stuff since its so expensive.

Great and what of the 4.5L Duramax in the 1500s? That is what the consumer wants. GM, Ford - produce a 4-liter diesel half-ton or we'll buy a volkswagon Toureg... Dont make it come to that!

GM was forced to postpone this engine. read below...


GM Indefinitely Postpones 4.5L Duramax Diesel

General Motors has announced that it is putting a hold on a plan to bring a new 4.5-liter V8 diesel engine to market. The new engine would have been used in the light-duty Silverado and Sierra pickup trucks and estimates have it rated at anywhere from the mid-20s to the high-20s in miles per gallon. This would even be a significant improvement over GM's current Silverado and Sierra hybrids, which get 21 mpg city and 22 highway.

The move is just one of many tough choices GM has had to make to cut costs ahead of a U.S. government decision to see if the struggling automaker will get an additional $16.6 billion in bailout funds.

What makes this pill even harder to swallow is that the new engine is just a year away from being ready for production - which would take place at GM's Tonawanda, N.Y. plant.

As for the engine itself, it has a unique cylinder head design that eliminates intake and exhaust manifolds. The lightweight block also has "advanced castings" for the crankshaft-bearing journals and oil system.

GM secured several new patents in the design of the 4.5-liter diesel engine and it apparently is both as smooth and as quiet as a gasoline engine. With most of the ground-work already complete, General Motors has stated that it would be willing to work with another company on bringing the new diesel V8 to market if there were any reasonable offers.

More: GM Delays New 25 MPG Diesel Engine for Silverado and Sierra on

Last edited by nsap : 03-12-2009 at 07:15 PM.

so...I take it that embargo lifts Wednesday?

I think the real story is that thanks to all the emissions crap they put on diesels now they have to be "certified" to run on 20% bio-diesel. But an engine from 10 years ago will run on pure bio-diesel.

Yeah yeah yeah, we all know about the 4.5L Duramax being dropped. So was the 4.4L Powerstroke, along with the small Cummins V-8 that was scheduled for the Ram 1500. Looks like Wednesday will be the big day.

It's too bad that government regulations have killed diesels in 1/2 tons and compact trucks. Where are we supposed to get biodiesel from? MacDonalds drive through?
The government keeps making rules that seem to do more harm than good.

That's because the environmentalist's real objective is to stop the use of petroleum based engines and make us all drive plug-in electric cars. So they target the best option for improving fuel economy, because they actually want to drive up fuel prices.

Environmentalists killed half-ton diesel pickups? Sorry, it was Ford, GM, and Chrysler's market departments. Fact is very few people would be willing to buy a $42,000 half-ton. I guess the manufacturers just don't believe all the folks that claim they would buy such a truck. In any event, that Manhindra truck ought to satisfy those who really want a light duty diesel. Manhindra will be able to sell a small diesel at a price most folks would be willing to pay because of their very low non-union Indian labor costs.

The more I read about the Maindra the lower my expectations get. It sounds like they have a terrible history safety and quality.

Mahindra's claims about its towing and hauling are exaggerated at best. And it still costs as much as a full size, for a 2 mpg advantage over a 18k ranger (the I-4 ranger which has a towing rating closer to what the Mahindra can actually pull down the highway). $5000 for 2 mpg really? A year from now people will be trading them in on the last Ranger/Dakota runs when they realize they can't tow their bass boats up a decent hill.

@BigBob - emission rules and the increased costs of the emission systems and their associated complexity are killing 1/2 ton and compact diesels. Manufacturers will not sell an engine that will not make money. People seem to be willing to pay 8 - 10 grand for a HD diesel but they won't in another application.
A 30 - 50% reduction in fuel economy due to the new emission systems have contributed to decreased diesel sales.
Mahindra is going to have to meet the same emission standards as the "domestics". Mahindra will have to set up an assembly plant in the US as an import will get hit with the "chicken tax". No one will buy it with a 25% tax tacked on.
Diesels are a convenient scapegoat for governments in their quest to look environmentally conscious. Here is a link to an article about what is going on in California:

But the price on diesels is a direct result of environmentalists, extra equipment that reduces efficiency adding cost while lowering mpg and power. Followed by new equipment added to get the power back up to what is expected by consumers (while actually holding together and not making the engine heavier), adding more cost. Then the marketing department says, "we can't sell these things in half tons where the EPA ratings are posted on the windows." I'd like to see the 4.4L in the F-150, or maybe something between it and the 6.7L in a F-250 since that's probably what I'll buy next, but until the price comes down or the mpg goes back up I can't see paying for it.

