Roots Blown Landcruiser

Toyota’s big-foot Landcruiser is held in high regard all over the world – it’s the el-supremo of genuine off-roaders. But its separate chassis and sheer bulk add up to a lot of kilograms - 2500 of them, in fact. And not even 170kW worth of Toyota V8 muscle can give it a decent shove along.

Here enters Bullet Australia and their bolt-on blower system.

The Bullet Supercharger System

The name Bullet may be familiar to our Australian readers – it’s the company behind the head-banging Toyota V8 powered roadsters that are built using MX-5 tubs. Well, not surprisingly, Bullet Australia knows Toyota V8 engines inside-out and have expanded the business to include bolt-on blower systems. One of the latest kits is engineered to suit the 4.7-litre V8 (2UZ-FE) available in the 100 series Landcruiser GXL/VR/Sahara and Lexus LX470.

So let’s get into the tech details.

At the heart of the Bullet Australia blower system is a Harrop BH112 supercharger using Eaton rotors. This type of blower – known as a Roots - incorporates two helically formed counter-rotating rotors which help reduce pulsing from the outlet. Roots type blowers are generally reliable and are employed by many car manufacturers including Mercedes, Jaguar, Ford and Mini.

The blower unit is installed on the lower section of the Toyota intake manifold using a laser-cut steel adaptor plate. Bullet Australia also provides the necessary pulleys, a longer V belt, a different top radiator hose and a modified coolant cross-over pipe. Everything is arranged so that the blower can be concealed under the factory engine cover (not fitted at the time of our photo shoot).

The intake to the supercharger comprises a cast aluminium elbow (found at the rear of the blower) which connects to a relocated Toyota throttle body. A replacement flexible pipe joins to the standard airflow meter and airbox.

In most configurations the blower is configured to deliver a maximum boost pressure of 6 psi. This gives the desired power increase while keeping charge-air temperatures to a minimum. At the time of photography, there was no form of intercooling but a water-to-air intercooler and cast intake manifold assembly have now been completed. There is currently no information regarding price or power gain of these parts.

Note that Bullet Australia has recently revised its market line-up so that every Landcruiser/Lexus V8 blower kit comes with an engine management upgrade - a UniChip interceptor. The UniChip is tuned on a chassis dyno and gives the flexibility to optimise mixtures and ignition timing across the range. Bullet Australia can supply a pre-programmed UniChip – called the Bullet Smart Chip – or you can have tuning performed by your local UniChip agent. Also supplied is a switch that allows you to select between two separate UniChip maps – one map optimised for 98 RON unleaded and another suited to low-grade 91 RON. The injectors, fuel pressure regulator and fuel pump remain standard.

With the supercharger set to 6 psi and a UniChip installed, you’ll typically see a power gain of around 50 percent. A standard 4.7-litre Landcruiser generates about 110kW at all four wheels (on a Dyno Dynamics chassis dyno) and the supercharger adds 55kW. There’s also a massive increase in torque through the entire rev range – as you’d expect with a positive displacement supercharger. The complete kit retails for AUD$8590 (supply only) or AUD$9590 (fitted).

As an option, Bullet Australia also recommends the fitment of their in-house developed header/exhaust upgrade. The company tested a variety of components and configurations before settling on a system that delivers maximum power together with a very refined note. At the front of the system are custom headers which are port matched to the heads and feature a ceramic heat barrier coating to maintain stable under-bonnet temperatures. From the back of the collectors exhaust gasses are put through twin 2 ¼ inch mandrel pipes, twin high-flow cats, a two-into-one junction (which flares to a single 3 inch mandrel pipe), a central muffler and rear resonator.

With backpressure eased, the supercharged Toyota V8 spins much more freely through the top-end and delivers a substantial power gain. Bullet Australia claims power is increased a further 18 percent over standard – a total of 185kW at all four wheels! Oh, and you’ll also enjoy improved fuel consumption and a sophisticated V8 burble. Supplied cost is AUD$2490 (or AUD$2950 fitted).

The final option – and one which Bullet Australia will now promote given the completion of their water-to-air intercooler – is a boost pressure upgrade. With a revised set of pulleys and a new belt, the Harrop supercharger is spun faster to deliver a maximum of 9 psi boost. Interestingly, this extra boost generates relatively little extra power without the benefit of an intercooler - only about 5kW at the wheels - but it is expected to make a bigger difference in conjunction with the ‘cooler. The boost pressure upgrade costs AUD$260 (supply), around AUD$80 for fitment and extra for any additional tuning.

On the Road

AutoSpeed recently had the opportunity to drive Bullet Australia’s development Landcruiser equipped with their blower kit (set to deliver 9 psi boost) and upgrade headers/exhaust. The only difference compared to an off-the-shelf kit is the fitment of a Fuel Doctor experimental fuel catalyst.

The first word which springs to mind is effortless. With 9 psi boost from the moment you stab the throttle (as evident by a manifold boost gauge), there’s a mountain of torque to propel the Landcruiser with minimal fuss. There’s no need to take the engine to high revs in any normal driving circumstances.

However, keep the throttle buried and the supercharged V8 holds strong torque to around 5000 rpm. No, it’s not a drag machine it’s quick enough to put a smile on your face and highlight the vehicle’s non-sporting handling characteristics – as we found out... The upgrade exhaust sings a glorious song and is never intrusive. Blower whine is also at around OE levels.

The effortlessness of the extra grunt would make this an excellent upgrade for anyone towing heavy loads - though we’d be reluctant to go for the non-intercooled 9 psi configuration if you expect to hold the engine at high load while climbing hills. Interestingly, the standard auto transmission of our drive vehicle felt pretty well matched to the grunt of the supercharged engine – there’s no immediate need to alter trans characteristics, but traditional shift mods can be performed if requested.

For a total cost of under AUD$13,000 (fitted) this could be the ultimate final touch to your ‘Cruiser.

Update Bullet Australia now offers a supercharger kit to suit the newly released 4-litre Prado/Hilux and a range of other vehicles. Check out their website for up-to-date details. Contact: Bullet Australia +61 7 3382 0018 www.bulletcars.com