Rail pressure

[siclilly]

My question is about rail pressure! How much is to much,is there a limit of how much each truck can handle(lb7,lly,lbz). I know what happens when you dont have enough. If anybody could give me a quick lession that would be great! thanks.

 

[malibu795]

efi live wise the max controlable is 190MPA or 27,500 psi.

normal idle pressure is ~5000psi +/- 200psi

LB7 and LLY have a had time hold 23,000 on a 500hp tune in stock from even with a lift pump and a shim mod for the LLYs


LBZ will hold 26,000 all day long.

i brough my rail pressure to 22,000-23,0000 by 1600rpm so i could take advantage of the added atomiztion of the higher fuel pressure for MPG reason and a quicker throttle repsonse IMO

dual fuelers can do 27,500 all day no problem and VERY easily
JMHO

 

[siclilly]

if you can hold 27000 should you? 5th gear locked up burried at 120 full throttle is 27000psi to much? stock cp3 ppe lift pump.

 

[malibu795]

yep i would

 

[siclilly]

ok cool thanks! just wondering if there was a fine line were an up in rail pressure is not needed.

 

[JoshH]

LBZ will hold 26,000 all day long.

All day long? I need a refund then.

 

[ripmf666]

All day long? I need a refund then.

Might have something to do with those MPI twins you have lol:cool2:

 

[rcr1978]

The question I have since the LB7's have a problem with cracked injector bodies or problems with pushing balls out of seats. How much faster is this going to happen when running over 160mpa lets say 170-180mpa if you can make it?

 

[malibu795]

The question I have since the LB7's have a problem with cracked injector bodies or problems with pushing balls out of seats. How much faster is this going to happen when running over 160mpa lets say 170-180mpa if you can make it?

dont know... but you will have a hard time geting 160MPA + on a stock single lb7 cp3 at WOT conditions

 

[turbo_bu]

...
i brough my rail pressure to 22,000-23,0000 by 1600rpm so i could take advantage of the added atomiztion of the higher fuel pressure for MPG reason and a quicker throttle repsonse IMO... JMHO

Don't mean to hi-jack this thread, but I just started playing with increased fuel pressure to try and get another 1-2 MPG out of my LB7 (occurred to me after looking at stock LB7 / LLY and LBZ tables). Were you able to increase timing with the higher fuel pressure, or was it a matter of better fuel atomization which increased your MPG? So far, I have pushed the timing out and was wondering if I need to increase fuel pressure to get any more mileage out of it.

 

[malibu795]

depending on throttle and rpm i run between 4-10* of main inj timing between 1600-2200rpm in the cruising area vs 0-3* stock setup

on my lb7 i run 20-23,000 in the cruising area
i start ramping the rail pressure by 1400-1500rpm up to 160mpa

 

[dmaxtruck]

I've got the big sticks from ATS and I'm now running about 22k - 23k actual rails on 24k - 25k commanded respectively on a single unmoded CP3, FASS 150, and fuel rail shim kit in my LLY.

Idle is around 4k to 5k actual with 4.5k commanded.

Basically Mike keeps lowering my pulsewidth to get the rail up, and she's running great. Rainy here again today (5 inches in 7 days!!!) so I can't test last nights changes yet, but we just lowered pulsewidth again at the high end.

 

[2wd_Sled_Puller]

U Can Never Have Enough:d