fuel press to vp44

R

redcam622

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Jan 21, 2010
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whats the max fuel pressure you can feed the vp44..I have a in tank conversion pump with an inline 150gph..it reads 21psi at cruise and 14-15 at full boost..just wondering if this will affect anything.
 
This will vary depending on who you talk to. There has been a lot of discussion on this. It will probably be easier to search for it.

Most people go by the book and keep it around 14psi.

I never did regulate mine when i did the cam and i was seeing 25-27 idle and something over 30 when i go on it. I think it came back down when i was at full throttle but dont know how much. Im running a 12v lp with the cam. I disconnected the fuel guage since it only maxed at 30. It was anoying tapping off the peg.
 
I've been running 24psi idle, 16wot. since I installed this vp44 70k miles ago.
 
I run a MITUSA pump. 15.8 all the time....
 
With my Fass150 I saw 21-22 idle and WOT it might drop to 15-16psi. That was with the Edge Comp box, TST Comp or the ADR, all were the same pressurewise with 7x14 injectors.
 
JFlagg said:
With my Fass150 I saw 21-22 idle and WOT it might drop to 15-16psi. That was with the Edge Comp box, TST Comp or the ADR, all were the same pressurewise with 7x14 injectors.
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Thats awesome! My old fass would drop to 5psi.
 
I read that with the in tank lp to look at total volume not psi. Any truth to this?
 
I just plumbed in a holley blue in line with the in tank pump as a pusher...24 idle 15-16lbs @34lbs of boost at 3400 rpm shift point.
 
I have been told that you can't "drown" a vp. At one point i was seeing about 35 psi at idle with a little modification to a Holley Blue and the vp didn't seem to mind. The Holley however burnt up pretty quick.
 
Chip suggested to me a few years back no more than 25 psi because that's what the holley & stock carter with Scotty fittings push @ idle.
 
Could person install a stiffer spring into a FASS if pressure has gone down over time and get 20+ out of it or is it only made to produce so much pressure?
 
cummins724 said:
Thats awesome! My old fass would drop to 5psi.
Click to expand...

Yeah, even Dan at FASS thought that was weird when he saw that. His answer was its a fluke pump, lol. Even kept those pressures when the pump was getting loud and I replaced it... new pump kept the same pressures too, so who knows?


Also, I was told that VPs don't like TOO much pressure because you can rupture the diaghram. I'm no pump guy, so I took that at face value... I know 21-22 psi was enough to keep my II HRVP happy for 90K miles before I sold it 2 years ago and as far as I know its still running.
 
I've run 34psi @ idle and 28psi WOT for the last 130K miles with Mach 7s and Comp on 5x5 Day in and Day out. No hard start problem either.

Lavon
 
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