Engine/Transmission (1998.5 - 2002) pumps, lines & whatnot

[csutton7]

Blkdemon--man to offend me is pretty tuff to do--I didn't even think of it as offensive--I knew what ya meant--so no problem----so your regulator is between the filter & VP is that right??---chris

 

[Blkdawdg]

My regulator is between the pump and the filter.

 

[Bill Kondolay]

What happens if you pump too much fuel does the fuel heat up?

 

[willyslover]

Bill. . can't help but to get heated up in my thought process. . In the injected Sprint cars we used high volume low pressure [at the pump] and big return lines [gas again of course]. . logic for me is the same approach with diesel. . but again diesel is not my strong suit. . so I'll just idle on the sidelines on this one

 

[Bigsaint]

I have been running this over and over in my head, as most of you have. Is it really about pressure or volume? If you you have a pump that is rated at 140 GPH, way more than we could ever use and your WOT FP is around 1 or 2 psi's, is that pressure reading high enough as their is still volume going in ? I realize that 0 psi's is no good, but what about 1 or 2 ? If the VP44 is calling for fuel, the lift pump is running at say 10 psi's, but the "gates" are open as the VP44 is using the fuel as it is provided by the lift pump, so, instead of seeing 10 psi's, you see 1,2,3, or whatever, below your normal cruising FP reading as there is less restriction on the inbound fuel that is being pushed forward by the lift pump. The only way I can describe it would be the garden hose, mentioned earlier. Say you turn on the garden hose, with the sprinkler attached, wouldn't the pressure of the water be higher as it comes out of the sprinkler head, compared to if you removed the sprinkler and just let it run out of a open hose. You would still have the same volume, but less restriction and therefore less psi's. What do you think ? I was talking to Mike at A. W. D about this the other day and he is also under the belief that, unless you have less than 1-2 psi's at WOT, the volume is still there and you are okay. The only way to test this to confirm that you are okay, in my mind, would be if there is still smooth acceleration at WOT, i. e. , no bucking or missing. If your truck see's, lets say 1-2 psi's at WOT, but accelerates smoothly with no hesitation, etc. , would it be a safe assumption that the VP44 is happy with the volume that it is receiving ? Ouch, I have a large headache now !!!

Scott W.

 

[Bill Kondolay]

Lets say you have 14 psi at the inlet of the vp44 pump at wot or if you have 3 psi at the inlet of vp44 pump at wot which pump will last longer? Which one is flowing more feul back to the tank 14 psi or 3 psi?

 

[Mopar-muscle]

well some of you guys ain't gonna like this , especially those led to believe (and those that believe it) ... the bigger is a MUST theory .

spent a couple minutes #ad
running some tests with a DIGITAL/mechnical flow meter and a MECHNICAL fuel pressure gauge , items under test ... 2000 RAM , DD2's , DD TTPM on level 2 (??) and a HOT PE , ( all levels tested the same at WOT)factory pickup , factory lift pump , factory fuel filter housing unmodified , all banjo bolts intact and unmodified except the banjo to the input of the lift pump is replaced with a 90* swept areoquip type -6AN hose end , the bolt at the lift pump had the schrader cut off and drilled and tapped to a 1/8 npt ( for the gauge) and the banjo fittings between the lift pump and the fitler housing have been drilled to 9/32nd . again all banjo bolts are not drilled out as i have on my ram ( test conducted on the DTT RAM ) .

we installed ( LaserBob is helping me and getting #2 fuel poured on his head #ad
#ad
) a Sonnex digital flow meter ( inside ID is 5/16") in the return line back to the tank , cut in right at the trans crossmember . gph numbers are fuel returned to the tank .


DD2 , DD TTPM
FP volume
idle 11 psi 18gph

cruise 8 psi 24gph

WOT 2 psi 30gph


DD2 , TTPM , HOT PE ANY LEVEL
FP volume
idle 11 psi 18gph

cruise 8psi 24gph

WOT 0 psi 30gph


yes you read that correctly , fuel pressure went to 0 and the fuel volume back to the tank did not change from WOT with 2 psi . the truck did NOT stumble , buck , spit , fart , fall on it's face , nothing , ran like all heck at 0 psi , i will note , my truck ran the same at 0 psi with the DD3's , EZ and a HOT PE .

tomorrow we will install -8 lines and an HP carter pump , take flow readings in exact same spot and see what the results are .

