Stage 2 Tuning Mods

"All you need to know about taking your car to stage 2"

After people have applied a mod or two to their car they usually want to take things further, and this is what we will explain in this article.

Talking about stages is not that helpful because many people have different ideas on what each stage is, so please read this stage 1, 2 & 3 tuning guide to get an overview of what most tuners mean by the stages.

We assume that you are familiar with stage 1 mods, and have read our stage 1 tuning article.

You will get more from a stage 2 setup if you have done some of the things suggested in stage 1 to address airflow into and out of the engine.

Those mods didn't make much difference to a car until you are starting to push the power levels higher moving to stage 2.

Here is our video on stage 2 tuning mods on our YouTube Channel.

Aims of a stage 2 tune

You really want to get the maximum power from your engine and are looking for more complex mods.

A stage 2 mod, is any part which requires or needs other parts to be fitted.

While you can argue that multiple stage 1 mods could apply we would discount that because each of those mods can be fitted in isolation and will work perfectly well.

Stage 2 mods

So stage 2 mods take us out of the realms of a casual DIYer and move us into a little more skill and knowledge is required.

Mistakes make on stage 2 parts can really be detrimental to your cars performance.

The most common stage 2 tuning parts include

Typical Stage 2 Mods often include:

  1. Fast Road Cam
  2. DPF and Cat Replacement with Higher Flow Rates
  3. High Flow Fuel Injector & Fuel Pump Upgrades
  4. Ported and polished head
  5. Power/Sport Clutch
  6. Lighter Flywheels
  7. Nitrous Kits
  8. Intercooler Upgrades
  9. Remaps
  10. Turbo Upgrades

You'll notice that many of these involved taking things apart and fitting parts inside the engine, which is another common understanding of stage 2 mods, (although this is not always the case).

Nitrous Kits

You might also add a nitrous kit, but this is not legal in most countries and states for road use so would technically come under our classification of a stage 3 mods.

Stage 2 Exhaust Mods

We discussed stage 1 exhaust mods in this article so we will discuss stage 2 mods, so these are exhaust mods that will not just bolt on to the car.

Typically a modern exhaust contains a range of sensors feeding back information to the engine about how efficiently the engine is burning.

When components are removed or altered this can sometimes cause the cars ECU to panic, and go into a limp home mode where power is cut for safety, so a tune/remap is essential to avoid this.

Removing pollution control such as a decat or test pipe or EGR removal or DPF removal would be non road legal stage 3 mods, but you can still replace these items with better flow performance alternatives, and these will typically add power. But usually upset the cars ECU and it will need tweaking to take this mod into account.

A very high flowing exhaust can also affect engine scavenging and cause low-end power loss unless other mods are carried out. The key is always to remove a restriction in the engine, and for some exhausts, you have to add a restriction, by making a lot more power for them to work effectively.

Stage 2 Camshafts

A fast road cam is one of the biggest power gainers you can add to most engines, but they are quite complex, and choosing the wrong profile can wreck an engine and dramatically affect the drivability of your car.

The cam operates the opening and closing of the valves, so it makes sense to make sure the head and intake are flowing correctly and that the fuelling matches the engine's new need thanks to the extra fuel.

You may also need to adjust the tick over or idle speed to prevent stalling, and will almost certainly need to adjust the ignition timing to take into account the new cam profile.

Choosing a performance cam is outside the scope of this article, so please read our more in-depth guide on camshafts.

Ported and Polished Head

The cylinder head is carefully polished and shaped to maximize flow into the engine. This requires the engine to be stripped down, and you should get the head skimmed and fit a good quality gasket and decent head bolts if you are planning to make more power.

Engine timing and fuelling will often need adjusting when the head work has been carried out otherwise you may experience flat spots or power dips.

It also makes sense to have a 3 or 5 angle valve seat to improve the flow around the valves, improve the valves efficiency and to get maximum flow at smaller valve lift points.

Newer engines are much better designed than those I worked with 20 years ago, so thankfully there is often little improvement to be made on some performance engines heads so your efforts are best spend elsewhere.

For more information please see our article on porting and polishing a head

Stage 2 Power/Sport Clutch

I fitted a heavy-duty clutch to my car thinking it would be better but later found out that the stock clutch cable and ancillary components were not strong enough to cope with it and kept breaking.

A decent performance clutch can usually bolt on without too much fuss, but it requires gearbox removal and will not add power on it's own which is why it is regarded by many as a stage 2 mod.

Whilst you are replacing the clutch it makes sense to upgrade the flywheel with most opting for a slightly lighter unit, to give faster changes to engine RPM.

We have covered this more in our feature on performance clutches.

