GM Planning New Engine Larger Than New 6.6L V8 L8T
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Earlier this month, General Motors officially announced the new 6.6L V8 L8T gasoline engine for the 2020 Silverado HD dually and 2020 Sierra HD. Based on GM’s fifth-generation Small Block engine architecture, the iron block motor makes 401 horsepower and 464 pound-feet of torque. But GM is planning an even bigger gasoline V8 engine, according to GM Authority sources familiar with the matter.
Details about the new engine are currently scarce, and we have received conflicting reports on the matter. However, sources from disparate parts of the industry have lined up on two things.
- The 6.6L V-8 L8T is the largest GM gasoline engine “for the time being.” We keep hearing that phrase in different forms and contexts from sources far and wide.
- The displacement of the other engine will be “well over” 8.0 liters.
As it stands, GM would use the future, high-displacement eight-banger in Class 7 trucks, which it is considering co-developing with Navistar – as we were first to report back in November. GM and Navistar have developed a very close relationship over the years, having co-developed the Class 4, 5 and 6 2019 Silverado Medium Duty and International CV chassis cab trucks. In addition, Navistar currently performs contract manufacturing of the cutaway versions of GM’s Chevrolet Express and GMC Savana commercial vans.
Stay tuned to GM Authority for further updates on the rumored new engine and for round-the-clock GM news coverage.
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Might it be something along the lines of the 8.8L propane engine that Navistar already uses in their school buses?
I hope not, as you may already be aware; the Fuel Economy in those Propane School Buses really do suck, from Columbus, GA. to Atlanta is about 100 miles and those Muscogee County Propane buses can’t even be used for Long Range Field Trips based on the poor Fuel Economy that they result in, the older Diesel School Buses would have to fill in for those tasks. Though overall, it would be nice for GM/Navistar to add a greater Powertrain option beyond the 6.6 Gas..Let’s hope that 8.8 gets the Green Light even 8.8 Diesel would be a true powerhouse.
It’s not an 8.8 liter that GM developed in 2010 to replace the 8.1 liter big block. It’s an 8.0 liter. To see the specs go to the GM engine website GMpowertrain dot com. When it opens, click on “PRODUCTS”. You will see the bottom row list on the left side as an 8.0 LFI. GM never installed it in any medium duty trucks, because a few months after they built the first few 8.0 liter engines for testing, they canceled the manufacture of the medium duty trucks and long school bus and motorhome chassis. Unlike the 8.1 liter, the 8.0 was designed with full water jackets between each cylinder so it will not overheat when running on propane. The aftermarket companies who use it as an 8.8 liter either bore and stroke it to get 8.8 liter size.
Why not just build an electric motor to fill the same promises as this motor..?
I hope you are being sarcastic.
Why? Because Class 7 and 8 commercial truck requirements go far and above any electric technology.
Electric stuff is fine as pie in the sky stuff that you invest in and maybe a turn a profit on in a decade or more. ICE is how you make money right now and today, especially when it comes to big trucks like the ones that would get the motor in questions.
I have spoken to a few engineers who know about this program… it is almost at a point of being green lit, and there will be a ton of collaboration between GM and Navistar.
Because the battery for said electric motor would not fill the same premises as the gas tank for this motor
Zach, will it fit in the new RED CHEVY BLAZER? Lol
Make it in Mexico too so Americans don’t get the jobs.
Zach, why don’t you just finish the ninth grade first and then maybe put your two on on here?
Model S 800lb batt, so what 10k lbs and 60g batt like it’s nothing, and 2 day charging time. Does having oatmeal for brains hurt? Electric is a pipe dream for the substitute religion green worshipers.
These trucks need to operate in cold weather, below freezing. Whatever range they are advertised to provide, with present battery technology an electric motor would not deliver the goods in deep winter.
Ford??, Lol I knew GM would let Ford show thier 7.3 off first.
Woah, 8 Liter!? i was thinking they should build a truck V8 based off of the LSX 454 block. Its bullet proof and would make an easy 500 ft/lb of torque at relatively low rpm’s. But i guess GM isnt messing around.
I hope GM has better luck with Navistar than Ford did with the 6 liter diesel. That engine was a disaster for Ford. Gas fueled or no if I were GM I’d RUN from Navistar and build it totally in house.
That engine became a disaster after Ford decided to Ford-dernize it.
The pre Maxxforce DT466 was probably the best mid-size diesel ever made. The 7.3/T444E was awesome too.
