what are the limits? where do things start to go really bad? i just go a rail gauge today and not sure what should scare me.

 

i've never seen a clear answer to that question. I've heard the relief valve will let go around 27 to 27.5k psi. I've seen as high as 26k on my truck with no problems.

i'm no expert on the subject, but i think what harms the injectors is having dirty fuel and running 25k+psi. those little particles can do more damage at that pressure. also, running pressure higher than 25k is probably risky as well, but you'd have to be running something like an mp8 at 100% or stacking pressure boxes to get that high I suspect (or have a modified cp3).

hopefully some folks in the know will chime in and give you a better answer.

 

Supposedly if you run a 2 micron filter you dont have to worry about it as much.

 

im in the process of figuring out a 2 micron kit and lift pump upgrade. tonight i was able to hit about 26500 with my preadtor and quad stacked. i was just wondering how much damage i was doing.

 

I have been runin 25+ for a long time and I dont like it and I dont suggest it but thats what I run. MP8 has been off for a long time as my smarty adds pressure and I dont have a RV any more, just a cap, and a 2mk filter. I hope to send my injectors to Don M one day and see what kind of shape they are in. The highest you can read accurately ( as the sensor wont really go any higher) is 27,500.

IMO I would like to keep it at 25k or less and I am pretty sure some have dyno tested and with aftermarket injectors and modded pumps, the gain is minimal if any over 22-23k.

 

The RP gauges are good for monitoring how different SW & boxes modify the fuel pressure in the map, but since the sensor won't read over 27.5KPSI - you don't really know how much higher it might go when you max the gauge.

That's why Don M's stix are good insurance, since he designs/tests them for ~ 39KPSI, IIRC.

 

I've been running mine to where it will spike and max the gauge at the 27.5k. John at Floor It has seen as high as (I think this is the number he told me - it's been a while) 34k on his custom gauge.

 

I think more than a peak pressure number, the average running pressure is more important.

I have not ever seen where a WOT high pressure run has hurt anything. I do believe that running around town at 23K all the time could hurt things.

 

That is basically what John told me and I think that came from Don M. It's when it holds high pressure for a long duration. The Diablo Predator has a bad habit of holding rpms after you let off the throttle. My gauge on one dyno pull stayed at 27.5 for a few seconds. John didn't like that too much. I believe he also said something about it being bad when high and not at WOT because then it's not actually injecting a lot of fuel and so that pressure is just sitting in the injector rather flowing through it at WOT. That wasn't probably a very good explination, but hopefully you get the idea.

 

my rail pressure is about 22k at 70mph on the highway for hours at a time

 

i usually run around mmostly stock but when i add all the electronics is when it gets that high. anyone else with a quad railgauge-dose your truck rev up a few rpm's as your turning the key off? mabye only like 100-200 or so not a big deal just wounering if it was the gauge or if i hooked something up wrong.

 

I cant say 34k is 100% accurate but he told me the same thing, it was somewhere between 33 and 39 and 34 maybe be it I can can t remember. Point is, it was higher than any of us should be runnin.