What is good PSI for PRIMARY fuel pressure?

[Motorhead]

See my signature for my mods. I put a sending unit on my fuel line aft of the Glacier 2 mic filter and before the CP3. I am running the stock in tank fuel pump. I run the Smarty jr on the 70hp setting and the turbo is stock. The Glacier 2 mic filter has 17,000 mi on the spin-on element. I run the 7 mic fleetguard filter insert in the stock filter. The stock 7 mic filter has 3,000 mi on it.
I an running a SPA digital gauge. I wired in a two pole ON-ON switch so I can switch from reading my Boost to reading the Fuel pressure and only using one gauge. Basically I am switching between TWO pressure sending units.

Here is my pressure readings.

IDLE at 10-11psi.
DRIVING normal is 9-10 psi.
WOT through the gears is about 7-8 psi.

Is this OK or NOT???

 

[CKelley1]

a little above average most run around 8 psi 6 wot

 

[JWadford]

its fine, as long as it stays in a positive pressure.

 

[Motorhead]

I had read somewhere on the TDR that guys were questioning wether the stock pump was enough when you ran the Glacier or other 2 mic filters. The most I plan to run is the Smarty jr.

 

[p-Bar]

Boy if you are running a 2 mic filter I sure wouldn't be running the stock fuel pump.

 

[Motorhead]

Boy if you are running a 2 mic filter I sure wouldn't be running the stock fuel pump.

OK... . Why?

That is why I posted this question

 

[p-Bar]

Would you rely on a oem pump that design was for a 10 micron filter originally the reason for the change to 7 micron stock was to protect the injectors. Bosch made recomendation to Chrysler that it should have been 5 micron . As soon as I have the money my oem is gone. Hope this helps

 

[AH64ID]

See my signature for my mods. I put a sending unit on my fuel line aft of the Glacier 2 mic filter and before the CP3. I am running the stock in tank fuel pump. I run the Smarty jr on the 70hp setting and the turbo is stock. The Glacier 2 mic filter has 17,000 mi on the spin-on element. I run the 7 mic fleetguard filter insert in the stock filter. The stock 7 mic filter has 3,000 mi on it.
I an running a SPA digital gauge. I wired in a two pole ON-ON switch so I can switch from reading my Boost to reading the Fuel pressure and only using one gauge. Basically I am switching between TWO pressure sending units.

Here is my pressure readings.

IDLE at 10-11psi.
DRIVING normal is 9-10 psi.
WOT through the gears is about 7-8 psi.

Is this OK or NOT???

You're running a little more pressure than me, but I have 3 filters. Are you running the big line kit as well?

With my SJR on SW1 or SW2

I see 9-9. 5 at idle
8ish normal cruise
5-5. 5 psi WOT

5 psi is more than plenty for a CP3, some say you can run down to 2-3psi and have no worries. I plan to change my filters at 30K miles.

Boy if you are running a 2 mic filter I sure wouldn't be running the stock fuel pump.

The in-tank LP is more than capable of 3 filters. I have just shy of 28K miles on my 3 fuel filters with the in-tank LP and have only just recently (last 2-3K miles) started to be able to pull the psi below 5 under upper rpms at WOT. I will easily get 30K out of these filters, then change them. My filters are rated 20, 5, 2um all absolute. Nominal they are 4,1-2,<1.

OEM is about to release a 5um absolute filter for the 5. 9

Would you rely on a oem pump that design was for a 10 micron filter originally the reason for the change to 7 micron stock was to protect the injectors. Bosch made recomendation to Chrysler that it should have been 5 micron . As soon as I have the money my oem is gone. Hope this helps

What are you planning to run?

 

[Tinman]

I ran the Glacier Walbro pump for a while with the stocker as a back up. I had a switch to toggle between the two. I use a Stanadyne Fuel Manager 1000 with a Donaldson 2 micron filter between the stock 10 mic filter and CP3. With the stock pump, I could easily pull the FP to zero with well less than full throttle with stock fueling. So my experience is that the stock pump is inadequate for a dual filter set up. Your pressure seems to be fine. I think the question is how long will the stock pump last with that set up. For a variety of reasons I switched to a Raptor pump and swapped fuel canisters with my wife's Libby. My stock pump has found a nice home there.

