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I still have a ways to go to catch up with former member Illflem - and he's been gone for quite a while...
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Engine/Transmission (1998.5 - 2002) Modifying fuel system so temperature input to VP44, 80* - 100*, your inputs.
- Thread starter rweis
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YUP - that's what some call it alright! :-laf :-laf
Comes from being on this board quite a while, and retired - with lots of spare time...
I still have a ways to go to catch up with former member Illflem - and he's been gone for quite a while...
I said
Gwedekind replies:
A few months back, I had my spare VP-44 on my desk - and I removed the overflow valve completely, leaving the inlet and outlet ports totally empty and open. I then tried to blow in and thru the pump to see if there was a direct and open internal passageway from one to the other - on that test, at that time, there was NO flow between them, or any of the exiting fuel line ports.
And even if that pathway IS occasionally open due to internal alignment of mechanism, it (to me) wouldn't be reliable enough to use a a major cooling scheme.
I can't say much more than that.
Gwedekind replies:
A few months back, I had my spare VP-44 on my desk - and I removed the overflow valve completely, leaving the inlet and outlet ports totally empty and open. I then tried to blow in and thru the pump to see if there was a direct and open internal passageway from one to the other - on that test, at that time, there was NO flow between them, or any of the exiting fuel line ports.
And even if that pathway IS occasionally open due to internal alignment of mechanism, it (to me) wouldn't be reliable enough to use a a major cooling scheme.
I can't say much more than that.
Last edited:
rweis said:
OK... Thanks Bob.
I was also thinking that I would like to move the VP44 re-circ from the fuel module to the tank fill vent as you did, but I forgot to mention it earlier. That fruit also seems to be easy to reach and very ripe.
Why do think that my #1 and #2 will offset? It is because the cooler would actually act as a heater if OAT was greater than fuel temperature? Mundyver said that he had good results from doing that to his truck. I would just need to open the bypass during the cooler months to allow the fuel heater to be effective.
I might take another look at the VP blower system as you have done. I know only a little about the VP. I suspect that the electronics are near the top under the plastic cover. I guess, that you might not cool the entire pump but hopefully cool just the electronics particularly during the heat soak after shutdown. Gary seems to have cornered a large part of the market there using that heat sink.
Thanks again;
Jim
Okay idea ... throw some pros and cons back at me ... Disconect heater core, flush all anti freeze out, connect fuel lines (pre VP44) to heater core, turn HVAC control to max heat (to open blend door in unit so all air passes through core) turn on AC to cool core and fuel before getting to VP ... I run with the AC on all the time now anyhow, I wonder how cool you could get the fuel, you could adjust the HVAC control to raise or lower the temp depending on the OAT ...
The way our HVAC works is ALL air blows through AC core, then the HVAC control adjusts the blend door deflecting air either through the heater core (Control in hot position) or bypass it altogether Control in cold position) or a mix (blend door half open) and control in the red/blue area.
The only downside is the AC would not be as cold as normal and the heater would not be as hot as normal (100* fuel running through it instead of 190* coolant) ... Might try this this weekend and see if the cooling of the cab is severely compromised.
This may work for us guys who are in warm climates (We don't need no stinkin heater in Texas) ... but may not be practical for northerners.
Watcha think ... still does not address the issue of soak though.
Kevin
The way our HVAC works is ALL air blows through AC core, then the HVAC control adjusts the blend door deflecting air either through the heater core (Control in hot position) or bypass it altogether Control in cold position) or a mix (blend door half open) and control in the red/blue area.
The only downside is the AC would not be as cold as normal and the heater would not be as hot as normal (100* fuel running through it instead of 190* coolant) ... Might try this this weekend and see if the cooling of the cab is severely compromised.
This may work for us guys who are in warm climates (We don't need no stinkin heater in Texas) ... but may not be practical for northerners.
Watcha think ... still does not address the issue of soak though.
Kevin
Kevin, - now that is thinking outside of the box. If that proves out, man what a GREAT idea. A heater core "leak" would be a major fuel spill problem though!
Jim - The cooler up front is a good idea I think. I have never seen the OAT greater than the fuel temp. The tank fuel temp (on mine, empty, 1400 rpm) starts out at the same as the OAT and slowly rises to OAT+10* and settles there forever. Not exactely sure why that equilibrium of OAT+10*. If I go faster (higher VP pump rpm) then the 10* differential widens by 1* / 100 engine rpm. I know the rpm ticks = 125 rpm (another DC wonderful? idea).
The OEM ff I think picks up a lot of heat from the engine compartment.
The ff is directly bolted to the engine and hangs right along the hot block side where it can be a great aluminum heat sink. Even if you mechanically insulate the ff from the block, which would help, you still have an approximately 100 sq " heat sink (circumference * height) sitting right next to the block at 180*.
Now if you could totally insulate the ff, move it, get the heat off of it somehow, then great. However as I remember, removing the OEM ff lowered the input fuel temp about 15*. I removed my OEM ff totally and put an inline ff (8um) in down on the front frame crossmember. Not saying that is the thing to do, and when I get back to the OEM ff and figure out how to insulate it totally, I will reinstall it.
My under bed fuel cooler (H7B) with the 1k CFM fan cools the fuel about 10*. An up front cooler would do a better job with cooler incomming air, but you negate 15* of the cooler with the OEM ff.
