Looped Return / Tank Return Hybrid

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

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Looped Return / Tank Return Hybrid

Postby tylerkck » Tue Jun 15, 2010 1:45 pm

I'm working thru the different plumbing and valving options for a two tank system.

A looped return is nice because the heat in the hot VO is not wasted to the tank and because hot VO doesn't touch the air in the tank (increasing polymerization).

Returning the VO to the tank is nice because any air pockets are expelled (instead of compounded) when discharged into the tank.

Racers use box's with trap doors in fuel cells and oil pans to keep the pick up submerged during high G manuevers. See link for example of an oil pan, looks like they are worried about slosh from hard braking. http://65corvette.nonethewiser.net/mont ... p_door.jpg

I was thinking I could build a box around my pick up, with a trap door (acting as a check valve) on the side near the bottom. The box would extend nearly to the top of the tank and the VO return would dump right into the box..... Allowing the air bubbles to escape and yet still allow the hot return VO to be sucked up and used again.

Does this sound like a logical best of both worlds option? What are the problems with it?

I have concerns about gumming up the hinges of the door. Any input? How do float style level transmitters hold up? Would I be fine just using aluminum? Maybe just leave openings (relatively small) around the bottom.

Thanks for any input.
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Postby SunWizard » Tue Jun 15, 2010 3:19 pm

Its not hard to prevent any air leaks if you use the best hose clamps and good hoses. If you have most of the system under pressure (stock on cummins and mercedes and most others) its very rare to get air leaks since there's only a few connections under a slight vacuum, you get a small VO drip instead. I haven't had air problems in >4 years on my truck or car, and they are always looped on VO. The reason you hear so much about air leaks is many use plumbing where filters and many connections are under vacuum.

Sending all that heated VO through long hoses, back to the tank even with a "trap box" cools it down a lot, its better to use all the heat.

If you have an air leak, you need to fix it. Even if you have a return to tank, leaks will affect performance and IP life since that air is going through the IP. So adding extra hoses and complexity in the tank isn't worth it.

My float style level senders have been working fine in truck and car, and I haven't heard of many problems with them unless you use bad VO and get a poly problem. If you get bad poly you have bigger things to worry about like how to clean it out of the tank and lines, and you could clean the sender while doing that.
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Postby tylerkck » Tue Jun 15, 2010 5:26 pm

Youv'e convinced me that air leaks wont be a problem. Especially since my LP will be back by the tank and push thru the fuel filter.

"Sending all that heated VO through long hoses, back to the tank even with a "trap box" cools it down a lot, its better to use all the heat."

My pump isn't under the hood like yours, so I have to send that VO all the way back to pump anyway, one more foot of hose and I'm at the tank. Insulated and bundled lines aside, I could insulate the box from the rest of the tank to conserve the heat. However, in my case it wont be any "better" to "use all the heat". I realize that that is the case for most SVO conversions, you want to get the VO as hot as possible thus lowest possible viscosity. My truck has a VP44 IP and the max fuel temp I feel comfortable running thru it is 120F.....I have some more research to do on blending vs. viscosity vs. temp, but I will be posting my approach soon. By only heating the VO blend to 120F (or not at all) I don't think I have to worry about conserving every bit of heat possible.

"If you have an air leak, you need to fix it. Even if you have a return to tank, leaks will affect performance and IP life since that air is going through the IP. So adding extra hoses and complexity in the tank isn't worth it."

I agree that air leaks negatively effect IP performance and life, even with a return to tank. AND the more air you have being fed thru the IP, the more IP performance and life will be affected. As you know the VP44 is a sensitive pump and isn't cheap. Having the return to tank takes out any air returning from the IP instead of putting it back into the line. With a constant air leak you will have a constant amount of air being fed thru the IP, IF it is returned to tank. A looped return will allow the air to build up, thus allowing more and more air to be fed thru the IP. One of the conversion layouts I sketched up had the VO line held at a constant pressure via pressure regulator or manual valve located just upstream of the switch over valve, with the bypass from the valve going back to the tank. This setup would give the air a chance to escape BEFORE the IP. How do you know when you have an air leak anyway? Also, I wouldn't say it adds all that much complexity or hose. The extra hose is 12-18" on hmm 8' maybe, a box with hinged flaps is pretty simple, and a connection to the tank vs. a connection on the vacuum side of the pump.

