Now that the Alfa Giulia and Stelvio have been on the market for a number of years, it was inevitable that turbo upgrades are being developed. But turbo technology is not easy. It takes a lot of knowledge and experience to get at a well-functioning product. JTD Performance from the Netherlands, is a small company that has focused on the phenomenon of “Turbo upgrades”. Which started developing for Alfa Romeo JTD(m) models in particular (hence the company name).

However the development of turbo upgrades for petrol engines is of course inevitable. That is precisely why an upgrade for the Giulia/Stelvio 2.0T engine was recently added. JTD Performance has asked us to develop suitable software tuning for this upgrade.
The trick is to find the right balance between turbo pressure and ignition behavior. The inlet temperature and fuel quality are of great importance.
Our Performance Logger SD has proven to be a very important aid in the development of this software. The Performance Logger SD makes it possible to measure and store all important engine parameters 4 times per second on an SD memory card. And all of this under “real live” conditions, (i.e, on the road).

The Performance Logger measures, among other things, the engine speed, the air mass, the ignition advance, the intake temperature before and after the intercooler, the cooling water temperature, the mixture ratio, but in particular the torque and power are also measured.

The last step in the development was a test on the dynamometer. Purely to check the torque and power results of the Performance Logger. The comparison between them was nearly the same.

The turbo is designed for about 370 hp. That is, the turbo is capable of pumping air to produce 370 horsepower. The engine must be able to handle that air and mix it properly with gasoline, ignite and then exhale. An important restriction in breathing is the exhaust and especially the catalytic converter. A “low resistance” catalytic converter is almost mandatory for this setup. Otherwise the back pressure behind the turbo will be too high. These catalysts are also called 200-cell or race-cats.

The graph above shows a result from about 380 hp. Thanks to the low outside temperature (0 C/32 F) the intake temperature after the intercooler is about 20 C/68 F. This results in more compressed air and therefor more power. The low temperature also resolves in a more stable ignition timing which also results in more power.

The torque and power values on the Performance Logger show values between 360 and 385 horsepower. The main influencing factor is the inlet temperature. The best power is measured in freezing weather. In 20-22 *C/68-71* F degrees, spring-like weather we see about 360 hp. Via the power bank measurement we arrived at 505+ Nm/372.5 ft-lb and 365 hp corrected DIN power. The measurement is corrected to standard values for outside temperature (20?C/68?F), outside air pressure (1013 mBar/14.69psi) and air humidity (55%).

The turbo pressure is set in the max torque range to a maximum of 3.0 bar(43.51psi), at maximum power we lower the turbo pressure to about 2850 mBar (41.33psi). The rev limiter has been raised to 6500 RPM because top power is on average around 5900 RPM. The speed limit of 6500 RPM only works when manual shifting is selected. With automatic gear shifting, the gear changes automatically only reach 6000 rpm.

At very low revs, the engine has become slightly less powerful. That makes sense. The compressor wheel is slightly larger so that it starts building up pressure a little later. In practice, there is hardly any noticeable turbo gap.

How to order

The upgraded turbocharger can be ordered through JTD Performance or at one of it’s resellers. The engine management software is provided by us directly in our workshop, via a reseller or by using our Powergate OBD flash tool.

Direct link to the JTD Performance website page: https://jtd-performance.com/en/product/upgrade-turbo-giulia-stelvio-2-0-t-2/

Optional: ZF8HP gearbox tuning

From February 2023 we are able to adapt the gearbox to our wishes. Basically, ZF8HP gearbox tuning.
We focus on shift moments in all DNA positions and eliminating inconveniences. Everything aimed for more driving fun & pleasure.