How much supply pressure is too much for a P7100?

J

Joey Blunts

Diesel Enthusiast
Joined
Sep 30, 2011
Messages
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Hello CompD how's it going this is my first post here I've lurked for a bit and been on other forums for a few years. I like to consider myself fairly knowledgeable, competent, mechanically inclined, I search before posting, and I got grammatical skillz.

Introductions aside;
how much supply psi is ok to push to a P7100? I have a Tork Tech OFV and its maxed out but my FP only gets to like 32 no load and drops to 25-22 WOT. I tried adding a bic pen spring to my stock OFV but didn't flip the original spring and it idled at 60. I was afraid this was too high and would blow internal seals in the pump so stuck my Tork Tech back in.

You pinch the return line and its supposed to spike to 60-80, they wouldn't tell you to do so if that would blow seals, and this site Bosch P7100 Injection Pump | Black Smokin' by Diesel System Services says you don't want anything under 50psi under load. Is that just for a heavy modified competition setup pump?

Anyone know what pressure will blow seals or which seals in the pump would leak?
 
Joey Blunts said:
Hello CompD how's it going this is my first post here I've lurked for a bit and been on other forums for a few years. I like to consider myself fairly knowledgeable, competent, mechanically inclined, I search before posting, and I got grammatical skillz.

Introductions aside;
how much supply psi is ok to push to a P7100? I have a Tork Tech OFV and its maxed out but my FP only gets to like 32 no load and drops to 25-22 WOT. I tried adding a bic pen spring to my stock OFV but didn't flip the original spring and it idled at 60. I was afraid this was too high and would blow internal seals in the pump so stuck my Tork Tech back in.

You pinch the return line and its supposed to spike to 60-80, they wouldn't tell you to do so if that would blow seals, and this site Bosch P7100 Injection Pump | Black Smokin' by Diesel System Services says you don't want anything under 50psi under load. Is that just for a heavy modified competition setup pump?

Anyone know what pressure will blow seals or which seals in the pump would leak?
Click to expand...

You say you have grammatical skillz??


Just push a couple hundred psi to it, you'll learn how much it can take that way!

Chris
 
Thanks, after searching and reading and reading and searching, and the replies to this thread, I've seen people pushing way more than I was worried about.

I didn't think excessive fuel pressure would net me any more power, I was more curious/ scared 50-60 would blow out internal seals as a "reputable" local guy told me anything over 45 will kill my ip. He's an old man who hoards dodge cummins and hates on everyone elses truck but he'll try to give you misinformation and make you lowball offers and the only useful stuff he can tell you is the maintenance schedule. Some of my friends jerk off to him but as many times as I ask him questions he never has any useful info and frowns upon modifying the truck as if its a mortal sin.

Thanks CompD :-D

And signature600, I gots maadd grammatical skillz. Haha
 
I honestly think pressure is one of those things related to overall tuning. Pressure vs horsepower will change from pump to pump. Based purely on my testing with my 160 pump, (which has a cam design that is most likely to benefit from higher pressure), HP increased tremendously going from 35 psi to 65 psi. HP increased an average of 83 HP throughout a 1/4 mile pass. The biggest seat of the pants difference is in the 2500 RPM+ range. I am currently working on yet another switchable lift pump to test power gains in the 75-85 psi range to see if power continues to increase with added lift pump pressure on this 160 pump.

On my 98' daily driver with 180 pump, I experienced a mild 25 HP increase going from the stock pressure that fell 25 to 15 psi at WOT to a modified stock setup that falls from 45 to 35 psi at WOT. I have a feeling that with further testing, HP gains will cease once it maintains 45-50 psi WOT. The 180 pump's cam design allows for a lot more fill time than a 160 pump.
 
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