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GM HIGH-TECH PERFORMANCE APRIL 2008

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GMHIGHTECHPERFORMANCE.COM 073

LS9Lives!

2009LS9

We at GMHTPhave sung the praises o every

new LS V-8 or the past decade, and the song

remains the same: building o o the original Gen III

in 1997, every new GM mill gets more strength, more

sophistication, and more power. The everymans LS1;

the high-strung LS6; the big-inch, ultra-exotic, and ultra-

high-revving LS7just when it looks like the General had

pushed the LS envelope as ar as it can be taken, the wizards

at GM Powertrain mix up a wicked combination o new-school

technology and old-school musclecar torque. The result is the

supercharged, 620hp LS9, slated to power the second coming

o the King O The Hillthe 2009 Corvette ZR1.

GM will continue to deliver the worlds best powertrains,

said Tom Stephens, group vice president or GM Powertrainand Quality, at an LS9 press conerence in Detroit. Were

going to have more un with production perormance, where

a customer can check a box and get [what they want]. And

when you experience the LS9 in the Corvette ZR1, the terms

perormance and renement take on a new meaning.

This blown 6.2L engine was developed or the 2009

ZR1 Corvette, and as the olks rom GM Powertrain tell us,

Ultimate perormance is the goal. That is easy to see when

you combine exotic titanium with ultra-strong orged steel

and aluminum or the rotating assembly, throw on high-fow

LS3-style cylinder heads, then bolt up an enormous, 2.3L

blower with intercooler and start pushing 10-plus pounds o

boost.

But look beyond the 620 peak horsepower and 595 lb-t

All hAil the

bAddest

smAll-block

evera620-horse

monster

that willpower the2009 Zr1

byrickjensenphotography

courtesyofgeneralmotors

620+hp/595+lb-ft6.2L, 319-T5 aluminum block103.25mm (4.06-inch) bore x92mm (3.62-inch) strokeForged steel crankTitanium rods9.1:1 forged aluminum pistons withoil-spray cooling356-T6 aluminum heads

Titanium 55mm (2.16-inch) intakeand hollow-stem, sodium-lled40.4mm (1.59-inch)exhaust valvesOset-rocker valvetrain layout.555-inch-lift camshaft2.3L intercooled superchargerpushing 10.5-psi boost100hp/liter target


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074


techLs9 Lives!

BlockThe 2009 6.2L block isa shared casting withall other 6.2L blocks. Itoers 20 percent strongerbulkheads, comparedwith 07 6.2 blocks, witha hone over travel lletradius change from 3to 10mm. An additional20 percent increase inbulkhead strength is

realized by optimizing theNo. 2 and No. 3 bulkheadwindows. The LS9 hassix-bolt mains with forgedsteel bearing caps, dowelalignment, oil squirters,and fully machinedsurfaces. Deck plates withthe same mass as thecylinder heads are usedfor boring and honing thisblock for the best headseal, least oil consumption,roundest cylinders, andbest overall performance.

crankshaftThe forged steel crank uses a smaller reluctor wheel than its LS siblings, and uses a

9-bolt ywheel ange for more clamping strength (LS3 has a six-bolt). Its dampenerhas a keyway and friction washer for supporting high engine loads.

connecting rodsTitanium rods are used for ultimatestrength and light weight, allowing the

LS9 to rev to its 6,600-rpm limit.

2

3

1

o torque: the supercharged LS9

makes big power at lower rpm and

carries it in a wide arc to 6,600 rpm.

GM Powertrain testing shows the

engine makes approximately 300 hp

at 3,000 rpm and nearly 320 lb-t

o torque at only 1,000 rpm. Torque

tops 585 at about the 4,000-rpm

mark, while horsepower peaks at

6,500 rpm. The engine produces

90 percent o peak torque rom

2,600 rpm to 6,000 rpmthat peak

number shows 595 on paper, but, as

Stephens says, No way Im going to

let it out o here without 600 lb-t!

Our kind o madman.

Feast your eyes on the pics

and specs o this groundbreaking

new enginethe most powerul

production vehicle mill that GM has

ever made!j


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chLs9 Lives!

GMHIGHTECHPERFORMANCE.COM 077

istons

he LS9s aluminum slugs feature anodized top lands for high temperature and load durability, a polymer-coated skirt and oating pins foroise and wear resistance, large pins with thick walls, drilled oil drainbacks, and oil spray coolingthe rst use ever on a small block!

