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AU Falcon Turbo Project

This is an information page for anyone looking to turbocharge an AU Falcon 4.0L Intech using a Haltech Elite 750. Before starting out, you’ll need to ask yourself a few questions to determine the correct direction to head in:

  • Is your car an automatic, and if so, do you wish to retain standard gearbox shift logic?
    • In my case, my car is an auto and I wanted to retain the standard shift logic. This is controlled by the AU Falcon’s standard ECU, meaning that the Haltech Elite 750 must be wired in as a piggyback style setup.
    • If you don’t require auto shift logic, or if you have a manual, there is an option to wire in the Haltech Elite 750 as a standalone setup.
  • Will you retain the AU’s standard coil pack block, or will you go coil on plug?
    • In my case I am keeping them, which means the Haltech will need to be configured to run a ‘Wasted Spark’ ignition setup and use a Haltech Triple Channel OEM Igniter. Only three ignition channels are required, as each channel ignites two spark plugs at once.

In addition to the above, a WB1 Wideband Controller Kit + Wideband O2 Sensor is required.

Wiring in the Haltech Elite 750

From this point forward, all information below is for wiring up a Haltech Elite 750 into an AU Falcon in a ‘Piggy Back’ style setup. The stock AU Falcon ECU is retained, but several wires are either intercepted or tapped to allow the Haltech to access sensor data and other information.

At this stage I would recommend Hooton Harnesses if you’re not confident to create your own patch loom. Simply tell Bill how you’re planning to set it up, and he’ll make you a loom to suit. Then all you need to do is follow the wiring information provided via the following link:

View: AU Falcon Haltech Wiring Guide

The AU ECU handles the auto gearbox shift logic, dash and other vehicle functions, whilst the Haltech takes over all aspects of running the Intech 6.

Base Map & Engine Start

Haltech provides an excellent resource on their website with most of the information required to setup a base map on the Haltech Elite 750. I used a generic Haltech base map for the Elite 750, and then used information from the page above to customise it to better suit the AU Falcon.

With very little effort, I was able to get the engine to fire and then run roughly on 3-cylinders. Due to an issue with how my loom was made, I needed to add “Home+” and “Home-” wires which spliced into the AU Falcon’s wiring loom – giving the Elite 750 a proper cam position signal. Bill Hooten later mentioned that only a “Home+” and “Trigger+” wires are actually needed for the engine to run properly.

Regardless, adding Home+ and Home- fixed the problem and the engine ran beautifully.

Download: MotoringBox AU Falcon Base Map V1
Download: MotoringBox AU Falcon Base Map V2

**USE AT YOUR OWN RISK** These base maps were created on a Fairmont Ghia with an Intech VCT with stock injectors. V2 has some improvements to idle, rev limiter, gear selector settings & more.

At this point, if you’ve followed the install process and loaded the base map correctly, your AU Falcon should now start, idle and even drive. Idle and fuel trims have been set, so the Haltech will continue to fine tune these settings as you drive. I would recommend driving sedately until you get a proper tune.

Fuel System Upgrades

For running any meaningful levels of boost, you’ll need to upgrade the fuel system – preferably larger injectors, a bigger fuel pressure regulator, and also a pump which can flow more fuel and keep up with the increased demand.

  • All AU Falcons run 200cc Bosch injectors and a 2.7 bar (39psi) fuel pressure regulator (FPR)
  • As a comparison B-Series XR6 Turbo’s run 295cc injectors and a 4.0 bar (58psi) FPR
  • At a bare minimum, used B-Series XR6T injectors and FPR could be used and will fit an AU Intech.
  • The stock AU fuel pump will most likely not flow enough fuel to support any meaningful levels of boost.

I used a BA XR6T spec 4.0 bar FPR, but decided to go for larger injectors – the same 1000cc Bosch/Raceworks injectors I used in my BA XR6T a few years prior. Perhaps a bit large for the turbo Intech build I have in mind, but they behaved well at idle and low RPM’s in a Barra – so I didn’t see any negatives in going slightly larger here.