Stage 2 Fuel Upgrades, Injectors & Fuel Pump Upgrades,

Just fitting larger injectors or a better fuel pump will not make any more power, and will usually need some adjustment to the car's computer, or you'll be running rich or lean.

Fuel injectors do not add power, the car will only burn fuel to match the air supply but it's good practice to over specify your injectors so they cope with a power hike and your tuning.

With any tuning project you are aiming to push more air and fuel into the engine so you will find that the stock air and fuel systems usually top out and will get flat spots.

So making sure your fuel delivery is over specified, with most tuners recommending around 20% of spare capacity is the way to go here. This will usually require an upgrade to your fuel pump as OEM fuel pumps often run pretty near to the maximum rate for the OEM injectors.

Without these fuel upgrades, you cannot hope to make large power gains.

Intercooler Upgrades

This is a turbo engine mod, and most manufacturers provide the smallest intercooler they can get away with, so there is often a restriction in both airflow and the intercoolers ability to resist heat soak.

By citing your intercooler to the front of the car it will be much more effective than one located off to one side in the wheel well or elsewhere in the engine bay.

You can read more on intercooler upgrades here.

Nitrous kits

Whilst most nitrous systems are stand alone bolt in parts you need to increase the fuelling and because the nitrous is only periodically used you will need to supply enough fuel to match your nitrous shot.

Nitrous Oxide adds a lot more oxygen to your engine as it burns, allowing you to burn more fuel and make more power.

This on older engines can be fixed with a fuel injector in the intake and most modern engines can have a piggyback ECU to manage fuel delivery during the nitrous shot.

It does make nitrous a fairly complex mod, and we should point out that even though Nitrous is popular in some circles it is generally not a road legal modification in most countries and states.

For example it is banned because you'd be carrying an explosion risk around with you, or where only one fuel type is permitted it will technically fall outside of this rule as it is another fuel type.

Because nitrous oxide is a very explosive gas it should only be fitted by a competent person, failure to correctly install a nitrous system can prove catastrophic.

Lighter Flywheels

The flywheel stored rotational kinetic energy and resists changes in engine speed. So a lighter flywheel will make the engine rev more freely and it will feel more sporty, plus you have the added benefit of cutting out weight from your engine.

If you have a fast road camshaft you need to weigh up your flywheel options carefully but most cars will benefit from a small weight reduction and this will enhance your enjoyment of the car.

Very light flywheels can cause running problems so may need you to adjust your idle, and on some engines they are just not suitable, so read our flywheel guide for more in depth advice and tips on the pros and cons of this upgrade.

Stage 2 Remaps

A tune/remap was our no 1 mod in the stage 1 category, but it really comes into it's own when you take a stage 2 approach and add other mods.

Whereas stage 1 engine tuning/remapping just takes you power level to the best it can be with OEM part by cutting down the margin of error that manufacturers build in a stage 2 allows you to push past this boundary.

By using higher quality part, stronger components, a better flowing turbo and tightening up the fuel supply and spark you can really make significant power gains.

When you exceed your OEM map power levels by 30% you start hitting restrictions in the intake and exhaust and stage 2 allows you to remove these restrictions.

Depending on your car and the mods you choose you can see power gains of 50% or more when combining mods to achieve a stage 2 tune.

Stage 2 Turbo Upgrades

Very few cars will happily cope with a turbo being bolted on, or a larger turbo fitted. At the very least you'll need to ensure the mapping is set up correctly for this to work.

A larger turbo will require new pipework and other mods to physically attach it, and the car will also need a map adjustment and fuel upgrades for this to make more power.

We've seen turbo upgrades with other supporting mods adding 100% more power so this really is one of the biggest power gains you can make on a turbo engine second only to a remap.

Typically when you have a power gain of 40% you'll run into many other issues around the intake, fuelling and exhaust which will all need to be addressed if you want to get the most power from your car.

When you choose a turbocharger or supercharger there are lots of things to take into account, so thankfully we have covered this in our forced induction upgrades section.

When Does Stage 2 Become Stage 3?

Most people regard stage 3 as off road, motorsport only or competition mods only. They are usually not road legal or would be impractical to use on a road due to their nature.

While some stage 2 mods can be regarded as off road only, they do not necessarily make the car impossible to drive to slow stop-start traffic or over bumpy road surfaces.

If your track times are important to you and the car will only be used off road, then it makes sense to jump straight in at stage 3 tuning.

We will cover stage 3 mods in a future article if there is enough demand for it, please let us know in the comments below if this would interest you and please also let us know what mods you've done to your or if you feel we have missed any information out in this article, we are all here to learn and share what we know.

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