
04 _ LIGHT-DUTY CAPABILITY
XFE: thE drivE For Economy
ActivE FUEL mAnAGEmEnt (AFm)
With this advanced technology, all eight cylinders operate during starting,
idling and torque-intensive tasks like accelerating, hauling heavy loads
or towing. But in everyday driving, once Sierra has reached cruising
speed, AFM can temporarily deactivate four of the eight cylinders. A
sophisticated Engine Control Module (ECM) continuously measures load
conditions, including throttle input. Under light loads, it automatically
closes select intake and exhaust valves and cuts fuel delivery for half of
the cylinders. When the driver demands brisk acceleration or full torque
to move a load, the ECM activates all cylinders — within 20 milliseconds
— so full V-8 power is always right there, on tap. Transitions are virtually
indiscernible to most drivers. AFM helps Sierra XFE models offer the
best conventional engine fuel economy in its class.
1For more on XFE,
see next column and page 32.
AFM: vortEc 5.3L v-8 vAriAble vAlve tiMing (vvt): vortEc 4.8L v-8 / vortEc 5.3L v-8 / vortEc 6.2L v-8
1
EPA-estimated mpg 15 city / 22 hwy.Sierra 1500 XFE 2WD. Excludes other GM vehicles. 2Excludes other GM vehicles. 3
Maximum trailer weight ratings are calculated assuming a base vehicle, except for any option(s) necessary to achieve the rating, plus
driver. The weight of other optional equipment, passengers and cargo will reduce the maximum trailer weight your vehicle can tow. See your GMC dealer for additional details. 4E85 is 85 percent ethanol and 15 percent gasoline. Visit gm.com/ e85 to see if
there is an E85 station near you. E85 EPA-estimated mpg for Sierra XFE 11 city/ 16 hwy.
Sierra XFE models use a combina-
tion of mechanical, aerodynamic
and mass-reduction enhancements
—
including the aluminum block
Vortec 5.3L V-8 with AFM
—
resulting in an EPA-estimated
22 highway mpg. Still, the XFE
powertrain provides a max
trailer rating of 7000 pounds.
3
horSEPoWEr
torQUE
Economy
EmiSSionS
in thE miX
corE vALUES
SiErrA 1500 vortEc EnGinE tEchnoLoGiES
vortEc 5.3L v-8 vvt With AFm
SiErrA XFE 2Wd
15city
EPA-ESt. mPG
22hW y.
EPA-EST. MPG
bEttEr V-8 FUEL ECONOMY1
thAn Any comPEtitor
vortEc 6.2L v-8 vvt
SiErrA dEnALi
403hP
417Lb-Ft
oF torQUE
MOST V-8 HALF-TON HP
AND TORQUE2
vortec cylinder heads :swirl, tumble the intake charge, which improves the air / fuel mixture to enhance performance >irridium - t ipped spark plugs last up to 100,000 miles >>
electronic throttle control :for reliability and more precise throttle response >polymer-coated floating-pin pistons for long life >
ONSTAR VEHICLE DIAGNOSTICS :CHECkS ON kEy OpERATING SySTEmS, INCLuDING THE VORTEC ENGINE >CAN SEND yOu A mONTHLy REpORT by E-mAIL; INCLuDES REmINDERS Of SCHEDuLED mAINTENANCE
onStAr vEhicLE diAGnoSticS :chEckS on kEy oPErAtinG SyStEmS, incLUdinG thE vortEc EnGinE >cAn SEnd yoU A monthLy rEPort by E-mAiL; incLUdES rEmindErS oF SchEdULEd mAintEnAncE
vortEc cyLindEr hEAdS :SWirL, tUmbLE thE intAkE chArGE, Which imProvES thE Air / FUEL miXtUrE to EnhAncE PErFormAncE >irridiUm - t iPPEd SPArk PL UGS LASt UP to 100,000 miLES >>
ELEctronic throttLE controL :For rELiAbiLity And morE PrEciSE throttLE rESPonSE >PoLymEr-coAtEd FLoAtinG-Pin PiStonS For LonG LiFE >
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