Best Way to Beef Up a 2009 Chevy 5.3 Engine

[Editor's Note:This LM7 engine upgrade guide is part of a serial of LS engine upgrade guides  assembled by a squad of LS experts at Superlative Racing that we are sharing at OnAllCylinders. For a primer on the entire LS engine universe, readLS Engines 101: An Introductory Overview of the Gen Iii/IV LS Engine Family.]

…

Intro to LM7 Engines

Meet the hidden jewel that helped beginning the LS-swap craze.

The LM7 (along with its L59 FlexFuel E85-capable brother) are the Gen. III, five.3L iron block truck engines you can pick up in wrecking yards for most $600.

There were a couple key areas where the LM7 excelled:

1. It makes sense for engine swaps.

Fully dressed, it'south a bit lighter than Gen. I/II engines and easier to observe ane in good shape. Even bottled up and 25 cubic inches smaller, it matched the power and torque of the F-body LT-1's. The later 2004-07 versions were right there with the C4 Corvette's LT1. With the availability of engine swap kits, information technology merely makes practiced sense to use Gen. III/4 engines.

ii. Drag racing.

The aluminum blocks made good power naturally aspirated, merely they aren't the best choice with big heave and nitrous. Although the fe block LM7 is a bit heavier, you can actually cascade the coals to information technology. Considering of their strength, these engines are likely to meet a power-adder sooner than afterwards.

…

[ Every engine spec you lot'll demand can exist found hither:LM7 5.3L Vortec 5300 Engine Specs: Operation, Bore & Stroke, Cylinder Heads, Cam Specs & More.]

…

How to Get More than Power From Your LM7

These engines started life in GM trucks, but at that place's just every bit much of a chance today that you lot'll spot them under the hood of a turbocharged drag car.

This article is focused on the power-adder pathway for upgrading the LM7, whether it will remain in a truck or be swapped into a automobile.

The LM7 is one of the virtually popular LS engines for several reasons:

• With iron block strength, information technology is a great choice for heave or nitrous applications.
• GM made a bazillion of them over eight years. The affluence of LM7 engines available helps keep prices down.
• Gen. three engines didn't accept AFM (Agile Fuel Management) or VVT (Variable Valve Timing), and then yous don't accept the expense of an AFM or VVT delete kit.
• The heads menstruum similarly to LS6 heads, but have a heave-friendly 9.5:1 compression ratio.

Exercise they have a downside? But 1. At 216 pounds, the block is 100 lbs. heavier than the aluminum LS1 block.

Basic Bolt-On Upgrades for LM7 Engines

Trucks are the everyday hotrods of the 21^st century.

Many people start off calculation acold air intake and aftermarket frazzle.

The problem is that the engine starts to sound Really adept and owners find themselves wanting to go faster.

Trucks often come with mechanical fans that sap horsepower. An electric fan kit will free upwardly the power. All these can be done in the garage, but the melody won't exist optimized.

At this point, we recommend you talk to your chassis dyno tuner and determine on a reckoner developer. Whether yous're towing on low-octane or springing for practiced fuel, a tuner can dial-in the ECM and have it to the side by side level.

Shift points can be raised which also makes it easier melody for a bigger cam and injectors afterward. Additionally, installing a colder thermostat will open up the tuning window.

Below are more upgrades that will meliorate LM7 engine performance.

…

Upgrading the LM7 Camshaft and Valvetrain

If you only do i thing to the engine, make information technology a cam swap.

The tiny 191 at .050-inch cam actually held these engines dorsum.

An LS3 or LS9 cam makes good power, but not where you want information technology, if the engine remains in a truck.

What you need is a cam that delivers a gut-punch correct where the converter hits. We recommend a dedicated truck cam.

If the engine is going in a lighter motorcar with gear and converter, you lot can exist more aggressive.

What'southward the divergence betwixt a truck cam and machine cam?

To maximize torque in the mid-range in a truck cam, manufacturers close the intake valve at about 40 degrees (@.050 in.) afterwards bottom dead centre and alter the intake valve opening to set the idle quality.

The bigger the engine, the smoother it will idle for any given cam, which is why you'll see the 5.3L LM7 getting slightly smaller cams than the 6.0L engines.

What if you accept a power adder?

More often than not,supercharger cams and nitrous cams will have slightly more than lobe separation and longer exhaust duration.Turbo cams reduce overlap with less exhaust duration in relation to the intake.

Intake Duration (@ 0.050 in.)	Horsepower at the wheels subsequently bolt-ons	Idle Quality	Notes
191° (Stock)	260-270 whp	Shine	Heavy drivetrain.
215°	+l hp	Slightly noticeable	Good with motorcar and stock converter.
220° - 230°	+75 hp	Steady lope	Converter recommended. However tin bulldoze daily.
230° - 240°	+100 hp	Lopey	Fly-cutting the pistons may be required. Heads and intake adept for another 50+ hp.