Diesels are now at the point gasoline engines were in the mid 70's. Skyrocketing fuel prices combined with environmentalists and insurance companies said "hp = bad", they added smog pumps, catalytic converters and lowered engine compression. The net result? Engines costed more and got fewer MPG, it took almost 20 years and overdrive transmissions to recover. Pickups got around this to a large degree until about '78 I think it was.

When I think about emissions restrictions I always remember my best friend's dad when I was in high school. He had an old chevy dually with a 454 4bbl and 4:56 gears, it got 13 mpg pulling a 40ft gooseneck with a backhoe on it. He bought a brand new '91 chevy one ton, 454, 4:10 gears, he drove it for about a week and it was getting 9 mpg unloaded so he took it back and said "There's something wrong with it, it's only getting 9 mpg." They told him "You're lucky to be getting that."

Why not make a slightly detuned version of a 6.6 put it in a 3/4 ton short bed (extended or crew cab) truck, tune and gear it for fuel economy and sell it that way. Even if it made 250-270 hp it's still have 450+ torque and that plenty for most people. I bet you could pull 25-28 mpg out of a 6.6.

@Enjelus - I agree with you 100%. This is the'70's as far as diesels are concerned. I wouldn't take a chance on a Mahindra diesel pickup. I wonder how big a hassle it would be to go out and buy a small p/u with a diesel in a country that has them and "drive" it back.

here's a quote by Lou,

Diesels are a convenient scapegoat for governments in their quest to look environmentally conscious. Here is a link to an article about what is going on in California:

I forgot Lou is a self proclaimed know it all. Diesels are a superior engine for torque and towing over a gas engine. Why are all the semi's diesel engines Lou? Your not going to say enviorment are you? Half of the cars in Europe are diesel engines you self proclaimed know it all!

The diesel engines also offer superior fuel economy on trucks and GM'S 4.5 liter diesel promised highway fuel economy up to 30 mpg!

The government needs to let the market dictate what the manufactures sell and get out of the way of what consumers want.

Even with with current emissions standards diesels still get better economy in a "heavy load environment", also semi's have different emissions standards.

With the current emissions equipment and fuel prices diesels only offer a real savings when used for heavy towing. This wasn't the case 10-15 years ago when diesels were getting 30%-50% better economy over gas engines with similar power ratings.

Europe is a different matter, I don't know what their emissions maybe like, but their fuel prices are a lot higher.

@Bob - Current diesel emission sytems have reduced the fuel economy of diesels 30 - 50 %. You then factor in diesel prices that are the same or higher than gasoline.The current emission systems have increased the cost and complexity of diesels. Why do you think Ford, GMC, and Dodge have killed the introduction of "baby" diesels in 1/2 ton trucks? Most of the world runs diesels in cars and compact trucks but those engines do not meet North American standards which are the toughest in the world. I'd love to see diesel 1/2 ton and compact pickups. We will not see any of these engines until the auto companies can sell them at a price people can afford, and at a price they can make a profit.
I sense some pent up hostility. Must be the Bob and Barrack story.

@Bob, I don't think that Lou was disputing the fact that diesel engines make more power and get better fuel economy than a gas engine. What i think Lou was saying is that with the government Reg's on diesel fuel emission requirements is making it harder for the manufactures to build a cost effective diesel engine in North America. I buy only diesel pick-ups so it gets costly for me too when a new truck costs more and more because of emmision equipment. My 2007 DPF equiped Duramax crew cab gets 23 mpg (empty) 14 mpg with 12000 lb trailer, My new 2010 3500 Cummins crew cab gets 24mpg (empty) and 14.5 mpg pulling same trailer. This is still not too bad considering a half ton gas V8 gets less and wieghs less. The problem is a half ton diesel wil cost 50-60 thousand bucks, and at that price they might as well buy a HD truck with more capability. Emission regulations have put a huge damper on half ton diesel trucks coming to market. Too bad though because would't it be nice to have all that extra torque in your light duty pick up and get 30 mpg. I was in heaven when they first talked about the 4.5L Duramax half ton, so for now i will keep driving the HD trucks.

@snowman - thanks - exactly what I meant.

Emission laws make me sick. A half-ton diesel would save so much fuel, compared to a regular gas engine. Not to mention the amazing performance increase. If only if only.

"I wonder how big a hassle it would be to go out and buy a small p/u with a diesel in a country that has them and "drive" it back."

