Unichip Q4  and

Performance Exhaust

LandCruiser 200

Install and road test

While the twin-turbo diesel 200-series is no slouch, like most vehicles, the tuning of the engine is imperfect. There are compromises due to mass production requirements and manufacturing costs. Because of this, there are a growing number of 'performance chips' available for the 200 (and other common-rail diesel vehicles) in addition to computer (ECU) 'reflashing' services and performance exhaust systems. Like any modification, the price, quality and results of these modifications vary widely.

This article will give some information on the performance chip and remap options available, what I chose for Project 200 and why.

Performance Chips, 'Pedal' chips and ECU Reflashing / Remap

Installing a Performance Chip or conducting ECU reflashing (AKA Remapping) are essentially two ways to achieve a similar outcome: Improve the performance and/or fuel economy of the vehicle. There's a large range of options available, varying in sophistication, mode of operation, price and results:

Fuel rail performance chip
Identifying a fuel rail chip
Click to enlarge

Fuel rail pressure chips: The vast majority of brands on the market are ‘rail chips’. They operate by interfering with the signal between the common rail pressure sensor and the ECU, causing the ECU to demand an increase in fuel pressure. This can result in more power and/or better economy. A side-effect is that they slightly advance fuel injection timing, and boost will often increase due to the additional fuel. However, neither of these are actually controlled by the chip despite claims to the contrary by some manufacturers. These ‘rail chips’ typically have a rotary dial or a few buttons on the device to control how much the fuel pressure is varied.

Fuel rail chips can be easily identified by the way they are attached to the engine. If a chip only plugs into the fuel rail pressure sensor, then it is one of these chips. Obviously, because of this single connection, the only thing they can control is fuel pressure. Rail chip technology was developed in Europe in the late 1990s, and there are far more sophisticated options available today.

It should be noted that despite their limitations, there is nothing inherently wrong with these chips and I was quite happy with the results I achieved from a rail chip on a previous vehicle many years ago. Their primary advantage is cost, with good options available for around the $1000 mark, although some brands cost substantially more.

Update July 2017: I was a little surprised last month, to receive legal threats over this article, first via a phonecall, followed a few days later by a lawyer’s ‘Cease & Desist’ letter. These came from a well-known diesel servicing/chip company. They demanded I remove any reference to their particular rail chip’s brand name in this article. Although disappointed by this behaviour, I have therefore removed references to all brands here other than Unichip. As I’d previously written, there’s nothing inherently wrong with rail chips, but don’t let anyone ‘pull the wool over your eyes’ with claims that their chip can do something it can’t.

Remember: If the only place a chip attaches to the engine is the common rail pressure sensor (see photo above), then it’s a rail chip. All a rail chip can directly control is fuel rail pressure. 

Injector duration chips: These chips plug into each fuel injector. Some older models attached at the injector controllers. They do not control injector timing, they only extend injector duration. This can increase power, but can also increase fuel consumption as the extended injection is not as efficient due to (late) timing and potentially lower fuel pressure. As with the rail chips, newer technologies have left these chips behind. There are very few chips that operate using only this method, and they do cost around twice the price of a rail chip.

Pedal chips (Throttle controllers): This type of chip plugs into the accelerator pedal. They do not increase engine power or torque whatsoever. These devices simply modify the signal from the accelerator pedal to the ECU, essentially telling the ECU that the pedal has been depressed further/faster than it has. In isolation, I can't see much reason for purchasing one of these devices, particularly given the cost which can exceed $300 for some brands. That's a lot of money when you can get the same result by planting your foot faster! However, if it's something you're interested in, then there are options available for under $200.

ECU Reflashing (Remap): Reflashing (or remapping) overwrites some of the factory engine control parameters in the ECU, adjusting the operation of fuel pressure, injector timing/duration and turbo boost. It's relatively new for the 200 series and can improve power and/or economy. Althought it can achieve good results, my main concerns with this option are that it cannot be 'unplugged' in the field (should you need to return to standard settings for some reason), and there is no facility for the user to adjust the settings. Every other performance chip provides some form of user adjustment.

Combination / 3D chips: The most sophisticated types of performance chip have the ability to control multiple engine parameters simultaneously and relative to each other. This is sometimes called '3D tuning'. These modern chips are far superior to rail pressure or injector duration chips because they are able to adjust both pressure and duration, plus offering real injector timing and boost control. These chips plug into the main ECU harness. This is the case with the chip I have chosen, the Unichip Q4.

Why the Unichip Q4?

Because it's a very sophisticated chip, with the ability to control a wide variety of functions, monitor engine sensors and has easy and comprehensive user adjustability.

