MENUTuning the Fiat TwinAir
"Comprehensive guide to tuning the Fiat TwinAir engine!"
We are frequently seeing threads inquiring about getting more power from the TwinAir and wanting to know what are the best tips for TwinAir modifications. So let us look into Fiat TwinAir mods and outline the best mods that work on this great engine and point out some potential pitfalls along the way.
We shall review TwinAir tuning and summarise the best upgrades. Fiat TwinAir are fantastic to work on and with the optimum tuning modifications like remaps, turbo kits and camshafts you will maximise your driving pleasure.
Just because particular upgrades are are common on TwinAir it doesn't mean it is good, we shall ultimate upgrades that will give your TwinAir the biggest power gain return for your cash.
Altering your TwinAir camshaft will make a dramatic difference to the engine power band. Choosing a higher performance camshaft profile raises the power band accordingly.
NB: Fast road camshafts commonly raise the power throughout the rev range, you might lose a little low down bhp but your higher rpm power will be lifted.
Motorsport camshafts, raise the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.
A Motorsport and race camshaft will just annoy you whilst driving around busy urban areas.
You should ideally optimize your power band to your usage of the car so for a road car stick with a shorter duration TwinAir camshaft
Each engine responds better to more or less aggressive cam durations than others.
The map and fuelling also have a large bearing on the torque gains you'll make.
Extending exhaust or intake durations can alter the torque band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.
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Guide to the best TwinAir tuning mods & Upgrades
- ECU Map Tuning & Remaps
Some cars may require a piggyback ECU's or aftermarket ECU's to change the OEM map, but remapping is the most vital step of your tuning project to fully maximise your mods. Expect 10-20% on NASP engines and 30-40% on turbocharged units.
- Strengthen Your Engine
Tuned cars will show up weaknesses, typically in the turbochargers, clutch and internal engine components. Whilst most engines can cope with mild tuning mods, TorqueCars recommend that you upgrade the internal components before these weak spots manifest themselves.
- Mods that Remove a Restriction
A restricted intake or exhaust will have an impact on your performance, so use a better flowing air filter/induction kit and better flowing exhaust (sports cats where legal are a good option) whenever your tuning creates a flow restriction. Turbo engines also benefit from intercooler upgrades as these resist heat soak for longer periods of time.
- Mods that Improve Fuelling
Every tuning project will aim to increase the air supply, but fuel supply is just as vital and will need to match the air the engine can utilise, a fuel pump and injector upgrade are usual mods, but also in many cases the fuel regulator will need improvement.
- Mods to Provide better Airflow
Increasing the air supply is just as essential as improving fuelling, we suggest you look at head mods (flowing and porting, 5 angle valve jobs), fit bigger valves, fast road cams and forced induction upgrades (adding a better flowing turbo) to improve air intake.
TwinAir Tuning Stages
Stage 1 TwinAir modifications: Sports exhaust manifold, Panel air filters, Remaps/piggy back ECU, Fast road camshaft, Drilled & smoothed airbox, Intake headers.
Stage 2 TwinAir modifications: fuel pump upgrades, induction kit, high flow fuel injectors, Fast road cam, Sports catalyst & performance exhaust, Ported and polished head.
Stage 3 TwinAir modifications: Twin charging conversions, Internal engine upgrades (head flowing porting/bigger valves), Engine balancing & blueprinting, Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Competition cam.
A remap helps unlock the full potential of all the upgrades you've done to your TwinAir.
It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but power output will depend much on the upgrades you've done and the condition of your engine.
Pulling fuel and air into the TwinAir engine is the main goal to any tuning task.
Intake headers take the air from the filter and allow it to be sucked into the engine cylinders.
Design and flow rate of the Intake can make a large improvement to fuel atomisation and engine efficiency on the TwinAir.
We often see intake manifold are in desperate need of aftermarket tuning parts, although some makers provide well optimised intake manifold.
Big valve conversions on the TwinAir, doing some 3 or 5 angle valve jobs and porting and head flowing will also lift bhp, this will allow you to get a better bhp increase on other tuning parts.
Turbo upgrades for the TwinAir
NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your TwinAir
The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes superb power gains.
When an engine is fitted with a turbocharger modifications are relatively easy and turbo charged engines will have harder and stronger components.
However most engines will have power limits
Research these limitations and upgrade to better pistons and crank to handle the power.
We see many people spending a fortune on turbocharger upgrades on the TwinAir only to watch the car throw a rod when it's used in anger.
Larger capacity turbochargers tend to suffer a bottom end lag, and little turbochargers spool up much more quickly but won't have the peak end bhp gains.
Thankfully the selection of turbos is always improving and we commonly find variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end bhp.
Twin scroll turbos divert the exhaust flow into 2 channels and push these at differently profiled vanes in the turbo. They also improve the scavenging effect of the engine.
It is common that there is a limitation in the air flow sensor MAP/MAF/AFM on the TwinAir when a lot more air is being drawn into the engine.
You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp and torque at a much lower level.
Adding a supercharger or additional turbo will make large power gains, although more complex to get working. We have this in depth look at twinchargers if you want to read more.
Uprating TwinAir fuel injectors
Don't omit to ramp up the fuelling when you are increasing the power - it makes the car more thirsty. 
It is important to over specify your injector capacity.
The accepted safe increase is to add another 20% when buying an injector, which takes into account injector deterioration and allows you some spare capacity should the engine need more fuel.
We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.
Best TwinAir performance exhausts
Only look to boost your exhaust if your exhaust is actually creating a restriction.
On most factory exhausts you'll find the exhaust flow rate is still fine even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.
Sports exhausts increase the flow of air through the engine.
But if the exhaust pipe is too large, ie: it's over 2.5 inches bore, you will lose a lot of your flow rate and end up sapping power and torque.
Typically exhaust restrictions are in the catalyst installed, so adding a better flowing sports alternative will help avoid this restriction.
Problems and issues to look out for on the TwinAir
The TwinAir engines, if regularly serviced and maintained, are generally very reliable and have few issues.
Regular oil changes are vital on the TwinAir, particularly when the engine has been modified and is putting down more power than the manufacturer intended.
For more information on Tuning your TwinAir engine please join us in our friendly forum where you can discuss tuning options in more detail with our TwinAir owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.
We need your help to complete and improve this page, so do give us your feedback in the comments box below.
We really like hearing from our readers, and hearing about which tuning parts were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our TwinAir guides and tips are kept up to date.
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