My sister has the 8.1L in her 2002 Silverado 2500HD. Uses it to pull her fifth wheel, loves that engine. I expect that’s the engine GM will revitalize and re-release.
Mine’s in a 3500. Excellent pulling engine, does better with a bobcat trailer than our F-550 V10. Shifts much smarter, pulls harder, and sounds way cooler (it matters to me.).
BRUCE, you have not been paying attention. GM spent the redevelopment money for the GM big block in 2010 to get the new 8.0 liter engine to replace the older tech 8.1 liter. The two engines only share one part and even have a different firing order. The first six blacks and heads were sent to Brian at Thomson Automotive in Michigan. It had an ultra low RPM torque camshaft. With a 10 to one compression ratio, on gasoline, Brian told me he got 518 lbs feet of torque at just 1800 RPM. That cam was set up for industrial use in very big forklifts that carry 15,000 pounds. The max HP came in at 2800 RPM. The big difference between the 8.1 and the 8.0 liter was the newer 8.0 had full water jackets between each cylinder, so it would not overheat on propane, which is the favourite cheap fuel for farms, remote mines and industrial users. The 8.0 was supposed to be installed in the GM Medium Duty 7500, 6500, 5500 and 4500 trucks for the 2011 model year, but GM shut down that Janseville WI medium duty factory, because very poor labour and union relations. The new design 8.0 big block was never installed in any GM vehicles. The new bigger GM engine for the present day 2019 Medium Duty Silverado 4500HD, 5500HD and 6500HD and Navistar ( International ) trucks is based on the 2010 development work. With the 4.25 inch stroke of the 8.0, you get 488 cubes and with a 1/4 inch longer stroke, you get a 516 cubic inch inch engine or 8.45 liters, much bigger than the 2020 Ford 7.3 gas engine. LINK TO EXISTING 8.0 https://gmpowertrain.com/engines/8l-lfi.html
Mark, that link to the 8.0 LFI says that the firing order is 1-8-7-2-6-5-4-3. That is NOT different from the Vortec 8100’s firing order, also 1-8-7-2-6-5-4-3.
BTW- Janesville ceased building medium duty GMT-530 TopKIck/Kodiak medium duty trucks in 2002 and the 2003-up GMT-560 TopKick/Kodiak (van cab) was built in Flint until GM stopped medium duty production in 2009. The reasons for abandoning the medium duty line were unprofitability and the GM bankruptcy.
The 8.1 has full water jackets between the cylinders
I HAVE A 2002 8.1 COUPLED TO A ALLISON TRANS WITH 430,000 MILES, i HAD FIVE OF THESE IN MY BUSINESS AND MY EMPLOYEES BOUGHT 4 OF THEM AND ALL BE ONE IS STILL IN SERVICE THE OTHER WAS TOTALED. MY POINT BEING IS THAT IF GM DOESN’T COUPLE THE NEW ENGINE TO A ALLISON TRANS THAT WILL BE A FATAL MISTAKE.
What is the point of all those liters when the current light duty 6.2 L gets 19 more hp and almost same torque?
Low end power and durabilty. The 6.6L will have more power at earlier rpm’s. And the larger displacement will make the power easier, causing less stress on the engine. A 350 V8 making 350 hp will last longer than a 350 V8 making 600 hp. I know its not that drastic but you get the point.
Dont be surprised,new big block on the way!
The bottom end of the torque curve no doubt looks better, would have to overlap them to compare.
A bigger engine is needed for heavy Medium Duty Class 6 and 7 trucks because when you run them on CNG natural gas you loose too much HP and torque. GM figures show a loss of 50 lbs feet of torque on a gasoline 6.0 liter compared to running the same engine on 105 octane propane. Propane has more energy per pound than even diesel fuel, and it is about 37 percent hydrogen by weight, so it burns very hot. If GM decides to stroke the new 8.0 liter industrial engine, with a 4.5 or a 4.6 inch stroke compared to the 4.25 inch stroke it is sold with, it will have about 520 to 540 lbs feet of torque if they put a cam phaser in it. That torque rating will drop about 70 lbs feet of torque on CNG. That’s why they need a bigger engine for the Class 7 trucks which are rated up to 33,000 pounds Gross Weight rating.