The Unichip Q4 can control fuel pressure, injector timing, injector duration, turbo boost and pedal input. This results in the ability of the installer to conduct full '3D' tuning, which means adjusting the various parameters relative to other parameters. For example, increasing fuel pressure based on turbo boost levels, or injector timing based on RPM. This sort of tuning is not possible with fuel rail or injector-duration chips. 3D tuning means the Unichip has the ability to get greater performance and efficiency gains than less sophisticated chips.

Another big plus from my perspective is the ability to have 5 presets programmed, providing the driver with the ability to make changes depending on the requirements at the time. The settings can be changed via either a dash switch or (optionally) via a bluetooth module and phone app. In my case, I chose Max Performance; Max Economy; Towing; Standard; and Immobilise as my 5 preset maps. I chose the Bluetooth module as I didn't really want another switch on the dash.

The other major factor in my decision is engine safety. Common rail engines are incredibly expensive. In the case of the 1VD-FTV engine in the 200-series, a new replacement costs around $30,000. Most chips rely solely on preprogramming to keep the engine within a safe operating range. Because it can access the engine sensors, the Unichip Q4 includes built in sliding-scale protection based on water temperature, and can also be fitted with an (optional) exhaust gas temperature (EGT) sensor.

During the installation, I also discovered another great feature of the Q4: It includes customisable outputs which are able to control other devices based on predefined conditions. In my case, I had Power curve create a custom output which will automatically deactivate my torque converter lockup system when throttle position exceeds 50%. Given the additional power and torque provided by the Unichip, I thought this would be a prudent step.

Performance Exhaust

I had planned on fitting an exhaust at around the same time as the performance chip, to allow the engine to breathe better making the most of the additional gas volume generated by the Unichip. I also wanted a bit more exhaust note from the 'Cruiser's V8. There are several companies making exhausts for the 200 these days, some made in Australia and others fully imported from China and sold here by local companies. I hadn't decided on a brand, when Unichip offered me one of their newly designed 2-into-1, stainless exhaust systems for the 200.

Pat from Power Curve noted that he'd actually seen some exhausts deliver a power drop on standard 200s, possibly caused by insufficient backpressure. When I mentioned this to Paul from Unichip, he said that their exhaust had been specifically designed to address this, with a 'unique cone/venturi' element in the dump pipes to deliver a combination of good flow while maintaining some backpressure.

I'm not an exhaust designer, so I can only report on the results. The Unichip exhaust certainly delivered, with a 5% power increase (pre-chip), which was a surprisingly good result given Pat's experiences with other exhausts on the 200. Once the chip was installed, the exhaust provided an additional 10% power increase over the figures for the chip alone.

The exhaust delivers a throaty V8 note compared to the standard system, although if you're looking for something similar to an old Ford or Holden petrol V8, you might be a little disappointed. Unfortunately, the 200's turbos suppress and change the noise coming out of the motor and it's impossible to get the same sort of sound from the twin-turbo 1VD. I really enjoy the new note though, which delivers some additional turbo whistle and sounds very nice under load, but without noticeable drone when cruising on the highway. The video above gives some idea of how it sounds.


Unichip Q4: Unlike most of Project 200's modifications so far, I had the chip and exhaust professionally installed by Patrick from Power Curve Performance in Nambour on Queensland's sunshine coast. Because they are fully tunable, Unichips really need to be fitted by a professional installer. This allows you to get the most out of the installation as your vehicle can be precisely tuned for optimum results.

I chose Power Curve to do the install after spending some time talking to Patrick about the 200 and the options available for it, in both chips and exhaust systems. I was impressed with his thorough knowledge of tuning 200s, and as I was already planning a trip to Queensland it seemed like a good opportunity to get the chip installed and tuned.

The Unichip is a plug-and-play system. A standard installation simply involves unplugging the factory plugs from the ECU on the firewall, plugging in the Unichip plugs, then plugging the original ECU cables into the Unichip. However, I preferred to have the Unichip modules inside the vehicle, rather than exposed to the elements in the engine bay. Additionally, I have a compressor installed near the ECU and space is a bit tight. So Patrick extended the wiring through the firewall and installed the Unichip modules behind the glovebox.

Unichip Exhaust System: The exhaust could certainly be fitted yourself, but as I wanted dyno results pre and post-exhaust, it really needed to be installed on the same day as the Unichip to achieve this. It's a very easy bolt-in installation, using all the factory mounting points. The system has no problems fitting around the Long Ranger tank or the KDSS system, however a small modification was required to the Outback Accessories rear bar to stop the rear resonator touching part of the bar near the towhook.


