Car Craft – November 2019

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30 CAR CRAFT NOVEMBER 2019

In Car Craft’s previous test, we ran the 5.3L

with no accessories and a Meziere electric

water pump. Installation of the Vortech

required we use the factory accessories,

so we reinstalled the alternator and power-

steering assembly.

After running the 5.3L with the cam

swap, we began installing the Vortech

supercharger kit. Here we install the first

of the two blower mounting plates to the

passenger-side cylinder head.

Using the supplied hardware and aluminum

spacers, we installed the second blower

mounting plate.

Next, the Vortech supercharger

was bolted to the mounting plate.

The Vortech kit relies on the stock truck

crank pulley.

Vortech supplied the supercharger for its

5.3L kit with a 3.60-inch-diameter blower

pulley. The pulley featured a tamper-proof

(warranty-voiding) cover.

The Meziere

electric water

pump was

replaced by

the mechanical

factory truck

water pump.

To minimize belt slippage, the Vortech kit

features an adjustable belt tensioner and

idler assembly.

motor to install the Vortech. The kit

included the necessary blower mount,

supercharger head unit, and discharge

tube assembly. It was necessary to

install all of the front accessories,

minus the A/C compressor and mount.

(The Vortech supercharger kit was

designed to run with all of the accesso-

ries in place.) When we tested the LS9

cam, we had removed all accessories

and run the 5.3L with a simple Meziere

electric water pump. To test the blower

kit, we removed the Meziere and rein-

stalled all of the belt-driven accessories.

Vortech provided the necessary

blower mount, idlers, and tensioner

that allowed a single six-rib serpentine

belt to drive the accessories and the

supercharger. The affordable low-boost

kit did not include (or require) an inter-

cooler, but the aluminum discharge

tube did feature a mounting flange for

the supplied blow-off valve. Installation

was quick and easy, taking a fraction of

the time of a typical turbo system.

Since we had previously upgraded the

stock injectors to 80-pounders from

ACCEL, the supercharged 5.3L was

now primed and ready for action.

Thanks to the LS9 cam swap, the

supercharged 5.3L now had proper

cam timing and the additional rpm to

play with. Since boost supplied by the

Vortech increases with engine speed,

the cam swap allows us to take full

advantage of the supercharger. After

dialing in the pump-gas-friendly tune

on the Vortech, we managed to coax

peak numbers of 581 hp and 504 lb-ft

of torque from the supercharged 5.3L.

Typical of a centrifugal supercharger,

the boost curve started at just 2.5 psi

down at 3,000 rpm and rose to a peak

of 10 psi at 6,400 rpm. Though our kit

did not feature it, at this power level

we might start to look at pinning the

crank pulley, but it showed no signs of

slippage during our test. The power

gains offered by the blower kit

increased with engine speed, not unlike

a good cam swap. Running 10 psi, the

blower kit improved the power output

by a solid 180 hp, making it one serious

bolt-on. Having run the cheap $100

cam on this blown motor, we can’t help

but wonder what might happen with a

real cam, an intercooler, and maybe

some E85? Stick around, we might just

find out!