Modding upgrading and tuning the Fiat TwinAir engine!

All you need to know about "TwinAir Modifications"

TwinAir Modifications Guide

How to modify and upgrade the Fiat TwinAir

"Comprehensive guide to performance tuning the Fiat TwinAir engine!"

Our friends at TorqueCars often are getting emails asking how to improve the TwinAir from people wanting to know what are the premier TwinAir upgrades. So let us look into Fiat TwinAir modifications and outline the best modifications on this great engine and point out some problems along the way.

The Fiat TwinAir really good project engines and with the ultimate tuning parts like remaps, turbo kits and camshafts you will greatly maximize your driving opportunities.

In this article we consider TwinAir tuning and highlight the premier upgrades.

The ultimate TwinAir mods on an engine are obviously the ones that give the best gains for your money.

We won't be swayed by popular TwinAir mods, they need to be cost effective.

TwinAir induction kits

Improving air intake on the TwinAir

You need air and fuel for an engine to work. If there is not enough fuel then it will run lean, if there is too little air it runs rich losing power . We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the whole point to any engine tuning project to force fuel and air into your TwinAir but this has a knock on effect with the air flow sensor.

It is not unusual that there is a limitation in the air flow sensor MAP/MAF/AFM on the TwinAir when loads more air is being sucked into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped torque at a much lower level.

Intake manifolds take the air during the suck phase from the air filter and allow it to be pulled into the engine cylinders with fuel for the squish phase.

Structure and rate of flow of the air Intake manifold can make a large effect on to fuel engine efficiency on the TwinAir.

We often see intake are improved through an upgrade, although some manufacturers provide well optimised intake.

Increasing the TwinAir valve size, doing a bit of port work and head flowing will also lift bhp and torque, & more importantly will give you a greater bhp and torque increase on other parts.

TwinAir performance cam tips.

Each engine responds better to extreme camshaft durations than others.

The ecu map and fuelling also will say much on the torque gains you'll get.

Altering valve 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.

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 cams commonly bump the bhp across the rev band, you may sacrifice a little low down bhp but higher rpm power will be higher.

Motorsport cams, bump the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

In a road car you should ideally to match your power band to your driving style.

You'll never have ever thought a TwinAir Race cam is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the TwinAir

Stage 1 TwinAir parts:

Intake headers, Remaps/piggy back ECU, Sports exhaust manifold, Drilled & smoothed airbox, Panel air filters, Fast road camshaft.

Stage 2 TwinAir parts:

induction kit, high flow fuel injectors, Ported and polished head, fuel pump upgrades, Fast road cam, Sports catalyst & performance exhaust.

Stage 3 TwinAir parts:

Competition cam, Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger), Twin charging conversions, Crank and Piston upgrades to alter compression.

Carefully think through your options and then find your upgrades and set yourself a power target to avoid wasting your time and money.

Mapping allows a tuner to fully realize the full potential of all the tuning parts you've done to your TwinAir.

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but power output often depend much on the tuning parts you've carried out and the condition of your engine.

Turbo modifications on the TwinAir

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the 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 impressive power gains.

When your car is fitted with a turbo mods are more reliable and most turbocharged engines use stronger components.

However you'll find engines will have power limits

We recommend you find these restrictions and fit better pistons and crank to survive the power.

We see many mechanics spending a a stack of money on turbo upgrades on the TwinAir only to see the car catastrophically fail when it's used on the roads.

Larger turbochargers tend to suffer a bottom end lag, and low capacity turbochargers spool up really quickly but do not have the peak rpm torque gains.

In recent times the market of turbos is always moving on and we commonly find variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbos divert the exhaust gases into 2 channels and flow these at differently profiled vanes in the turbo charger. They also boost the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large torque gains, although more complex to get working. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the TwinAir

Don't forget to ramp up the fuel delivery when you are increasing the performance - it makes the car more thirsty. Experienced mechanics will tell you to be generous with your injectors flow rate.

The accepted safe increase is to add 15% capacity when fitting an injector, which takes into account injector deterioration and affords some spare capacity should the engine require more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended TwinAir performance exhaust upgrades

You only need to to uprate your exhaust system with an upgraded one is if the current exhaust is actually causing a restriction in flow.

On most factory exhausts you'll see the exhaust flow rate is still ok even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Sports exhausts will certainly help air flow from the engine but avoid an exhaust that is too large or you could will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

Typically exhaust restrictions are traced to the filters installed, so adding a freer flowing sports alternative will help avoid this restriction.

Decat pipes (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the TwinAir

Like most engines an TwinAir, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the TwinAir, failure to do this will exacerbate engine wear, on a tuned TwinAir this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your TwinAir why not pop over to the forums at TorqueCars where you can chat about TwinAir tuning options and read about others projects who may be planning to do similar modifications on their TwinAir.

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