Is there a way to lower the psi on a Fass 150? I have 20 psi at idle and 18.5 WOT and would like to see 15 wot and 17 18 at idle. Iv heard of a different pressure spring? Link? Thanks

I’d leave it. It’ll settle out over time and filters will clog a bit and bring that number down as well. Only spring I’ve found that’s put an actual psi associated with it is from Vulcan and it’s a 17psi Airdog spring but it’ll work in your FASS. So you could do that if you wanted. I went that route but only because I was having all sorts of issues with the FASS springs. Psi when I first installed was 18.5 idle 17 at WOT. Now I’m 17 idle 15.5 WOT.

Is that a used Fass you got from someone else? Did they stretch the spring or something?

 

20 psi is higher than Fass sets them and tests them at is what they told me

 

 

.

Edited March 27, 20187 yr by GSP7

10 minutes ago, notlimah said:

I’d leave it. It’ll settle out over time and filters will clog a bit and bring that number down as well. Only spring I’ve found that’s put an actual psi associated with it is from Vulcan and it’s a 17psi Airdog spring but it’ll work in your FASS. So you could do that if you wanted. I went that route but only because I was having all sorts of issues with the FASS springs. Psi when I first installed was 18.5 idle 17 at WOT. Now I’m 17 idle 15.5 WOT.

Sounds like you’ve got he cats meow formpressures.

Yea can't complain. I didn't mind it before but at least it's still within the limits. I am going to be changing filters here soon and also routing my fuel lines back through the stock fuel basket to get the extra filtration so we'll see what pressures look like after that, I don't expect much change.

those sound like decent numbers 20 is about as high as you can go with the vp. you could try removing the spring and clipping off a coil or two

7 hours ago, tylertrebilcock said:

those sound like decent numbers 20 is about as high as you can go with the vp. you could try removing the spring and clipping off a coil or two

If I’m going to do that I’m gonna get the whole new spring so I don’t risk getting the truck grounded if I mess the spring up lol. 

 

8 hours ago, notlimah said:

Yea can't complain. I didn't mind it before but at least it's still within the limits. I am going to be changing filters here soon and also routing my fuel lines back through the stock fuel basket to get the extra filtration so we'll see what pressures look like after that, I don't expect much change.

I’ll be changing all 3 of

my filters as well today.... 

2 minutes ago, Marcus2000monster said:

I’ll be changing all 3 of

my filters as well today.

Why didn't you just get them with pump, or just in case. 

@notlimah what filters are you planning on using Fass or something else. Here is a Fass site with filter cross reference, https://www.fassride.com/portfolio-item/replacement-filters/

I just got this one from Dap.

• Donaldson P551313 (3M)

, Fass says it's okay to use, but it only flows haunted GPH, I'm not entirely sure how many GPH Fass filters flow. Someone has to make it for them, and I heard rumors that it is Donaldson that does. 

Just now, Dieselfuture said:

Why didn't you just get them with pump, or just in case. 

@notlimah what filters are you planning on using Fass or something else. Here is a Fass site with filter cross reference, https://www.fassride.com/portfolio-item/replacement-filters/

I just got this one from Dap.

• Donaldson P551313 (3M)

, Fass says it's okay to use, but it only flows haunted GPH, I'm not entirely sure how many GPH Fass filters flow. Someone has to make it for them, and I heard rumors that it is Donaldson that does. 

What do you mean? My Fass did come with filters. Im switching them for new being they have 20k on them.... 

3 minutes ago, Marcus2000monster said:

What do you mean? My Fass did come with filters. Im switching them for new being they have 20k on them.... 

Wow you already put20k on them, do not know that. Even then I still don't believe in changing filters until I start seeing PSI drop

8 minutes ago, Dieselfuture said:

Wow you already put20k on them, do not know that. Even then I still don't believe in changing filters until I start seeing PSI drop

No no i didn’t even put 1k on them lol. I bought it used and he had the 20k on hem lol. My Fass sounds like a rock tumbler and supposedly new filters will make it run smooth like it should haha. 

9 hours ago, notlimah said:

also routing my fuel lines back through the stock fuel basket to get the extra filtration so we'll see what pressures look like after that

 

No change. I'm already in that position now. It has no effect on pressures. 

1 minute ago, Mopar1973Man said:

 

No change. I'm already in that position now. It has no effect on pressures. 

Inplumbed my Fass through the stock canister and still have 20 psi idle and 18 wot

Why would you want lower pressures?

10 hours ago, tylertrebilcock said:

those sound like decent numbers 20 is about as high as you can go with the vp. you could try removing the spring and clipping off a coil or two

20 is not the max pressure for a VP.  

@notlimah - it has the Vulcan airdog spring with the end coil curled to keep the ball from sinking into the spring.  Hasn't changed pressures from when it was set over a year ago.

5 minutes ago, trreed said:

20 is not the max pressure for a VP.  

 

But it's not going to change the performance nor lube or cool it any better. Return port is on the left. So raising the fuel pressure above 20 PSI is not going to improve anything. 

 

 

I understand the internals of a VP....  But saying "20 is about as high as you can go with a VP" is not the same as saying "raising the pressure above 20 is not going to improve anything."

2 hours ago, Dieselfuture said:

Why didn't you just get them with pump, or just in case. 

@notlimah what filters are you planning on using Fass or something else. Here is a Fass site with filter cross reference, https://www.fassride.com/portfolio-item/replacement-filters/

I just got this one from Dap.

• Donaldson P551313 (3M)

, Fass says it's okay to use, but it only flows haunted GPH, I'm not entirely sure how many GPH Fass filters flow. Someone has to make it for them, and I heard rumors that it is Donaldson that does. 

 

I’ll be using Donaldson filters as well.

 

18 minutes ago, trreed said:

Why would you want lower pressures?

20 is not the max pressure for a VP.  

@notlimah - it has the Vulcan airdog spring with the end coil curled to keep the ball from sinking into the spring.  Hasn't changed pressures from when it was set over a year ago.

 

Ah, that’d explain why he’s seeing a little higher then me. I might do the same to my spring when I get things apart for this filter change.

Is this the top part that needs cut out? And where my fingers are is where I need to drill the half inch holes right? And the last pic is the part that stays out of the basket right? The directions aren’t just the easiest to follow lol

Your basket is different than mine I can not comment, but man you got some crap in there, changing filters would be a good idea after fass will polish your tank.

I Jim know going to be putting a sump in. I just fouled up the basket and straw. 

If I were you I'd just look at getting a whole new module from Vulcan before I ran a sump. Just food for thought.