Banks’ latest project, dubbed the D-Max Type-R, will race a diesel in 25-hour endurance races. This is an entirely new venue for diesel and one that poses an entirely new set of problems for Banks to solve.

After choosing the General Motors LLY V-8 engine platform to power the roadracing truck, the engine was dissected and every part was inspected. Endurance racing finds weaknesses and Banks engineers would need to find them first and address each one. In Banks’ January 2005 Project Update (#2), the Banks D-Max Type-R Engine Program was discussed and many of the ways Banks’ race shop crew planned to strengthen and upgrade the LLY engine were detailed.

In this issue, we’ll show you the design process of Banks proprietary LLY intake manifold design for use with twin turbochargers. The Banks intake manifold is designed to supply air from each turbo and charge-air cooler directly into a bank of four cylinders.

Designing an intake manifold for the LLY is an unusually complex process since air reaches the heads via sixteen intake runners. There is one intake runner per valve and two intake valves per cylinder. LLY heads have one long runner and one short runner per pair of intake valves to promote ‘swirl’ in the combustion chambers allowing more complete combustion. In fact, 2006-model LLY heads have redesigned combustion chambers that promote even more swirl than the earlier (2004 1/2-2005) models.

Banks’ interesting intake manifold design has three siamesed pairs of intake runners in the middle of each bank of cylinders and a single runner at each end port. The manifold employs long runners with converging walls for a ram-effect. Years of design experience and flow-bench testing gave Banks’ design team a good starting point for runner length and shape.

A pair of ‘log-style’ intake manifolds have an opening in the front of each plenum that a boost tube will bolt onto.

Much emphasis was placed on developing an appropriate plenum volume while smoothing flow into the runner inlets at the plenum floor. There will also be removable crossover tubes that join one plenum to the other. Different diameter crossover orifices will allow Banks’ engineers to determine what degree of balance from one turbo to the other the engine ‘prefers.’ If it is found that the engine ‘likes’ an isolated plenum design, they can also be blocked off.

Banks’ Chief Designer, Bob Robe is designing and overseeing the engineering and casting process of the Banks proprietary LLY twin-turbo intake manifold. After Robe drafted a full-scale layout of his design, Banks Lead CAD Designer, Matt Hill transferred the design to SolidWorks. Hill’s CAD drawings will be used to ‘print’ plastic mock-up parts from Banks’ Dimension Fusion deposition Modeling (FDM) machine.

These full-scale mockups may be bolted to the engine in the truck to verify their form and fit and to act as standins as related interfacing parts are developed.

In a future update, Banks aluminum twin-turbo intake manifolds will be cast in A356 aluminum and heat treated to a T-6 condition and machined by Banks’ machinists. Stay tuned.