A lot of side tracking here, but back to.... you convinced me that air leaks wont be a problem. Air is introduced into the lines everytime you change a filter, but that shouldn't be very often. However, everytime you shutdown or rather everytime you stop pressurizing the VO line it will empty some of the VO and displace it with air, right?- Isn't that why truck manufacturers return the fuel to the tank?

So if I went with a trap door box return and don't use bad VO, do you think I'd have to worry about the hinges/doors sticking?

Is there some other benefit to a looped return?- back flushing with diesel? One of the conversion layouts I sketched up would allow diesel to back flush all the way from switch over valve to the tank, all the VO line.... if pureflowtech's bench test of backflowing thru the newly revised raptor shows decent flow (said they'll have something next week)- or if you can run pump in reverse.
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Postby SunWizard » Wed Jun 16, 2010 9:01 am

tylerkck wrote: How do you know when you have an air leak anyway?

On mine air would build up when running all day and it would affect performance, but I haven't had any air leaks. If you are having trouble, a clear inline strainer is the easiest way to tell.
Air is introduced into the lines everytime you change a filter, but that shouldn't be very often.

I run on D2 when changing either filter, so any air gets returned to the D2 tank.
However, everytime you shutdown or rather everytime you stop pressurizing the VO line it will empty some of the VO and displace it with air, right? Isn't that why truck manufacturers return the fuel to the tank?

Where would the air come from to displace it? The system is sealed. Air from filter changes is the main reason for the stock return.
So if I went with a trap door box return and don't use bad VO, do you think I'd have to worry about the hinges/doors sticking?

Only if you had a poly problem which means bigger things to worry about.
Is there some other benefit to a looped return?- back flushing with diesel?

No, backflushing a heated supply line isn't needed, and can be bad if you backflush a filter since many aren't designed for it, as well as sending particles back to the lines and tank.

Here is another idea for you, a limited loop return: From the highest low flow rate point in the loop where air would collect (like the top of a filter) you add a fitting with a needle valve or orifice which lets a tiny amount of VO return to the tank, along with any air. This is what most mercedes use stock.
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Postby tylerkck » Wed Jun 16, 2010 4:17 pm

With no air bubbles, can you see flow? Here are some flow sights... http://www.mcmaster.com/#flow-indicators/=7k4n1b Would a flow indicator be necessary or is a sight enough to see flow in the line?

“Where would the air come from to displace it? The system is sealed. Air from filter changes is the main reason for the stock return."

Logically you're right, the system is sealed as long as the pickup is submerged; the IP return has a check valve on it and the return from the injectors... if air is allowed into the injector lines you won’t be able to start, right?- so there can't be a path there. How do you know that auto manufacturers return to tank only for the air introduced from filter changes?- logic?- knowledge?- please share.

The weekends are when I travel long enough distances to get up to temp and run VO. There’s a chance I could go weeks without running VO. Logically there should be no way for air to enter the system, but it just doesn’t sit right with me. It must be truly sealed…. You think with good clamps, hoses, connectors, etc. that air won’t enter the system after it has sat for a month?- 2 months? One way to know for sure is to put a clear section at the highest point in the feed line (my tank will be in the bed for the first runs, then under the bed).

I've thought about filling the tank to the brim when I get back and letting it sit until the next trip, but would relatively clean, good, dry VO show separation/settling after awhile?- does the sloshing from driving keep it from settling? I thought I might have to drain the tank between trips….With the pickup dry I think the lines would drain down to the tank and settle in the low spots of the line, filter, etc. What do you think? If you plan on emptying your second tank for a period of time, do you think it would be good poly prevention to pour a few gallons of diesel in the VO tank, run it unheated thru the lines to purge them?

”Here is another idea for you, a limited loop return: From the highest low flow rate point in the loop where air would collect (like the top of a filter) you add a fitting with a needle valve or orifice which lets a tiny amount of VO return to the tank, along with any air.”

