HOW much of a difference does the "Blue Spring Kit" actually make for fuel pressure?

[WorkHorseWill]

My 2005 has been feeling a bit sluggish on top-end throttle lately. I’ve heard everyone talking about the Blue Spring upgrade. WHAT exactly does it do, and HOW does increasing the fuel pressure protect my injectors? Is it worth the $60 and an hour of my time?

 

[IronBackbone]

It’s not about making more power, it’s about stopping your truck from eating itself. What happens over time is the factory regulator spring gets weak and your fuel pressure drops below 45 PSI, especially when you're wide open throttle.

How increasing pressure protects your injectors: These HEUI injectors use fuel as a cushion. If the pressure is too low, the internal plunger literally hammers against the seat because there isn't enough fluid to dampen the blow. For $60, it’s the cheapest insurance you can buy. If you lose an injector, you're looking at $250+ per hole plus labor. Just do it.

 

[DieselDusty]

I did mine last month and what a difference it made in throttle response. My truck had that same sluggish feeling you're describing on the top end. How much of a difference does it make? I went from 42 PSI at idle to a rock-solid 62 PSI.

The truck just feels crisper now when I step on it. You have to remember that these 6.0Ls are incredibly sensitive to fuel pressure. If you're feeling a lag, your injectors are likely starving for fuel. An hour of your time is a generous estimate; it’s a pretty easy job if you have a set of Torx bits and some patience with the housing bolts.