 

[Bent6]

I'm going to chime in on this subject even though I don't even begin to pretend being an expert on diesel fuel systems. The whole problem here is the injection pump scenario. When and if DC/Cummins gives us a common rail fuel injection system, the problems will be solved. This is where I am drawing my knowledge and opinions from.

As anyone can see from my signature, I know what it takes to provide a 1400hp turbo engine with fuel but there again it is a gasser. We run 3 pumps to the rail - it is a common rail system with electo-mechanical injectors with pressure regulated according to manifold boost pressure. In turbo gassers, fuel pressure/volume is directly proportional to turbo boost. Evidently, the same does not apply to a diesel engine. The engineers at DC/Cummins never intended for the wick to be turned up on these beasts - this is where it all begins.

The first problem we have begins with the lift pump. It has been my experience, as well as that of many other of my Turbo Buick brethren, that fuel pumps work much better as "pushers" than "suckers". A well thought out "sucker" pump will be okay as long as it has a good "pusher" behind it but this should be avoided if at all possible. For this reason, I feel that a lot of the problem could be solved if we could come up with a submersed pump in the tank itself that has a constant supply of fuel to "push" instead of "suck". Next, we need to determine the amount of pressure drop through the filter/heater. Finally, we need to measure the pressure at the VP44 INLET. The only uncertainty to me is the VP44's return of fuel to the tank - similar to a common rail system. In the race car, a common rule of thumb is that as long as you don't see a pressure drop @ WOT in high gear, you have enough fuel pump. From what I have read, the VP44 returns any unused fuel to the tank, therefore, if we could determine that the VP44 is still returning an adequate amount of fuel to the tank, we could assume(this term has burned me more than once!) that it has enough fuel since it is only going to use what it needs. We can hit the VP44 with 200psi of pressure, but it can only flow so much fuel and that's it! I feel as long as the pressure to the VP44 stays above 5psi or so, it is getting all the fuel it can use. Now this is not to say that the stock lines will be adequate for a seriously modified engine but you should be getting the picture. Throw in a hot fueling module and the whole flow capabilities of the VP and the lines change.

It seems to me the ideal setup would be as follows:
1) In-tank lift pump
2) Adequate sized line (AN 6-8) throughout
3) Return type regulator between filter & VP44
4) Return lines to tank from regulator & VP44
5) Fuel pressure readings taken after the regulator/before the VP44

Depending on the amount of restriction/pressure-drop through the filter/heater, the regulator may need to be located just before the filter/heater to avoid overloading it. Sorry so long but these are just my thoughts from my racing experience with a turbo gasser. The flow qualities of diesel fuel are unknown to me.


Mopar-muscle - you must have posted while I was typing this. From what your tests indicate, my theory that the VP44 will only use the fuel it needs are true. If the flow #'s being returned to the tank were as good as you say, the 0psi is not a problem. It seems the pump is flowing freely - if there were a fuel starvation issue, the return #s would have shown it and the engine would have definitely been cutting out/popping to let you know!
------------------
Will - -- email address removed -- - 98. 5 3500, black, 24v, auto, 4. 10, fold-away gooseneck hitch, Poweredge EZ w/ boost elbow, K&N Filter, Isspro 50# Boost, EGT (pre-turbo), transmission Temp gauges mounted on A-pillar, & more to come!
38ft United Expressline X-Treme Race Car Hauler weighing in @ 12000# loaded
Other Bad Habit:
'87 Pro-Street Buick Grand National, 272cid Stage II Buick V-6, SINGLE turbo, 1400hp, 1200ft/lbs @ 24# boost
Best 60ft: 1. 11
Best 1/8 mile: 4. 99 @ 142mph
Best 1/4 mile: 7. 70 @ 179mph
And Lookin' For More!!!
So I'm A Turbo Man!
Boost On!

