Updated: Jan 9
Tuning companies often use stage 1, stage 2, and stage 3 changes. These stages and changes are sometimes not clearly distinguished or defined.
To explain what modifications and improvements normally go under these different tuning levels, we have created this article.
Stage 1+ and stage 2+ are occasionally used to refer to upgrades or alterations that occur between stages, such as BOVs.
Stage 1 tuning mods are usually inexpensive and can be installed on their own.
Stage 2 tuning mods require additional parts and can be more expensive.
Stage 3 tuning mods are generally motorsport only, expensive, and typically not road legal.
Stage 1+, 2+, etc., are used to describe supporting modifications between main stages.
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In most cases, a stage 1 mod may be installed without the need of any extra parts. A true stage 1 modification item doesn't require any other engine modifications to function properly, aside from perhaps some mounting bolts or clips.
Other changes are not required but might help the modification reach its full potential. They are at the lower end of the tuning range in terms of total benefits. They are often easy to install and less expensive.
Stage 1 changes should function on a standard engine. Stage 1 upgrade examples include a straightforward remap, an induction kit or free-flowing replacement air filter.
Stage 1+ is also used on occasion. These often involve transitional changes from stage 1 to stage 2 or further improvements to a stage 1 remap, such a performance cold air feed, intake ducts, etc.
While stage 2 modifications are normally more expensive and complicated than stage 1 modifications, they usually only result in an increase in power of 20–50% compared to a stage 1 remap (in the case of forced induction vehicles).
However, they nearly always require additional labour or parts if you want them to function reliably or at all.
In stage 2, the following modifications are common.
Sports catalytic converter or de-cat
Larger intake pipes
Additional supporting changes, such as blow off valves, wastegate actuators, larger boost pipes, larger throttle bodies, upgraded camshaft, etc., are often stage 2+ modifications.
Stage 2 or stage 2+ modifications often increase power without changing or introducing forced induction.
The forced induction is often upgraded during stage 3 changes, for example by installing or modifying a turbocharger. Sometimes it may be installing hybrid turbos, upgraded supercharger, or completely changing the forced induction setup.
Additionally, it could refer to other engine changes, but some tuning companies may classify them as stage 4 or stage 5 alterations.
Instead of a fixed horsepower, think of power improvements as percentages. When selling components, the majority of businesses simply provide a peak power increase figure.
Through the whole rpm range, you will never achieve that peak gain. It might be lower at the low end of the rpm with the peak power at the high end of the rpms. With some modifications, we occasionally notice a power decrease at low RPMs.
When tuning a vehicle, you typically increase the power by a certain percentage. So you may not gain power or torque at the low end. Your % will provide more benefits when you are in the peak power range.
If your car is naturally aspirated, you may only gain 5-10% from a tune. It all depends on what engine and vehicle you start out with, a forced induction 2.5L is going to react a lot better to a 1L naturally aspirated engine.
For a forced induction engine you may gain:
15-50% peak power gain for stage 1
an extra 15-30% for stage 2
For stage 3 modifications it depends massively on what changes you make, sometimes you can double or even triple the power output of the engine with the right stage 3 setup.
Additionally, be in aware that some tuning businesses may just package their components in packs with the labels stage 1, 2, and 3, and sometimes even 4 or 5.
Sometimes, removing stage 1 modifications or changing them is necessary before moving on to stage 2, especially a stage 1 remap.
Ensure you remap the vehicle after all modification have been installed, this ensures your car is working correctly with the parts installed.
Although tuning levels and stages follow a similar layout across most tuning companies and part manufactures, it can vary massively.
It also depends on the vehicle being tuned since some stages differ based on the forced induction method or whether the engine is naturally aspirated. Some cars also require certain modifications before others.