Fuel­ish Plea­sure

Ad­dress­ing the fuel side of Duramax per­for­mance up­grades with hot­ter injectors

Diesel Power - - Contents - Words by JA­SON GONDERMAN + Photos by JA­SON GONDERMAN AND MON­ICA GONDERMAN

IN­CREASED AIR and fuel­ing com­prise the short list of con­trib­u­tors to hop­ping up diesel en­gines. Of course, lim­it­ing per­for­mance gains to those two en­ti­ties is grossly over­sim­pli­fy­ing things, but you get the pic­ture. No mat­ter which pow­er­plant is un­der the hood, its lim­it­ing fac­tors are the same: The stock tur­bocharger can only flow so much air and OEM injectors so much fuel. Once they’re maxed out, it’s time to up­grade.

With our ’02 Chevro­let Sil­ver­ado 2500HD’s 6.6L Duramax LB7 engine’s air and fuel­ing al­ready up­graded by a Fleece Per­for­mance Engi­neer­ing Chee­tah tur­bocharger and a 42-per­cent-over CP3 injection pump from In­dus­trial Injection, we know the next step to­ward our LB7 putting 650 hp on the ground is re­plac­ing its orig­i­nal injectors.

For this, we turned to the ex­perts at Dynomite Diesel Prod­ucts, a com­pany that has been in busi­ness for nearly two decades and ei­ther builds, mod­i­fies, or ser­vices fuel injectors for prac­ti­cally all the mod­ern diesel-pickup en­gines—and even a few less-than-mod­ern units. If you

fre­quent the diesel drag-race or sled-pull scenes, you’ll rec­og­nize the com­pany’s prod­ucts powering some of the fastest and most pow­er­ful trucks on the cir­cuit.

Diesel injectors are rated two ways: in horse­power over stock and per­cent­age of flow over stock. To al­low a lit­tle wig­gle room for fu­ture im­prove­ments, we opted for the com­pany’s 100hp in­jec­tor set, which flows 60 per­cent more fuel. Dynomite claims the squirters will sup­port up to 800 hp, and we should see a 1-mpg in­crease in fuel econ­omy as well.

In­stal­la­tion is straight­for­ward and fol­lows any nor­mal in­jec­tor-ser­vice pro­to­col. A py­rom­e­ter is rec­om­mended to keep tabs on ex­haust gas tem­per­a­ture us­ing any in­jec­tor with a flow rate greater than fac­tory. While small noz­zle up­grades can be made with no ad­just­ment to tun­ing, at the level we’re run­ning, it’s sug­gested that af­ter­mar­ket tun­ing be em­ployed.

LB7 injectors are known to be the most trou­ble­some of the en­tire Duramax fam­ily. For­tu­nately, Bosch has con­tin­u­ally im­proved the injectors’ de­sign and now pro­duces squirters that are far more re­li­able. Still, even the best LB7 injectors need ser­vic­ing...

1. Dynomite Diesel Prod­ucts’ up­graded injectors are noth­ing short of beau­ti­ful. Like kids on Christ­mas, we en­joyed open­ing each and ev­ery one of the in­di­vid­ual boxes, even though we knew what was in­side.

2. There’s no mis­tak­ing a DDP in­jec­tor. The com­pany’s logo is laser-etched into the body.

4-5. It’s im­por­tant to re­mem­ber to in­stall the two O-rings. One goes on the in­jec­tor body and the other on the high-pres­sure fuel in­let. You’ll want to lube the body’s O-ring with clean oil be­fore drop­ping it into the cup.

3. Ev­ery­thing needed to in­stall the new injectors (O-rings, cop­per washer) is in­cluded.

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