[This message has been edited by Bent6 (edited 04-25-2001). ]

[This message has been edited by Bent6 (edited 04-25-2001). ]

 

[csutton7]

MM--you are a "DIESEL GOD"--do you plan to test a relocated pump and how many different pumps and how many different HP setups are in the mix???

Big Saint's analogy is correct and it makes sense--

0 psi doesn't mean there's no fuel-it means the VP is a mean sucking machine that can easily outrun the stock pump on the pressure side, but the stock pump still provides enough fuel for everything to work==volume, volume, volume makes everything work... .

The Mallory engineer said that the 3/8" supply and 5/16" return could handle a lot of HP and it looks like he wasn't blowing smoke--

can't wait for the next round of results--

BENT 6--couldn't have said it any better myself-but instead of an in the tank pump I'm headed for the bulkhead in the bottom of the tank to gravity feed the pump--like you said though pump placement and supply line route are extremely important and we shouldn't lose sight of this-even when we find out for sure that the stock lines can handle a lot more than we thought--the pumps are going out for a reason and I think it's placement & the tank supply that's causing this---whereas before I looped in the stock lines with the pump placement problem... .


GREAT JOB MM... ... . of course I'm sobbing thinking of my monetary outlay..... chris



[This message has been edited by csutton7 (edited 04-25-2001). ]

 

[Fred Swanson]

You better keep a close eye on Mr Bill, he's getting you all thinking and using your head.
Great last post MM. Everyone's thinking line pressure to the VP44, now we see gph on the return line. Flows are the same, even with additional juice to the injector pump. Sounds like enough fuel is feeding the VP, even at 0 psi inlet pressures.
Interesting to see gph readings on the return line, can the same tests show inlet gph numbers, to see how much fuel is being used up by the pump?


------------------
Fred Swanson
Co-Owner
Canyon State Components, LLC
www.canyonstatecomponents.com

'00 QC,SB,4x4,Auto,3. 54 w/LSD,Trailer Package,Tow Package,DTT's
TC(91%)(80psi),DD2's,EZ,HOT PE,K RE-0880,Cummins RED Valve Cover

[This message has been edited by cscpusher (edited 04-25-2001). ]

 

[Mopar-muscle]

chris , thanks , but you give me way more credit than i deserve , this is mostly because i'm a cheap SOB and don't want to spend anymore than i have to . if i had taken up an offer i got a few weeks ago , i'd have spent less than the couple hundred bucks i already did . as far as testing different pumps with different lines and configurations , thats tough , i can't see buying $1000 worth of pumps that are overkill for the job . the stock filter is a factor in total flow , but you can get as much as 60gph thru it , a bit more than designed , but the VP44 uses less . yes it is best to have a bit extra , but do we really need to feed something that requires maybe 45 gph at worst case ( WOT with 550 flywheel HP potential) with a pump that flows 220 gph ? that extra flow is going to cause a problem and carter is the only one that claims their pump can run continuously at max pressure , it has a built in bypass .

the dodge engineers only screw up is placement of the pump and how they feed it, on this system #ad
.

cspusher , yes he's funny that way , between this topic and taking in all i can trans wise , i'm afraid my head is going to explode #ad
. yes i could get a reading of flow feeding the pump , that will give total fuel flowing to the injection pump . with the amount of fuel flowing and amount returning we could see how much is required to actually fuel the engine . this type of data may have to wait till i return home and do it on my own truck as i have probably spent a bit more time than expected and its enchroaching on the real reason i'm here .

[This message has been edited by Mopar-muscle (edited 04-25-2001). ]

 

[Un-Hemi]

I don't understand how the lift pump can be returning MORE fuel to the tank at WOT than it does at idle. It doesn't make sense. Please explain.
Tom

------------------
Tom Glover - VE7DQ, C-GWTG
99 QC SLT, LWB 4x2, ETC/DGP, Wht/Agate, etc.

 

[mikel]

One thing that I am confused about (there are many, but I can only handle one at a time #ad
) is why would a regulator be needed on our trucks? Someone mentioned earlier in this thread that the vp44 return opens at 14psi, so as long as the supply pump was not putting out way too much volume, shouldn't the return on the vp44 serve as a regulator? By way too much volume I mean more than can physically be returned to the tank by the 5/16" hose.

