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Engine/Transmission (1998.5 - 2002) Poll: What Kind Of Lift Pump Do You Run
- Thread starter GWedekind
- Start Date
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Engine/Transmission (1994 - 1998) 12-valve Engine Miss Poll (please read before voting)
- Vaughn MacKenzie
- Replies: 9
- Status
yes, but even the FASS hasn't proven to be long-term reliable. Lots of reports on here about hitting them to get them going and other annoying little problems.
IMO, the ultimate LP solution is an aftermarket 24V cam with a matching LP.
Consider the ~$600 cost of a FASS. Now consider that you can get a PREMIUM camshaft (the best on the market, imo) for $750, and add a mech LP to that for ~$120.
So for, $600 you can get an unproven FASS.
Or, for $870, you can get a stone-axe reliable, never-have-to-touch-it-again fuel system, and a cam that gives vastly improved response, practically eliminates lag, lowers EGT, and gives better MPG!!
Can a FASS eliminate lag, lower EGT, and give better mpg????
Even going bigger on the camshaft, and adding $600 for valvesprings, it's still a BARGAIN in my book.
Remember-- price is not value. Value is what you GET for a given price. That's why I say that an aftermarket cam from Don M (F1diesel) or Piers Diesel that has the LP lobe on it is a STEAL.
JMO
IMO, the ultimate LP solution is an aftermarket 24V cam with a matching LP.
Consider the ~$600 cost of a FASS. Now consider that you can get a PREMIUM camshaft (the best on the market, imo) for $750, and add a mech LP to that for ~$120.
So for, $600 you can get an unproven FASS.
Or, for $870, you can get a stone-axe reliable, never-have-to-touch-it-again fuel system, and a cam that gives vastly improved response, practically eliminates lag, lowers EGT, and gives better MPG!!
Can a FASS eliminate lag, lower EGT, and give better mpg????
Even going bigger on the camshaft, and adding $600 for valvesprings, it's still a BARGAIN in my book.
Remember-- price is not value. Value is what you GET for a given price. That's why I say that an aftermarket cam from Don M (F1diesel) or Piers Diesel that has the LP lobe on it is a STEAL.
JMO
The stock pump with a 4600 pushing to it seems to work great. That with some bigger lines/fittings from the stock pump up to the VP44 will support big HP.
Support big HP, yes.
Reliable? NO! Been there done that...
Is the FASS reliable? I'm no longer so sure. Having it in the truck for about 1. 5 years. I have to stretch the spring once every 2 month. And yes, it's already the stronger spring they provide upon request. Soooo, what Hohn sez looks every day more like a musta have it to me. :-laf
Marco
I started this poll because I tried the Carter 4601HP pumps relocated at the frame and went through 2 in a year ( approx 20K miles each) and now having issues with Holley Blue(s) with fuel pressure flux. Just like Marco mentioned, Im also stretching springs to try and keep the pressure up there. So if FASS has the same popet design as the Holley for an internal pressure relief Im considering keeping the Holley and plugging the internal bypass almost completely closed which brings the pressure up to about 25-30 psi and running a return style regulator to get it back to a reasonable 10-15psi. I did this one time before on my race car with Methanol as a fuel and it worked great and the pump lasted along time ( 3 seasons ) before I switched back to gas.
Marco said:
I disagree. I've put over 50k on my current truck over the last 1. 5 years with no problems. We have sold lots of those and they work very well.
If you want complete reliability, install the old 12v lift pump setup and a cam. 'Course, you'l spend 5x the money doing it. If you figure out how many pumps you can replace for that cost, I'm sure you'd see that it would take quite a few failures to make the 12vLP/cam setup more economical.
Just got done reading the "pumps, lines and want not " post... . whew!
Regarding the Carter reliablility issues, I think back on my 2 4601 pump failures and they both still spun when powered, they just stopped producing pressure and volume. I dissasembled and inspected them and found no visible damage to the rotors or vanes. I kept one of them and used it one time as a spare for transferring fuel from a 55 gal drum and noticed that it still pumped but very very little. So maybe the failures on the relocated carters could be that the internal bypass was stuck open. Carters arent serviceable like the holleys and I bet the failures out there on relocated carters are the internal bypass. I have to fess up. . I didnt and dont run a prefilter. Holley and Carter has a brass prefilter screen inside that can be removed and cleaned but I bet they are bigger than 20 micron.
Regarding the Carter reliablility issues, I think back on my 2 4601 pump failures and they both still spun when powered, they just stopped producing pressure and volume. I dissasembled and inspected them and found no visible damage to the rotors or vanes. I kept one of them and used it one time as a spare for transferring fuel from a 55 gal drum and noticed that it still pumped but very very little. So maybe the failures on the relocated carters could be that the internal bypass was stuck open. Carters arent serviceable like the holleys and I bet the failures out there on relocated carters are the internal bypass. I have to fess up. . I didnt and dont run a prefilter. Holley and Carter has a brass prefilter screen inside that can be removed and cleaned but I bet they are bigger than 20 micron.
