6.6 gas

ApertureX · February 7, 2019

Just a little comparison chart I made for myself, but I figured I'd share with the class for discussion sake. Both trucks listed are 4WD Crew Cab with a Standard Bed:

Edited February 7, 2019 by ApertureX

magnum74 · February 7, 2019

Great chart, thanks. They really beefed up the 2500's.

ApertureX · February 7, 2019

Audio quality varies throughout the video, but @ 15:05 the 6.6L engineer states:

- 6.6L torque is improved 20% across the entire RPM range, not just peak

- Torque peak has lowered to around 4000 RPM

- E85 is NOT available on the new 6.6L

Edited February 7, 2019 by ApertureX

C/K Man · February 7, 2019

Notice the engineer said that E85 capability was not available at launch. Might mean that it is coming, just not in 2020.

redwngr · February 7, 2019

GM Authority website says GMPowertain confirms it wil be rpo code L8T.

http://gmauthority.com/blog/gm/gm-engines/l8t/

GM 6.6 Liter V-8 L8T Engine

The L8T is a gasoline engine produced by General Motors for use in Heavy Duty pickup trucks. The engine displaces 6.6 liters in a V8 configuration and an OverHead Cam (OHV) layout otherwise referred to as push-rod.

It is part of GM’s fifth-generation Small Block engine family and made its debut in the all-new 2020 Chevrolet Silverado HD and 2020 GMC Sierra HD.

Overview

The 6.6L V8 L8T is built on a cast-iron Small Block, enabling it to have long-term durability. Thanks to aluminum heads and direct injection, the engine delivers more precise fuel control resulting in a higher compression ratio of 10.8:1. That enables a power output of 401 horsepower and 464 pound-feet of torque (in the 2020 Silverado HD and 2020 Sierra HD), with strong performance at low rpm, where it is needed when pulling away with a loaded cargo box or trailer.

The L8T also features a forged steel crankshaft, forged powder-metal connecting rods and additional high-strength components to provide the added strength and durability demanded by Heavy Duty truck customers.

The L8T replaces the 6.0L V8 L96 / LC8 engine and makes over 11 percent more horsepower and over 21 percent more torque.

Vehicle Applications
Manufacturer   Model Year   Make   Model   Transmission   Power (hp / kW) @ RPM   Torque (lb-ft / Nm) @ RPM
General Motors Company   2020   Chevrolet   Silverado HD   6-speed auto (6L90)   401 / 299 @ 5200 (SAE certified)   464 / 629 @ 4000 (SAE certified)
General Motors Company   2020   GMC   Sierra HD   6-speed auto (6L90)   401 / 299 @ 5200 (SAE certified)   464 / 629 @ 4000 (SAE certified)

Specifications
GM RPO Code:   L8T
Type:   6.6L V-8 gasoline
Bore & Stroke (in / mm):   4.06 x 3.86 / 103.25 x 98
Block Material:   Cast iron with nodular iron main caps
Cylinder Head Material:   Cast aluminum
Compression Ratio:   10.8:1
Valvetrain:   Overhead-valve, two valves per cylinder, variable valve timing
Fuel Delivery:   Direct fuel injection
Power (hp / kW @ rpm):   401 / 299 @ 5200 (SAE certified)
Torque (lb.-ft. / Nm @ rpm):   464 / 629 @ 4000 (SAE certified)
Predecessor:   6.0L V8 L96/LC8
Successor:   None currently

Read more: http://gmauthority.com/blog/gm/gm-engines/l8t/#ixzz5esWm11G5

Gagliano7 · February 8, 2019

On 2/1/2019 at 10:44 AM, ApertureX said:

To keep the engine in it's highest torque band when towing, just like what they did on the light duty 1500's and what they did for the diesel 6.6L in the new HD's. It's for maximum performance and saving gas if you are not in tow haul mode. Really, that is the whole reason we even graduated from '3 on the tree' in the first place (points to those who get the reference without Google).

My father had a work van with the 3 on a tree and every so often it wood get stuck in 2nd gear and you have to go underneath and move the linkage to free it up. Nothing like doing that in the snow. The good old days.

Gagliano7 · February 8, 2019

That Ford LS engine i hate to say it looks awesome. Simple and no direct injection. That engine will find its way into many older vehicles in the future. I wish Chevy would have done the same.

