Fuel pressure help

Ridemywideglide said:
You should get the adjustable OFV mentioned. I stretched my spring (probably too far) and I get ~42 at idle, and it never drops below 35psi at WOT.
Click to expand...

ya see the problem with that is you are restricting flow THROUGH the pump. as yall probably know, the pump uses diesel to cool off and while havin the high pressure is nice, dead headin the fuel at the pump aint the way to get it.
 
honestcharlie56 said:
ya see the problem with that is you are restricting flow THROUGH the pump. as yall probably know, the pump uses diesel to cool off and while havin the high pressure is nice, dead headin the fuel at the pump aint the way to get it.
Click to expand...

So what is the proper way to do it if I may ask?? Looks like Bosch was wrong....

Chris
 
its all about the flow rate, even if your flow rate is slow you can still dead head it and get the pressure, but if you have a strong pump you can have a higher flow rate and still maintain a healthy pressure. What do you mean, looks like bosch was wrong.?
 
What flow rate through the stock lines equals 42psi?

Pressure is flow and restriction....simple as that. If the pump is dead, it won't make pressure even if you block the outlet completely...the p-pump is designed to run with a pressurized fuel supply to aid in filling the plungers. Bosch designed the overflow valve into the system for that purpose.

Chris
 
Signature600 said:
What flow rate through the stock lines equals 42psi?

Pressure is flow and restriction....simple as that. If the pump is dead, it won't make pressure even if you block the outlet completely...the p-pump is designed to run with a pressurized fuel supply to aid in filling the plungers. Bosch designed the overflow valve into the system for that purpose.

Chris
Click to expand...

I dont know if were on the same page, sorry if its my bad english. What I'm getting at is "dead heading" the Ppump. As in no return flow from the pump. Bosch designed the overflow valve to maintain a constant pressure in the Ppump and have a constant flow through the pump.....to cool it.
 
honestcharlie56 said:
ya see the problem with that is you are restricting flow THROUGH the pump. as yall probably know, the pump uses diesel to cool off and while havin the high pressure is nice, dead headin the fuel at the pump aint the way to get it.
Click to expand...

Well I have to restrict it in order to get any pressure. If it were an open return it would run at 3psi... Not too good, but I guess the pump would stay pretty cool. Volume doesn't mean anything getting the fuel in your motor without pressure to utilize it.
I still get plenty of fuel out the return line.
 
Ridemywideglide said:
Well I have to restrict it in order to get any pressure. If it were an open return it would run at 3psi... Not too good, but I guess the pump would stay pretty cool. Volume doesn't mean anything getting the fuel in your motor without pressure to utilize it.
I still get plenty of fuel out the return line.
Click to expand...

man what makes yall think I'm trying to say you should have no pressure...:bang, I know you have to have the restriction to make pressure, THE TRICK is to have a good balance between the flow and pressure. You'll know when you dont have the volume to make power, the second you start to roll into it you FP gauge will fall right off. Like I have been saying the whole time. its all about pressure and flow. By no means was I saying to block off the return and run crazy pressure, and by no means was I telling yall to just open the bypass the OFV so you can have this amazing flow rate throught the IP. I am sorry for my lack of a better way to put this.....
 
honestcharlie56 said:
I dont know if were on the same page, sorry if its my bad english. What I'm getting at is "dead heading" the Ppump. As in no return flow from the pump. Bosch designed the overflow valve to maintain a constant pressure in the Ppump and have a constant flow through the pump.....to cool it.
Click to expand...

Must have been the bad English...and my tired brain...my apologies.

I thought you were talking about dead heading the lift pump.
Chris
 
honestcharlie56 said:
man what makes yall think I'm trying to say you should have no pressure...:bang, I know you have to have the restriction to make pressure, THE TRICK is to have a good balance between the flow and pressure. You'll know when you dont have the volume to make power, the second you start to roll into it you FP gauge will fall right off. Like I have been saying the whole time. its all about pressure and flow. By no means was I saying to block off the return and run crazy pressure, and by no means was I telling yall to just open the bypass the OFV so you can have this amazing flow rate throught the IP. I am sorry for my lack of a better way to put this.....
Click to expand...

I know you weren't trying to say that we should have no pressure. But pressure is a function of restriction, no way around that. I don't know what flow rate is needed to cool the pump, but I've had no ill effects in 3+ years. I was told at one point that 50psi is about the max you want to run into the 7100. Don't know how valid that is.
 
Ridemywideglide said:
I know you weren't trying to say that we should have no pressure. But pressure is a function of restriction, no way around that. I don't know what flow rate is needed to cool the pump, but I've had no ill effects in 3+ years. I was told at one point that 50psi is about the max you want to run into the 7100. Don't know how valid that is.
Click to expand...

I've never had a problem runnin around 45psi, never had any reason to go any higher.
 
honestcharlie56 said:
I've never had a problem runnin around 45psi, never had any reason to go any higher.
Click to expand...

They've been run up over 100psi...but a few people around here have tested it, and saw very little gains above 45psi or so!!


Although CDS does suggest 55-60psi on their 13mm pumps, IIRC!
Chris
 
Signature600 said:
They've been run up over 100psi...but a few people around here have tested it, and saw very little gains above 45psi or so!!


Although CDS does suggest 55-60psi on their 13mm pumps, IIRC!
Chris
Click to expand...

Could be that's what I was told too, it was a while ago.
 
You must log in or register to reply here.
Back
Top