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

[WyoJim]

Lets assume we are injecting and burning 15 GPH and we are getting 20 MPG. Would that mean we are going 300 miles per hour?? Hmmmm!

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98. 5 24 valve auto, QC, LB, EZ, DTT vb 9 1/2ft 3500# slide in S&S Camper

 

[Un-Hemi]

WyoJim, if you can get 20 mpg at Wide Open Throttle, yer a better man than I, WyoJim! At WOT you might be going 300 mph with the HP MM is developing.
Just joking, guys! See? Ya gotta read it carefully!
Tom
p. s. Apologies to Rudyard Kipling
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Tom Glover - VE7DQ, C-GWTG
99 QC SLT, LWB 4x2, ETC/DGP, Wht/Agate, etc.

[This message has been edited by TommyTurbosaurus (edited 04-30-2001). ]

 

[Bill Kondolay]

Tom
The vp44 pump does not allow any excess fuel in, that is why we are seeing the higher pressures at the inlet of the vp44 pump with NO increase in flow.
Bill

 

[Mopar-muscle]

tommy turbo , interesting thought on removing the overflow and putting in an orifice , but unless you do some type of mod to increase flow thru the VP44 itself , taking away the overflow valve could cause problems internally , the VP44 is designed use only to use a certian amount of fuel , as the flow meter in the return line showed , messing with its charteristics is an area i won't tread on .

i'm sensing some frustration from a number of people , its hard to understand this flow vs. pressure thing as we have been led to believe that more pressure equals more flow . it took alot for me to change that way of thinking and a few guys have alot invested because of that way of thinking .

as bill said above , cleaning up the banjos (mine will be completely removed though i am now thinking of running a couple of tests with different sized holes to keep WOT pressure at 2-4 psi with different configurations as the pressures i saw on the test mule used unmodified banjo bolts (2) and an unmodified filter housing ( mines been monkied with) . also move either the factory lift pump (or a moderate flow pump with an internal bypass and pressure adjusted to no higher than the factory dodge spec) as far rear ward as possible ... there is a hole in the framerail behind the tank with this in mind i may have a second pump on the engine as a back up , still hate to be stranded .

i'm opting for the factory pump but will be looking to see if carter has a lower gph 15psi pump as i looked in summit catolog and their 76gph pump is only 7 psi .

 

[Un-Hemi]

Bill, I agree. The VP-44 won't (can't) deal with the higher pressures. . While it is using whatever fuel it requires to run the engine, it can't vent the extra volume made available by the higher pressure because of the restriction of the regulator valve, which will be wide-open. Because of the valve's construction, it's possible that it 'maxes' out on return flow. It becomes the 'most' restriction in the system, and it's 'after' the VP-44.

I think that instead of not allowing excess fuel in, rather, it cannot allow excess fuel out! Higher pressures in the VP-44 could cause significant damage if the seals were to blow.

Bill, a question: Is the hole in the inlet of the VP-44's regulator valve as large as the one for the P-pump? I had a look at a P-pump regulator on Friday, and the entrance appeared to be about . 125 or so. Not very large, in my estimation.

Thanks for your consideration.

Tom

[This message has been edited by TommyTurbosaurus (edited 04-30-2001). ]

[This message has been edited by TommyTurbosaurus (edited 04-30-2001). ]

[This message has been edited by TommyTurbosaurus (edited 04-30-2001). ]

 

[Mopar-muscle]

TT , no i haven't plumbed it from the outlet of the VP44 , right now the flowmeter and myself are 3000 plus miles apart , if its owner can't do this test , then i'll have to make arrangements for shipping to get it here and do the test . i may get it anyway as i would like to compare the test on another RAM to back up our original numbers .

i still find it hard to believe that there is that much fuel coming from the head , i've seen the size of the orifice in the barrel valve of the VP44 , its barely . 90 , if its even thats big . no matter how fast it spins i can't see 30 plus gph going thru it . but what do i know .

bill the carter pump number is 4594 , 7psi 76 gph . summit price is 52. 95 , US .

 

[Un-Hemi]

MM, this is where I start to get on shaky ground. Where's the barrel valve? Is that part of the high-pressure distribution system? If it is, then rest assured that you can crank a huge volume of fuel through it at 17000 psi or whatever it runs at.

There are 6 injectors. If the flowback from the manifold is 30 gph, then each injector is releasing . 0833 gallons per minute into the return manifold. That's less than a 10th of a galloon. #ad
each. Per minute. Is that a lot? I don't know. At WOT your engine is turning, what?, 3200 RPM? Each injector is cracking 1600 times a minute. There are 1600 events per minute happening with each injector, perhaps enough for each injector to put out . 0833 gallons per minute into the return manifold. That's . 000026 gallons per event. Not much diesel. I apologize. It wasn't my intention to dazzle you with numbers, just my attempt to illustrate that sometimes lots of little piddles can turn into quite a stream.

I'm kinda sad, in a way, that I have become so embroiled in all this. I think I know the secret of the Caramilk bar, so to speak, but I can't put my money and time where my mouth and my thoughts are right now. Sorry.

I could also be totally, utterly, absolutely wrong about all this, but, at least, I will have learned a lot more about the fuel delivery system on the 24V than I knew before!

Carry on the excellent work.

Tom

[This message has been edited by TommyTurbosaurus (edited 04-30-2001). ]

[This message has been edited by TommyTurbosaurus (edited 04-30-2001). ]

[This message has been edited by TommyTurbosaurus (edited 04-30-2001). ]

 

[TXRam]

Hey Tommy, we're on the same page with this!

Bill, give me a call and we can discuss the pressure vs. flow stuff.

I would say until we learn more about the VP44, rule of thumb would be maintain between 2-15psi at the inlet under ALL conditions. This should mean that you don't overwork it by making it "pull" fuel from the lift pump and that it isn't overpressured at the inlet.