ApertureX · February 8, 2019

1 hour ago, Gagliano7 said:

That Ford LS engine i hate to say it looks awesome. Simple and no direct injection. That engine will find its way into many older vehicles in the future. I wish Chevy would have done the same.

While a big block engine would be nice, I can't wait to get the 6.6L and throw a supercharger kit on it as soon as it's available to get the max torque out of that stroker.

magnum74 · February 8, 2019

1 hour ago, Gagliano7 said:

That Ford LS engine i hate to say it looks awesome. Simple and no direct injection. That engine will find its way into many older vehicles in the future. I wish Chevy would have done the same.

GM didn't need to reinvent the wheel with this engine. Ford made the 7.3 because they had to. If you're suggesting that the industry won't be chomping on the bit to get the stroked 6.6 into their builds I think you're completely wrong. Having said that, I like idea of the 7.3. I'll wait for some real empirical data from these trucks, though. Will a clean slate 7.3 perform/outperform enough against GM's minimal investment to make it worth it? What about fuel economy? Using more fuel for negligable real life performance is not going to get me into a big block. Within a couple years I'll be repacing mine and it's likely Ford or GM, not big the AFM 6.4 though the 8-speed is exactly what it needs. I'm glad us HD gas buyers have new options to stir it up a bit.

SierraHD17 · February 8, 2019

2 hours ago, ApertureX said:

While a big block engine would be nice, I can't wait to get the 6.6L and throw a supercharger kit on it as soon as it's available to get the max torque out of that stroker.

If you are expecting to be able to tune a 2020 HD gas truck I honestly wish you luck. In the 9 years of the e78 with the L96 you can barely tune one if them with a blower... if at all properly. If they pull another stunt like that with the 2020 trucks having its own proprietary ecm I would doubt it ever getting anything meaningful for support.

Now pulling the 6.6 out of one of these ugly ass HDs and tossing it into like 2014 to 2018 half ton is a different story.

ApertureX · February 8, 2019

2 hours ago, SierraHD17 said:

If you are expecting to be able to tune a 2020 HD gas truck I honestly wish you luck. In the 9 years of the e78 with the L96 you can barely tune one if them with a blower... if at all properly. If they pull another stunt like that with the 2020 trucks having its own proprietary ecm I would doubt it ever getting anything meaningful for support.

Now pulling the 6.6 out of one of these ugly ass HDs and tossing it into like 2014 to 2018 half ton is a different story.

Whipple claims to have fixed that problem for the 2014-2018 HD engines, so there is hope.

https://whipplesuperchargers.com/index.php?dispatch=products.view&product_id=395

SierraHD17 · February 8, 2019

They all offer kits for the trucks. It does not mean you will ever get what you want out of them. 2011 through 2019 is virtually identical.

ApertureX · February 9, 2019

TFL has posted their video on the 6.6L

brendon444 · February 10, 2019

Excited for gm to finally replace the old 6.0. Funny some saying gm should keep it as it’s tried and proven. With this mindset we should still be using small block tech from the 60’s.

I want a gas HD truck but the mileage and low output kept me from buying a 6.0. I personally want AFM and direct injection. This will also be my daily driver so mileage is a huge factor and reason I don’t have one now.

I currently have a 5.3 and 6.2 in half tons and am amazed with the 6.2 mileage for the power output. Pull a 8000lbs trailer so that’s where I would like the HD.

Now for the commercial fleet side, I keep hearing that mileage isn’t important. I work at a company that runs 100’s of trucks with the option of using the gm 6.0. All I hear is underpowered and to hard on fuel and I agree. I don’t want to fuel up everyday and not have the range. So when it comes time to order a new truck hardly anyone orders this option. We get a choice.

Edited February 10, 2019 by brendon444

SierraHD17 · February 11, 2019

The 6.6 does not have afm and hopefully never will. Reliability is a lot more important on the fleet side at least to most companies including mine. My competition uses Rams that consistently lose camshafts but the cheap trucks match their cheap demeanor lol. If you think a 6 liter is that awful you really should try a 2500 ram with a 5.7 lol. This new 6.6 will be a power improvement but with GMs usual tuning don't expect it to be anything like a 6.2 half ton.

Edited February 11, 2019 by SierraHD17