Big Rig Owner

September 2013

Issue link: http://read.dmtmag.com/i/164130

Contents of this Issue

Navigation

Page 21 of 83

20 www.bigrigowner.com September 2013 was jettisoned in favor of a supercharger/ turbocharger combination. The intent of the change was to improve throttle response for better acceleration off of the corners (of which there are many on the hill climb courses). An 8.3 liter twin screw supercharger replaced the turbocharger as the primary air motivator, first pulling air through a triple array of Banks Ram-Air filters. Boosted air is delivered from the supercharger to the compressor inlet of a wastegated turbocharger. The pressurized air from the turbo is fed through the air-toair charge cooler before reaching the intake manifold. Exhaust gases pass through a stainless steel equal length double wastegated TorqueTube exhaust manifold before driving the turbine wheel of the turbo charger. Although the system is capable of producing 180 PSI maximum boost pressure, The wastegate will control pressure to be to a nominal 60 PSI, holding a lot in reserve. Water-Methanol X2 There are 2 discrete injection systems feeding a 50/50 mixture of water and methanol into the 14.0L 6-cylinder engine. First, a Banks Double-Shot system feeds the fluid to the inlet of the supercharger through 4 nozzles. This system has 2-stage functionality to allow for a smooth progression of flow. Triggering of the system is based on the supercharger outlet temperature. The pump is driven by pulse width modulation (PWM) allowing pressure to be increased progressively. As the supercharger outlet temperature increases, the pump pressure will be increased to about 250 PSI, at which point the second stage will kick in feeding the second pair of injectors. After the air has been pressurized by both the supercharger and the turbocharger, another blast of water-meth is delivered by another Double-Shot system. Six injectors are installed in the intake manifold, one in coverstory 0913.indd 3 Cover Story each individual intake runner, injecting water-methanol as close to the cylinder head ports as possible. These 6 injectors are all fed by a common manifold. In this system, triggering will occur based on boost pressure. At about 30 PSI of boost pressure the system kicks in and is fully active at 50 PSI in the intake manifold. Double Shot Auto-Chiller Another Double-Shot Injection System was used to further increase the intake air density. Air Density is increased whenever temperature in the system can be reduced. The air-to-air intercooler is a density machine that acts to cool the boosted intake air by transferring the heat as it passes through a series of finned tubes to the ambient air flowing over the face of the charge air cooler. In normal operation, the maximum effectiveness of this operation is limited by the temperature of the ambient air. By adding a spray of water to the exterior of the intercooler tubes with a Double-Shot Auto-Chiller, the intercooler effectiveness can be increased. In this case, five nozzles are arranged to mist the face of the intercooler with water in 2 stages, the first stage beginning to spray through 3 of the nozzles, the second stage adds the remaining two. This system will trigger based on intercooler outlet temperature, and will begin to operate at 100°F, with full operation achieved at about 150°F. 8/7/13 11:52 AM

Articles in this issue

Links on this page

Archives of this issue

view archives of Big Rig Owner - September 2013