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Q&A About Tuning Common Rail Diesels

What exactly is a custom dyno tune? & how long does it take?

At Ultimate Diesel Tuning we are able to customise the data in your factory ECU, controlling all of the engine’s parameters such as boost, fuel injection, torque limiters and much more. This allows complete customisation of the vehicle’s standard/factory ECU (Engine Control Unit) to produce more engine power & torque, safely & reliably. Each vehicle is tuned on the dyno to ensure safe operation, accurate data logging and perfect results for each and every client. We are able to customise each tune to how the owner uses the vehicle as well as the age and condition of the engine. This is not a “one size fits all” service.

What is a “dyno”?
A dyno is a drive-on machine used for tuning (commonly referred to as a “rolling road”) – the car will be driven onto the rollers on top of the dyno & strapped down, which allows us to apply load to the engine and drivetrain whilst the vehicle remains stationary, in real time to replicate road driving conditions. Data is captured from the engine/vehicle via the dyno measure critical tuning parameters. In turn, the dyno also calculated horsepower and torque to show improvements in performance. This ensures an accurate tuning process. The dyno can also load up the vehicle to simulate real driving conditions. We can even program the weight of a caravan into the dyno too so it thinks that the vehicle is towing a caravan! This is absolutely the best and safest way to tune a vehicle.

What is the custom dyno tuning procedure – how do you do it?
Once the vehicle is strapped down on our dyno, its ECU is then connected to our tuning software. The vehicle is tested and measured on the dyno at varying speeds & RPMs. With the “as arrived” data captured, the then work through the maps in the ecu’s software, optimising the tuning maps within the ECU in order to achieve the desired gains in power & torque, nice & safely. The vehicle is then retested on the dyno in the same manner as when it arrived to give an accurate measure of the gains from the software changes. The results are studied and further changes are made via the tuning software. This process of making changes and re-testing on the dyno is repeated until the results are achieved. As you can see, this is not a simple or quick process. In fact, it can take up to a full day to tune one vehicle. 


What results can I expect after a custom dyno tune? 

The tune will give the car substantially more power & torque & the owner should notice an improvement in economy too. Also expect much better engine response (less turbo lag down low) & complete throttle control. It will tow with ease, will be much easier to overtake, will be much easier & safer to pull out of intersections in a hurry & will be much smoother to drive. We will achieve a much better & nicer driving experience, with a saving of fuel costs.

How does a custom dyno tune by UDT help with improving fuel economy?

At the end of the day, fuel usage is all about throttle usage. With the extra power & torque that we achieve with custom dyno tuning, the owner of the vehicle does not have to apply the throttle as much in order to get the vehicle to move. The vehicle will be able to be driven with less throttle and less rpm in the driving cycle to achieve the same result (because torque is produced earlier in the rpm range). Therefore, less fuel will consumed to achieve the same result. 


Is it dangerous for the engine/does it harm longevity of the engine?

No. If tuned correctly (like how we carry it out here at Ultimate Diesel Tuning), then no it is not dangerous for the engine & it will not harm its longevity. It is totally safe & reliable!


Do any parts of the driveline need to be upgraded for a custom dyno tune?

Only the clutch for SOME manual vehicles, such as the 70 Series Landcruisers, RG Colorados & Hiluxes, because they simply will not be able to handle the gains in torque that we will achieve. We carry clutch upgrades out here at UDT too! But, other than that, no, there are no other components that need upgrading, the factory items are all OK.


What is the difference between a chip & a custom dyno tune?

Custom ECU tuning is far superior to a “chip” solution. Recalibrating the factory engine maps within the software of the factory ecu provides a seamless solution for the vehicle owner, yields the best results and is the most cost effective way to upgrade the performance of their vehicle. 


A “chip” in most cases is simply a voltage manipulator. It alters electrical signals from engine sensors and sends these altered signals to the factory ecu. This is not working within the ecu, rather it is trying to trick the ecu to produce a power increase. This is an outdated solution, made popular when the technology was not available to retune the software in the ecu. It is obsolete by today’s standards and should be avoided.


Apparently, diesel “soot” is an issue. So, what is soot & what does it do to diesel engines?

Most modern diesel engines are fitted with an EGR (Exhaust Gas Recirculation) valve, which redirects exhaust gas back into the intake manifold of the engine (instead of sending it out the exhaust pipe). This exhaust gas contains carbon “soot” and mixes with wet engine oil vapours, creating a tar-like sludge of carbon deposits which quickly cake the inner linings of your intake manifold & intake runners, amongst other parts. This build-up restricts air flow & drastically reduces your engine’s efficiency & performance; contributes to poor fuel economy & actually ultimately can cause engine failure. EVERY engine fitted with an EGR Valve (as a guide – from the year 2005 onwards) will develop this issue, usually from 30,000klms onwards. The engine needs to be cleaned out & free of soot, which will restore your missing power & torque & economy.

What is the cleaning procedure for soot?
We use an on-car “soot cleaning” machine, which we hook up to the engine’s intake manifold. A cleaning solution sprayed at high pressure completely breaks down and dissolves the soot build-up from the front of the inlet manifold all the way to the valves inside the engine, in the direction of airflow which is where it is restrictive. It then dissipates & burns out through the bottom end of the engine & the exhaust as a vapour, so there is no risk of any type of damage to any engine components. The procedure takes 3-4 hours to complete, possibly more, depending on how contaminated the engine is. 

Afterwards, we carry out an engine oil flush plus engine oil and oil filter change, to ensure no contamination of the oil. 

For further information on custom dyno tuning, soot cleaning or anything else common-rail turbo-diesel performance related, give the guys at Ultimate Diesel Tuning a call on 1800034373, email them on or visit their website:

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