Chevrolet Performance Launches L8T Crate Engine
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Chevrolet Performance is now offering the naturally aspirated 6.6L V8 L8T as a new crate engine.
For those readers who may be unaware, the naturally aspirated 6.6L V8 L8T is the same powerplant cradled by gasoline-powered variants of the Chevy Silverado HD and GMC Sierra HD heavy duty pickups, and now, the L8T is the largest-displacement LT-family engine on offer from Chevrolet Performance. Peak output is rated at 401 horsepower at 5,200 rpm and 464 pound-feet of torque at 4,000 rpm, but unsurprisingly, the V8 also packs in loads of low-end torque along the way. Maximum recommended engine speed is 5,600 rpm.
In terms of construction, the L8T block is made from cast iron and incorporates six-bolt nodular main bearing caps, while the crankshaft is made from forged steel. The connecting rods are made from forged powder-metal, while the pistons are made from hypereutectic aluminum. Compression ratio is set at 10.8:1.
Further features include oil-spray cooling for the pistons and production-style exhaust manifolds. The L8T crate engine package also includes the throttle body, oil pan, PCV tube, evap tube, oil dipstick, oil fill tube, and cap, as well as a high-pressure direct-injection fuel pump pre-installed. However, it does not include the controller, harness, oxygen sensors, or Front End Accessory Drive system. Alternatively, customers can opt for the L8T Long Block option, which includes the direction injection cylinder heads, coil-on-plug ignition, oil pan, and dip stick, but does not include the intake manifold, throttle body, fuel pump, or fuel injectors.
In terms of transmission options, the 6.6L V8 L8T crate engine is available to connect to the SuperMatic 6L80-E six-speed automatic, with customers offered a few options for the torque converter, including a 2400 – 2800 stall, and a 3000 – 3400 stall. Further related parts and accessories include an accessory drive system, both with and without air conditioning, and the L8T controller kit required to run the L8T crate engine with the 6L80 automatic transmission.
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It’s a great engine, but why can’t they give us more Buick, Oldsmobile, or Pontiac crate engines? It would be nice if I could stop by a GM dealer and order a updated modern day version of the 400 Pontiac Ram Air 3, or a 455 Buick Stage 1. Why should we have to settle for the ordinary, run of the mill Chevy crate engines?
They call it the L8T because if you use a Chevy engine, you’ll probably be L8T to wherever you need to be.
I agree with you 100%👍 only people who use trucks for what they are meant do (tough work) would know how tough and reliable 8.1 engines are! Its a shame GM doesnt make Big Blocks anymore! The good thing is that my fleet are only 8.1’s and 454’s. They don’t win many races but they do outlast all others in reliability especially diesels at least in my experience! It would be nice have the new GM trucks with Big Blocks again!
The editor of this article state that the L8T engine has a low RPM torque peak. Nonsense. That’s not a low RPM . A high torque peak of 4000 RPM is now low RPM. Here’s the best example of a modern low RPM peak torque, it’s the Ford 5.4 liter truck engine, that had max torque at just 2500 RPM. How about the GM base engine 8.0 liter big block still under production, ( not the 8.1 liter ), has a max torque peak as used in heavy long 40 passenger school buses factory modified to run on propane or CNG. The torque peak is 2800 RPM and in some cases the development that GM contracted out to a Michigan shop, for the modern version of the 8.0 liter big block propane test used a a max torque peak of just 1800 RPM. The compression ratio was 10 to one. Max HP was just 2800 as developed in the shop running it on gasoline before it was sent to another company in Michigan for the propane development. GM sells the complete engine minus the intake manifold so the propane conversion shop adds their own intake and liquid propane fuel injectors. Here’s the direct link to the GM site for the 8.0 engine at the GM Powertrain site. https://poweredsolutions.gm.com/products/lfi-engine Notice is offered with a slight overbore of 4.27 inches instead of the normal 4.25 inch bore. It’s a high deck block so the old stroke of 4.25 stroke is can be increased to a high torque 4.75 inch stroke. Some of the GM aftermarket companies only offer a stroke of 4.5 inches when they modify the GM long block and they change the cam and add a different stroke crankshaft. Some of the industrial versions offered by these companies offer more than one version of the modern big block, by offering a bigger bore and longer stroke. Some of these companies also offer industrial versions of the 8.0 engine that to run on LPG propane or CNG, use a higher compression ratio or a turbocharger. By the way propane has a high 104 octane rating and CNG has the equivalent of 120 octane. Freightliner website has the details of the 8.0 liter school bus engine but it’s an 8.8 liter because it has a different crank. HP is rated at a low 225 but torque is higher at 510 foot pounds. No new diesel school buses are allowed in California for the past 8 years. Propane fuel contracts can lower the cost of fuel so it’s about 40 percent less than gasoline. There’s no carbon buildup when using propane of CNG. Propane is a dry fuel, so when the engine is first started the propane vapour doesn’t wash oil off the cylinder walls, like gasoline, so the propane allows about triple the life of wear on valve seats and cylinder walls and rings and bearings. A propane fueled engine minimum wear, makes it better than a diesel engine for long tern use. Yes, i said better, based on my 25 million miles ( 40 million kilometer ) fleet operation over a 25 year period of time. Your diesel comments are not valid because you don’t know a thing about running a commercial vehicle on propane. Diesel engines have serious problems with the carbon and the new cats that require cleaning of replacement after just 150,000 miles. Ignorance is bliss, i won’t respond to ignorant opinions comparing diesel to propane. Propane is the cleanest alternate fuel because it is 36 to 37 percent hydrogen and it’s found underground and doesn’t require a refining process, just a separation process in the oil field, where it’s pumped into rail cars, storage tanks or trucks for shipping directly to markets. Diesel fans, please reread this article.