Driblet-in .500-in. lift cams are popular, but LS6 springs let you to run .550-in. lift and extend the rpm range. Spring life isn't a problem considering trucks generally don't spend a lot of fourth dimension at high rpm.

Beyond that, .575 to .600 in. isn't a trouble with dual valve springs.

The stock rockers are proficient up to 175 lbs. of seat pressure and 450 lbs. open. You volition want to install a trunnion kit for added reliability.

There are a few other parts needed for a LM7 cam swap such as an LS2 timing chain , LS7 spec lifters , LS2 timing chain damper and adapter, likewise as.080 in. wall pushrods.

…

LM7 Power Adders

In general, about LM7 owners volition add boost or nitrous before they brainstorm serious cylinder head work. Before we get into the power adders, there are a couple of things to address.

one. A iv-corner steam kit reduces hot spots that tin can cause the piston rings to butt and snap the piston'due south band lands.

2. Any power volition put yous well past the limitations of the stock injectors and fuel pump. We'll accost those in the adjacent section.

Now for the fun stuff:

• Anitrous oxide kit (at low settings) is great for street driving with stock internals. Up to a 200-shot system is mutual. Keep in mind the tight piston ring gap is the limiting factor beyond that. If yous desire to get serious, a single-aeroplane intake is less prone to suspension from a nitrous backfire. A plate organization has better distribution than the original intake, but an eight-nozzle fogger system is even better. Running higher-octane fuel is brash.
• Truck engine bays make plumbing equipment turbos easy. Unmarried turbo systems using turbo exhaust manifolds are an inexpensive way to make big power. If you lot're running a unmarried turbo, the T4 hot-side fits well, merely the pocket-size-turbine diameters limit exhaust catamenia. The 650 whp begins to experience similar 400 did in a bustle, so accept this into consideration. Five-band manner exhaust housings open up the turbine options and brand plumbing easier. Although twins are a piddling more expensive out of the box, you'll take more room to abound.
• Aroots-mode supercharger is dependable and makes great torque in the depression- and mid-rpm range. It's peachy for melting tires.
• Acentrifugal-style supercharger is lightweight and makes more than power at loftier rpm. This is partially due to a larger intercooler mounted in front of the radiator.

…

Upgrading the LM7 Fuel Organization and Tuning

The manufactory LM7 injectors were but rated at 22-25 lbs. and won't back up much more than 380 hp.

Program on upgrading to largerfuel injectors to run across the fuel demands of increased power.

Custom tuning will be required to properly adjust the fuel and ignition timing. Truck manifolds had i.ix-in. injectors versus the longer Gen. Three car injectors or the shorter Gen. IV injectors. The connectors are different as well, only adapters and spacers can exist used to fit car injectors on an LM7.

Continue in mind, the all-time injectors are fully characterized which helps your tuner maximize idle quality, etc.

When running boost, you tin can utilize a water-methanol system to supply extra fuel and lower-charge air temps.

The manufacturing plant pump is adept to most 430 whp. Many fuel system upgrade options are bachelor. Drop-in fuel pump modules and external pumps are popular. Other options to maintain or increment pump pressure includeelectronic voltage controllers and hotwire kits.

…

Upgrading the LM7 Intake Manifold and Throttle Body

If you accept a power adder, the intake and throttle body can accept a backseat for a while longer. If you are naturally aspirated though, upgrading the intake and throttle body is commonly done before the heads.

The factory truck-manner manifold has long runners for meliorate depression-end torque. Porting the intake is an option and a good value.

If y'all're looking for more ability and torque, the Trailblazer SS intake is a step up and a larger 90mm 4-bolt throttle trunk tin be fitted.

The F.A.S.T. LSXRT intake allows a bigger 102mm+ throttle torso. Truck engine bays also conform Tunnel Rams. These trade a little scrap of torque downwards low for more up high—and nothing looks cooler.

Manifold Way	Pinnacle Horsepower	Torque
Single Plane	+10 hp	Losses everywhere below 5500 rpm. *Simply recommended for nitrous or boost.
Trailblazer SS	+ten hp	Maintains torque and pulls alee at 4500 rpm.
F.A.South.T. LSXRT	+25 hp	More low-stop and elevation-cease.
Tunnel Ram	+35 hp	Slightly lower below 3000, equal at 4500, and big gains beyond 5500.

Enquire your tuner virtually going with a Speed Density tune. Doing so removes the MAF brake and will give yous a bit more than power.