I also sourced a 460lph fuel pump upgrade (again, arguably a bit big for what I need) to make sure the fuel supply will always be solid. Something around 255 – 325lph should be sufficient in most cases, but the Walbro 460 is surprisingly quiet and so far seems to be running fine on the AU’s stock fuel pump wiring.

T.I. Performance sell all of these parts and provide the dead time specs for the injectors, which you’ll need to configure in NSP.

Beginning the Turbo Installation

Before you move on with the install, one very important modification must be completed first – the installation of a turbo oil-drain into the engine sump. The AU Intech has no provisions for this, so a new hole must be drilled, tapped, and a suitable fitting installed. This is fairly high stakes, as any mistake made during the drilling and installation of this fitting may result in your sump having to be removed, which means either pulling the engine out, or dropping the K-frame in order to gain access.

With this in mind, I ordered a fitting and had a qualified mechanic drill and install it for me. Here’s a link to the fitting I ordered, which was a “7/8 X 9/16 – JICM X UNOM NIPPLE”. The 7/8″ end fitted up perfectly to my Mamba oil drain kit, and the 9/16″ end was chosen to reduce the size of the hole which needed to be drilled into the sump. In hindsight this made the internal diameter a little small (7mm) but it was drilled out to 10mm to mitigate any potential issues. With that out of the way we can continue!

After removing my aftermarket headers and dropping the BA Turbo manifold + turbo into place, two things became immediately apparent.

  1. When the Barra manifold sits on the Intech adapter plate, there’s only a tiny amount of space between the turbo and the side of the engine bay, and;
  2. The lines from the AU’s power steering pump are going to be in the way.

In order to help things fit better, I had to relocate the red positive cable which runs from the battery to the starter motor. This is relatively easy, simply unclip it from the engine bay and move it down as low as possible – either by drilling new holes for the cable mounts or finding a way to cable tie it in its new location.

In addition, one of the upper suspension arm mounting bolts also had to be ground down using an angle grinder, as it protruded through into the engine bay and was hitting the front housing of the turbo. With it removed, the manifold and turbo now sit perfectly in the space – potentially the driver’s side engine mount could be spaced up a bit to tilt the engine slightly to gain more space.

The high pressure power steering line sits directly in front of the turbo inlet, but I was able to loosen the fitting on the pump and then gently twist and bend the line to re-route it closer to the engine mount / the side of the engine itself. You’ll want to move it far enough so the turbo inlet pipe will fit, but not too far otherwise the line will start getting too close to the exhaust manifold.

The issue with BA XR6T intake piping

This seemed to free up enough space for our intake piping, but I fear the power steering pump may still get in the way once we start running hot-side intercooler piping.

On the cold-side of the intake, the BA Turbo crossover fits an Intech by using 10 – 15mm spacers, although a custom mounting bracket will need to be fabricated for the third mount which sits above the rocker cover. The hose which runs under the crossover for the blow-off valve (BOV) fouls on the AU’s square loom connector which sits between the intake manifold and the rocker cover. To fix this, you’ll either need to remove the entire BOV setup and block the openings, or re-route the BOV hoses over the top.

The AU’s airbox looks like it’ll work if we hollow out the fit the BA intake rubber piping after some minor modification, although I am going to investigate this further in the near future.

Depending on the turbo you’re using, you may encounter issues using the factory B-Series 3″ intake pipe. It’ll fit up fine to a factory Garrett turbo, but using an aftermarket Pulsar turbo with a larger 4″ inlet creates an issue. Luckily, you can solve it by using a 4″ to 3″ 90-degree silicon joiner, and trimming the intake pipe to suit.

The aftermarket Pulsar turbo also creates an issue with the wastegate actuator limiting how far you can clock/rotate the front housing – meaning the outlet ends up pointing a bit towards the side of the engine bay. Using a 60-degree silicon should fix this, when combined with an aftermarket turbo to intercooler hot-side piping kit.

There’s also going to be issues with the AU coolant expansion tank being so close that the hose coming out the bottom of it actually rests on the turbo. To fix this, a BA/BF style coolant tank appears to fit fine, apart from two brake lines coming out of the ABS module needing to be bent out of the way slightly.

