Diesel World

TIME-TESTED, FRESH LOOK

- Cars · Cummins

be treated to the lat­est and great­est the In­di­ana en­gine builder has to of­fer. A com­pe­ti­tion-ready, 391 ci Cum­mins is built around the use of Scheid’s bil­let-alu­minum dry block, which ac­cepts cylin­der lin­ers, has been fire-ringed, and sports a fac­tory 6.7L Cum­mins crank, bil­let-steel rods, and low-com­pres­sion Di­a­mond Rac­ing pis­tons. A high-flow, 12-valve bil­let-steel head re­sides up top and an­chors to the block by way of ARP 14mm head studs.

SIGMA PUMP & 5X35’S

For its un­matched in­jec­tion rate, the Sigma is still king in the Su­per Stock class. The cast-alu­minum body, 16mm plunger pump hang­ing off the side of Todd’s en­gine pro­vides more than enough fu­el­ing to clear 3,000hp on the dyno. The Sigma re­ceives its fuel sup­ply from the back side of an Avi­aid two-sec­tion wet sump oil pump. Ob­scene amounts of fuel make it in-cylin­der thanks to over­size, 0.120-inch in­jec­tion lines and a set of Scheid’s bil­let, triple-feed body in­jec­tors, equipped with 5x0.035-inch noz­zles.

120 PSI OF BOOST

A two-stage, triple-turbo con­fig­u­ra­tion com­prised of three Hx82-based jour­nal bear­ing Holsets with bil­let com­pres­sor wheels han­dles boost pro­duc­tion. Thanks to great flow through the bil­let cylin­der head, a rel­a­tively tame (for Su­per Stock), 120 psi of over­all boost is all that’s nec­es­sary to make the kind of power that’s needed to run at the front.

?? ?? Like many en­gines in the Su­per Stock class, Todd’s Cum­mins em­ploys a two-stage, triple-turbo sys­tem. In this ar­range­ment, two iden­ti­cal Hx82-based Holsets serve as the at­mos­phere unit while a third HX82, bolted to a T6 foot Steed Speed ex­haust man­i­fold, acts as the high-pres­sure charger. To keep drive pres­sure in check, the trio is waste­gated to pro­duce a max­i­mum of 120 psi of boost. After two stages of com­pres­sion, in­take air is routed through a San­dridge Cus­toms wa­ter-to-air in­ter­cooler. In con­junc­tion with burn­ing through 100 pounds of ice per hook, the in­ter­cooler sys­tem drops the en­gine’s in­take tem­per­a­tures to 90 de­grees F. A boost-trig­gered wa­ter in­jec­tion sys­tem brings ad­di­tional cool­ing into the equa­tion, with a se­condary stage ac­ti­vat­ing should EGT ex­ceed a pre­set max­i­mum. For ul­ti­mate fu­el­ing, the almighty Sigma pump got the call. The cast-alu­minum Sigma, sourced through Colum­bus Diesel Sup­ply, makes use of 16mm plungers and 0.120-inch in­jec­tion lines. At the end of those Cnc-bent lines sits a set of Scheid’s bil­let-body, triple-feed in­jec­tors. SAC style, 5-hole noz­zles are uti­lized and elec­tri­cal dis­charge ma­chin­ing is em­ployed for max­i­mum dura­bil­ity. Each in­jec­tor ori­fice mea­sures 0.035-inches, ef­fec­tively mak­ing them 5x35’s in in­jec­tor speak.
Like many en­gines in the Su­per Stock class, Todd’s Cum­mins em­ploys a two-stage, triple-turbo sys­tem. In this ar­range­ment, two iden­ti­cal Hx82-based Holsets serve as the at­mos­phere unit while a third HX82, bolted to a T6 foot Steed Speed ex­haust man­i­fold, acts as the high-pres­sure charger. To keep drive pres­sure in check, the trio is waste­gated to pro­duce a max­i­mum of 120 psi of boost. After two stages of com­pres­sion, in­take air is routed through a San­dridge Cus­toms wa­ter-to-air in­ter­cooler. In con­junc­tion with burn­ing through 100 pounds of ice per hook, the in­ter­cooler sys­tem drops the en­gine’s in­take tem­per­a­tures to 90 de­grees F. A boost-trig­gered wa­ter in­jec­tion sys­tem brings ad­di­tional cool­ing into the equa­tion, with a se­condary stage ac­ti­vat­ing should EGT ex­ceed a pre­set max­i­mum. For ul­ti­mate fu­el­ing, the almighty Sigma pump got the call. The cast-alu­minum Sigma, sourced through Colum­bus Diesel Sup­ply, makes use of 16mm plungers and 0.120-inch in­jec­tion lines. At the end of those Cnc-bent lines sits a set of Scheid’s bil­let-body, triple-feed in­jec­tors. SAC style, 5-hole noz­zles are uti­lized and elec­tri­cal dis­charge ma­chin­ing is em­ployed for max­i­mum dura­bil­ity. Each in­jec­tor ori­fice mea­sures 0.035-inches, ef­fec­tively mak­ing them 5x35’s in in­jec­tor speak.

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