…

[ Trying to observe an LS or LS-based Vortec engine for a swap or build? Check out Function one  and Role 2  of our LS Spotter's Guide.]

…

Upgrading LM7 Cylinder Heads

• The stock heads can be CNC ported for more airflow and milled upwards to .030 in. for more compression. Flow numbers tin can be as high as 325 cfm at .600 elevator. Lightweight hollow stalk LS3 valves tin exist cut to two.000 in. to fit the seats. Betwixt the lite valves and better springs, the engines will pull cleanly to 7000 rpm. Keep in heed, if you're looking to boost to 800+ hp; a heavy duty aftermarket stainless intake valve is a bit tougher and won't tulip every bit chop-chop with the oestrus.
• A improve option isaftermarket cathedral port heads. They reduce downwards-time, they're all new, and you can usually offset the added cost by selling your original heads. Valve angles are typically laid over to 13.5 degrees and two.040-in. intake valves are common. They flow great and the cross-sections are keen for heave. When comparing heads, look at .400 lift numbers as a general indicator of how the heads will perform. With a medium-sized cam, 400+ whp naturally aspirated is common even with the heavier truck drivetrain.

…

Upgrading the LM7 Rotating Assembly

Nonetheless looking for more?

As mentioned earlier, the pistons are a weak point and you lot probably know a guy that'due south popped one. A set offorged pistons should be high on your priority list. They have stronger wristpins, thicker ring lands, and the added valve reliefs let you lot to run big cams. If you're going over 800 horsepower, a prepare of .200 wall tool-steel pins is a good thought.

There are exceptions, but Gen. Three rods first getting dicey effectually 750 whp and the bolts don't like much more than than 7,000 rpm. The 2004½-07 modes were bushed for full-floating pins and were stronger. If you're getting forged pistons, it's best to as well go forged connecting rods with vii/sixteen-in. rod bolts.

The LM7 crank was bandage but stiff. They've been known to handle over ane,000 whp. The main reason for going with a stroker forged crank is for the added cubic inches. The extra cubes bring boost on quicker which means you can use bigger turbos.

Performancerotating assemblies are available in many combinations.

Notes of caution:

• The v.3L iron blocks had shorter cylinder sleeves than the aluminum blocks (5.430 in.  vs. 5.500 in., on boilerplate). Much of the piston skirt drops out of the bottom of the cylinder at BDC. The best piston manufacturers have compensated for this by eliminating skirt taper until a indicate well in a higher place where it meets the bottom of the cylinder sleeve at BDC. Any skirt taper at this intersection acts as a razor blade and will vesture out the piston quickly.
• The pattern deck elevation of the block is 9.240 in., but it'due south mutual to find them in the 9.230-in. range. It's all-time to measure deck superlative earlier ordering your rotating assembly. Thicker head gaskets or using an aftermarket half dozen.098- to 6.100-in. rod will ensure enough piston-to-head clearance.

Engine Size	Bore Dia.	Piston Comp. Peak	Stroke	Rod Length	Wristpin Dia.
5.3L (325 c.i.d. - stock)	three.780 in.	ane.338 in.	3.622 in.	half-dozen.098 in.	0.9431-.09449 in.
5.7L (347 c.i.d.)	three.905 in.	1.338 in.	iii.622 in.	6.098 in.	0.9431-.09449 in.
half-dozen.0L (363 c.i.d.)	iii.800 in.	one.115 in.	4.000 in.	six.125 in.	0.927 in.
vi.3L (383 c.i.d.)	3.905 in.	1.338 in.	iv.000 in.	half dozen.125 in.	0.927 in.

…

Upgrading the LM7 Engine Block

The 5.3L iron blocks can be bored to the LS1'south size.

If y'all're running boost and nitrous, near will just hone the blocks to three.800-in. or up depending on piston and ring availability.

The blocks have been known to withstand 1,300 whp with proper machining, racing fuel, and an first-class tune.

Head and primary studs are brash if you're making more than 850 whp. Four head bolts per cylinder aren't optimal, but you can O-band the block if you're aiming for thou+ whp.

The manufacturing plant main caps aren't doweled. It'south better to reduce ignition timing and recoup with added boost to reduce the cylinder pressure spikes that lift heads and cause the main caps to trip the light fantastic toe.

…

(Information for this article originally appeared in the "Upgrading the Gen. 3, 5.3L, Iron Block, LS Truck Engines"article atAcme Racing'southward searchable database of FAQ tech info.Go at that place and search "LS engines" for a comprehensive collection of LS engine tech information.)

hastingsfuser2001.blogspot.com

Source: https://www.onallcylinders.com/2018/03/08/lm7-5-3l-engine-upgrade-guide-expert-advice-for-lm7-mods-to-maximize-performance/

Share this post