Common Rail vs. TDI: Which is Better?

Hello,
I have a simple question! The turbocharger on my Alfa 156 2.4 JTD (Garrett) operates with a boost pressure of 0.68 bar. Now, I've read that the turbochargers on TDI PD engines operate with pressures of 1.3 or 1.5 bar (130 hp/150 hp)? Why such a big difference?
'During the OBD-II engine optimization, my boost pressure was increased to 0.88 bar, which I still find very low (of course, it always has to be in line with the fuel injection amount and duration, etc., because simply increasing boost pressure alone won't increase power).'
Regards .
Monchi.

Hello,

What is the horsepower of your 2.4L engine? Of course, a larger displacement requires less boost pressure to achieve the same power output.
"But even a series with just 0.7 bar seems a bit low to me... how do you arrive at your measurement(s)?"

Best regards, Rainer.

.......the information comes from the unreliable tuner (www.rdi-motorsport.com). My car had 136 horsepower and 304 Nm of torque before the OBD-II tuning, and supposedly now has 171 horsepower and 374 Nm of torque.........our VW specialist, Krogel Motorsport (www.kwl-motorsport.com), has a dynamometer, so I'll get it tested there !!!!!.........but I actually want to sell this car and buy a brand new Ibiza TDI Sport PD with 96 kW !!!!!!
CU
Monchi.

MONCHI wrote:

The information comes from the unreliable tuner (www.rdi-motorsport.com); my vehicle had 136 horsepower and 304 Nm of torque before the OBD-II tuning

.

Hello,

die 136 PS sollten ok gehen bei CR, 2,4l und 0,7 bar, aber niemals 300Nm. Perhaps 260...
The issue with turbo boost pressure is a matter of design and specifications. If Alfa builds a 2.4-liter engine and wants to target the market in the 100 kW range, then 0.7 bar is sufficient, as Rainer already mentioned. VW, on the other hand, uses a 1.9-liter engine and therefore needs to boost it more. This initially has nothing to do with the different fuel injection systems (common rail/pump injector). However, there's a limit where higher turbo boost pressure becomes impractical because the corresponding amount of fuel cannot be injected quickly enough. The limiting factor here is the injection pressure, and in that regard, pump injectors (PD) currently have an advantage.

Best regards, Uli.

Okay, so the standard values for all Alfa 156 2.4 JTD engines produced between 1998 and 2000 are 136 horsepower and 304 Nm of torque. You can find this information everywhere (260 Nm would be almost as low as a 1.9 AFN TDI).
...the new 2.4 JTD 20V will have 370 Nm of torque and 175 horsepower as standard!! I just can't find any information anywhere about the turbo boost pressure.
CU
Monchi.