Alfa Romeo JTS Tuning

"All you need to know about tuning and performance parts on the Alfa Romeo JTS engine!"

TorqueCars will review and look at JTS tuning and outline the premier modifications. Alfa Romeo JTS great bases for a tuning project and with the right performance modifications like a remap, turbo improvements and camshafts you will positively maximise your driving pleasure.

We provide a guide to JTS tuning and summarise the ultimate modifications. Alfa Romeo JTS make awesome project engines and with carefully chosen modified upgrades like ECU maps, turbo improvements and camshafts you will definitely improve your driving opportunities.

History, Power & Specs of the Engine

This engine came as a straight for and V6 configuration and  interestingly JTS stands for Jet Thrust Stoichiometric, which is Alfa's version of direct injection. It was based on the twin spark and offered quite a bit more power across the rev range.

1.9 L (1,859 cc) 2005–2011 158 hp) @ 6500 rpm 140 lbft) @ 4500 rpm

Alfa Romeo 159

2.0 L (1,970 cc) 162 hp @ 6400 rpm 152 lbft@ 3250 rpm

  • 2002-2005 Alfa Romeo 156
  • 2003-2004 Alfa Romeo Spider & GTV
  • 2004–2010 Alfa Romeo GT

2.2 L (2,198 cc) 182 hp @ 6500 rpm 170 lbft@ 4500 rpm (Based on the Ecotec block.)

3.2 L (3,195 cc) 256 hp at 6200 rpm  237 lbft at 3800 rpm (Based on the GM high feature engine and modified by Alfa)

Tuning the Alfa Romeo JTS and best JTS performance parts.

Best JTS parts

Just because particular upgrades are appear in lots of JTS projects it doesn't mean it is good, we shall best upgrades that will give your JTS the best value for money to power increase.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large power band gains are on offer for cam upgrades.

Fast road cams normally bump the bhp through the rpm band, you may sacrifice a little low end bhp but the higher rpm power will be lifted.

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

A Competition cam will just annoy you whilst driving in heavy traffic.

You should ideally match your engines power to your usage of the car so for a car driven daily stick with a shorter duration JTS cam

Different JTS engines respond better to mild cam durations so set your engine up on a rolling road.

The map and injectors and fuel pump also have a large bearing on the bhp gains you'll make.

Longer valve durations can alter the bhp 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.

Typical stage 1 mods often include: Fast road camshaft, drilled & smoothed airbox, Sports exhaust manifold, Remaps/piggy back ECU, Panel air filters, Intake headers.

Typical stage 2 mods often include: high flow fuel injectors, fuel pump upgrades, induction kit, Fast road cam, Ported and polished head, Sports catalyst & performance exhaust.

Typical stage 3 mods often include: Crank and Piston upgrades to alter compression, Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Competition cam, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions.

Carefully think through your options and then buy your tuning mods and set yourself a power target to save yourself from expensive mistakes.

ECU flashing should help to establish the full potential of all the tuning parts you've fitted to your JTS.

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but power output may differs on the tuning parts you've carried out and the condition of your engine.

Pushing fuel and air into the JTS engine is the main goal to any engine performance tuning task.

Intake manifold carry the air from the filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.

Shape and rate of flow of the Intake headers can make a substantial effect on to fuel mixing and power on the JTS.

It's not uncommon that intake manifold are in dire need of a performance upgrade, although a few makers provide well optimised intake manifold.

Larger JTS performance intake, exhaust valves, and doing a bit of port matching and head flowing will also improve performance, the fantastic side effect is it will give you increasing the performance increase on other tuning mods.

Turbo upgrades

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 JTS

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.

We see many people spending a lots of money on turbo upgrades on the JTS only to suffer the humiliation of seeing the engine block explode soon after it's finished.

Larger turbos often experience a bottom end lag, and low capacity turbos spool up much more quickly but won't have the high rpm torque gains.

Thankfully the market of turbochargers is always moving on and we are seeing variable vane turbochargers, where the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbochargers divert the exhaust gases into a couple of channels and direct these at differently designed vanes in the turbo. They also improve the scavenging effect of the engine.

It is not unusual that there is a restriction in the air flow sensor MAP/MAF/AFM on these engines when loads 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 limited torque at a much lower level.

Adding a supercharger or additional turbo will make large power gains, although more challenging to get working. We have this guide to twinchargers if you want to read more.


You will need to ensure that the engine is not starved of fuel so need to look at the fuelling when you start extending past 20% of a bhp and torque increase.It makes sense to be generous with your flow rate on the injectors.

The rule of thumb is to add 20% capacity when specifying an injector, which takes into account injector deterioration and gives 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.

All the following flywheel power targets will assume an injector duty cycle of 80% and a base of 58psi of fuel pressure at idle.

4 Cylinder NASP engines

  • 58 PSI 285cc/min 200hp
  • 58 PSI 426cc/min 300hp
  • 58 PSI 568cc/min 400hp


You may need to uprate your exhaust if the existing exhaust is actually creating a restriction in flow.

On most factory exhausts you'll see your flow rate is still ok even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Please dont run with the largest exhaust you can find this will slow the exhaust rate - the best for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Typically exhaust restrictions come around the catalyst installed, so adding a better flowing high performance aftermarket one will improve air flow, and rather than doing an illegal decat, will keep the car road legal.

Weak spots Issues & problem areas on the JTS

The JTS engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

Regular oil changes are vital on the JTS, especially when tuned and will help extend the life and reliability of the engine.

If you would like to know more, or just get some friendly advice on Tuning your JTS engine please join us in our friendly forum where you can discuss tuning options in more detail with our worldwide members, or read our tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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