|As one would expect, Australia's foremost exponent of Forced Induction, APS is heavily involved with the improvement of the Falcon XR6-Turbo.
Drawing on over 20 years experience in turbocharged engine enhancement design and manufacturing, APS has produced the ultimate High Performance intake plenum and supplementary fuel system for the Falcon XR6 Turbo.
At extremely high flow rates and high power levels over 400 kW, the standard intake plenum creates issues that affect not only the amount of charge air that is delivered to the inlet ports but also the air distribution to each cylinder. Whilst addressing the flow rate issues are relatively easy, charge air distribution is a tough nut to crack.
As always there is no substitute for 20+ years of world class intake system production experience - get it right the first time! With outstanding air flow rates and optimum charge air distribution, the APS Intake Plenum delivers a level of performance that other manufacturers can only aspire to achieve.
Best of all, the APS plenum also has provision for an additional 6 injectors in order to supply the precise amount of fuel at extreme engine power levels. By utilizing additional fuel injectors, optimum sized main injectors are utilized in order to deliver excellent throttle response and fuel economy under normal driving conditions - but at full throttle and high power, the additional injectors are available to supply additional fuel. This approach is far superior to very large individual injectors that perform poorly at low flow rates (low duty cycle) and result in high fuel consumption and lacklustre throttle response. The APS plenum is designed to accept the standard XR6T injectors in order to deliver the most cost effective solution for the XR6T performance enthusiast and you can now enjoy the best of both worlds - excellent throttle response and frugal fuel economy under normal driving conditions along with precise fuel delivery through the additional injectors at insane horsepower levels - all in a very cost effective package!
Equal charge air distribution to each cylinder is critical not only for safe and efficient engine operation, but also in order to deliver the absolute maximum power and torque. This is one aspect of induction design that the original engine manufacturer expends a great deal of engineering effort in order to ensure that each cylinder receives the exact amount of air required at all engine speed and throttle position combinations. Ford has chosen well by centralising the throttle body right in the middle of the inlet plenum. This configuration keeps the throttle body to cylinder distance as close and as even as possible. This is particularly important due to the long length of the XR6T engine where the distance from number 1 cylinder to number 6 cylinder is particularly great. This fact alone mandates that other configurations are inappropriate for this engine.
Even though APS had experimented with end entry and other configurations on the XR6T engine, the centrally located throttle body is by far the best solution. To better explain this, the following discussion highlights the issues involved in achieving equal charge air distribution and the impact different air flow rates have upon distribution to each cylinder.
A classic end entry solution used by many manufacturers is quite common on small capacity engines that have intake runners to each cylinder spaced relatively close together. The total length however is quite small in comparison to that on the XR6T straight 6 configuration.
With this end entry configuration on the XR6T engine, at low air flow rates as found during idle and low engine speed conditions, the majority of air flow is consumed by the cylinders that are close to the end entry (red). This means that those cylinders run lean (red) whilst the cylinders that are far away from the end entry run rich (blue) due to the small mass of air that reaches them. Very few cylinders have the correct amount of air supplied to them (green).
As the engine power levels increase, more air is forced through the end entry. At these higher levels of air flow, the mass of air and speed of air (hence the momentum of incoming air) become significant. Air flow is momentum based and this means that as the speed and mass of air increases, the majority of air distributed to each cylinder moves from those cylinders close to the end entry to those that are further away.
At very high engine power levels, the charge air distribution to each cylinder is the opposite of that experienced at low engine speeds detailed above. Much of he charge air is blown past the cylinders close to the end entry and a rich condition is experienced on those cylinders (blue) - whilst the cylinders furthest away from the end entry run lean (red) due to the high mass of air reaching them. Again, few cylinders receive the correct amount of air (green).
The net effect of all this is that the state of engine tune - hence power level achieved safely is compromised by the leanest cylinders and the others simply run richer than optimum.
The above end entry configuration can be quite effective in a small capacity engine where the distance between the first and last cylinders is relatively short. On the XR6T however that is configured with substantial distance between first and last cylinders, the above end inlet configuration was deemed unsatisfactory for any benefits the different entry location may offer.
The final solution to this problem adopted by APS with the XR6T plenum is to maintain the central entry as adopted by Ford for this engine.
The central location not only ensures more even distribution of charge air to each cylinder, but also presents the air to each inlet port at a more appropriate entry angle. Rather than having to turn the air by 90 degrees to enter each port, the APS intake plenum delivers a relatively straight and easy entry path to each intake runner port.
In addition, due to the fact that each cylinder receives an equal amount of charge air for combustion, there are no mixture variations between cylinders and equal power is produced by each. This also means that rather than tuning for the leanest cylinder and forsaking power from those running rich (due to receiving a smaller quantity of air), the APS plenum delivers a far superior platform where each cylinder maintains an equal air/fuel ratio and maximum power is available from all cylinders.
By far the most advanced intake plenum available for the XR6T. As always there is no substitute for 20+ years of world class intake system production experience - get it right the first time! With outstanding air flow rates and optimum charge air distribution, the APS Intake Plenum delivers a level of performance that other manufacturers can only aspire to achieve.