John, the 6.2 liter is not a heavy duty truck engine. Notice that it is not offered in the 2500 or 2500 pickup trucks. The 6.2 has a very thin cylinder wall compared to the 6.0 liter in the HD pickups. They run too hot when pulling the maximum load trailer. The number one thing is the 6.2 liter stroke is too short to be a serious torque engine. GM offers a longer stroke on the new 2020 design 6.6 liter gasoline engine and the torque number shows that with 464 lbs feet of torque on regular gas. The torque and HP rating on the 6.2 is with 93 octane gasoline and semi-synthetic oil. If you run the new 2020 engine with 6.6 liters on 93 octane, you will gain about 35 pounds feet of torque because it has the latest tech stuff on the engine to get the maximum torque. Even the truck 4.3 liter V6 gained about 20 pounds feet of torque when it used higher octane fuel, based on the GM test results. .
Quit running cheap gas,use premium fuel or e85.GM needs to run a true duel exhaust,get rid of that power loss,too much back pressure!GM can make a torque monster out of any of there motors,they chose not to,until someone makes one to beat what they have,this is why stock is gay.Everyone knows just have a motor made,they always run better than stock.
https://www.chevrolet.com/performance/crate-engines/big-block-zz-572-720-r
The new design 8.0LFI engine that GM supplies to industriai users and Freightliner Chassis Corp for full size school buses and motorhomes, was designed to run on propane or natural gas CNG. As i recall, the 572 cube engine uses an older design from 1998. GM developed and Thomson Automotive first tested the high deck 8.0 liter big block many years later in 2010. The 572 cube engine is a Generation V engine with a big bore, but i don’t think you can cram a 4.75 inch stroke into it. It has much different design that the 8.0LFI engine that GM developed and tested in 2010 and never put it in any GM trucks. There are 4 different companies that offer the new design 8.0LFI as an industrial engine to use propane or CNG. See those companies at GMPowertrain dot com, under the heading “Industrial”.
first, the ZZ572 is still based off the 1960s mark IV L88 heads. It makes 620hp by sheer will power.
torque is proportional to *displacement* and volumetric efficiency. For a given displacement, increasing stroke decreases bore size, which means smaller valves, which means lower volumetric efficiency, which means less torque. Long stroke increases piston speed, and (because of a shorter rod) increases frictional losses, and decrease longevity.
These motors are so under valved it’s silly. Small valves leads to high pumping losses, which equals poor fuel economy. Big valves do not hurt torque! Consider any 4 valve truck engine. Relative to the 5300, a 496 would need a 60mm intake valve to have the same pumping loss (which seems massive compared to the 8100’s 54mm valve).
They need to stretch an LTX. I would give it a 111mm bore, 105mm stroke, 58mm intake valve, square ports (in the same location as the 8100), long rods, and short intake runners – all working together to maximise fuel efficiency. I figure 450hp @ 4600 rpm, and a minimum of 525 lb-ft @ 3600 rpm is reasonable. The short runners will boost low rpm by 15-20% over a “tuned” runner, and improve fuel economy via lower pumping losses and port cross-talk. Aluminum heads will make it only ~100lb heavier than the small blocks. Bonus would be the 700 hp/700 lb-ft crate engines.
This big boy will be designed for truck work, not performance you would want in a car. Trucks need torque more than HP. Torque is the ability to do work, horse power is how fast you can do the work.
That doesn’t mean it wouldn’t be fast if it made it into HD pickups. The 8.1 for example is a peppy motor.
Might be a V10 ls engine.
SEE MY OTHER COMMENT RE TORQUE AND HP FOR THE 8.0 LITER LFI BIG BLOCK.
MY DREAMS ARE COMING TRUE!! Big Blocks Forever!
Live to dream.. one has to wonder whether this means the return of the LS7 7.0L OHV-2v V8; but this is the opposite of what General Motors CEO Mary Barra said she was planning for the company and electrifying the fleet by 2025 as the need for more horsepower and torque should translate to Chevrolet Silverado trucks adopting the Chevy Volt architecture with a 500 hp electric motor from the Buick Enspire concept CUV with a fuel cell or a 3.0L V6 recharging the battery.