I really like that; I want extra protection for the VP44. That’s similar to the concept I spoke of, except I expected to return much more VO. I like the idea returning more VO only because during the summer months I’ll want the VO blend just about as cool as I can get it……the stock fuel system raises the temp of diesel, with my AirDog lift pump and filters, ½” line, I’ve seen the fuel as hot as 112F yet this summer, the outside temp was in the 80’s. The AirDog has an external bypass, so most of the 95 gph goes right back to the tank. The raptor pump has an internal bypass; I believe it will add more heat to the fuel then the AirDog, unless more of its flow is externally bypassed.
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Postby SunWizard » Wed Jun 16, 2010 5:21 pm

tylerkck wrote:With no air bubbles, can you see flow? Here are some flow sights... http://www.mcmaster.com/#flow-indicators/=7k4n1b Would a flow indicator be necessary or is a sight enough to see flow in the line?

Seeing flow isn't needed, a sight would be only to spot or troubleshoot an air leak.
How do you know that auto manufacturers return to tank only for the air introduced from filter changes?- logic?- knowledge?- please share.

Logic. Who knows what the makers think except their engineers, and they probably disagree with each other .
You think with good clamps, hoses, connectors, etc. that air won’t enter the system after it has sat for a month?- 2 months?

That wouldn't matter since I will be starting on D2 with a full return to tank each time.
I've thought about filling the tank to the brim when I get back and letting it sit until the next trip, but would relatively clean, good, dry VO show separation/settling after awhile?- does the sloshing from driving keep it from settling?

No, settling isn't a problem even if it occurred.
I thought I might have to drain the tank between trips….With the pickup dry I think the lines would drain down to the tank and settle in the low spots of the line, filter, etc. What do you think?

A few months sitting in the tank would be OK if you keep the tank full, and use a valve to turn off coolant flow to any FPHE and heated pickup.
If you plan on emptying your second tank for a period of time, do you think it would be good poly prevention to pour a few gallons of diesel in the VO tank, run it unheated thru the lines to purge them?

Yes for > 2 months of non use.
I like the idea returning more VO only because during the summer months I’ll want the VO blend just about as cool as I can get it……the stock fuel system raises the temp of diesel, with my AirDog lift pump and filters, ½” line, I’ve seen the fuel as hot as 112F yet this summer, the outside temp was in the 80’s. The AirDog has an external bypass, so most of the 95 gph goes right back to the tank. The raptor pump has an internal bypass; I believe it will add more heat to the fuel then the AirDog, unless more of its flow is externally bypassed.

The VP44 can handle 160-170F VO just fine, there are many people using that temp. This is the temp that a FPHE will consistently generate due to your coolant being always around 180F, and most FPHE having far more capacity than needed in warm weather to cover cold weather, so VO will be this temp regardless of how much VO flow you put through it. I don't understand how you are going to regulate the VO temp to be consistently <120F, that seems to be complex with varying ambient temps. Higher return flow isn't a good way to regulate the VO temp since VO flow and ambient temp varies greatly.

VO temp below 160F will also reduce performance, and blending D2 in the VO tank is a poor way to compensate due to the extra work and $ at each fillup and you can have problems getting thorough mixing unless you do it in another tank before fueling.

The main weakness of the VP44 is that it will fail if you get inlet pressure <5psi, and a clogged filter can cause this, so most add an alarm.
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Postby rkpatt » Wed Jun 16, 2010 6:55 pm

I use what might ber be considered a limited loop return . There is a tee in the reurn loop pointing up with a valve (brass icemaker valve ) that allows a small amount oil fuel (a hopefully any air goes to the top of the to the WVO tank return . This is the way I set it up originally so I really don't whether it was really necessary but it seemed like a good idea .
Last edited by rkpatt on Tue Jun 22, 2010 6:41 am, edited 1 time in total.
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Postby tylerkck » Thu Jun 17, 2010 5:36 pm

“Seeing flow isn't needed, a sight would be only to spot or troubleshoot an air leak.”
I agree, just curious… can you actually see the VO moving thru a clear section if it is air free?

“That wouldn't matter since I will be starting on D2 with a full return to tank each time.”
Nice, a benefit of the single LP conversion.

“A few months sitting in the tank would be OK if you keep the tank full, and use a valve to turn off coolant flow to any FPHE and heated pickup.”
Not having to drain the tank means I don’t have to concern myself with flushing, that just made things a lot easier! As usual you've been a big help! Thank you. :D

“The VP44 can handle 160-170F VO just fine, there are many people using that temp.”

I have only been able to contact one guy that is running VO thru a Cummins VP44, cumminscanuk. The temps he runs are on par with your numbers, even up to 190F. He’s got less than 17,000 miles running veg. If you know others, please please put me in contact with them. I heard of one guy that is local to us, that has been running VO on his for 5 years, I was told he replaced the IP once during that time…..but does he even exist!?

