MORE POWER & RE­LI­A­BIL­ITY

DITCH­ING THE FAIL­URE-PRONE VGT TURBO ON FORD’S 2011–2014 6.7L POWER STROKE

4 Wheel & Off Road - - CONTENTS - Mike McGloth­lin BY ED­I­[email protected] PHO­TOG­RA­PHY MIKE MCGLOTH­LIN

Ditch the fail­ure-prone VGT turbo on Ford’s ’11-’14 Power Stroke.

IN­STANT THROT­TLE RE­SPONSE, BIG TORQUE, AND THE abil­ity to get loads mov­ing in a hurry were great sell­ing points for the 2011 Su­per Duty. Thanks to a vari­able­ge­om­e­try tur­bocharger, re­verse-flow cylin­der heads, and a Bosch in­jec­tion sys­tem uti­liz­ing piezo­elec­tric in­jec­tors, Ford’s 6.7L Power Stroke V-8 packed 400 hp and 800 lbft of twist when it de­buted. How­ever, power rat­ings on pa­per don’t al­ways pan out in the real world. With roughly 50 per­cent of all mod­ern diesel trucks be­ing equipped with some sort of pro­gram­mer or other power adder, it didn’t take long for 6.7L Power Stroke own­ers to find the weak­est link in the chain: the Gar­rett GT32 SST turbo.

Equipped with vari­able­ge­om­e­try tech­nol­ogy, a ce­ramic ball-bear­ing cen­ter car­tridge, and an elec­tron­i­cally ac­ti­vated in­ter­nal waste­gate, the GT32 SST

had all the bells and whis­tles but proved to be a big re­stric­tion for the en­gine. The dual com­pres­sor wheels sat back-to-back on a com­mon shaft, but their small 46mm in­duc­ers yielded a power curve that ran out of steam be­fore 3,000 rpm, not to men­tion that the tur­bine side was un­der­sized by to­day’s stan­dards. Once the

6.7L en­gine is sad­dled with a pro­gram­mer, the re­stric­tive GT32 SST can pro­duce shaft speeds in ex­cess of 150,000 rpm. In lay­man’s terms, the fac­tory turbo is a tick­ing time bomb once it’s asked to cope with power lev­els be­yond stock.

Even­tu­ally the fu­el­ing added by a pro­gram­mer will over­speed the turbo, caus­ing it to self-de­struct. This places truck own­ers in a unique dilemma: spend $1,900 on an OEM re­place­ment unit that might meet the same fate, or in­vest in a proven al­ter­na­tive.

En­ter Mary­land Per­for­mance Diesel’s bud­get turbo kit for 2011–

2014 Fords. The com­pany’s sys­tem re­places the fac­tory charger with a time-tested unit from BorgWarner while reusing the fac­tory in­ter­cooler pip­ing and the up­per and lower in­take man­i­folds. If you’re the owner of a 2011–2014 Su­per Duty in need of a turbo, you should con­sider this op­tion. For $2,725.95 this sys­tem adds un­matched re­li­a­bil­ity to your truck, along with a no­tice­able bump in power.

11While the Gar­rett GT32 SST tur­bocharger (left) found on the 2011–20146.7L Power Stroke is state-of-the-art and a fas­ci­nat­ing piece, it’s no­to­ri­ous for over­speed­ing when pushed hard. Luck­ily, af­ter­mar­ket com­pa­nies like Mary­land Per­for­mance Diesel (MPD) of­fer a sound so­lu­tion: a bud­get­friendly, bolt-on sys­tem that re­places the prob­lem­atic turbo with a proven one from BorgWarner (right). When it comes to the Gar­rett GT32 SST fac­ing off against the BorgWarner S366 SX-E, it’s a clas­sic case of com­plex and in­tri­cate ver­sus sim­ple and proven. Ex­otic ver­sus con­ven­tional. Con­tra­dic­tory in nearly ev­ery way, the GT32 uti­lizes vari­able-ge­om­e­try tech­nol­ogy while the S366 SX-E is fixed ge­om­e­try. The GT32 fea­tures dual cast 46mm com­pres­sor wheels com­pared to the S366 SX-E’s sin­gle 66mm forged milled wheel. A ce­ramic ball-bear­ing cen­ter car­tridge re­sides in the GT32, whereas a jour­nal bear­ing cen­ter sec­tion can be found in the S366 SX-E.

44 Up-pipes with heavy-duty ex­pan­sion bel­lows and the ap­pro­pri­ate mount­ing gas­kets are also in­cluded in MPD’s bud­get turbo kit. The up­pipe on the left con­nects to the pas­sen­ger side ex­haust man­i­fold, while the unit on the right links to the one on the driver side. If see­ing up-pipes con­fig­ured in this un­con­ven­tional fash­ion con­fuses you, re­mem­ber that the 6.7L Power Stroke uti­lizes re­verse-flow cylin­der heads. This means the ex­haust man­i­folds re­side next to the lifter val­ley (where the in­take man­i­fold would be on a tra­di­tional V-8).

3 In or­der to work in con­junc­tion with the fac­tory hot-side charge air pipe (the tube that spans from the turbo to the in­ter­cooler), MPD mod­i­fies the com­pres­sor hous­ing out­let of the S366 SX-E turbo. And be­cause this con­nec­tion point sees the most boost, MPD ma­chines grooves into the edge of the out­let (in ad­di­tion to the bead on the end). This al­lows the sup­plied 3 in­ter­cooler boot a rough sur­face to grab onto and es­sen­tially rules out the pos­si­bil­ity of blow­ing an in­ter­cooler boot un­der ex­treme pres­sure.

6 Af­ter the coolant and oil lines were dis­con­nected from the fac­tory turbo and the waste­gate so­le­noid har­ness un­plugged, the GT32 was fi­na­gled un­der the cowl and off of the en­gine. Then the pedestal gas­ket sup­plied by MPD was in­stalled, fol­lowed by the S366 SX-E (shown). To sim­plify our in­stal­la­tion, MPD bolted the S366 SX-E charger to its re­spec­tive bil­let-alu­minum turbo pedestal and in­stalled the braided stain­less steel oil feed line prior to ship­ping us the kit. 6

5 Gain­ing ac­cess to the fac­tory turbo takes some time, with the air in­take, ra­di­a­tor hoses, in­ter­cooler pipes, air in­take valve, and up­per and lower in­take man­i­folds all hav­ing to be re­moved be­fore enough room ex­ists to loosen the turbo’s four pedestal bolts. To un­bolt the fac­tory up­pipes from the ex­haust man­i­folds, both the pas­sen­ger-side and driver-side in­ner fend­er­wells were re­moved. 5

2The ex­haust side of the BorgWarner S366 SX-E of­fered in MPD’s bud­get turbo kit fea­tures a 73mm tur­bine wheel (ex­ducer) in a quick-spool­ing, non-waste­gated 0.91 A/R hous­ing, and a T4 tur­bine in­let flange. While the fac­tory turbo re­quires both coolant for cool­ing and oil for lu­bri­ca­tion, theS366 SX-E uses en­gine oil for both those func­tions. This is just an­other way that MPD’s bud­get kit sim­pli­fies the tur­bocharger sys­tem, not to men­tion that it’s less tax­ing on the en­gine coolant. 2

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