Pump replacement from an 81kW TDI engine

Hello,

I want to increase the injection pressure at the injector nozzle on my 1Z TDI engine (using injectors from a 5-cylinder TDI) to counteract the 'sooting.' Since I read somewhere that the fuel injection pumps in the 81 kW TDIs have a higher pressure, shouldn't that also work here? Or not?
What is your opinion on this? Am I mistaken? According to the documentation from a Bosch service center, my standard pump (1Z) delivers slightly more power at approximately 2000 RPM than the 81 kW pump that I once examined. Unfortunately, I can't say whether both of them achieved the same quantity at the same pressure.
Because then I wanted to reduce the turbocharger boost pressure.
Okay, boost pressure is around 1.3 bar, resulting in approximately 130 horsepower.

Okay, to start with the basics: If the injectors and the control unit remain unchanged, but you increase the injection pressure, then it is certain that more fuel will be injected. And injecting more diesel fuel into the combustion chamber inevitably increases the tendency for soot formation.

The only options are to inject less fuel or inject it earlier. If the goal is to inject less fuel, smaller injectors, a smaller pump, or a chip modification could be considered. If you're planning to change the LD anyway, modifying the chip is probably the most sensible option.

PS: Your demands for reduced soot emissions and a lower turbocharger pressure contradict each other, unless you are willing to accept a significant loss of power.

Regards,
Guste is also currently working on a chip and developing future .216 nozzles for the AHU=1Z system.

PS: Your demands for reduced soot emissions and a lower turbocharger pressure contradict each other, unless you are willing to accept a significant loss of power.


Absolutely!

I agree with guste100.

Hi,
First of all, thank you for your opinions.

I think that if two pumps (1Z and AFN) have almost the same flow rate (according to Bosch specifications), the AFN pump can only generate a higher pressure with larger injectors (0.185 for the 1Z and 0.205 for the AFN) if the cam profile in the AFN pump rises more steeply with the same stroke compared to the 1Z pump.

The higher injection pressure can then only be a result of the steeper impeller design of the AFN. In addition, the leak in the AFN pump should be smaller due to the rapidly increasing pressure.

'It's true that a higher pressure also injects a bit more diesel.'
I might join you.

Let's assume I'm swapping the injectors for those from an AFN 205 (previously from a 5-cylinder TDI). To inject the same amount of diesel, the injection duration would have to be slightly longer with the 205 injectors compared to the larger injectors.
Isn't it true that a longer injection duration increases the tendency for soot formation?

I thought about the boost pressure and decided not to run it at 1.3 bar, but rather at 1.1 bar to protect the turbocharger.



Oh, it's gotten a bit long again.