How far can we push the 2.0L turbo engine in the’Alfa Romeo Giulia ? While the Veloce version produces 280 ch as standard, some tuners are determined to prove that this Italian four-cylinder engine still has plenty of room for improvement. In the Netherlands, JTD-Performance has just taken things a step further by announcing 412 HP. And the most interesting part is how this power was achieved.
From 280 to 365 HP : an impressive first upgrade
It all starts with a stock Alfa Romeo Giulia Veloce 2.0 Turbo. The Dutch tuning firm JTD-Performance first performs an electronic remap in collaboration with Squadra Tuning. The result: approximately 310 HP and 470 Nm of torque. This is a relatively well-known modification among owners.
But the team doesn’t plan to stop there. They then install a 2263 hybrid turbocharger, an additional heat exchanger to improve cooling, a downpipe with a 200-cell catalytic converter, and a Ragazzon exhaust system with a rear silencer featuring valves. New engine and transmission mapping then allows the car to reach approximately 365 HP and 490 Nm. That’s already a respectable amount of power for this four-cylinder engine, but JTD-Performance wants to go further. The problem: like many other tuning firms, the company has hit a ceiling of around 360 to 370 HP.
The secret behind the 412 HP lay in the turbocharger
To understand what is limiting power output, JTD-Performance equips its Giulia with several sensors and measuring instruments supplied by the American specialist Banks Power. This equipment allows the team to analyze exhaust gas temperatures and pressures to identify factors that are limiting engine performance, as well as a data acquisition system from Squadra Tuning.
The results indicate a backpressure problem in the exhaust system. The hybrid twin-scroll turbocharger (twin-scroll) generates excessive pressure upstream of the turbine, which impairs the engine's performance at high RPMs. The tuner then decides to completely replace the turbo with a larger, single-scroll model (single-scroll).
And the results are immediate! Without even modifying the engine mapping, the pressure at the turbine inlet decreases by about 0.5 bar, and power increases by about 40 chevaux. The measurements also show a 13.6 percentage point improvement in the cylinder scavenging ratio, allowing the engine to expel exhaust gases more efficiently. Result: 412 HP, which is 132 HP more than the original Giulia Veloce!
A Giulia that revs up to 6,600 rpm
This new configuration also changes the engine’s character. Torque now kicks in about 500 rpm later, but unlike the previous setup, power no longer drops off at high RPMs. It continues to climb, reaching 412 HP at around 6,300 rpm, and remains above 400 HP up to 6,600 rpm, the redline at which the rev limiter has been set. A few days before unveiling these results, JTD-Performance had also posted an impressive video showing its Giulia accelerating, notably up to 200 km/h.
And now, the goal is 420 HP!
This isn't the first four-cylinder Giulia to break the 400 HP barrier. We had previously featured a British racing Giulia, for example. with 430 HP, as well as a American preparation equipped with a large turbocharger.
But JTD-Performance's work is particularly interesting because of its technical approach and the wealth of data it shares. And the story isn't over yet. The tuner believes that certain elements can still be optimized and is now aiming to 420 HP. This brings the Giulia Veloce a step closer to the performance of its big sister, the Quadrifoglio, which boasts 510 HP from its twin-turbo V6!
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And then there are guys like me who are struggling to find original vehicles 🙄