For the avoidance of doubt, there is no official definition of what different stages mean – it’s typically marketing jargon that companies like us over the years have come up with to try and give customers a general idea of what modifications they’d need to take their car further than just a software remap.
ECU Remapping – What Is It?
It’s first important to understand the actual definition of ECU remapping. ECU remapping, in short, is the reprogramming of a vehicles ECU. It’s that simple. Whether we talk about various stages of remapping or not, the ‘remapping’ process is always the same: download the ECU’s data, manipulate it, upload and overwrite the new software version to the ECU. Whether we look at a ‘stage 1’ or ‘stage 2’ remap, the tuners job and processes during the remapping part of the tune, are ultimately the same, it’s just that the goalposts can move slightly.
Why Do Stages Exist?
You can only take an engine so far. What we mean by this is that you can only push stock components to a certain level of output before limitations in the factory parts are hit. For example, a stock turbo on a made-up car may be capable of 2 bar of boost pressure. However, if the stock injectors cannot deliver enough fuel to safely mix with 2 bar of boost pressure, a tuner may cap boost pressure at 1.6bar. In this example, the injectors are a limiting factor.
Stages exist to give a rough idea of what kinds of changes (vehicle modifications) need to be made due to limiting factors in a drivetrain. Anything past a ‘stage 1 remap’ will require physical modifications to be made to the drivetrain.
It is worth noting that what is required for different stages does ultimately depend on what the limiting factor is for the previous stage but this is all vehicle dependant. Whilst this is not a 100% accurate depiction of what each stage means for EVERY car, we’ve generalised, below, what each stage would typically refer to in most cases.
Stage 1 Tune
Typically, when people talk about ‘ECU remapping‘, they are usually referring to what is also known as a ‘stage 1 tune’. This is effectively modifying only the factory software on the vehicle’s ECU.
Stage 2 Tune
A stage 2 tune usually refers to ‘breathing modifications’ being factored into the equation when remapping. In this example, the following upgrades are generally what we could consider as breathing mods:
- High-flow or catless downpipe
- No GPF/PPF/OPF
- Uprated intake kit
- Uprated intercooler or chargecooler
Stage 2 remapping, along with the physical modifications can usually see anywhere from another 20-60bhp on top of what a stage 1 tune would provide.
Often, the first limiting factor on a stage 1 tune for most cars is exhaust flow or exhaust gas temperatures. These are both affected by factory exhaust and emissions systems. Uprating the intake and intercooler allows for cleaner, cooler air (which is more dense) to enter the, maximising the amount of fuel that can be safely combusted.
As mentioned, this is not a definitive list of mods required. If we look at the B58 engine, for example, we would not need to uprate cooling for stage 2. We would, however, recommend upgrading the factory charge pipes (a relatively inexpensive modification) because the stock components are prone to failure after tuning. We can also offer a ‘stage 2+’ solution which is for B58 equipped vehicles with the upgraded TU fuel pump. This is called a stage 2 ‘+’ because this modification wouldn’t really be worthy of the ‘stage 3’ name but the limiting factor at stage 2 is the high-presssure fuel pump.
If we then look at the 3.0TFSI supercharged engine in the B8 Audi S5, some companies would have a stage 2+ solution if the vehicle was equipped with an upgraded supercharger pulley whereas some would only offer a stage 2 solution if the pulley had been done.
Stage 3 Tune
A stage 3 tune almost always refers to a remap applied to a vehicle with the aforementioned breathing mods AND an uprated turbocharger, usually a hybrid turbo.
Companies like TTE, Pure and others, will develop uprated hybrid turbochargers for certain vehicles. These turbochargers will normally maximise what a stock engine can handle, without needing to forge internals or make other drastic changes to the engine or gearbox.
A hyrbid turbocharger is a unit that uses the factory turbo externals/casing and has larger internals to allow for even more charged air to be generated.
If we take the 2.5 lump found in the RS3, a TTE 777 hybrid turbocharger can provide enough air for the engine to produce over 450bhp (depending on fuel) more than the standard car, a whopping total of 850bhp just from a hybrid turbocharger and stage 2 mods.
Taking A Car Further
It doesn’t stop there, either. If people have ambitions for more power than what stage 3 offers for their car, people often opt for ‘big turbo’ upgrades rather than just a hybrid turbo. This is a completely different unit and often doesn’t use any of the stock components found in the factory turbo.
Naturally, this can mean a lot more work is required to get the most out of the big turbo such as installing forged pistons and connecting rods, making custom exhaust manifolds and potentially uprating gearbox components.
This level of tuning typically isn’t referred to in stages but I suppose one could consider this as ‘stage 4’.
There you have it, a rough idea of what the tuning community means by various stages of tuning. At Phantom Tuning, we can provide the software remapping for all stages of tuning. We don’t currently offer any mechanical work on-site at either of our branches, so you would need to look to have physical modifications done prior to arrival if you’ve booked in a stage 2 or custom tuning session with us. However, if you’re not sure who to go to, we can always recommend local firms that we trust to fit any parts you need.
Remember, if you want to book a tuning session with us, you can do this by entering your reg here and following the steps. As always, if you have any questions, feel free to call us, send us a message on our contact page or message us on our socials.