BlowerThe LS9s supercharger, dubbed R2300, is a Gen VI Eatonfeaturing four-lobe rotors with 160 degrees of twist (comparedto the old three-lobe, 60-degree design). Its coated lobeshave an interference t during assembly, meaning that theyare set up for maximum eciency. The Gen VI design oersabout 20 percent more airow capacity, 15 percent thermaleciency improvement, and 35 percent less parasitic lossversus a Gen V blower. It is said to build power quicker atlow rpm, while still sustaining the needed power at high rpm.Finally, it is designed for quiet operation, a smooth idle, andleaping tall buildings in a single bound.

intercoolerLS9s intercooler is a liquid-to-air, tube-in-n design packagedwith the supercharger. It utilizes two very small heat exchangerslongitudinally mounted, aluminum bricks to cool thesupercharged, heated intake air 140 degrees before they hit theintake ports. A separate, dedicated heat exchanger system withreservoir sits in front of the radiator. The packaged blower andcooler arrangement allowed it to be used in the ZR1 Corvettes tightengine bay and with its low hoodthough it took several months ofwrangling to get it to work, according to GM.

fuel systemProducing 620 horses and still passing emissions presenteda challenge for the GM team. A dynamic set of 48 lb/hr fuelinjectors and a unique dual-pressure fuel system was utilizedto t the bill. One large fuel pump runs at 250 kpa (36 psi)and 600 kpa (87 psi) depending on the fuel needs, and a fuelsystem control module switches between the low and highsettings. A center-feed fuel rail is utilized for less pressurevariation and less noise. Fuel shuto happens at 6,600 r pm.

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8

4 6

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cylinder headshe LS9s heads are similar to the L S3/L92 head, but utilize a 356-T6 material that oers improved strength over previous heads, andetter heat resistance with the supercharged millespecially in the bridge area between the intake and exhaust valves. A special

manufacturing process called spin casting guards against porosity and creates a much stronger head. One neat trick is a wingn the intake ports that creates a swirl motionanother is the four-active-layer head gaskets (typically, only two layers are used) andtainless 12mm head bolts (typically 11mm), both for increased holding capacity. Ti tanium 2.16 intake and sodium-lled, hollow.59-inch exhaust valves are used, with an oset intake rocker for optimum airow path.

camshaftOne of the benets of forced induction is that the camshaft d oesnt have to be hairy to make awesome power. GM chose a cam with555-inch intake and exhaust lift for the LS9. Low overlap means a smooth idle and good low-speed manners.


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techLs9 Lives!

Testing included 100 hours at WOT, and actual andsimulated 24-hour test tracks.

A special engine cover reduces noise, and is visiblethrough a see-through window on the ZR1s hood.

LS9 is the most powerful production vehicle engine inGM history, making 115 hp more than the LS7.

According to Tom Stephens of GM Powertrain, This isnot the end of the road where power is concerned. Yikes.

9 10

other ls9 features:

LS9 has a revised dry-sump system. Higher g-levels mean oilstarvation issues, and this system, for the LS9 and 2009 Z06s,improves the scavenging performance and increases the dry sumpcapacity by 30 percent. It holds a total of 10.75 quarts of Mobil 1, andcan handle one-third more g-force.

The lifters, rockers, and valvesprings are LS3 pieces. LS7 retainersare used for high-rpm operation.

A single 87mm electronic throttle body is used.

Dual belt system: an 11-rib belt runs the blower, power steering, andwater pump, another runs the alternator and air conditioning.

A larger water pump bearing is used to handle theincreased load.

Coils are rocker-cover-mounted, not bracket-mounted.

The LS9 uses shorter spark plug wires versusthe LS7/LS3.

Spark plugs are iridium-tip center/platinum padground electrode.

Coils/injectors are routed to a jumper harnessfor quick connect simplication.

Dual-wall, stainless-steel manifolds and close-coupled converters are used.

A gerotor oil pump ows 32.3 gpm; theres an oilcooler on the side of the block.

LS9 runs on an E67 control module.

Assembly will happen at the Performance Build Center inWixom, MI.

GM is the rst OEM to use the Gen VI 2.3L supercharger.

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