Yes, the VP44 can “handle” 160-170F just fine, if by handle you mean pump. It will pump fuel up to 199F before it sends an error code and derates the engine. How much it’s life span is decreased by doing so is still a bit of a mystery for me. The VP44 uses the fuel it pumps to lubricate AND cool itself. I’ve read a couple un-verified things; Bosch sets the max fuel inlet temp at 158F, beyond which diesel fuel loses too much lubricity….Bosch sets the max temp at 98F, beyond which not enough heat is transferred away from the IP. With Bosch’s latter revisions to the VP44 and their rebuild kits, most all failures are due to overheated electronics. VP44’s computer is mounted directly to the pump housing. The computer is cooled by a heatsink, fuel enters the inlet cavity of the pump and flows under the heatsink, about 70% of the fuel that enters the IP is returned to the tank. The failures are from overheating or heat cycling the lead-free soldered connections inside the computer. The connections become weak and eventually fail. More failures come from hotter climates vs. cold, so obviously fuel temp is directly related to life span. http://forum.mopar1973man.com/showthrea ... d-pictures

“I don't understand how you are going to regulate the VO temp to be consistently <120F, that seems to be complex with varying ambient temps. Higher return flow isn't a good way to regulate the VO temp since VO flow and ambient temp varies greatly.”

I never thought of controlling return flow to regulate fuel temp. Again, I still have to finish research and do some testing of blending vs. viscosity vs. temp…. but I hope I can blend in the summer months to get my processed WVO’s viscosity down to that of “cool diesel”…..or whatever viscosity I feel comfortable with. Given the fuel system on this truck I should see about the same increase in VO temps as diesel temps without circulating any coolant, <120F. In the winter, I would still run a blend, but would also need to circulate coolant to bring the temp of the VO blend up to the acceptable range. The conversion layouts I’m considering include the ability to circulate coolant and VO while running on diesel, I have fuel pressure and temperature at the IP, and another pressure and temp sensor I’ll put somewhere on the VO side. I’ll turn on the VO pump and open the coolant flow valve (manual valve located on the coolant return line), and watch the gauges as the VO temp increases, then switch over to the VO blend. The VO temp could increase or decrease at this point, depending on the initial VO switch over temp and; now 70% of the hot VO is being returned vs. 100%, but the 70% is now also taking on heat from the IP. I’ll adjust the coolant flow valve accordingly and adjust as needed. I should have a pretty large window of acceptable fuel temp and most if not all the driving will be on the highway, so I’m hoping I won’t have to constantly adjust the valve. I’m guessing the VO blend would be light enough down to 50F….my upper limit is of course 120F.
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Postby tylerkck » Thu Jun 17, 2010 5:41 pm

rkpatt- "There is a tee in the lreutn loop pointing up with valve (brass icemaker valve ) that allows a small amount oil fuel (a hopefully any air goes to the top of the to the WVO tank return . This is the way I set it up originally so I really don't whether it was really necessary but it seemed like a good idea ."

I bet it would help, to get more air out you could move the tee vertically up and add an extension (bigger the better) to the tee before the valve.
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Postby SunWizard » Fri Jun 18, 2010 11:12 am

tylerkck wrote:“Seeing flow isn't needed, a sight would be only to spot or troubleshoot an air leak.”
I agree, just curious… can you actually see the VO moving thru a clear section if it is air free?

No.
“That wouldn't matter since I will be starting on D2 with a full return to tank each time.”
Nice, a benefit of the single LP conversion.

That's a benefit of all good conversions, having a full return on D2 is easy since its already there stock.
With Bosch’s latter revisions to the VP44 and their rebuild kits, most all failures are due to overheated electronics.