MARY BARRA DOESN’T KNOW ABOUT THIS NEW DESIGN ENGINE BECAUSE IT WAS DEVELOPED IN 2010. AS AN INDUSTRIAL ENGINE AND MEDIUM DUTY 2010 TRUCKS, BUT NEVER USED. IT’S NOT, LET ME REPEAT, NOT AN LS DESIGN. LINK TO 8.0 NEW DESIGN 10.2 INCH HIGH DECK, 8.0 L BIG BLOCK AT JEGS
LINK https://www.jegs.com/i/Chevrolet-Performance/809/19256820/10002/-1
HERE IS THE LINK TO THE BARE BIG BLOCK NEW ( NOT LS ) DESIGN 8.0 LITER GM ENGINE AS DESIGNED IN 2010 BUT NEVER SOLD IN ANY MEDIUM DUTY TRUCK. THE ENGINE WAS FULL WATER JACKETS, MUCH DIFFERENT THAN THE 8.1 LITER MEDIUM DUTY HIGH DECK BLOCK. LINK TO JEGS https://www.jegs.com/i/Chevrolet-Performance/809/19256820/10002/-1 END
That 8.0 @ Jegs is just an slightly updated Big Block Chevy V8. I cannot fathom them re-releasing that engine in a new truck. The head design severely limited allowable compression ratio without high octane gasoline, and before they went semi-internal balanced in 2001, their durability in real HD applications was nothing compared to current 6.0 LS-based V8. In 8.1 configuration, I seem to recall ~340 hp and ~450 ft lbs, both short of the new 6.6.
If this is a class 7 exclusive, I can’t imagine them investing much $ in it for the limited sales opportunities. Seems like a tall deck version of the newest LS with ~4.25″ stroke would get the engine into the mid-500 ft lb range. I think that’s a better option than updating the 1965 era big block.
HERE IS THE LINK TO THE BARE BIG BLOCK NEW ( NOT LS ) DESIGN 8.0 LITER GM ENGINE AS DESIGNED IN 2010 BUT NEVER SOLD IN ANY MEDIUM DUTY TRUCK. THE ENGINE HAS FULL WATER JACKETS, MUCH DIFFERENT THAN THE 8.1 LITER MEDIUM DUTY HIGH DECK BLOCK. LINK TO GMPOWERTRAIN DOT COM FOR THE 8.0 LFI AS SOLD ONLY AS AN INDUSTRIAL ENGINE, NEVER INSTALLED IN ANY GM TRUCKS. https://gmpowertrain.com/engines/8l-lfi.html
MARY BARRA DOESN’T KNOW ABOUT THIS NEW DESIGN 8.0 LITER ENGINE BECAUSE IT WAS DEVELOPED IN 2010. AS AN INDUSTRIAL ENGINE AND MEDIUM DUTY 2010 TRUCKS, BUT NEVER USED. IT’S NOT, LET ME REPEAT, NOT AN LS DESIGN. LINK TO 8.0 NEW DESIGN 10.2 INCH HIGH DECK, 8.0 L BIG BLOCK AT WEBSITE GMPOWERTRAIN DOT COM
LINK https://gmpowertrain.com/engines/8l-lfi.html
That 8.0L is a Mark VI design, like the 1996-2001 Vortec 7400. It’s a generation older than the 8.1L. That 8.0L is currently used in propane fueled Freightliner medium duty trucks and school bus chassis. I doubt that engine is the one referred to in this story.
BOB, You are wrong. I consulted with the GM engineer every Friday at Thomson Automotive when Brian Thomson was developing and testing the new design big block which is 8.0 liters. That was in 2010, but a few months later GM stopped building the medium duty trucks, so there was no 2011 model of the Medium Duty 7500, 6500, 5500 or 4500 truck. here is the difference as told to me by Brian. There is only ONE part shared between the old 8.1 liter and the never-sold-in-a-truck new design 8.0 liter. The firing order is different as well. I’m not here to insult anyone, but if you guys refuse to read my dozens of other comments on this 8.0, that’s on you. GO TO THE FEBRUARY 2019 WEBSITE GMPOWERTRAIN DOT COM AND CLICK ONTO PRODUCTS. LOOK AT ALL THE PRETTY PICTURES AND FIND THE ONE THAT SAYS 8.0 LFI. IT IS SOLD TODAY, IN 2019 AS THE LATEST DESIGN OF BIG BLOCK AND IS USED BY FREIGHTLINER IN SCHOOL BUSES AND MOTORHOME CHASSIS. NOW YOU KNOW……IF YUR NOT TOO LAZY TO CLICK.
THIS ENGINE IS THE 2010 NEW BIG BLOCK DESIGN, SOLD TO FREIGHTLINER TODAY AS A LPG ENGINE.
