Engine/Transmission (1994 - 1998) 12V LP - How Much Does it FLOW?

[TRadke]

I've only had my truck for a month now (my first diesel, LOVIN' IT!), so pardon the newbie question(s)... don't have any manuals yet.



How much fuel does the stock mechanical lift pump flow, say from 1500 - 2200rpm?

Obviously, output and pressure vary with engine speed, so I'm just looking for a range of volume/flow rate.



Truck is a 98 Quadcab 4WD Auto. Completely stone stock, 111K mi.



This site is a GREAT resource... sooooo much info, I'm having trouble getting any REAL work done .



TIA,

Ted

 

[Joe G.]

It flows enough for a lot of high horsepower modified engines. Most of the fuel goes through the injection pump and out the overflow valve to return the the tank. Is there a specific reason for wanting to know the flow rate? You might want to get hold of Piers at PDR and see if he knows.

 

[Bobcat698]

How would one get ahold of Piers, he left PDR months ago...

 

[TRadke]

Is there a specific reason for wanting to know the flow rate?

Yes, there is.



I want to design a fuel system for veggie oil (SVO/WVO) operation. Sure, I could just go out and buy a turnkey conversion kit... but where's the fun in that?



This will require a second fuel system, up to the P7100 IP. The stock fuel system will be retained intact (system will be switchable between VO and normal #2/Bio-D operation). I'm running B100 now, she likes it.



VO needs to be heated, to flow and atomize properly. A separate LP will be used to push the heated VO (100* - 150*) thru a filter and up to the P7100.

I want to make sure I spec the appropriate (electric) LP, with nice light current loading for long life... the trick is finding a 12V pump that can handle the heat in extended operation. Oil-scavenge pumps (dry-sump and/or turbo oil-feed) are looking promising, as they are designed for hot oil.



From what I see, lotsa VO types got The Blues from iffy pumps. I don't wanna be switching pumps out - I wanna do it once - I want Bombproof, befitting of the mighty Cummins.



I'd consider using the stock LP for double duty, but the plumbing run is kinda long, fuel-purge would take a while. Not real keen on the pressure fluctuations I'm reading about, either.



Since it's an auto, only light bombing is planned. I will never be pulling more than a 5K trailer/boat.

Ted

 

[Vaughn MacKenzie]

TRadke I can tell you from experience when the fuel line broke on my '96 I lost 1/8 tank of diesel in less than a mile- and there was still enough fuel getting to my inj. pump to keep me at 70 pulling a trailer with a car on it



You might want to read this https://www.turbodieselregister.com/forums/showthread.php?t=169045

and this about a guy's engine oil turning to slime https://www.turbodieselregister.com/forums/showthread.php?t=169925

before converting to WVO



Vaughn

 

[TRadke]

Vaughn,



Yeah, I saw that thread, but thanks anyways for the links.

(And thanks for the hydro sound files also!)

He admits that the problem was in his fuel prep (water removal). This is absolutely critical, and frequently overlooked/underappreciated.



You bet, there are some real issues to running this stuff successfully. Reliably. I truly believe it can be done.

There are tons of horror (and semi-horror) stories about conversions and fuel prep gone awry.



Believe me, I've been researching this for many months. Which is how and why I selected this particular powertrain.



I'm afraid a lot of folks rush into this, in "freedom-fuel" euphoria. I love a technical challenge, and am confident in my abilities. Based on the experiences of others, I plan to fully design robust fuel-processing and fuel-system conversions, before I ever turn a wrench or fill a barrel. But no guarantees in this kind of endeavor...



Thankfully, resources like TDR make it possible for those of us who Can't Leave Well Enough Alone!



Cheers,

Ted

 

[TRadke]

Oil analysis is on the short-list agenda.

I haven't had the truck for long, so I need to see what I bought(!) and baseline it.

Then a bypass filter system (Frantz, MotorGuard, Spinner II - haven't decided yet).



Ted

 

[Vaughn MacKenzie]

Sorry I missed that, looks like you've been reading up Ted

 

[MMcCallie]

I was planning to use a separate fuel system on my PSD, but one of the reasons i switched to a Cummins is because, from what i understood, the 12 valve lift pump will pull either fuel just fine. Perhaps you know something i don't. Why not heat in the tank and use a solenoid to switch between tanks before either fuel can get to the engine?

 

[TRadke]

Yep, the P7100 IP is Da Bomb for VO use... that's why I'm here.

Why not heat in the tank and use a solenoid to switch between tanks before either fuel can get to the engine?

I don't want to heat the fuel in-tank for three reasons:



1) - IMHO It's a fairly inefficient way to heat the VO. 20+ gallons of VO is a huge thermal mass... fine if you're on a long trip, too slow for daily use.

2) - Heating the VO increases oxidation rate. This reduces the heat content of the VO.

3) - Heating the oil also increases rancidity/spoilage rate... also speeds algae growth... stinky fuel... plugged filters... eeeeeeewwww.



From my research, it seems much better to heat the fuel just before it goes into the IP. Smaller quantity of fuel, quicker, more efficient.

Also, cooler VO lasts much longer in storage.



Injecting VO (whether hot or cold) into a cold engine is a huge no-no... that's where a lot of folks (especially single-tankers) overlook this and run into trouble.

Once the coolant's fully warmed up, there's plenty of heat available for fuel heating.



My real goal is to reduce fuel switch-over (after cold-start) time as much as possible, yet retain healthy engine operation. I've got some ideas for doing this, but I'm still working out the thermodynamic reality-checks.





Soooo - any ideas on the flow rate of the stock mechanical lift pump????

Anybody????

How about a source for a brushless mag-drive pump suitable for high-viscosity/high teperature oil? Target VO LP pressure is 25-30psi at the IP inlet.



Cheers,

Ted

 

[bodacious]

The information I have from Cummins Engine Co. for 1994 175 hp.



normal fuel comsumptiion-lb/hr 68. 4



maximum fuel flow to pump-lb/hr 380