Modded cp3 rail pressure question

[Big P]

At what pressures are these pumps designed to run at. I understand the the relief valve in the rail is designed to dump the extra fuel at 28,000psi (just a guess on that number), but you get the idea. I also know that this destroys the relief valve because they are not designed the be opened constantly.

So, with a modded pump installed, and there is no pressure box installed on the truck, wouldn't the rail pressure sensor tell the ecm current rail pressure, and in turn send a signal the the FCA to cut back fuel? How do they work? What is the peak/highest sustained pressures for a Stage 1?

I think if I ever put a modified pump on my truck, it would just be a Stage 1. The only reason would be to maximize the parts that are on my truck now. I'm not looking for over 550hp, 500hp is more realistic for me. Thanks

 

[lmills]

Yes, with no pressure box installed the cp3 will act like it is stock but deliver more volume. The xtra pressure has to be brought on with a pressure box.

 

[WCounts]

I got one of the first stage I pumps and the pressure at idle is at 7000 psi. Any thing above idle is what the ecm calls for. The injectors on the 04. 5 and newer will flow more than the stock cp3 can put out and the stage I will keep the rail pressure at what the ecm calls for.

 

[Lightman]

At what pressures are these pumps designed to run at. I understand the the relief valve in the rail is designed to dump the extra fuel at 28,000psi (just a guess on that number), but you get the idea. I also know that this destroys the relief valve because they are not designed the be opened constantly.

So, with a modded pump installed, and there is no pressure box installed on the truck, wouldn't the rail pressure sensor tell the ecm current rail pressure, and in turn send a signal the the FCA to cut back fuel? How do they work? What is the peak/highest sustained pressures for a Stage 1?

I think if I ever put a modified pump on my truck, it would just be a Stage 1. The only reason would be to maximize the parts that are on my truck now. I'm not looking for over 550hp, 500hp is more realistic for me. Thanks

The stock CP3 will give you 550 with out any problem been there done that

Piers put down 66* with his truck on a stock CP3

 

[Diesel Power]

well i'll let you guys handle this one... ... ..... :-laf

 

[Big P]

Ok, so a modded pump, weather it's a stage 1 or 2, will supply the rail with any psi that it demands up to 23206 psi (stock pressure), with no pressure box installed. With a pressure box installed though you will see 26,000-30,000psi?

 

[Big P]

well i'll let you guys handle this one... ... ..... :-laf

If you want to sell one, give me a reason to buy one... ... ... ... ... :-laf

 

[lmills]

Ok, so a modded pump, weather it's a stage 1 or 2, will supply the rail with any psi that it demands up to 23206 psi (stock pressure), with no pressure box installed. With a pressure box installed though you will see 26,000-30,000psi?

You got it. Another thing to consider is in order to get full flow out of these pumps you have to run a pressure box. The pressure box tells the ECM the rail is low and calls for more fuel, by doing so it opens the FCA which delivers the additonal flow.

 

[Diesel Power]

If you want to sell one, give me a reason to buy one... ... ... ... ... :-laf

i would like to sell one but these guys are telling you the truth Oo.

 

[Diesel Power]

Ok, so a modded pump, weather it's a stage 1 or 2, will supply the rail with any psi that it demands up to 23206 psi (stock pressure), with no pressure box installed. With a pressure box installed though you will see 26,000-30,000psi?

any box thats on your truck fools boost, once that is done you will mash the peddle and the cp3 will provide what ever is nessisary to get the boost it's looking for, so if you fool the boost it's trying to get to say 30psi when your allready at 60psi, so it will fuel longer and harder, untill you run out of fuel, stage one is no more than a modded FCA and rear gear housing, resulting in around 10% more fuel to the injectors, a stage 2 from I. I results in a 67% increase in fuel to the injectors. so there is a big difference in pump stages and who does it as well, a modded pump will make it so your truck has plenty of fuel all the time (depending on what stage you have), but the pressure is different thatn volume alone. every mod pump will increase pressure and volume to some extent. it really depends on the mods done and once again who does it, i say this because everyones different ways of making power than the next guy, i have first hand knowledge of the floor-it pumps along with the I. I pumps. so i know how they work. you can see psi as high as 30+ psi and as low as 28psi between pumps, as its not somuch the pressure made but th evolume but thats very expensive to measure. this and much more could be said on the subject. if you need more info would be glad to assist over the phone.

 

[Big P]

I agree totally with the volume part. You probably don't need more than 25,000-26,000 psi of rail pressure for even honed or edm'd nozzles for good atomization, but you will need big volume. That's why I asked about the rail pressure without a pressure box installed. I understand that they are designed to be used with a pressure box, but you will still gain more hp under peak hp and better drivability too. Thank you for the info guys.

 

[Diesel Power]

I agree totally with the volume part. You probably don't need more than 25,000-26,000 psi of rail pressure for even honed or edm'd nozzles for good atomization, but you will need big volume. That's why I asked about the rail pressure without a pressure box installed. I understand that they are designed to be used with a pressure box, but you will still gain more hp under peak hp and better drivability too. Thank you for the info guys.

if you could get a constant 26-27kpsi @ wot you would be doing awesome, hopefully my new RP guage will help me tune this thing to the max.