8.0L LFI TECH SPECS
Type 8.0L Chevy Big-Block V-8
Displacement 488 ci
Compression Ratio 9.9:1 nominal
Valve Train Fully adjustable
Balanced Internal
Camshaft Type Hydraulic Roller
Firing Order 1 – 8 – 7 – 2 – 6 – 5 – 4 – 3
Bore x Stroke 4.270 x 4.250 in
Fuel Type LPG/CNG
Maximum Recommended Engine Speed 4500 rpm
Horsepower 375 hp @ 4200 rpm (Gas)
315 hp @ 4500 rpm (CNG)
Torque: 475 lb-ft @ 3200 rpm (Gas)
390 lb-ft @ 3500 rpm (CNG)
Pistons Hypereutectic alloy
Cylinder Head Fast burn iron
Intake Manifold Stainless steel
Exhaust Manifold Stainless steel
Crankshaft Forged steel
Connecting Rods Forged steel
Damper Cast iron
LINK https://gmpowertrain.com/engines/8l-lfi.html
Like I said, the 8.0L you are referring to is a Mark VI design. Look at the intake port configuration, it doesn’t have the cathedral ports the Mark VII 8.1L had. Firing order is different, fewer head bolts, bore and stroke different. The 8.0L is is a different engine than the Mark VII Vortec 8100 8.1L. Read my post, I never said they were the same or related.
ALL MY COMMENTS ABOUT THE NEW DESIGN BIG BLOCK 8.0 ARE BASED ON FACTS THAT I KNOW ON A PERSONAL BASIS AS TOLD TO ME BY BRIAN. . I DEALT WITH THE GM ENGINEER EVERY FRIDAY AND BRIAN AT AS THOMSON AUTOMOTIVE WAS DEVELOPING THE NEW DESIGN ENGINE. I WAS ADVISING BECAUSE MY VARIOUS FLEETS HAD RUN ABOUT 25 MILLION MILES ON PROPANE. GM HERE IN CANADA USED TO ASK US TO REMOVE ENGINES THAT HAD RUN 200,000 TO 300,000 KM ON PROPANE AND THEY GAVE US A BRAND NEW ENGINE AND PAID FOR OUR LABOUR AND FLUIDS AS WELL. GM TOOK OUR USED ENGINES TO OSHAWA WHICH WAS WAS THE DEVELOPMENT CENTER FOR PROPANE AS USED ON THE LAST FEW YEARS ON THE SHORT 3500 SCHOOL BUS CHASSIS. DISREGARD THE OTHER IDIOTS ON THIS CHAT. BRIAN GOT 518 LBS FEET OF TORQUE AT JUST 1800 RPM BECAUSE HE WAS USING A LOW RPM CAMSHAFT THAT IS USED FOR MAKING ELECTRICITY WHEN RUNNING ON PROPANE.
The 3500 bus chassis is a van based product. The lpg option engine was/is a converted L96 6.0l LS based engine formerly done by IMPCO and now converted by PSI.
Homer, you are wrong about the GM engine code for the propane 6.0 liter V8. The GM engine code is LC8 and is advertised as a CNG and LPG Ready-To-Convert engine. It’s delivered in the trucks with the full gasoline system, so you can add the LPG equipment to it and run either fuel sepertately. It is offered as a factory install on both Isuzu/GMC and Mitsubishi Fuso tilt cab trucks as well as GM 2500 and 3500 pickup trucks and the chassis cab 3500 and 4500, as used for the short school buses, motorhome chassis and cubevans. The Isuzu versions with that 6.0 liter engine use a GM 6 speed automatic as standard equipment. The Mitsu Fuso uses an Allison 6 speed auto trans with the 6.0 liter gas engine and the Fuso offers a 4 Wheel drive option, great for working in muddy offroad fields. Or the North Pole under contract to Santa Claus.
I am not sure what point you are trying to make, the LC8 is a converted L96 6.0l. The base unit trucks ( Vans and pickups) are assembled by GM as incomplete vehicles and sent to PSI on a ship thru code for installation and modification for bi fuel system. There were multiple suppliers making the conversion for GM, but it is now down to PSI. A person cannot simply go to a dealer and order an LC8 incomplete truck to be shipped directly to themselves without having a Fleet Account Number, it must go on a ship thru code to PSI where it is completed with components which enables compliance with Federal MVSS standards and GM durability requirements. The door certification sticker is shipped with the incomplete vehicle when sent to PSI, and installed after the bi fuel upfit is complete.
BOB, let me repeat. The 8.0 liter is a new never before used design on any GM car or truck. It was designed and built for test purposes for the very first time in 2010. You need to check the Wiki page and find out that the VI version you are referring to is a design from years before. I never bothered to update the Wiki page because, GM never installed it in any cars or trucks. IT IS NOT A GENERATION VI ENGINE WHICH GM INTRODUCED IN 1996. THAT’S 14 YEARS BEFORE THE 8.0LFI WAS FIRST TESTED, IT’S A 8.0LFI, AS GM REFERS TO IT ON THEIR 2019 WEBSITE OF UP TO DATE ENGINES. .
