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Some Good, Gentle Efficiency Upgrades to a Direct-Injection Chevy Gen. V 5.3L LT Engine - Pak Auto Services

Some Good, Gentle Efficiency Upgrades to a Direct-Injection Chevy Gen. V 5.3L LT Engine

Some Good, Gentle Efficiency Upgrades to a Direct-Injection Chevy Gen. V 5.3L LT Engine


I’m rebuilding a 2014 L83 5.3L engine for my Silverado pickup and I’m contemplating making some modifications to enhance the efficiency barely. I’ve appeared into including bigger gasoline injectors and maybe different components. I’m not going racing or something however I assumed for the reason that engine is aside, this could be a great time to vary a few issues to enhance the ability. Thanks.


The 5.3L (325ci) engine utilized in your 2014 Chevy Silverado is a member of the Gen. V engine household which GM debuted in your mannequin yr of 2014. The numerous distinction for the Gen. V engines is direct injection (DI), which changed port injection used within the Gen. III and IV LS engines. One other main improve for this engine household is that the truck blocks are actually aluminum as a substitute of forged iron and compression for DI has elevated from the older truck engines at 10:1 to a way more environment friendly and highly effective 11:1.

Advantages of E85 & Greater Octane Fuels

Talking of energy, your engine makes a formidable 355 hp and 383 lb.-ft. of torque on gasoline. Since most of those engines can run E85 as Flex Gas engines, the ability goes as much as 376 and 416 lb.-ft. of torque! These are big will increase over a 2003 5.3L port injected engine that was rated at 285 hp and 325 lb.-ft. of torque.

This energy improve is basically aimed toward taking full benefit of the octane score of the E85 gasoline, since in any other case the engines are supposed to run on 87 octane gasoline. However proper out of the gate, you’ve the potential to make over 400 hp. If E85 shouldn’t be accessible in your space, you’ll be able to nonetheless run the next octane 91 gasoline and so long as the detonation sensors don’t pull the timing again, it would make a minimum of 350 hp.

Understand that these rankings are internet horsepower numbers. When in comparison with typical “scorching rod” energy numbers, all retailers use the normal correction issue that’s value roughly one other 5 p.c extra energy. So on a standard SuperFlow dyno, your bone inventory 5.3L engine would in all probability make someplace round 370 hp and 400 lb.-ft. of torque.

These are nice numbers.

Variable Valve Timing

Past simply working E85 or mixing your personal gasoline to run one thing like E50 that provides a lot of the octane advantages whereas nonetheless retaining 50 p.c gasoline, there are a few different concepts you would possibly think about.

The primary is to retain the advantages of variable valve timing (VVT).

A couple of years in the past, we put a direct injected Gen. V LT1 on the dyno and spent half a day making an attempt to enhance energy by altering the cam place with VVT. We couldn’t discover any energy anyplace, which implies the manufacturing facility has performed an ideal job of optimizing the ability these engines make—so don’t remove the VVT.

It helps make torque at low rpm and likewise improves energy on the high finish.

Deleting Lively Gas Administration (AFM)?

AFM or Lively Gas Administration is GM’s model of displacement on demand, which deletes 4 of the eight cylinders when the engine is beneath gentle load (like cruising on the freeway). There have been numerous documented issues with AFM that relate to poor engine oil upkeep the place the screens that preserve junk out of the lifter ultimately plug up with particles and the AFM system fails. There are additionally points with the lifters themselves failing.

With the engine aside, it is a good time to delete your entire AFM bundle. Scoggin Dickey presents an entire AFM delete bundle that replaces the eight lifters and the camshaft with an an identical non-AFM cam that’s really the identical cam utilizing the 6.6L truck engine that doesn’t have AFM. That is essential as a result of the AFM cam employs completely different timing specs for the AFM lobes vs. the opposite 4 cylinders.

The package contains the cam, lifters, head gaskets, new trays, new head bolts, and a brand new crank bolt, plus the plugs to dam off the AFM ports within the block. Individually, you can too purchase the small plugs essential to dam off the hydraulic circuits which is able to can help you re-use the unique lifter valley cowl. It may be changed with a non-AFM cowl, however that’s a bit costlier than the press-in plugs. In fact, it will nonetheless require customized tuning to disable the AFM software program within the ECU. This should be achieved with assist from a educated LS/LT engine tuner.

A Primary Cam Swap

An alternative choice is to retain the VVT and AFM however nonetheless change the cam. A number of firms supply AFM-compatible cams. We discovered a COMP XFI cam (CCA-624-500-13) that appears attention-grabbing. It’s a really quick period cam, however nonetheless provides roughly 17 levels of added period to enhance low-speed torque and general energy. We’ve included the cam specs beneath. COMP additionally says this cam requires the usage of a COMP section limiter which reduces the entire motion of the VVT phaser to forestall piston-to-valve contact.

Whereas the unique small block Chevy would all the time reply to a greater cylinder head, the direct injection engines are already outfitted with excellent flowing cylinder heads—so all these engines actually need is a bit more cam to wake them up much more. It will be very simple to make 450 hp or extra with only a easy cam change and maybe some gentle tuning.  

There are many choices by way of gentle will increase in energy that ought to not require huge modifications to the software program. The Gen. V engines supply spectacular cylinder head stream proper off the manufacturing facility flooring.

All it wants is a bit more cam timing to create a very highly effective engine.

COMP XFI AFM Hydraulic Curler Cam for Gen V LT Specs

at 0.050″
Sep. Angle
Consumption 262 210 0.572″ 115°
Exhaust 274 222 0.529″
Cam Half Quantity: CCA-624-500-13

The L83 5.3L truck engines that appeared in 2014 modified to a Gen. V design that features direct gasoline injection, greater compression, higher cylinder heads, and better of all—extra energy! These engines are actually displaying up in junkyards and would make a wonderful scorching rod motor for an engine swap. (Picture/GM)

5.3L Gen. V LT Camshaft & AFM Delete Components Record

  • COMP Cams XFI AFM GM Gen V Camshaft, CCA-624-500-13
  • COMP Cams Cam Phaser Limiter Equipment, CCA-5456
  • Scoggin Dickey AFM delete package, 5.3L, SDAF53
Jeff Smith has had a ardour for automobiles since he started working at his grandfather’s gasoline station on the age 10. After graduating from Iowa State College with a journalism diploma in 1978, he mixed his two passions: automobiles and writing. Smith started writing for Automotive Craft journal in 1979 and have become editor in 1984. In 1987, he assumed the position of editor for Scorching Rod journal earlier than returning to his past love of writing technical tales. Since 2003, Jeff has held varied positions at Automotive Craft (together with editor), has written books on small block Chevy efficiency, and even cultivated a formidable assortment of 1965 and 1966 Chevelles. Now he serves as an everyday contributor to OnAllCylinders.


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December 2022