Before I get into the results after installing the performance chip and exhaust, it's important to remember a few things. These results apply to my vehicle under the conditions present at the time of testing. They should only be taken as indicative for any other vehicle due to variability in vehicles, modifications, specifications, testing equipment, fuels etc.

There are a series of dyno graphs below which give the figures, but they don't describe the way the feeling of the vehicle has completely changed. There is an absolutely massive improvement in performance, particularly in the mid-range. The difference in rolling acceleration (such as for overtaking) must be experienced to be believed.

As I write this, I've had the Unichip and exhaust installed for a few months, and have settled on running the 'Max Economy' tune most of the time. I find it to be the best combination of substantially improved performance, while using less fuel than standard. Scroll down for more information on fuel economy, plus a comparison table of performance and economy in various configurations.

Standard Vs Unichip Q4 + Unichip exhaust

This graph is essentially the complete "before and after".

It shows the standard 200, and then after the installation of both the Unichip exhaust system and the Unichip Q4, set on the 'Maximum Power' setting. In combination, the chip and exhaust delivered a remarkable 53% increase in power and torque over standard.

Standard Vs Unichip exhaust

This graph shows the effect of the Unichip exhaust system in isolation. It compares the standard 200-series, and then after the installation of the Unichip exhaust. The exhaust increased power by around 5% and torque by around 20% at the peaks, and an even greater improvement at lower RPM.

Unichip Q4 Max Power Vs Unichip Q4 Max Power + Unichip exhaust

This graph shows the effect of the Unichip exhaust once the Unichip Q4 has been fitted. You can see that the exhaust itself produces greater gains with the chip fitted than on the standard engine. I suspect this is because the improved flow of the larger exhaust is more effective when dealing with the increased exhaust volume generated by the chipped engine.

Standard Vs Unichip Q4 Economy Vs Unichip Q4 Max Power

This graph shows the difference between a standard 200, a 200 with the Unichip Q4 on the Economy setting, and a 200 with the Unichip Q4 on the Max Power setting. All of these dyno runs were performed with the standard exhaust system.

This graph demonstrates one of the great advantages of the Unichip over other performance chips. These three settings (and two more) are all selectable at the flick of a switch (or via an iPhone app).

Power and Torque 'at the flywheel' Versus 'at the wheels'

The graphs above all show 'at the wheels' results from a chassis-dyno, while manufacturers quote figures 'at the flywheel', measured on an engine dyno. 'At the wheels' figures are substantially lower, as they allow for losses which occur throughout the driveline.

I've had many questions from people trying to compare these numbers, so I've produced a graph which shows approximate 'at the flywheel' figures, using data and approximate driveline losses extrapolated from the graphs above.

Fuel economy with performance chip and exhaust

Although most performance chip manufacturers claim both performance and economy gains from their chips, in reality they generally deliver one or the other. Economy is important, so I wanted to perform a controlled test of the Unichip and exhaust to find out how they effected economy.

To test the economy, I drove a roadtest loop before fitting the chip/exhaust, then repeated the loop twice afterwards with the Unichip set on the 'Max Economy' and 'Max Performance' settings. Traffic conditions were similar for each loop and I tried to hold consistant speeds and use the cruise control wherever possible to minimise variables. The temperature was slightly cooler during the chip+exhaust runs than the standard run (22º Vs 24º Celsius).

The test loop was 141km in length and included mostly 80km/h rural roads and highways, along with a short section at 100km/h, and several small sections at 50-60km/h. The loop takes in quite a lot of undulating terrain, and varies in elevation from 20m to 1100m above sea level.

Before fitting the Unichip and exhaust, average fuel consumption on the loop was 13.5 L/100km.

After fitting the Unichip and exhaust, fuel consumption for the loop averaged 12.8 L/100km running the Max Economy tune. This equates to an improvement of 0.7 L/100km, or about 5.2%.

When running the Max Performance tune, fuel consumption increased to 13.8L/100km, or 2.2% over standard. Note that the more you make use of the additional power, the more fuel you'll use. There's no free lunch!

Performance and Economy - Overall comparison table

^ The dyno results represent power and torque at the wheels, not at the flywheel. The reason these are substantially lower than manufacturer-quoted figures (which are measured at the flywheel) is due to driveline losses.

* The 0-100 tests do not in any way indicate the best achievable times, they are simply for comparison with each other using the same method. They were performed from just-off idle and on a slight uphill grade. Times would improve by at least 2-3 seconds on a level road and with some pre-loading for the takeoff.

# The fuel economy loop consisted of almost entirely hilly terrain, and the vehicle is fitted with many heavy accessories, a full tank (273L) of fuel and offroad tyres. Again, the figures are only for comparison purposes, and would be lower on flat highway terrain, and with less vehicle weight.

Comments / Q&A