Above 60PSI but not exceeding 70PSI. Prolonged use over 70PSI has been known to cause o-ring failure on injectors.

 

Ford says 55 plus or minus 5. So 50 min, 60 max according to Ford. Most with aftermarket pumps and regulators will typically set somewhere around 60-65psi.

I've run as high as 90psi on my vegi system and never had any issues with o-rings, and I know some guys used to run boost referenced pumps that would push up towards 100psi, without issues. I think that o-ring theory is just a myth. However, it's typically not necessary to go that high anyways.

 

IIRC that is the Ford specs for the original fuel pressure regulator. The updated "blue spring" for the fuel pressure regulator holds the PSI higher.

 

Yes it does, but the new style fuel filters will flow less, thus the updated spring. They should almost counteract each other, but typically you will see higher pressures with the blue springs.

 

IIRC the only filter in the set that changed was the water separator.

---AutoMerged DoublePost---

Fuel filters used in production 6.4L engines have begun using an improved fuel filter to reduce fuel 'blow by' when the filter is at the end of its filtering capability (when the filter is nearly clogged and needs changing).

---AutoMerged DoublePost---

The filter doesn't "flow less" ................

 

I didn't really see an increase in pressure, but it didn't drop off as much under WOT.

---AutoMerged DoublePost---

I just noticed how old this thread was.

 

You're right, and yes they will be slightly more restrictive. I can see it on my fuel pressure gauge. You don't notice it really until they start getting some miles on them though. It's basically the reason Ford released this updated spring...

That whole "reducing fuel blow by" means more restrictive.

I saw an improvement across the board, but I can still drain pressure just as fast as I could before. It wont ever fix that.

 

Ummm, does that mean I may have a fuel pump issue? Why wouldn't I see an increase at idle but less drop at WOT, unless the mechanical gauge I used sucked?

 

Tough to say. Are you using a programmer? Where are you reading fuel pressure from? I'm not sure why you didn't see any increase at idle, that's where I notice mine the most. Think about what the spring is doing. Just holding a higher pressure before "relieving"... So if your pump can't keep up when fuel demand is high (WOT with a hot tune on), the spring doesn't matter at that point, cause the pump can't keep the volume up. Let off the throttle and the demand for fuel is real low, then the pump can keep up and make the volume and the spring regulates.

 

I have an SCT, tuned by IDP. I borrowed one and measured from the port. Had the gauge zip tied to the wiper arm. I think it was the gauge......I should have my EV2 in a couple of weeks. I read somewhere about running a bridge line between the heads and putting in a T to read from, did you post that?