I have to disagree with that, nearly all failures I have heard of (~30, including yours) were due to low inlet pressure, usually due to a failed lift pump which is a known weak design from dodge for those few years. This makes me question your info sources. You could check www.frybrid.com they claim to have sold many kits for VP44 trucks. See http://www.bluechipdiesel.com/injection ... lures.html and http://www.bluechipdiesel.com/VP44INFO.html where they agree that low inlet pressure is the main failure cause. They say the computer causes drivability problems & later sometimes fails due to heat cycles (not fuel temp.) You will still get heat cycles since that mostly comes from heat soaking from the block at each shutdown. Note they say later model Bosch made a better computer that doesn't have heat problems, so if you got the later upgraded model when you got your rebuild you shouldn't need to worry about heat anymore, this seems like a better solution than your complex conversion ideas. Bluechip basically says the opposite of your above quote: Bosch’s latter revisions have eliminated heat/computer failures. Low inlet pressures are still a problem and aren't covered by warranty.
I hope I can blend in the summer months to get my processed WVO’s viscosity down to that of “cool diesel”…..or whatever viscosity I feel comfortable with.

That will be a problem like single tankers have with no coolant heat you can get small amounts of invisible suspended fats/PHO will clog your filter. Processing to remove every bit of that is extra work usually needing a long and cold settling time.
Given the fuel system on this truck I should see about the same increase in VO temps as diesel temps without circulating any coolant, <120F. In the winter, I would still run a blend, but would also need to circulate coolant to bring the temp of the VO blend up to the acceptable range. The conversion layouts I’m considering include the ability to circulate coolant and VO while running on diesel, I have fuel pressure and temperature at the IP, and another pressure and temp sensor I’ll put somewhere on the VO side. I’ll turn on the VO pump and open the coolant flow valve (manual valve located on the coolant return line), and watch the gauges as the VO temp increases, then switch over to the VO blend. The VO temp could increase or decrease at this point, depending on the initial VO switch over temp and; now 70% of the hot VO is being returned vs. 100%, but the 70% is now also taking on heat from the IP. I’ll adjust the coolant flow valve accordingly and adjust as needed. I should have a pretty large window of acceptable fuel temp and most if not all the driving will be on the highway, so I’m hoping I won’t have to constantly adjust the valve. I’m guessing the VO blend would be light enough down to 50F….my upper limit is of course 120F.

I wouldn't want to be a human thermostat like that. Way too much watching guages and tweaking the valve, and too many chances for error.

50F sounds far too cool for any 2 tank rig, besides the inevitable fats/PHO I mentioned above, viscosity depends greatly on the type of VO you get and each batch will vary. You will be getting the drawbacks of single tank/blending people, without the benefits of simplicity, and being much more complex than any 2 tank I have heard of.
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Postby tylerkck » Sun Jun 20, 2010 10:39 pm

“That's a benefit of all good conversions, having a full return on D2 is easy since its already there stock. “

I agree, let me clarify; with a good conversion like yours you can purge air in the “VO side” just by starting and running on diesel. A two LP conversion could not.

“I have to disagree with that, nearly all failures I have heard of (~30, including yours) were due to low inlet pressure, usually due to a failed lift pump which is a known weak design from dodge for those few years.”

I’m pretty sure Chip told me low fuel pressure causes the electronics to overheat, I’ll verify that. Regardless, its not a concern for those of us who have a pressure sensor/guage, light/alarm, and quality LP.

“This makes me question your info sources. You could check www.frybrid.com they claim to have sold many kits for VP44 trucks. See http://www.bluechipdiesel.com/injection ... lures.html and http://www.bluechipdiesel.com/VP44INFO.html where they agree that low inlet pressure is the main failure cause. “

Correct, overheated electronics is the main cause of VP44 failures, low fuel pressure is the main cause of overheated electronics. Fuel pressure problems aside, overheated electronics is still the main cause of VP44 failures. I don’t think you read my link, there are references and sources you can verify, as noted I got a lot of help from Chip of bluechipdiesel.com. I need to contact Frybrid and see if they can point to customers running my truck, but Chip is the VP44 guru.

“They say the computer causes drivability problems & later sometimes fails due to heat cycles (not fuel temp.) You will still get heat cycles since that mostly comes from heat soaking from the block at each shutdown. “

The computer is cooled by the fuel, the cooler you can keep it the longer it will live. 190F fuel will transfer less heat away from the computer, quite possibly add heat to it. I’m aware of the heat cycling significantly contributing to “overheated electronics”, I mentioned it earlier. Fuel temp and heat cycling are directly related. Feeding the IP 190F will add to the effect of heat cycling, how badly is yet to be determined, whether or not it’s more severe than the heat cycling from shutdown/heat soak is also unknown. My Edge has a trans temp sensor, the sensor itself is good, but the harness or computer needs repairs. Once its fixed to stick it on the fuel inlet and return line to add to my posts in the forum I linked….I’ll post the results here too. I took a trip today, the fuel temp (as measured by the IP, displayed via Edge) while cruising down the highway got up to 123F, when I shut down it got up to +140F. I expected higher…need to repeat.

