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Discussion Starter #1
Hey folks
I finally got around to fitting an adjustable pressure reg to my 3.0lt. I cut the standard reg open, removed the parts and sealed it back up so as i could use it as a T piece. Mounted the new adjustable reg on the camshaft cover using a bracket I knocked up at work. Pretty happy with the result as im not huge on using non alfa bolt on parts. Anyway I have been playing with the pressure and have had the car running fine with pressure as high as 65 psi. Can anyone give me some advice on what would be the upper limits of fuel pressure and what the standard specs are in psi.
Note:running haltech efi and was running out of duty cycle hence the need for more fuel pressure
 

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Discussion Starter #5
Thanks mate. I thought it was around 35 to 40 psi however i wasnt sure as I was told by someone the other day that its about 45 psi which I thought was incorrect.
 

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1966-2013
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Ideally, that pressure should be set with the engine fully warmed up and idling and the vac line blocked off.

That way it ensures you get correct pressure when there's normal vac under normal driving conditions, and the pressure will rise properly when you're up on it and the vacuum drops.

On Bosch EFI systems, it acts sorta kinda like an accelerator pump onnaconna when the vac dumps (from you mashing the throttle) the injectors spray a bit more/harder when the pressure rises a bit which in turn helps alleviate/eliminate a flat response.
 

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Discussion Starter #7
I just booked the car in for a dyno session at Beninca later in the week. Im going to concentrate on full throttle mixture and get the injectors working at about a max of 80-90% duty cycle. Peter Beninca said I can go as high as 70 psi with regard to fuel pressure which sounds like alot but they know what they are doing. In any case i only want the max pressure set to meet the fuel demands required as i would rather not have 70psi in my fuel lines. I once had a fuel fire in the engine bay which has made me a tad worried. It will be interesting to see how much power this puppy makes with the AFM removed. Its already stupidly fast so i cant imagine it going much harder but I can only hope lol
 

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1966-2013
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I suppose I should ask how changing the pressure would alter the duty cycle, or do I misunderstand and you're intending on taking a different route to achieve that?

(I always understood duty cycle to be relative to the open and hold, though changing pressure could certainly alter the amount of flow at X duty cycle)


Random side note:

I see the EFI type clamp on your regulator, which is a good thing.

However, I recently found a small fuel leak on mine back at the main pump outlet where I have one of those clamps. The most I can figure is that it loosened up due to vibration.

As in it prolly wouldn't hurt to periodically go 'round and try to give them a turn to see if they are loosening up, at least until they corrode and won't loosen up without a chisel helping them. :) (I found 2 others that needed just a bit of tightening in addition to the one at the pump while checking all of mine)
 

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Discussion Starter #9
With the increase in fuel pressure I can now adjust the fuel maps on my computer and thus reduce the duty cycle to a max of 80-90%

I also have a surge tank to mount in the boot so yeah for sure I am going over the entire fuel system and will be replacing all the high pressure hoses as they have a few fine cracks appearing in them as they do when they get old.
 
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