Here you go, even GM says the 8.0L is based on the Mark V/VI design:
https://gmserviceinsights.com/2016/12/creature-feature-gm-creates-8-0l-industrial-crate-engine/
You are right it was designed primarily as a gaseous fueled industrial engine. Our local school district runs LPG 8.0L’s in both Freightliner school buses and medium duty trucks.
WHAT THE PRESS RELEASE IS SAYING IS THAT IT’S BASED ON A BIG BLOCK DESIGN, NOT THE L.S DESIGN
Yes, the Mark VI Big Block, not the LS. The production Big Block Marks are as follows:
Mark I, 1958-1964 348 and 409.
Mark II, 1963 427.
Mark III, design study only.
Mark IV, 1965-1990 366, 396, 402, 427, 454.
Mark V, 1991-1995 366, 427, 454.
Mark VI, 1996-2001 Vortec 7.4L.
Mark VII, 2001-2010 Vortec 8.1L.
This 8.0L is based on the Mark VI Big Block, not any LS and not the Mark VII 8.1L. Nonetheless, I really doubt the 8.0L is the rumored new engine. It does not have VVT or DI in current form.
The 8.0LFI engine was never classed as a Mark engine because GM didn’t get that far in 2010. It was never a complete fully running engine for GM. Even today, it is sold without any intake manifold, because GM never built it with one. When Brian Thomson developed and tested it, he put an aftermarket intake manifold on it. That is why Brian sent the first three engines he built and tested over to the other company in Michigan, so they could design and make an industrial suitable low RPM torque intake manifold with the fittings for propane. I only talked to that other shop about three times and they got caught short because GM stopped selling Medium Duty trucks. GM was going through a bailout and both the Canadian and Ontario and U.S. governments took billions worth of shares to help GM. Once again, there is no MARK label ever put on an incomplete engine. But, GM could now be adding a cam phaser to it, to boost the low end by about 35 to 55 extra lbs feet of torque. Brian told me that only one part was the same as the 8.1 liter engine. It was a clean sheet design, so GM could sell this truck engine to those who wanted to run it on propane or natural gas. By the way, when Brian got the engines running, they did not use a forged crank. That really shocked me and i told the GM engineer in his shop, that they were making a big mistake by using a cast crank. The other aftermarket companies got Callies to make a longer stroke 4.5 inch forged crank. That is how PSI sells it today.
Power Solutions International, (PSI), produces a 8.8l engine which is the market leader in gaseus fuel MD and HD truck powertrain. PSI is a large producer of engines for various transportation and stationary applications. They inherited conversion of GM LS based trucks for cng and lpg from another company that got out of the automotive business.
Because Navistar is currently using the PSI 8.8l engine, MD industry rumor is that this is the engine that Navistar will install in the 4500/5500/6500 MD they produce and brand as GM.
Yes, this is the PSI Illinois based company that uses the new design 8.0 liter GM developed big block in 2010. After Brian Thomson of Thomson Automotive developed and tested the 6 first engines that GM contracted to him, Brian sent the first 3 engines over to the other Michigan company for the propane intake manifold and testing. Brian only tested the engines on gasoline, ( he used a 10 to one compression ratio ) as he was not a propane expert. That other Michigan company DID NOT go out of business, it was bought by PSI. Yes, PSI offers both smaller LS type GM propane and CNG fueled powerplants, but they also offer huge 16 liter industrial versions and others of 35 Liter ( 2,136 cubic inch ) and 40 liter ( 2,440 cubic inch ) size. Here is the link to the GM industrial new design 8.0 liter as FIRST built in 2010, for those who keep ignoring the various TRUE facts that i keep posting. link https://gmpowertrain.com/engines/8l-lfi.html
Powertrain Integration was the company marketing the 8.0L to OEM’s, PSI was doing the 8.1L based 8.8L, which PSI assembles themselves. PSI did buy Powertrain Integration a few years ago. I think the company that was doing the CNG conversions of LS powered trucks was Impco, who did get out of the OEM CNG upfit business. PSI has taken over as GM’s preferred CNG conversion upfitter.