“Note they say later model Bosch made a better computer that doesn't have heat problems, so if you got the later upgraded model when you got your rebuild you shouldn't need to worry about heat anymore, this seems like a better solution than your complex conversion ideas.”

Bosch made a better computer to deal with these heat issues…. associated with driving on D2 in ambient temperatures. Chip didn’t tell me or write on his web page “it doesn’t have heat problems anymore”, just that it’s improved.

“Bluechip basically says the opposite of your above quote: Bosch’s latter revisions have eliminated heat/computer failures. Low inlet pressures are still a problem and aren't covered by warranty.”

Again, he never said it eliminated the heat/computer failures. Actually, he has spent a lot of time and money trying to find a solution that does truly eliminate this problem. The current solution he is working on seems to be the ticket (at least for D2 while running and heat soak after shutdown), please read the link and take a look at the attachments. Also, I never said low inlet pressures were no longer a problem…. If your inlet fuel pressure is too low the VP44 will fail soon after.

“That will be a problem like single tankers have with no coolant heat you can get small amounts of invisible suspended fats/PHO will clog your filter. Processing to remove every bit of that is extra work usually needing a long and cold settling time. “

Remember I’ve haven’t finished researching blending….. ratio vs. viscosity vs. temp and now fats/PHO…still I’ll be adding coolant heat in the winter time, couldn’t I just crack open the coolant flow valve during the summer?- the pickup coil and filter wrap would need it the most, right?

“I wouldn't want to be a human thermostat like that. Way too much watching guages and tweaking the valve, and too many chances for error. “

That is my biggest concern right now…..,but keep in mind I’d like to keep the temp below 120F, but I don’t have to, the IP isn’t going to die suddenly. If only It'd be nice if I could control coolant flow without automation, like a mechanical thermostat.

“50F sounds far too cool for any 2 tank rig…….viscosity depends greatly on the type of VO you get and each batch will vary. You will be getting the drawbacks of single tank/blending people, without the benefits of simplicity, and being much more complex than any 2 tank I have heard of.”

Can you expand on “50F sounds far too cool for any 2 tank rig”?- do you mean any 2 tank rig running un-blended VO?- Will it be difficult to get the viscosity of VO (at 50F) down to an “acceptable” range by blending? 60F, 70F? I’m partnering up with an experienced vegger (Drew) for collecting and filtering, he said we won’t accept PHO oil, the CF setup is very close to your design (you’ve seen it).

I don’t know if I’d call it “much more complex”; when you compare it to other good two tank two pump setups, I’m only replacing an on/off valve with a flow valve and maybe a press reg or needle valve. The flow valve could be as simple as a ball valve with % open indication, no real added complexity there. http://www.mcmaster.com/#ball-valves/=7l9tkx Still, there are times when added complexity is warranted. When you think about it I’m adding flexibility (ability to control fuel temp to IP), most the added complexity is operational, but that is at my discretion; I can just leave the coolant flow valve open and run like everybody else. I’m looking at 2-3 manual valves in the cab (like you, 3?), one of which I can vary (at my discretion, if I blend) to increase the life of the VP44.
2002 Dodge Ram 2500 HO Cummins 6speed. +130k miles, replaced IP at 57k. Edge Juice Attitude, Airdog 95, guages.....
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Postby SunWizard » Mon Jun 21, 2010 10:06 am

tylerkck wrote: “Bluechip basically says the opposite of your above quote: Bosch’s latter revisions have eliminated heat/computer failures.”

Again, he never said it eliminated the heat/computer failures.


Here is the part of the page I linked which says this right after he talks about the heat cycles issue:
"When you shut the truck off the latent heat in the engine heats up the computer and after many heat cycles the solder that holds the electrical components to the circuit board of the computer becomes crystalline and no longer makes a good electrical connection, causing intermittent drivability issues,"

"We have been selling these (upgraded) pumps for over five years and our customers that haul RVs for a living and do crazy mileage per year have not had any injection pump issues to date."