Intercooler & Piping Installation

Luckily, mounting the intercooler ended up being pretty straight forward – with some trimming to the lower air-dam on the front bumper required to make space. But once trimmed, there’s a ton of space in the front of the car for an intercooler, transmission cooler and power steering cooler. The power steering cooler can be moved back closer to the condenser by utilising the existing second bolt hole on the mounting brackets, and cutting the rest of the brackets off to suit.

The next issue we’ll need to deal with is running the piping from the intercooler to the crossover on top of the engine – which either needs to run underneath the driver’s headlight (cutting sheet metal will be involved) or utilising a gap above the driver’s chassis rail. Both are questionable when it comes to getting a modification plate later, so some research will be required before we go any further.

Angle Grinder Engineering

If you’re planning to run a return-flow style intercooler (like the factory BA XR6T unit) there doesn’t seem to be any other choice – you’ll have to remove a small piece of sheet metal from under the driver’s side headlight mount. This will allow you to use a factory B-Series hard pipe which runs under the headlight, under the battery and then pops out near the power steering pump. Minor modifications are required to the sheet metal under the battery tray in order to get things to fit nicely. How this affects engineering and obtaining a Mod Plate remains to be seen, but we’ll find out more about that later.

Boost Control

With the entire hot-side piping installed (from turbo to intercooler, and from intercooler to throttle) we can now turn our attention to setting up boost control.

The simplest way is to run a vacuum hose from the nipple on your turbo (if it has one) directly to the wastegate actuator – which means the gate will open whenever the boost pressure is high enough to overpower it. If it has a 5-psi spring, it’ll open at 5-psi. If it has a 10, it’ll open at 10.

Or you can do what I am doing, and use a 3-port MAC valve. This needs to be installed in the vacuum line between the turbo and the wastegate, and through the Haltech will be able to control the pressure bleeding through to the wastegate, and allow you to reliably run higher boost levels as you see fit.

If you followed the wiring diagram I provided at the start of this article, you’ll be able to utilise wiring from the AU’s narrowband O2 sensor to power the MAC valve.

Hitting the Road

Finally we’re ready to hit the road! Considering it’s running on a Haltech tune which I set up by myself, we’re taking it easy on the first drive to try and work around some gearbox issues – namely kickdown and shift settings which are not ideal for the now turbocharged engine.

To rectify the gearbox issues, you can either look into a BTR 4 speed Full Manual Transmission Controller which will allow you full control over which gear the gearbox stays in, prevent unwanted kickdowns, and provide much quicker shifts.

An alternative which I am currently investigating is using a Programmable J3 Chip to modify the stock AU Falcon’s ECU and tune the gearbox shift parameters.

A basic parts list of what I’ve used

View the parts list at T.I. Performance

Dealing with the BTR 4-Speed Transmission

Now that the AU Fairmont Ghia Turbo is on the road, it was pretty clear that the BTR 4-Speed and the AU ECU’s standard shift logic isn’t up to the job of shifting properly when the car is on boost. As mentioned above, manualising the gearbox with a BTR 4 speed Full Manual Transmission Controller would fix it, but the box will no longer shift automatically, and will shift firmly at all times – even when cruising.

I chose to with a Programmable J3 Chip to modify the stock AU Falcon’s ECU and tune the gearbox shift parameters. Keeping the factory-style shift logic, but configuring it to shift faster and firmer when we need it to. Jason from T.I. Performance configured a tune which would suit, and I loaded it onto the chip and installed it into the AU ECU. It is vital to follow the installation instructions provided!

The install was successful and the car now drives with the new gearbox tune, but some additional testing is required before I create a video or update this page – so stay tuned.

Conclusion

At this stage we’re pretty much done – the car runs and drives pretty much as I would expect. The tune is a vital part of this, so if you don’t have the confidence to set it all up yourself, you’ll need to take the car to a reputable tuner who can get it all up and running properly.

If you found any of this information useful and wish to support my projects, please consider chipping in with a PayPal donation: paypal.me/motoringbox 

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