Bob, you are correct. IMPCO is still in business, but not performing final assembly of bi fuel vehicles for GM. IMPCO’s GM business and some of their personnel shifted to PSI. The 8.8l engine is a PSI designed and assembled engine, architecturally based on 8.1l. Back on story subject for GM engine larger than 6.6l. unconfirmed information to me from a manufacturer’s employee is that Navistar will assemble GM branded 4500/5500/6500 MD with PSI 8.8l engine with engineering integration performed jointly between Navistar, GM, and PSI pending successful completion. So the question posed in the first post is an unconfirmed yes.
Might be a little more to it than that! We will have to wait and see, but I do think the PSI 8.8L has a future.
Homer, PSI did not design the 8.8 liter or the 8.0 liter big blocks. GM designed them. PSI just made some changes to the engine, such as a longer stroke on the high deck block. GM designed and cast the parts for the 2009 design 8.0 liter big block and then the parts for the first 6 engines were sent to Brian at Thomson Automotive to build and test and develop the right camshafts for it. The target was to build the cam for a very low RPM range, industrial engine for making electricity and other industrial versions, such as the large outdoor 15,000 pound forklift trucks. GM made a mistake, by only offering a 4.25 inch stroke in the new 8.0 liter when the 8.1 liter had a longer 4.375 inch stroke. Since the 8.0 liter was only designed and cast as a high deck block, a longer 4.75 inch stroke can be used. Brian told me that any crankshaft longer than a 4.5 inch in the big block flexes too much, that is why GM was concerned, because the original testing was not a forged crank, but a cast crank. GM tried to save money, by not using a forged 4.5 inch crank and that was a mistake. By the way, Brain got a best torque of 518 pounds feet at just 1800 RPM with the industrial low RPM range camshaft. The high RPM for industrial engines is only 2800 RPM, where the max HP occurs. Industrial engines are rated by international standards to run all day long at 1800 RPM, regardless of the fuel type, diesel, gasoline, propane or natural gas.
Still looking for information on the new 8+L engine. I have heard that PSI is looking to make significant upgrades to their 8.8L in 2020, but no indication this is the rumored engine for the larger Navistar/GM truck supposedly under development.
I hope its a premium gas engine for the HD and 55-7500 trucks. I would like to see it mirror the Atkinson cycle and near 14:1 compression ratio of the new camry that gave a 10% efficiency booste, DSF to reduce cylinder wear and increase economy by 15-18 % for a total 20-30% increase in fuel economy over traditional big blocks. it doesn’t matter how cheap up front an engine is if it eats you out of house and home. I would love an engine like this. Please be 8.8L!
Premium gas wouldn’t be fun. Picture a landscaping company with Chevy 6500HDs, mowers and equipment that they fuel from a gas tank at the shop. Who wants to have to buy premium for everything then, or have to buy two fuels?
Stay with the 8.0l.Increase the compression.Why have a large bore,extra stroke,low compression?Wake up!More compression = more torque,Didnt the high compression 427 teach you anything!
Richard, You are right about the too low compression ratio. The big blocks never had cam phasing, which allows to camshaft to be retarded during all RPM ranges, such when going up a steep hill or towing a heavy load. Ford just offered 2 different 2020 versions of it’s truck 7.3 gas big block, one with a lower CR and just 350 HP for the F-550, F-600, F-650, F-750 heavy trucks and motorhome and step van chassis while the F-250 to F-450 pickups get the higher 430 HP version with a higher CR. The GM 2020 gas 6.6 liter engine has a very high 10.8 to one CR but it is different, because the gasoline required is only regular. Cam phasing and very advanced engine computers and all the other high tech stuff, allows that 6.6 to be rated at 401 HP on regular gas. GM should offer a stroked 6.6 liter for the medium duty trucks, but the LSX high deck block won’t cut it, because it does NOT have full water jackets between each cylinder. A new LSX block needs to be cast, with full water jackets, then GM can use this version to sell to industrial users and marine versions, which run non-stop for hours or days at a time on CNG, propane and even alcohol fuels in some countries where ethanol is very cheap, EG: (Brazil which produces sugar cane ethanol ) You cannot haul very heavy loads if the engine has siamese cylinders, because there is not enough cooling between each of the 4 inner cylinders. By the way, the Dodge Hemi engines of various sizes, have full water jackets between each cylinder, making the 6.4 liter Hemi in the 4500 and 5500 Dodge trucks, a great engine if you want to run on propane, which needs a huge amount of cooling because the very high 104 octane propane, which burns so hot.
