Rail Pressure tuning help?

[AdamRRT]

Ok I have really no idea what is preferred for pressure tuning. That is as it applies to a daily driver. I have a theory of how I'd like the process to work. I'd prefer to keep stock rail pressure across the board. That way I minimize injector wear. Then at WOT of course crank it up as much as it makes power yet still cap it safely around 25,500psi.

But I know almost nothing about tuning rail pressure for power and for mpg.

All I really know about pressure is:
1 it makes the truck a blast to drive
2 it doesn't help my mpg. That's a marketing ploy IMHO. I believe we are already above the pressure at which we get optimal atomization. At least that is based upon multiple tanks of fuel at differing pressure settings. Yes despite the theory. I'm aware.

Anybody care to share a little info on what you've found to work best for a daily driver? No trade secrets. Just some basics. Thanks in advance. I appreciate the info.

[2007 5.9]

I run pressures for DD close to what a 03-04 CR operates at.

70mph@2000rpm 15,000psi

My graphs are smooth and linear from my 5500psi idle to 23,500 peak.

I don't run pressure over stock peak.

[AdamRRT]

Thanks Les.

[CIDRAUGHN]

Ive been finding that with larger nozzles (mine are in the 110% range) that a slightly higher RP results in a bit cleaner burn. Now Im not nearly as far along in the learning curve as you all, but thats just what Ive found so far. In the cruising range, im running 19k ish rail, with a smooth increase all the way up to a WOT RP of around 25K. That has helped get rid of much of my cruising haze. Also, making a pretty fast smooth ramp up to cruising RP from acceleration has helped clear out some smoke issues.

[killerbee]

All I really know about pressure is:
1 it makes the truck a blast to drive
2 it doesn't help my mpg. That's a marketing ploy IMHO. I believe we are already above the pressure at which we get optimal atomization. At least that is based upon multiple tanks of fuel at differing pressure settings. Yes despite the theory. I'm aware.

Anybody care to share a little info on what you've found to work best for a daily driver? No trade secrets. Just some basics. Thanks in advance. I appreciate the info.

High rail pressure is parasitic. That is the first thing to accept. No free lunch. So use only enough pressure to meet your torque and power needs. Steady empty cruise requires only 25-35 HP, so minimal pressure is required to keep pulse manageable in duration.

etc.

[AdamRRT]

Codraughn: thanks man. Makes perfect sense in bigger injectors. Just the relation of the fluid dynamics.

Killerbee: thanks man. Pretty much as I thought. But I had no clue about cruise settings. Thanks.

[tinman]

I'm playing with rail pressure some and minimizing wear is part of my goal. My thought is to find the minimally effective pressure, keep the curves smooth and nothing more than stock. Right now I have a tune that is running about 17-18k at cruising speed and kinda flattens out there until the commanded fuel gets up. That way the pressure doesn't change too much with the usual accelerations of highway driving.

[2007 5.9]

I have actually bumped mine up slightly at cruising speed to aid in some little hazing i have left ....so far its proving to be helpful in eliminating that last little bit of cruising smoke.