"Now that we have over 600 pumps in the marketplace and as we have less than a two percent failure rate we feel very confident we are selling a better product"

It sure sounds to me like he eliminated the heat cycling issue since people aren't doing anything special to cool the IP. In the southern parts of the country where ambient temps are often >110F, the fuel will be at least 150F and get higher at each shutdown, yet still no failures of the upgraded model.

And FedEx, who got Bosch to develop the upgraded model, seems to be happy with it, and they often get many repeated heat cycles per day since they start and stop often.

tylerkck wrote:Can you expand on “50F sounds far too cool for any 2 tank rig”?- do you mean any 2 tank rig running un-blended VO?- Will it be difficult to get the viscosity of VO (at 50F) down to an “acceptable” range by blending? 60F, 70F? I’m partnering up with an experienced vegger (Drew) for collecting and filtering, he said we won’t accept PHO oil, the CF setup is very close to your design (you’ve seen it).

Its fats that are more the problem, since most places cook some meat. Even with blending, the fats can still plug your filter and stay invisibly suspended in your VO unless you add long settling after the CF. Thats not a viscosity issue, the fats are like particles at that temp and won't melt until around 100F.

After you look at viscosity charts, you will see its temp that is by far the simplest, cheapest, least work, and most effective way to thin it, compared to blending. I have a viscosity tester and tested many blends, see my thread in the blending section here:
http://www.burnveg.com/forum/viewtopic.php?t=231
most the added complexity is operational, but that is at my discretion; I can just leave the coolant flow valve open and run like everybody else. I’m looking at 2-3 manual valves in the cab (like you, 3?), one of which I can vary (at my discretion, if I blend) to increase the life of the VP44.

Yes its operating it and mixing your blends that's more complex, as in: " Way too much watching guages and tweaking the valve, and too many chances for error. "

The coolant flow varies greatly with RPM, so cracking a valve a certain amount can't give a consistent flow, and will create a widely varying VO temp.

After reading all the pages from bluechip, and the many frybrid and other users who have no problems at VO temps of 170F, I don't think its going to change the life if you have the upgraded IP. Even if 170F did shorten the life a little (250k miles instead of 300k?) it would be worth it if I didn't have to blend all the time, which is another complexity and variable. That's the biggest complexity, not how many valves you have.

Also, operating at lower VO temps than everyone else who has converted could lead to other issues no one else has seen. I think those unknown viscosity/blending issues are much more likely to be a problem than heat cycling on the IP.
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95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
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Postby SunWizard » Mon Jun 21, 2010 10:30 am

tylerkck wrote:Correct, overheated electronics is the main cause of VP44 failures, low fuel pressure is the main cause of overheated electronics. Fuel pressure problems aside, overheated electronics is still the main cause of VP44 failures.

I still haven't seen anything that says this. Chip says near the top of the link I gave:
"What the common VP44 problems are….

The housings on the VP44 wear out due to low fuel pressure from weak lift pumps causing damage to the diaphragm in the front of the VP44 pump. This failure causes the steel timing piston to vibrate in the aluminum bore of the main pump housing and the result in a short time is the housing wears to the point that fuel bypasses the piston and full advance cannot be accomplished which causes the code 216. "

This is all mechanical due to low pressure, not anything to do with overheated electronics.
YVORMV - Your veg. oil results may vary.
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Postby rkpatt » Tue Jun 22, 2010 6:40 am

Yes, that is more or less what I did .

tylerkck wrote:rkpatt- "There is a tee in the return loop pointing up with valve (brass icemaker valve ) that allows a small amount oil fuel (a hopefully any air goes to the top of the to the WVO tank return . This is the way I set it up originally so I really don't whether it was really necessary but it seemed like a good idea ."

I bet it would help, to get more air out you could move the tee vertically up and add an extension (bigger the better) to the tee before the valve.
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Postby tylerkck » Tue Jun 22, 2010 10:21 am

Chip has told me that the IP gets the hottest right after shutdown too, but was vague on how he measured the temp. His goal for his latest VP44 cooling solution is to keep the temp below 135F…vague, not sure where/what temp he’s talking about. I'm going to contact some users on Frybrid and use my temp sensor/IP’s sensor to hopefully get a better idea of how severe the diesel heat cycles are and compare to different theoretical hot VO heat cycles. He doesn’t mention the heat soak of the IP itself; engine heat soak is to coolant as IP heat soak is to fuel.