From what I understand, the new L8T 6.6 block is basically a siamesed bore casting but with coolant passages drilled between the cylinders. Best of both worlds, strength of a siamesed bore casting but with enough cooling between the inner cylinders for heavy duty use. The Ford 7.3L also appears to be a siamesed bore casting, but it looks like Ford machined slots between the inner cylinders. Not sure how deep the slots are, but what I don’t like about them is that they are open to the block deck, possibly compromising head gasket sealing. Chrysler does this on some of their engines.
Word is the 6.6L is going into the Silverado 4500/5500/6500 and LCF 6500, but it will be rated slightly lower in those applications. Not sure if the medium duty 6.6L is actually different than the L8T (compression ratio?) or simply rated at a lower R.P.M.
Bob, you are wrong about one point. This website dais that GM was considering a larger cube engine than the 6.6 liter LS style for the Medium Duty Silverado heavy trucks. You CANNOT run the 10.8 to one compression ratio of the new 6.6 liter 2020 gas engine in a truck rated to be 22,500 pounds gross weight rating. If GM was to lower the CR on the 6.6, then both HP and torque will be too low. That is why GM needs to bring out a non-siamese cylinder high deck LSX block, that has full water jackets between each cylinder and run a 4.5 or 4.75 inch inch crankshaft to gain the torque needed for a very heavy truck and industrial engine. Make the bores smaller to keep the cubic inches from getting too big, but stroke that muther to the moon. Torque at a lower RPM range is the only thing that matters on a heavy truck engine. With the 10 speed transmissions, there is not need for a big cubic inch truck engine to rev more than 2,800 RPM even when the gas pedal is half way to the floor. Lower RPM means longer engine life and less engine wear and noise.
I thought the story was the 8L+ engine was going into an upcoming new larger class 7 Navistar/GM joint venture truck, not the current Chevy Silverado 4500/5500/6500 and International CV series.
GM does not want any problems with a new engine, so they might be testing the engine to the extreme for emissions reasons. Remember that the 2009 designed big block of the 8.0 liter, ( and never sold in any GM truck )did not have camshaft phasing. Maybe they are adding that onto the new 2020 version of the 8.0 liter. A company buying or leasing a 4500HD or a 5500HD is much more likely to want a gasoline engine than somebody ordering a 7 series truck or chassis.
Very very interesting, but is a 8.0 V8 DOHC twin turbo (Cadillac CT6 V-Series V8) not the better GM V8 engine for the trucks and buses from 2020. Here would be very high engine power and torque at low speeds possible and useful. Gasoline and CNG suitable and homologated in all US states. Technically more complex and a little more expensive, but cheaper and more ecological as diesel engines. Gasoline engines do not require any additional chemicals for exhaust gas purification, such as diesel engines with the toxic Adblue / Ammonia. Technologically, this is possible for GM as always. Hybrid support for V8 gasoline is possible, even useful, but also more expensive for fleet customers. Electric motors will be useful only for trucks in short-range distribution traffic. See information about trucks in Europe and Germany.
Greetings from Germany / Bayern / Regensburg to all V8 fans.
For heavy duty use, you typically want something more simple than twin turbos and DOHC. You need an engine that can take hard use and last a long time. There is a reason people loved the 6.0L and 8.1L. They were easy to work on, could take lots of abuse and lasted a very long time. Not too many people would trust a twin turbo dohc V8 in a heavy duty truck.
Hermann, the big difference between the car engines and the truck engines, is the block material. All medium duty trucks avoid the use of aluminum as the block material. GM already offers a suitable engine foe heavy duty trucks with the 8.0 LFI version. They use it in Freightliner school buses as a propane LPG version modified to run on CNG or propane by a couple of different companies. With 475 pounds feet of torque, without camshaft phasing, it’s not much more than a 454 LSX small block. The siamese cylinders of the 454 LSX tall deck version means it’s not good enough to be cool running on propane, because propane burns very, very hot. With a 10 to one compression ratio, the LSX 454 has from 500 to 515 foot pounds of torque, as per the GM Powertrain website. That’s with a too short 4.125 inch stroke, not enough for a serious heavy truck engine, when the compression ratio is lowed from 10 to one to about 9.6 to be able to use regular gasoline. The stroke should be at least 4.25 inch, like the original 496 8.1 liter big block which had a 4.375 inch stroke to get enough low RPM torque to be a reasonable commercial grade work truck and industrial engine. With a long 4.5 inch stroke, the LSX high deck 454 could put out about 525 to 540 pounds feet of torque with the compression ration in the mid nines.
When will the new 8.0 show up in the new Chevy HD trucks 4500/5500/6500?