Other - RASP
One thing I am finding out about the RASP that I find appealing. I am trying to get to the point of cooling the fuel to the VP44 enough that it will run at OAT fuel input temps. This means I am opening up the fuel system A LOT! Adding a cooler, changing the flow, replumbing this and that. Well, each time I open the fuel system it has to be purged. I think I have it purged, it cranks up just fine, runs just fine,
THEN
I am running along with the RASP at 17# and suddenly a blurb of air hits the RASP and 17# drops rapidly to -> 10psi (because the hobbs switch senses the RASP is not pumping and turns on the lp. The lp is in a different location (on the frame) and has good fuel available and keeps the VP at 10 psi). Then the RASP processes the air bubble in a few seconds and picks up the fuel delivery right back to 17#. Which also verifies the hobbs switch and the lp.
I really feel the mechanical (one source) WITH electrical (second different source) backup is about as fool proof as it gets. Even a mechanical like the 12V had I feel still needs a backup of some sort to be more redundant and reliable.
After using the RASP even if I did a camshaft driven lp I would still put a electrical lp on a hobbs switch JUST IN CASE the mechanical pump diaphram failed and to provide 10 psi before the first revolution of the crankshaft.
my . 02
Bob Weis
One thing I am finding out about the RASP that I find appealing. I am trying to get to the point of cooling the fuel to the VP44 enough that it will run at OAT fuel input temps. This means I am opening up the fuel system A LOT! Adding a cooler, changing the flow, replumbing this and that. Well, each time I open the fuel system it has to be purged. I think I have it purged, it cranks up just fine, runs just fine,
THEN
I am running along with the RASP at 17# and suddenly a blurb of air hits the RASP and 17# drops rapidly to -> 10psi (because the hobbs switch senses the RASP is not pumping and turns on the lp. The lp is in a different location (on the frame) and has good fuel available and keeps the VP at 10 psi). Then the RASP processes the air bubble in a few seconds and picks up the fuel delivery right back to 17#. Which also verifies the hobbs switch and the lp.
I really feel the mechanical (one source) WITH electrical (second different source) backup is about as fool proof as it gets. Even a mechanical like the 12V had I feel still needs a backup of some sort to be more redundant and reliable.
After using the RASP even if I did a camshaft driven lp I would still put a electrical lp on a hobbs switch JUST IN CASE the mechanical pump diaphram failed and to provide 10 psi before the first revolution of the crankshaft.
my . 02
Bob Weis
pardon my brutal honesty here but, the Holley Blues are known in the gaser world as being pretty crappy and unreliable. I had one on for about a month backing up the stock LP and just didnt trust it. I replaced it with the mallory 4140 (140GPH)
my pressures are 18 at idle and 13-15 or so at a constant speed on the highway. i cant pull it below 10PSI no matter how hard i try. that includes 10K hooked behind me and 60PSI of boost trying to break Barney Olfield's qualifiing time.
the Mallory is a bypass style and yes you can adjust it down to around 11PSI or so. I let it run wide open for pump life. I carry a rebuild kit for the brushes and seals in the glove box. i also have the stock LP on the engine still with it just capped off. i can easily open one line remove the union and fit it to the inny and outty of the stock LP and be back on the road in minutes. havent had to exercise that option yet though.
some may say the idle pressure is too high, i agree to disagree on that. i dont idle around, i drive it. my truck is very quiet at idle and while running down the road. i attribute that to good pressures and good fuel lubricity (I supplement with additives).
I'm just under spec running down the road and like it that way. I guess i could put a bypass return regulator up front somewhere but why complicate things is my thought. i could probably carry more volume if i replaced the stock filter housing with a higher flwing racor too, but why complicate things?
I dont prefilter either. I do filter (10micron) my 25 gall spare tank in the bed ahead of dumping it in the truck's tank.
my pressures are 18 at idle and 13-15 or so at a constant speed on the highway. i cant pull it below 10PSI no matter how hard i try. that includes 10K hooked behind me and 60PSI of boost trying to break Barney Olfield's qualifiing time.
the Mallory is a bypass style and yes you can adjust it down to around 11PSI or so. I let it run wide open for pump life. I carry a rebuild kit for the brushes and seals in the glove box. i also have the stock LP on the engine still with it just capped off. i can easily open one line remove the union and fit it to the inny and outty of the stock LP and be back on the road in minutes. havent had to exercise that option yet though.
some may say the idle pressure is too high, i agree to disagree on that. i dont idle around, i drive it. my truck is very quiet at idle and while running down the road. i attribute that to good pressures and good fuel lubricity (I supplement with additives).