At the very least I would think you'd be charged something similar to an import tax when you tried to retitled it, and at worst they'd require it to pass a smog test. And since it wouldn't pass that you'd have to have to have it modified to pass emissions. And since there's not actually anything wrong with the emissions you probably still wouldn't pass emissions and you have to show you spent a minimum amount of money with a certified emissions mechanic trying so you could get a waiver.

All in all it'd probably be easier to pull a new Cummins out of a wrecked Ram 2500 and wedge it into a ranger.

Even though diesels are common in other countries, there is nothing that would really meet the needs and wants of most Americans, as well as not meeting US emissions. Eg. Toyota Hilux with the 3.0L I-4 diesel. 120kw/400Nm(160HP/280lb-ft). It's got some torque, but it doesn't really get up and go. The same is true for the Nissan Navara, global Colorado/DMAX, Ford Ranger and Mazda B-series. The 4L V6 puts it to shame. In the UK, you can get a 2.5L version of the Hilux diesel with even less power. You can argue you would take loss in performance and a small bare-bones pickup for the benefit of fuel economy, but if you have been driving a 300HP V8 full-size American pickup, I give you a week in a small 4 cyl diesel, and you will be begging to have it back. They don't put the powerful 3L diesels in them, that you see in the Euro cars. A 3L V6 diesel should have about 190kw/550Nm+ now, as it will in the next gen Nissan Patrol, but you don't see these engines, or even anything close to them in any mid-size pickup anywhere in the world. Perhaps, the next gen Nissan Frontier/Navara? Couple that engine to a nice 6 speed auto in the Frontier/Navara, and that will be one mid-size pickup that will be hard to beat - except on price.

Yes, it is true that the increased cost of meeting diesel emission regulations has made the U.S. built light duty diesel truck too expensive to be commercially viable. The beauty of the Manhindra is that because of substantially lower labor costs, Manhindra will be able to offer a light duty diesel truck at a price the market for such a vehicle can afford to buy in large numbers. I expect to see a lot of this type of speciality light duty truck and SUV offered from Indian and Chinese manufacturers. They alone will be able to produce such vehicles and offer them at reasonable prices. And you watch, prety soon these Indian and Chinese manufacturers will each have a base of fanboys telling lies about how great they are in no time. Maybe instead of Ford vs. Chevy, it will be Manhindra vs. Landwind........ Who needs John Deere when you can buy a NorTrac. There are just as good, and a lot cheaper!

Even in cars fuel economy vs hp goes down quick after about 25 mpg. What can you have for 25 mpg? A 300hp V-8 mustang. What can you have for 30 mpg? A Toyota Corolla. I've driven my mothers corolla, put the cruise control on and drive from my house to town it does a double down shift (all the way up to red line) pulling some of the hills at 70. This isn't exactly hilly country either. My F-150 with an old 260hp 5.4L doesn't even come out of overdrive. It weighs almost twice as much and I still get 17 mpg.

Smaller engines don't always mean better fuel mileage, there's a point of diminishing returns to be sure and drive-ability goes downhill fast when its pushed past a point. Trucks are especially limited by drag and weight. Only increased power-train efficiency will improve them past what we see now.

Some people say they don't need power, but I ask would you feel the same way trying to merge into freeway traffic? Would you feel the same way pulling a bass boat up a hill at 45 in a Mahindra while someone passes you going 70 in a F-350 pulling a 20klb hay trailer?

I would love to see a baby duramax! speaking of MPG, GM has best in class MPG, my half ton chevy gets up to 23 HWY and towing a f150 on my 1400 lb trailer I was getting 14. import full size trucks barely get that empty!

Who's the ignoramous that said a half ton diesel would cost 50 to $60,000 dollars? The diesel engine upgrade on a 3/4 ton is around $8,000 dollars. Yes, emmissions are much tougher than they used to be, but all the assertions that it's just to costly to put a diesel engine in a car or truck is rediculous!

The diesel engines of today do meet the new emmisions standards and they are much quieter and cleaner burning with less smoke and smell of the diesel engines we grew up with. We will see diesel engines on half ton trucks in 2 to 3 years. Mark it down.

There are industry folks on this site and you know a light duty diesel pickup is both needed and wanted. I posted yesterday, dont make me buy a Volkswagon. So far, looks like I will have to. Shoot, the Toureg probably is the same price as one of these trucks (2500 and 1500 for that matter) and the Toureg already gets good milage, and its loaded.

Your call big three, you want the business come and get it... You know those drivetrains are production ready.