BlueChip…"We have been selling these (upgraded) pumps for over five years and our customers that haul RVs for a living and do crazy mileage per year have not had any injection pump issues to date."
You have to read the words carefully…. This was written when they had been selling the pumps for +5 years. They have sold some to guys who tow for living, not sure when/how many miles, etc. Again, this is running D2 in ambient conditions. ”issues to date”-who know when it was written, could have been a month after he sold his 3rd IP to an RV hauler, “and do crazy mileage per year”- he didn’t say they put crazy mileage over the years on his IPs. There is nothing wrong with his wording, no lies being told, just good marketing for the upgraded VP44.

BlueChip…"Now that we have over 600 pumps in the marketplace and as we have less than a two percent failure rate we feel very confident we are selling a better product" – Again, who knows when this was written, could have been 6 months after he started selling the revised IP.

“It sure sounds to me like he eliminated the heat cycling issue since people aren't doing anything special to cool the IP. In the southern parts of the country where ambient temps are often >110F, the fuel will be at least 150F and get higher at each shutdown, yet still no failures of the upgraded model.”

You’re right, it does sound like that…. He also writes “Most importantly, be sure that you have at least 5 PSI Lift Pump pressure UNDER LOAD at all times”- a lot of people take 5 psi to the bank and stop there, but he also says that 15psi is optimal (because it gives the maximum fuel flow thru the inlet cavity and return for cooling, the return bango has a 14-15psi pressure regulator and check valve) and sells higher pressure FASS lift pumps, he also writes “Computer failures are 90% of almost all drivability issues in my experience. This is from listening to all of you in the “Real World” and testing the accuracy of my diagnostic procedures daily. I am convinced that HEAT IS THE KILLLER OF THESE PUMPS…”- his caps not mine. I called him today, “I asked”-he said….”if your upgraded VP44 has a less then 2% failure rate and guys are towing heavy long miles, why have you put forth so much effort to better pump cooling?”- the upgraded VP44 is definitely better, but they still fail, especially pumps coming from the South. “Do you still see a difference in failure rates between hot/cold climate customers with good LP/warning system?”-absolutely.

“And FedEx, who got Bosch to develop the upgraded model, seems to be happy with it, and they often get many repeated heat cycles per day since they start and stop often.”

What did you read that makes you think FedEx is happy with Bosch’s revision?

“Its fats that are more the problem, since most places cook some meat. Even with blending, the fats can still plug your filter and stay invisibly suspended in your VO unless you add long settling after the CF. Thats not a viscosity issue, the fats are like particles at that temp and won't melt until around 100F. “

Is cloud point related to fats?- PHO? I read some of your viscosity link.…you wrote “Heating the VO is needed with blends if you want to use it below the cloud point of the VO, which is around 30F for most VO. Or else you clog your filter. “ Is 100F or 30F the minimum temp?

“The coolant flow varies greatly with RPM, so cracking a valve a certain amount can't give a consistent flow, and will create a widely varying VO temp. “

Most of my VO miles will be on the highway with fairly stable RPMs. Given the flexibility, I can just slowly open the coolant flow valve all the way for the brief “city type” driving I do towards the end destination and when getting close to home, but I bet I’ll just switch back over to diesel. How much do your VO temps vary with RPM?

“After reading all the pages from bluechip, and the many frybrid and other users who have no problems at VO temps of 170F, I don't think its going to change the life if you have the upgraded IP. Even if 170F did shorten the life a little (250k miles instead of 300k?) it would be worth it if I didn't have to blend all the time, which is another complexity and variable. That's the biggest complexity, not how many valves you have.”

I don't think you read all of his pages, in particular “Longer Life for VP44" page. I havn't concluded the lifespan will be unchanged, but I agree that IF it shortens the life a LITTLE, the complexity is not worth it. Fortunately I can run some test so that I can conclude for myself, besides nothing I've suggested has to be “re-done” to operate like everyone else.

“Also, operating at lower VO temps than everyone else who has converted could lead to other issues no one else has seen. I think those unknown viscosity/blending issues are much more likely to be a problem than heat cycling on the IP.”

You set an acceptable viscosity of properly processed “good enough” WVO…..at 170F (160F,190F, or whatever). Why can’t this number be lowered (not past 30F or 100F) after properly blending in say 20% diesel?
Last edited by tylerkck on Tue Jun 22, 2010 11:35 am, edited 1 time in total.
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