I'm just under spec running down the road and like it that way. I guess i could put a bypass return regulator up front somewhere but why complicate things is my thought. i could probably carry more volume if i replaced the stock filter housing with a higher flwing racor too, but why complicate things?
I dont prefilter either. I do filter (10micron) my 25 gall spare tank in the bed ahead of dumping it in the truck's tank.
well Robert and i posted at the same time. I like the research Bob has done and feel it IS important. I havent seen a substantial yield in results to justify the plumbing and logistical nightmares arrising from a system like his, or the cost for that matter.
I tend to be a minimalist when it comes to this. less is better. I sourced parts that are readily and are off the shelf available in most places i go. i have a failover (the stock LP) i also have repair parts with me (rebuild kit for the mallory) it supports 550+ HP and i cant complain. if i lose a VP over it then I'll still be money ahead as i see it.
i disagree with Keith's comment too. I'd like to point out a cam change is often done for other reasons. a LP lobe is just an added bonus. so you are really just talking about the cost of a 12V LP when looking at it this way. I had 245,000 miles on my last 12V'r and 320+ hp before the warmed over (tighter spring) factory pump let go. so I dont see a need for a back up system in that scenario.
you cant get much simpler than a pump, heated (stock) fuel filter and a pressure guage. $300 tops.
I tend to be a minimalist when it comes to this. less is better. I sourced parts that are readily and are off the shelf available in most places i go. i have a failover (the stock LP) i also have repair parts with me (rebuild kit for the mallory) it supports 550+ HP and i cant complain. if i lose a VP over it then I'll still be money ahead as i see it.
i disagree with Keith's comment too. I'd like to point out a cam change is often done for other reasons. a LP lobe is just an added bonus. so you are really just talking about the cost of a 12V LP when looking at it this way. I had 245,000 miles on my last 12V'r and 320+ hp before the warmed over (tighter spring) factory pump let go. so I dont see a need for a back up system in that scenario.
you cant get much simpler than a pump, heated (stock) fuel filter and a pressure guage. $300 tops.
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Todd I like the mallory gerotor design. i had one on a drag car that i used to race and it was nice and reliable. Yes the Holleys have a reputation but it was always the bypass sticking when ever they acted up.
The rasp setup like Bob Weis has sound pretty good but with a mild truck I think a decent electric set up is for me.
Prefiltering may be something to think about. My tank had some growth in it that kinda looked like brownish silicone that plugged up my inlet screen. It took about 150,000 miles to get to the point where I couldnt draw fuel out of it. When I dropped the tank I found the inlet screen sucked in and ripped. I removed all I could and the secondary screen that was inside the center of the module assy was also plugged solid. I cleaned the tank completely and installed the new DC in tank pump assembly which was cheaper than replacing the old style pick up assy. I have 5 psi at idle, 2 psi at cruise and afraid to open it up any further. I have no banjos and unrestricted #6 line all the way to the filter and VP. Before reading the "pumps lines and wantnot" post I thought that I really need fuel pressure but now the volume theories have me spinning. Without banjos and line restrictions I may have the needed volume with no pressure. DC follows that theory also when testing lift pumps but Im old school... pressure means GOOD and no pressure means BAD. So I hooked up the Holley blue to supplement the in tank and thinking about getting that in tank pump outta there.
Todd, How many miles are on your truck and did you ever have the tank unit out?
The rasp setup like Bob Weis has sound pretty good but with a mild truck I think a decent electric set up is for me.
Prefiltering may be something to think about. My tank had some growth in it that kinda looked like brownish silicone that plugged up my inlet screen. It took about 150,000 miles to get to the point where I couldnt draw fuel out of it. When I dropped the tank I found the inlet screen sucked in and ripped. I removed all I could and the secondary screen that was inside the center of the module assy was also plugged solid. I cleaned the tank completely and installed the new DC in tank pump assembly which was cheaper than replacing the old style pick up assy. I have 5 psi at idle, 2 psi at cruise and afraid to open it up any further. I have no banjos and unrestricted #6 line all the way to the filter and VP. Before reading the "pumps lines and wantnot" post I thought that I really need fuel pressure but now the volume theories have me spinning. Without banjos and line restrictions I may have the needed volume with no pressure. DC follows that theory also when testing lift pumps but Im old school... pressure means GOOD and no pressure means BAD. So I hooked up the Holley blue to supplement the in tank and thinking about getting that in tank pump outta there.
Todd, How many miles are on your truck and did you ever have the tank unit out?
Todd T said:
I agree that doing a cam has a lot of other benefits, and usually the LP part of it is a side bonus. In this context, it was brought up as a solution to the LP issues. As strictly a LP fix, it's a very expensive fix.
