Banks Sidewinder D-Max Type-R
By: Mike Magda,
© 2005 PickupTruck.com
are known for their longevity and durability. But entering a Duramax-powered
GMC Sierra in endurance road races against some of the country’s
top sports cars seems completely out of place.
Not to Gale Banks.
Banks has already set land speed records with a Cummins-powered Dakota
that was driven, not towed, to Bonneville. Now his current project—titled
Sidewinder D-Max Type-R—is out to radically change the perception
of diesel power on the race track as well as the street.
will compete in 2006 National Auto Sport Assn. series in the Super Unlimited
Class, which can include World Challenge and other high-end road-racing
cars. Plans had been made to run in the grueling 25 Hours of Thunderhill
this weekend (December 4-5), but testing on the just-painted truck wasn’t
A Banks spokesperson
said component evaluation was continuing and team owner Gale Banks didn’t
want to interrupt the test schedule just to be in the race. According
to Banks, endurance testing finds weaknesses in every part and he needs
to find and address each one.
will run in the opening test session on the 15-turn, 3-mile Thunderhill
course the Friday before the 25-Hour race as part of its evaluation but
will not compete this year.
diesel projects that focus solely on simply forcing more air and fuel
into the cylinders, the Banks team wanted to implement more racing tricks
and design innovations throughout the engine. Banks had access to four
stock 6.6-liter Duramax LLY engines for testing and development. In another
section of the shop, work centered on building a NASCAR-style chassis
and fabricating aerodynamically enhanced body panels.
block preparation was just as precise as any race engine. The block was
rifle-drilled to supply oil to the lifters. Banks CNC milled a billet
oil pan for the 7-stage dry-sump system. The custom pan also serves as
a block reinforcement girdle. Custom 4340 billet-steel H-beam connecting
rods are mated with stock pistons and crankshaft, but both components
are heavily modified. The crank was lightened and knife-edged while the
pistons were softened in the dome area and an inside lip around the bowl
was relieved. The piston crowns were also slightly beveled to allow for
expansion under higher exhaust temperatures. Final compression ratio is
much the engineers could do with the 4-valve cylinder heads. The Banks
team cut up donor heads in various cross sections but couldn’t find
enough metal to hog out as desired. Some porting was done with a CNC machine
to promote swirl, then additional shaping was handled with a hand grinder.
improvements included stainless steel intake and Inconel exhaust valves
(both 33mm) and smaller but stronger Eibach springs. The stock 2-piece
rocker bridges—those are the pieces that activate 2 rocker arms
from a single pushrod—were replaced with custom-machined units.
Despite the limitations of the port size, Banks improved air flow by 30
percent on intake side and 50 percent on exhaust.