Thanks,
Mike

 

[Steve Campbell]

So is it actually cavitation that shortens the life of the vp44 if allowed to get to negative (vacuum) pressure on the inlet side?

------------------
1999 Qcab 4x4 Driftwood
Lets move election day to April 16th Steve

 

[Todd T]

BZIN, yes cavitation and heat-up of the pump

Chris, keep in mind if you go with a bulkhead on the tank the pump (officially)needs to be mounted below it to avoid drainback when not in use.

 

[csutton7]

Todd T--got it covered, but thanks for the reminder

Mikel--need to add a regulator only if you exceed the capabilities of the stock return system--MM is right that it probably only takes a 60 gph pump to fuel these engines and the engineer I talked to said the same thing for up to 500 hp, so I would think that anything in the 100gph or above may require a return line, but even then a 100gph or 140gph pump may work great--problem being is how much can the stock line handle, so we know when to add the regulator --- a pump that flows more than 140gph should without a doubt use a return line IMHO----

 

[Todd T]

does anyone offer a 60-100GPH internally regulated pump? that would solve alot of plumming problems

 

[mikel]

Wasn't someone (MM maybe?) testing the summit 140gph pump? I wonder what the results of that were?

On the need for a regulator, wouldn't the pump need to supply high volume (more than 140gph) at the 14psi that it takes to open the return in the vp44? What I mean is 140gph at 0psi may equate to 70gph at 14psi depending on the pump, would this example need a regulator (140gph) or not (70gph)...

Thanks,
Mike

Thanks,
Mike

 

[Strick-9]

Tommyturbosaurus,

You asked how more fuel could be returned at WOT than at idle. At first that looked odd to me too. Here's how I see it.

The entire fuel system (all banjo bolts, filter, fuel heater) can be analyzed as a single restriction. Laws of fluid flow state that the higher the pressure drop across an orifice, the higher the flow through that orifice. If the pump maintains an output of 14psi then a lower pressure at the VP44 inlet will give more fuel flow.

My question is this. With all this new data, how do we explain HVAC's increase of 34 horsepower with his fuel system?

-Chris

 

[csutton7]

Strick-9... very good point, I think that the VP44 can use a lot of fuel otherwise why do we see a pressure drop when we floor it--that thing wants fuel to burn--yea it returns a lot but it's meant too, but the trucks that are on the higher HP level can use more fuel...

I think the stock lines can handle mild upgrades, but I want bigger lines for my truck and I don't want to see a pressure drop to 0 psi or below 10 psi for that matter--can I get it I don't know, but I'm trying--do I need it? well for now I do and that's the way I'm going--it just seems, like I said before, that the only way we can measure our fuel is with the pressure guage and if our guages start to read 0psi then we use this info to can the lift pump, so if this is the case why would you want to read 0psi at any time--it can't be good for the VP44, if it was then there wouldn't be a need for a lift pump in the first place!!!! Now what psi is acceptable at the lowest reading--me that's 10psi if I can get it through my -8 lines and top secret filter----for others it will be different-do I want more than 10 psi at the lowest reading-yes I do- but one has to be realistic at some point-eventhough some will say that's impossible with me--more of my . 02(talked with HVAC about the above and I believe he concurrs, to be honest he's way ahead of us in our thinking he just doesn't have the time to post everything)---

After talking with HVAC, and as I said in an earlier post, the gerotor pump is the style of pump to use vs. the sliding vane--I thought the BG was a gerotor, don't know how that slipped by me, but it's not-- they will have one out later this year--diesel is harder to move than gas and the vanes, I think, aren't up to the task for the long haul-builds up to much heat I think, but there are guys that are using them and are happy, so right now it's just out loud thinking and time will tell--

There are some in tank pumps out there & I believe Holley makes a gerotor style, but it'll take some adapting to make it work--how much-I don't know--I'd have to buy one and look at it to see---if this pump could work it would sure make life a lot easier for the mildly bombed and stock rigs and maybe for the higher HP rigs if you want to use the stock lines---downside is if it goes tits up you got to drop the tank---chris