Modding uprating the Fiat Firefly T4 engine!

Modifying and improving: "Firefly T4 Modifications"

How to modify and upgrade the Fiat Firefly T4

"Comprehensive guide to tuning the Fiat Firefly T4 engine!"

Sites like TorqueCars often are getting emails asking about how to improve the Firefly T4 from people inquiring about getting more power from the Firefly T4 and wanting to know what are the things tuners are recommending when it comes to Firefly T4 power upgrades. So let us look into Fiat Firefly T4 tuning mods and outline the best modifications on this great engine and point out some frequent tuning mistakes along the way.

Here we provide a guide to Firefly T4 tuning and show the best modifications. Fiat Firefly T4 are popular tuning projects and with the right upgrades like a remap, turbo kits and camshafts you will really enhance your driving enjoyment.

When talking about the best parts for your Firefly T4 engine, we are going to focus on the tuning parts that give the best value for money.

Firefly T4 induction kits

Improving air intake on the Firefly T4

You need air and fuel for an engine to work. If there is little supply of fuel then it will run lean, if there is too little air it runs rich losing power which risks damage to the Firefly T4. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Pushing air into each cylinder is the whole point to any performance tuning job.

You'll commonly see there is a restriction in the air flow sensor (AFM/MAF/MAP) on the Firefly T4 when considerably more air is being pulled 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.

The intake plenum transmit the during the engines suck phase from the air filter and allow it to be pulled into the engine cylinders.

Structure and rate of flow of the Plenum can make a substantial effect on to fuel mixing and power on the Firefly T4.

I usually find air intake manifolds are in desperate need of performance upgrades, although a few manufacturers provide reasonably well designed air intake manifolds.

Increasing the Firefly T4 valve size, carrying out port work and head flowing will also boost bhp, and importantly will make space for increasing the bhp increase on other upgrades.

Firefly T4 performance cam tips.

Each engine responds better to different cam durations so set your engine up on a rolling road.

The ecu map and fuel pump and injectors also will say much on the power gains you'll get.

Longer valve durations can alter the power 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 Firefly T4 camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

NB: Fast road cams usually increase the bhp and torque over the rpm band, you could sacrifice a little bottom end torque but high end rpm power will be better.

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

On a typical daily driver you need to optimize your power band to your cars usage.

I'd be amazed if you find a Firefly T4 Competition camshaft is a pleasure to live with when driving around busy urban areas.

Stage 1, 2 and 3 mods for the Firefly T4

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 Firefly T4 parts:

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

Stage 2 Firefly T4 parts:

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

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

Stage 3 Firefly T4 parts:

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

The Firefly T4 engines respond well to upgrades and we're finding that there is an increase of upgrades and tuning parts around.

ECU flashing will help fully realize the full potential of all the tuning mods you've done to your Firefly T4.

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 the end result usually vary depending on the tuning mods you've carried out and the condition of your engine.

Turbo modifications on the Firefly T4

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 Firefly T4.

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes significant power gains.

If the engine is turbocharged, tuning parts are going to make more power and you'll see that turbo charged engines are made with better components.

There are reliable limits for every engine, with some being over specified and some only just able to handle stock power

Discover these limits and install higher quality components to utilize the power.

We've seen mechanics spending a loads on turbocharger upgrades on the Firefly T4 only to have the car throw a rod when it's been enthusiastically driven.

Big turbochargers often experience low end lag, and low capacity turbochargers spool up more quickly but do not have the top end engines power gains.

Over the last 20 years the selection of turbo chargers is always increasing and we are seeing variable vane turbo chargers, where the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo chargers divert the exhaust gases into a couple of channels and flow these at differently profiled vanes in the turbo. They also increase the scavenging effect of the engine.

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

Tips about fuel supply on the Firefly T4

When you improve the bhp you will need to pay attention to to the fuelling.

More bhp needs more fuel. It is important to be generous with your injectors flow rate.

The accepted safe increase is to add 15% capacity when specifying an injector, helps cope with injector deterioration and provides a bit of spare capacity should the engine need 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 Firefly T4 performance exhaust upgrades

You only need to to replace your exhaust system with an upgraded one is if the current exhaust is creating a flow problem.

On most factory exhausts you'll see your 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 increase the flow of gases through the engine.

But if the exhaust pipe is too large, ie: over two and a half inches diameter, you will lose much of your flow rate and end up lacking power and torque.

Usual exhaust restrictions come around the catalyst and filters installed, so adding a better flowing sports alternative will help avoid this restriction.

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

Faults issues and things to look out for on the Firefly T4

Like most engines an Firefly T4, 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 Firefly T4, failure to do this will exacerbate engine wear, on a tuned Firefly T4 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 Firefly T4 why not pop over to the forums at TorqueCars where you can chat about Firefly T4 tuning options and read about others projects who may be planning to do similar modifications on their Firefly T4.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We want to know your experiences with tuning parts on your Firefly T4, it helps us improve our tips and keeps us current so please use the comments box to drop a tip.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.

Check out TorqueCars new YouTube channel, and see their awesome new content...


Please use our forums if you wish to ask a tuning question, and please note we do not sell parts or services, we are just an online magazine.

Help us improve, leave a suggestion or tip

Your Constructive comments on this article