 

[Bill Kondolay]

I love threads like this one.

Remember there are 2 pumps inside the vp44 pump.

I will try to hook up the flow meter on outlet of the vp44 pump on tuesday.

bill

 

[Arcticat]

MM you've got to get that flowmeter up here! I'll split the shipping with you and we can meet up this weekend in NJ. I would really like to put the meter on my truck, reason being that I am fairly sure the Summit pump I'm using is not internally bypassed, meaning that either it's flowing way more through the return line than the carters' 30gph, or that it will burn out very soon because it is hitting a roadblock at the VP44 and is working itself to death trying to achieve it's rated 140gph. Either way, we will learn something new I'm sure.

 

[mikel]

The docs that come with the Summit pump show it operating in a configuration that does not have a return line. I take that to mean that it has to be internally bypassed, and must be able to operate w/o a return.

Mike

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'99 QC 2500 SLT Driftwood 2wd SB 24v Auto 3. 55 LSD
ISSPRO boost and pyrometer, Autometer 3 gauge replacement pillar, Walker 24168, DTT VB
'00 Durango SLT 360, 3. 55, Patriot Blue
-- email address removed --
Howdy Agg's!

 

[Un-Hemi]

Arcticat, Mikel is correct. Very few pumps are *not* internally bypassed. Internally bypassed pumps are designed to do what they do, for a long time, so don't sweat it. The pump is only *capable* of delivering XXX gph (its MAXIMUM rated output) before the output pressure starts to drop. With any demand below XXX gph, the pump simply recirculates excess (XXX - demand) fuel internally. Again, it's simply the way it works. Nothing trick or complicated.

I have seen a few Whiz-bang race pumps that have an external bypass regulator mounted to the pump body that are designed to route excess fuel back to the tank, but they are the exception to the rule. They are normally on the stratospheric end of the price ladder, too.

Im most commonly available rotary electric pumps, excess fuel is normally routed from the output side of the actual pump cavity around to the input side of the cavity through a shuttle valve backed with a spring that sets the output pressure of the pump. This is inside the pump body. They're designed to work that way. For a long time. It's what they do.

 

[CCahill]

I'm not the techie that some of you are, and I do appreciate the work you guys have done..... My ? is this. . Isn't flow what we're looking for as opposed to pressure? Has any body hooked up a flow meter before and after the VP44 to see what the volumn is. I know that more pressure=more volumn, to a point. Then you have restriction in the inside surface of the line with even more pressure, if you try to get more flow. Just seems like we need the meters to tell us what's goin' on.
Theas guys like HVAC, and Joe Donnely are making a bunch of power and need more flow and pressure. . What do us mere mortals with minor mods REALLY NEED?. . I think Bill K. might have a good point, that most of us can get by with modified banjos and the like. . With Stage II's and a hot PE, what volumn and pressure doe's a guy really need?


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2001 Quad,4x4,AT,4. 10LS,LB,Loaded enough,stock,mostly... . 65 Chevelle sedan, Hella nice driver, 53 Nash Rambler Convt,1 of 653 built,[not a Metro], GM drivetrain, injection, and auto/od
Specialized FSR PRO Stumpjumper,Cannondale F2000, Loaded
MTD Lawn tractor with flames
12' fishin' boat, loaded. .

 

[Un-Hemi]

Does anyone out there know what the brake specific fuel consumption (BSFC) of the stock 215 HP ISB is? That will tell you how much fuel the thing requires for every horsepower it puts out. Can anyone point me to it?

Tom


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

[This message has been edited by TommyTurbosaurus (edited 05-01-2001). ]

 

[mikel]

TT,
Seems like that info was in one of the last two issues of the TDR. I'm at the office now, but I'll look tonight when I get home if nobody else get's it for you before then.

Mike

 

[Bad340fish]

Might check the engine plate on the timing cover, I think it has some info like that on it. Keep up the good work guys


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Clark
1999 2500 QC SB 5spd, EZ, Flowmaster 3 chamber, K&N Re-0880
1968 Barracuda Formula S Viper Blue 11. 98@112 Currently scattered all over the garage

 

[Todd T]

I'm not going to say who from, I dont want to drag him into this, but I have been told by someone we all know well in this business, that he believes "starvation" is not the cause of the pump failures. he has had several failed units apart and says they are failing do to the pump not getting fuel (lubrication) during closed throttle. and he believes that between shifts the pump is not getting any fuel and friction welding the rotor head to the shaft.

what do you all think of this point of view.
and please, if you know who I am talking of, dont say it here. I'm sure he doesnt want to comment at this time. I would just like to add a different point of view to look at this from.

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Todd,
2001 Q-cab SB 4x4 5spd 3. 55's,PowerMax3 adj. , A pillar Boost/EGT,4" turboback exhaust,custom built aluminum airbox W/K&N-RE0860 through the cowl, 310HP/675ft-lbs and more to come...

 

[Mopar-muscle]

huh?????

if the lift pump is running the injection pump is getting fuel , the injection pump spins with the engine and as long as you have a fuel source , the engine is running , its getting fuel to lube , cool and keep the engine running .

 

[Todd T]

yes this is true, MM, its letting just enough fuel through to keep the engine idling, but the pump is still winding down from 3200-3400 engine RPM's and only passing enough fuel to idle the engine... . so where is the rest going... . ???

 

[mikel]

Earlier I said I'd post about the BSFC of the 24 valve, so here it is. In issue 29 on pg. 48 is the info about BSFC. It says 2000rpm/. 334 and 1600rpm/. 337 and from the looks of the microscopic graph that was included, 3300rpm/. 4. I believe that all of these numbers are lbs/Bhp/hour.

Hope this helps,
Mike