Sorry to hear you are having trouble with them :hug:
I thought dual fuelers where supposed to be so reliable?
I thought dual fuelers where supposed to be so reliable?
Duel CP3s or single nodded CP3
- Thread starter cstephens93
- Start date
I've ran dual stock pumps for probably 30,000 miles. Only real problems are squeaky belts and a couple leaks.
I run very high pressures as well. The only issue with LLY and LB7's is that you cant control (or see for that matter) the pressure once it goes over 26k and some change. My race tunes flatline the pressure sensor at about 30' and stay that way the entire pass. There is a definite and track proven power difference running high pressures.
Made one pass on tune 3 at high pressure, 133mph trap speed. Another pass that night and truck wouldnt hold rail above 23k, but maintained it the whole pass, 123mph. At those speeds and my weight that is nearly a 200hp loss in power, just from rail pressure.
Made one pass on tune 3 at high pressure, 133mph trap speed. Another pass that night and truck wouldnt hold rail above 23k, but maintained it the whole pass, 123mph. At those speeds and my weight that is nearly a 200hp loss in power, just from rail pressure.
Once you command over the rail pressure sensor's limits, which no matter what dont read over 180mpa, the rail pressure will continue to climb, you just cant see it. So you command 190mpa, set all your limiters above that, and the truck will never actually "see" that pressure. As a result the FPR will continue to open to try and attain 190mpa. The truck doesnt know how much it is making, just that the sensor has stopped at 180mpa. Could be making 220mpa for all I know.
You command it in the Fuel Pressure Base table, obviously dont want to do it at normal driving mm3.
Since we are talking about a lot if guys running really high pressures and Mark does a lot of dyno tuning, I have a question for Mark. At what point have you seen on the dyno that more pressure didn't make more hp? I ask because when you add pressure you add heat to the fuel and may make less hp.
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Once you command over the rail pressure sensor's limits, which no matter what dont read over 180mpa, the rail pressure will continue to climb, you just cant see it. So you command 190mpa, set all your limiters above that, and the truck will never actually "see" that pressure. As a result the FPR will continue to open to try and attain 190mpa. The truck doesnt know how much it is making, just that the sensor has stopped at 180mpa. Could be making 220mpa for all I know.
You command it in the Fuel Pressure Base table, obviously dont want to do it at normal driving mm3.
Exactly anything over 190mpa you are shooting in the dark..
Does this explain why when I log my race tune from ATP, my truck wont make more than 23kpsi actual? Or is this entirely different....?
No, your truck won't make over 23k either because that is all the pump will support our that is all the tune is commanding.
I never understood that...why write a tune that commands 26kpsi, when the pump only supports 23kpsi.
More reason why I started this thread in the first place
My LBZ goes too 26k seems to hold well but dose drop too 25k at about 3,800 rpm. My top tune runs too 4,100 rpm I don't know if the tuning or something else is the limiting factor. This being said I think my stock pump is in pretty good shape. Exergy recommended either dual fuelers or a modified pump in order to take full advantage of any injector over 30%.
When I contacted Exergy my question involved narrowing pulse widths and increasing reliability on a stock bottom end at around 650 rwhp.
When I contacted Exergy my question involved narrowing pulse widths and increasing reliability on a stock bottom end at around 650 rwhp.
Your stock pump can support 26k psi. The tune has to be written for that. You do need a lift pump as well to supply your pump fuel. When you log the tune it will tell you what it us commanding and what you are getting. Those numbers match closely or do not match closely. It is typical to be down 2 to 4 thousand psi somewhere along the log. Does it fully recover and desired and actual match? If all us in good shape and it won't recover then you are in a situation where the pump can't fulfill the demand. If you have a log either post it here it you can email it to me to review for you if you would like. I will pm you my email.
If I read this right after you put 100 overs in the valley pump started knocking? And you put another new valley pump in and it still knocks? I ask cause I put 60 over and a second lbz cp3 in my truck and I defenatly hear a knock from my original valley pump?