Injector 'bar' question
 

Have a 1981 rabbit 1.6L diesel N/A.

Am seeing injectors advertised with different 'bar' numbers, but do not know what that means relative to my engine. 135 bar stands out ... but there are others.

What is the 'bar' rating for my engine; and what does it do if I get higher ... or lower ... rating numbers?

Thanks

The post is a bit old, but maybe this will help...

Bar stands for barometric, or about 1 atmosphere of pressure, 14.5psi

The injectors would be 1960psi and used on a N/A diesel. You can get higher pressure injectors like the 155bar ones for the 1.6l and 1.9l turbodiesel engines.

Michael

I have the detailed manual for this engine just let me know if more infos are needed about the injectors or anything else.
Just make sure to replace the washers (heatshielding)below the injectors anytime you remove the injectors.

x2 bar is pressure. on injectors i believe they are advertising pop pressure, since its a mechanical system not commonrail, the injector opening is controlled by pressure. when the line pressure gets to a certain point, the injector opens. Higher bar = later injection, higher pressure fuel shooting out of the nozzle.

nope- higher bar = more safety reserve against pressure feedback from the combustion chamber.
The high pressure prevents an accidental opening of the injectors and releasing fuel into the combustion chamber.(causing detonation- yes, a diesel can detonate)

Higher bar also means more fuel in the same time. Have in mind injection is time controlled, not fuel amount controlled.
your are also absolutely right with: opening is pressure controlled.

Nope. Higher bar means finer atomization.

Nope. The injection pump is a hydraulic piston, there is no way to increase the injected volume without putting more volume in the pumping chamber.

interesting- you know more than Bosch:

according to Bosch fuel under high pressure is compressible and injection process does not follow any longer static geometric displacement processes.

It's a dynamic process following acoustic laws.

the difference between a n/a VW diesel and a turbocharged engine is an additional increased control sleeve shaft with an increase of 1mm to 9mm to support a higher fuel amount.
The extended duration of the control sleeve around the shaft does also increase fuel amount injection.
(page 506ff)

With simple words: the fuel amount through a hose with 1 psi pressure within 1 minute is the same as the same hose with 2psi pressure within the same time of 1 minute???

now transfer that to a fuel line with 130bar and a fuel line with 150bar.
I doubt that you get the same amount of fuel.

the spray pattern will remain the same...
You need ten times more pressure to get a finer spray pattern(Common rail)

ive heard a mercedes 240 d injector will fit a 1.6 and has a higher pop pressure, any word?