If you plan is to do a cam down the road, then it is the way to go, IMO.
GWedekind said:
I'd be afrraid to back out of the driveway with those pressures. you should think about more volume and pressure if this is the case. if you are stock and only have 2PSI you'd never survive a fueling box of any kind for very long. i think those in-tank units are what 90GPH or so? my theory is that if at idle i'm blowing fuel past the overflow then i'm potentially blowing any air back out of the system too (it will take the path of least resistance). with lower pressures and less volume a bubble could stay trapped downstream until the flow picks up. (reads when you stomp on it and are working it hard).
the overflow is rated at 14PSI or there abouts. i'd prefer to be right on the edge of that and stuff as much fuel into it as i can at any given moment. keep that overflow open and circulate as much fuel as it can handle.
Gwedekind said:
i have 150K and some change on it now. it was bone stock with 132K on it when i bought it from Texas. I had this thing down to the short block and back a few times already but have never pulled the tank. my pressures arent indicating i need to at this point. a 5PSI drop at WOT is within reason when you add up the amount of fueling i have. (BD5's and the TST PM3 comp)
Pumps lines and whatnot. Greatest thread ever, too bad so many miss it.
Greatest flow occurs at 0PSI, yes ZERO. Why? Anyone ever used a CB radio and wondered why the antenna was 52 ohms? That is because the impedance of the transmitter output circuit is 52 ohms. Then coax cable is 52 ohms, so for maximum efficiency, the antenna must be the same 52 ohms.
If the antenna is other than 52 ohms some of the energy is "reflected" back towards the transmitter. VSWR or SWR of 1. 1:1 is the theoretical best.
Back to the fuel system. If the LP produces MORE fuel than the VP needs, some of the fuel is backed up (reflected back like above) in the lines. We call this pressure. Any SWR over 1. 1:1 or line pressure between the LP and VP, decreases efficiency. If the LP doesnt produce ENOUGH fuel we still get pressue but it is measured in - PSI (vacuum).
The *ideal* LP would produce EXACTLY the fuel the VP needs at any time and have an operating pressure of 0.
The VP has a vane pump on it's inlet that pulls fuel into the HP pump, then controls volume & timing for injection. This is why the VP can run without a working LP. The problem enters when the LP fails and the stalled vanes in the LP act like a closed valve making the VP work VERY HARD to pull fuel.
The simularity between VSWR and working pressure are very close but not exact. You can get the idea.
Any extra pressure applied to the VP simply opens the VP byapss valve. EXCESS PRESSURE DOES NOT COOL THE VP, it only opens the bypass valve.
Now I will crawl into my fox hole and wait for the rocks to start flying :-{}
Greatest flow occurs at 0PSI, yes ZERO. Why? Anyone ever used a CB radio and wondered why the antenna was 52 ohms? That is because the impedance of the transmitter output circuit is 52 ohms. Then coax cable is 52 ohms, so for maximum efficiency, the antenna must be the same 52 ohms.
If the antenna is other than 52 ohms some of the energy is "reflected" back towards the transmitter. VSWR or SWR of 1. 1:1 is the theoretical best.
Back to the fuel system. If the LP produces MORE fuel than the VP needs, some of the fuel is backed up (reflected back like above) in the lines. We call this pressure. Any SWR over 1. 1:1 or line pressure between the LP and VP, decreases efficiency. If the LP doesnt produce ENOUGH fuel we still get pressue but it is measured in - PSI (vacuum).
The *ideal* LP would produce EXACTLY the fuel the VP needs at any time and have an operating pressure of 0.
The VP has a vane pump on it's inlet that pulls fuel into the HP pump, then controls volume & timing for injection. This is why the VP can run without a working LP. The problem enters when the LP fails and the stalled vanes in the LP act like a closed valve making the VP work VERY HARD to pull fuel.
The simularity between VSWR and working pressure are very close but not exact. You can get the idea.
Any extra pressure applied to the VP simply opens the VP byapss valve. EXCESS PRESSURE DOES NOT COOL THE VP, it only opens the bypass valve.
Now I will crawl into my fox hole and wait for the rocks to start flying :-{}
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Texas Diesel - Any extra pressure applied to the VP simply opens the VP byapss valve. EXCESS PRESSURE DOES NOT COOL THE VP, it only opens the bypass valve.
Where IS the bypass valve located? How does it mix with the fuel that DOES go through the Vp44 for cooling? Does the bypass valve bypass the incoming excess pressure directly to the VP44 fuel return?
Bob Weis
Where IS the bypass valve located? How does it mix with the fuel that DOES go through the Vp44 for cooling? Does the bypass valve bypass the incoming excess pressure directly to the VP44 fuel return?
Bob Weis
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