I think I read somewhere one time that fuel pressure can advance timing but I can't find that info now. Is that right or am I having a brain fart again?

 

I think thats how the KSB works, here is a link to a description on what it does to allow the fuel through and advance timing.

http://www.appropedia.org/Bosch_VE


A solenoid is activated ..... While the valve is held open the transfer pump pressure regulation valve is overridden allowing higher pressure to be made within the pump housing. These higher pressures provide a 5 degree advance that reduces with engine speed.

 

I still don't quite understand does is change the pressure in the injector lines? The uestion I am trying to answer is does inlet fuel pressure alter the pump timing?

 

I thought that link had more detail, I will look for the site that had a better explanation on how the pump pressure was increased with the regulator bypass, I had it saved but then my laptop was stolen so I lost all my links. try this one instead, it has more explanation on how the pump works.http://mebonty.monobasin.net/vepump.html

If I understand it correctly, its the case pressure inside the injection pump that adjusts the timing. There is a pressure regulator in there so I would think that just increasing the inlet supply would not make any difference as the internal regulator would bleed it off. I believe the ksb overrides this regulator and increases case pressure to advance timing with the pump internal mechanisms.

"Timing: The timing is adjusted in response to engine RPM. At higher RPM s, the fuel pressure from the vane transfer pump is higher. Pressure changes effects a spring loaded plunger, and the resulting movement will move the cam rollers to either advance or retard the timing. There is also a cold start device which advances the idle timing manually"

This is just some stuff ive read, hopefully someone else will give you better direction later on.

 

To the best of my knowledge and understanding the answer to your question is no.

What are you trying to achieve?

 

Yes, increased inlet pressure does increase timing. As explained, the KSP increases case pressure which in turn exerts more force on the timing piston causing advance. Increasing inlet pressure has a similar effect by also increasing case pressure, but not as much. The way to correct for it is to use a stiffer spring behind the KSB.

 

Well i stand corrected. I would not have thought inlet pressure would directly increase case pressure.

 

I am only asking because I have a fass and it is set at 15 psi. I thought I read that fuel pressure affected timing somewhere a long time ago but my memory is bad. I was just wondering if my fuel pressure was affecting my timing.

 

I can not say for sure that increasing the injection pump inlet pressure over the 15psi will advance your timing, but i do know if you have a low fuel pressure supply and larger injectors your timing will be retarded due to a lack of case pressure.

 

dont think that would be a problem, isnt that what they are setting the regulator at for the high pressure piston lift pumps from a second gen? the only thing ive heard on supply pressure is popping the front seal out. I figured you where going the other way and trying to find a way to advance the timing more.

 

I was thinking about getting a timing spacer or jumping a tooth. I just didn't want to over do it if the fuel pressure I was running was already adding timing if that was the case.

 

From your sig we are running almost identical setups and i know for a fact I'm not running enough timing and I'm to the head.

 

I think I might try the timing spacer because I will get to keep the low end grunt.

 

I've read mixed reviews on if it was worth it if you are already advanced a lot

 

8-9 psi is the start ....from the voices in my head, in stock form.