We are going to see Turbo V6 and small Turbo V8 engines before a 1/2 ton diesel. HD trucks and their associated diesel engines have greater profit margins and people are already used to paying those higher prices. A person is more likely to see a return on investment wth a HD diesel. In tough economic times people don't have the extra cash for a diesel 1/2 ton. Most stories put the V6 Turbo and small V8 turbo gas engines at around 1,500 - 1,800 dollar premium. 5,000 dollars seems to be the number touted for a 1/2 ton diesel. Here is a link for a story on Ethanol Injected Turbo Boost engines. Several articles on this site point towards turbo gas engines as opposed to diesels.

What is it with everyone saying that the new emissions killed diesel fuel economy? That's not true at all. In fact, in our heavy equipment we've seen increases in fuel economy compared to their equivalent earlier tier emissions counterpart.

What most of you who say this aren't taking into account, is that modern diesels used in pickups are significantly more powerful than their pre-emissions counterpart and new trucks are significantly heavier than their pre-emissions counterpart. That's where the loss in fuel economy comes from.

My '95 Suburban 2500 has a 6.5L diesel making 190hp/390ft-lbs tq. New trucks are making near 400hp and 700ft-lbs tq......that's almost double the power from the same displacement. New crew cab 2500 pickups also weigh nearly a half ton more than my Suburban. It's obvious you are going to have a drop in fuel economy when you've increased weight by 15% and power by 50%!

If you want to see an equivalent diesel, wait for GM to bring out their 4.5L diesel. It has similar power ratings to heavy duty trucks from the late 90's/early 2000's, but from a smaller displacement. That's where you'll see the true fuel economy gains.

@Paul - Does heavy machinery use particulate filters that require regeneration cycles to "burn out" the trapped soot?
Those "regen' cycles in HD pickups contributed to a big drop in MPG.

@Bob - If you are going to insult people with big words like ignoramus, at least try to spell them correctly. Go do something that will challenge your brain.... like....well... trying to spell your name backword....

Paul, the diesel fuel economy has suffered from about 2007 till now. The only way they can seem to get good fuel econ AND meet emissions standards, is with Urea. But as others will point out, this is another upfront expense.

"Does heavy machinery use particulate filters that require regeneration cycles to "burn out" the trapped soot?
Those "regen' cycles in HD pickups contributed to a big drop in MPG. "

Yes they do. They do not yet use urea though.

We've found the trick to achieving the best mileage with DPF is to just run them. The only time the DPF burns extra fuel is during active regeneration. If you use the vehicle enough to keep it passively regenerating, then it rarely goes into active regeneration, and you don't really burn any more fuel than you normally would.

How does this translate into diesel trucks? A diesel truck that spends most of its time city or just sitting at idle, will get the worst mileage. A diesel truck used for long highway treks will get the best. Pretty much nothing has changed from the way it has always been.

Now, from what I've read in trade magazines, engines that use DEF will actually get better fuel economy than current EGR/DPF engines. IIRC, the numbers are around 3-4% (which is on top of the ~5% improvement EGR/DPF has). I don't know if that will translate into a noticeably greater cost savings though, as that is dependent on DPF prices and fill schedules. I'm hoping it does though, as even 6 or 7% overall would be a nice savings when you are spending hundreds of thousands on dollars on fuel each year.

@Paul - thanks. Great post.

I wouldn't say that HD trucks lost their MPG lately. The only truck that did is a 08-10 6.4 powerstroke superduty, gets around 12.

@ Lex... Not true. I personally know @ 15 guys with 08+ Duramax and only 2 get better than 12-13 without delete unit.

One gets a consistent 8mpg and been to dealer many, many times.

Dodge is slightly better than GM/Ford, but still nothing to brag about.

With delete GM/Ford both do 20+ mpg highway.

Gotta agree with Power Kid. My 6.7 Cummins averages 14.5 MPG in mixed driving. Before Dodge reflashed the computer, I averaged a little over 15.2 mpg (with a best of 17mpg). Supposedly this reflash lowers the maximum back pressure level and kicks the active regen cycle in sooner. Now I'm lucky to see 15mpg.

Regen cycles... it always amazes me how emissions can be improved by shooting raw diesel into the exhaust... its like an afterburner without the benefit. That they had to put something like that in should've told them particulate filters were a bad idea...

It's interesting how older diesel vehicles are fit to run on 100% biodiesel no problem with simple fuel line changes but the newer vehicles are only approved for small concentrations of it.

I own a Jeep Liberty Diesel and love it. It tows 5K Lbs at 19mpg.

Why is it that Cummins will allow biodiesel for commercial, and government issued trucks, but wont allow the public to use it? I love Cummins diesel engines, but this seems a little odd to me. Anyone know why?

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