 

[AH64ID]

I ran the Glacier Walbro pump for a while with the stocker as a back up. I had a switch to toggle between the two. I use a Stanadyne Fuel Manager 1000 with a Donaldson 2 micron filter between the stock 10 mic filter and CP3. With the stock pump, I could easily pull the FP to zero with well less than full throttle with stock fueling. So my experience is that the stock pump is inadequate for a dual filter set up. Your pressure seems to be fine. I think the question is how long will the stock pump last with that set up. For a variety of reasons I switched to a Raptor pump and swapped fuel canisters with my wife's Libby. My stock pump has found a nice home there.

Very interesting on your pressure. . I have talked to quite a few people with similar results as mine. I wonder if your pump was failing. I'm at almost 30K miles without so much as a hickup.

 

[p-Bar]

You're running a little more pressure than me, but I have 3 filters. Are you running the big line kit as well?



With my SJR on SW1 or SW2



I see 9-9. 5 at idle

8ish normal cruise

5-5. 5 psi WOT



5 psi is more than plenty for a CP3, some say you can run down to 2-3psi and have no worries. I plan to change my filters at 30K miles.









The in-tank LP is more than capable of 3 filters. I have just shy of 28K miles on my 3 fuel filters with the in-tank LP and have only just recently (last 2-3K miles) started to be able to pull the psi below 5 under upper rpms at WOT. I will easily get 30K out of these filters, then change them. My filters are rated 20, 5, 2um all absolute. Nominal they are 4,1-2,<1.



OEM is about to release a 5um absolute filter for the 5. 9







What are you planning to run?

Trying to get a brushless pump from a company I met at the SEMA show then stack it with a couple filters.



Thanks TINMAN thought I was smokin' crack

 

[big61fourby]

Very interesting on your pressure. . I have talked to quite a few people with similar results as mine. I wonder if your pump was failing. I'm at almost 30K miles without so much as a hickup.

Size of filter maybe? Haven't had any trouble with my CAT filters, but they are huge, pushing 12" long...

 

[AH64ID]

Thanks TINMAN thought I was smokin' crack

From my research he is the exception not the rule.



There are lots of people running more than one filter on the in-tank LP without issue, its really a good pump.

Size of filter maybe? Haven't had any trouble with my CAT filters, but they are huge, pushing 12" long...

My cat is a 1R-0750 and my baldwin is 7" long? Not sure.

 

[steved]

In my readings, the general "goal" is around 10psi and anything above "zero" at WOT. The CP3 is not a VP44, and does not need the lift pump to draw fuel (look at the setup on a Duramax), nor does it benefit from a certain supply pressure... anything over "zero" psi is pushing fuel to the CP3.

I remember reading the "horror" of the in-tank lift pumps (when first introduced) only pushing 8psi (and pulling to near "zero" at WOT) and that this would be certain death for the CP3... been a long time since then, and they seem to live just fine with those pressures. (In hind-sight, I would have probably left my fuel system alone if it had came from factory with the in-tank pump).

With that said, I've ran anywhere from 10psi to 22psi through mine, and mine seems to like the higher pressures... I think my pressures finally "wore in" at about 15-17psi (all this is at idle, I don't have an in-cab guage).

 

[Motorhead]

Well here is a question... .
Has anyone run an additional pump in SERIES with the stocker? In other words, The stock lift pump feeds into an additional pump inlet then to the CP3.

 

[steved]

While I don't know if anyone has done it with a 3rd gen, it was fairly common to see done in the 2nd gen... adding a LP to the frame near the tank, that fed the OE LP, then through the filter into the VP44. Typically it was either another OE Carter or a Holley fuel pump... search the 2nd gen forums, I'm sure there are plenty of threads...

As long as the filters are between the last pump and the CP3, adding a second LP should pose no issue. There is a thread on here where one member running a Frantz fuel filter that found metal shavings in the filter from the pump going bad.

 

[p-Bar]

how well can you suck thru the tank lp? that's your bottleneck

 

[steved]

I doubt the in-tank LP would be the bottle neck... the banjos throughout the system will be the main restriction...

 

[AH64ID]

I doubt the in-tank LP would be the bottle neck... the banjos throughout the system will be the main restriction...

Agree. . The in-tank pump is designed to be flow-thru.

 

[p-Bar]

Agree. . The in-tank pump is designed to be flow-thru.

Thought I read somewhere that they wern't that's good to know