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Power boost valves
stuart_g - 1/4/10 at 03:21 PM

I have an fse power boost valve on my car at present and the specs for it say that it is 1.7:1 ratio. Does this still apply if you don't use the vacuum connection.

Big Stu - 1/4/10 at 03:52 PM

I have just fitted one to the land rover, and I think the ratio is 1.7 times faster than a standard fuel regulator. I don't think it will effect the responce time however the vacuum tube is used to keep rail at a certain pressure above the manifold pressure therefore your rail pressure will not change with increasing or decreasing manifold pressure. Someone may know better than me but thats my understanding.

Cheers

Stuart

matt_claydon - 1/4/10 at 04:24 PM

quote:
Originally posted by stuart_g
I have an fse power boost valve on my car at present and the specs for it say that it is 1.7:1 ratio. Does this still apply if you don't use the vacuum connection.


No, without the vacuum you just get a fixed fuel pressure. A normal pressure regulator will decrease/increase fuel pressure by the same amount as the manifold pressure. A PBV will increase/decrease fuel pressure by 1.7 time the change in manifold vacuum. The latter will make an ECU very hard to program!

stuart_g - 1/4/10 at 05:53 PM

quote:
Originally posted by matt_claydon
quote:
Originally posted by stuart_g
I have an fse power boost valve on my car at present and the specs for it say that it is 1.7:1 ratio. Does this still apply if you don't use the vacuum connection.


No, without the vacuum you just get a fixed fuel pressure. A normal pressure regulator will decrease/increase fuel pressure by the same amount as the manifold pressure. A PBV will increase/decrease fuel pressure by 1.7 time the change in manifold vacuum. The latter will make an ECU very hard to program!


Excellent. I don't need to get a new one then. I'm not using manifold pressure for anything so a fixed constant fuel pressure is what I want. I'm having the car mapped in a couple of weeks so just wanted to be sure.