On the after shutdown blower, I can take as much data as you want. Twice a work day since late last summer I see the fuel temp at shutdown, the EBC at shutdown, and reset the highest temp reading in the digital thermometer to the then EBC reading. I go into work or home depending on which end of the drive. The OAT blower runs for 128 minutes flooding the whole VP outer case that has a thermal blanket loosely wrapped around it (the air is blown in between the VP and the VP side of the thermal blanket, about 1" spacing) to keep the engine block heat off of it but let the blower air circulate around the VP and that blower air exits the thermal blanket out the injector line end of the VP that is totally open. Day after day, month after month, the highest VP EBC temperature reading (the heat soak from the block) is about 4* higher than it was at shutdown. I totally believe the blower works because it floods an insulating OAT air barrier completely around the VP to keep the block heat off of the VP. Of course it helps that the thermal blanket also provides a thermal barrier to the block heat.
The return fuel to the filler (vent pipe on mine) is a good idea to use the entire mass of the fuel as a heat sink and not just return the fuel to the fuel cannister where the fuel pickup is. I also like it because it keeps the full tank fuel circulated through the filter. Remember the "pump, lines, whatnot... " thread saw a cooling fuel return rate of 30 gph at cruise speeds. That would recirculate (and refilter) the entire tank every hour. A good thing I think.
I will do some of the misting install tommorrow and report back.
Bob Weis
Jim - The cooler up front is a good idea I think. I have never seen the OAT greater than the fuel temp. The tank fuel temp (on mine, empty, 1400 rpm) starts out at the same as the OAT and slowly rises to OAT+10* and settles there forever. Not exactely sure why that equilibrium of OAT+10*. If I go faster (higher VP pump rpm) then the 10* differential widens by 1* / 100 engine rpm. I know the rpm ticks = 125 rpm (another DC wonderful? idea).
The OEM ff I think picks up a lot of heat from the engine compartment.
The ff is directly bolted to the engine and hangs right along the hot block side where it can be a great aluminum heat sink. Even if you mechanically insulate the ff from the block, which would help, you still have an approximately 100 sq " heat sink (circumference * height) sitting right next to the block at 180*.
Now if you could totally insulate the ff, move it, get the heat off of it somehow, then great. However as I remember, removing the OEM ff lowered the input fuel temp about 15*. I removed my OEM ff totally and put an inline ff (8um) in down on the front frame crossmember. Not saying that is the thing to do, and when I get back to the OEM ff and figure out how to insulate it totally, I will reinstall it.
My under bed fuel cooler (H7B) with the 1k CFM fan cools the fuel about 10*. An up front cooler would do a better job with cooler incomming air, but you negate 15* of the cooler with the OEM ff.
On the after shutdown blower, I can take as much data as you want. Twice a work day since late last summer I see the fuel temp at shutdown, the EBC at shutdown, and reset the highest temp reading in the digital thermometer to the then EBC reading. I go into work or home depending on which end of the drive. The OAT blower runs for 128 minutes flooding the whole VP outer case that has a thermal blanket loosely wrapped around it (the air is blown in between the VP and the VP side of the thermal blanket, about 1" spacing) to keep the engine block heat off of it but let the blower air circulate around the VP and that blower air exits the thermal blanket out the injector line end of the VP that is totally open. Day after day, month after month, the highest VP EBC temperature reading (the heat soak from the block) is about 4* higher than it was at shutdown. I totally believe the blower works because it floods an insulating OAT air barrier completely around the VP to keep the block heat off of the VP. Of course it helps that the thermal blanket also provides a thermal barrier to the block heat.
The return fuel to the filler (vent pipe on mine) is a good idea to use the entire mass of the fuel as a heat sink and not just return the fuel to the fuel cannister where the fuel pickup is. I also like it because it keeps the full tank fuel circulated through the filter. Remember the "pump, lines, whatnot... " thread saw a cooling fuel return rate of 30 gph at cruise speeds. That would recirculate (and refilter) the entire tank every hour. A good thing I think.
I will do some of the misting install tommorrow and report back.
Bob Weis
For those considering use of the vehicle A/C as a fuel cooling source, instead of messing with the heater core, why not tightly wrap some proper size copper tubing around the A/C accumulator - that large can looking thing back near the firewall on the passenger side - it gets very cold when the A/C is running, and is lots easier to get access to... 
Gary,
I thought of that also ... but that area is right near the turbo and downpipe and think you would lose some of the cooling efficiency unless you wrapped the entire accumulator and tubing coils to prevent heat soak from the area ... I dunno ... just tossing ideas around ... do you think alum tubing would be better than copper as far as heat transfer is concerned?
Kevin
I thought of that also ... but that area is right near the turbo and downpipe and think you would lose some of the cooling efficiency unless you wrapped the entire accumulator and tubing coils to prevent heat soak from the area ... I dunno ... just tossing ideas around ... do you think alum tubing would be better than copper as far as heat transfer is concerned?
Kevin
The Adjuster said:
You could place an outer wrap of aluninum foil around the mess as an insulator/barrier against turbo heat - and I suppose either aluminum or copper tubing would work...
Well, I got the mister installed on both sets of fuel coolers. Another 5* off the fuel temperatures. I was thinking about the comment "the low hanging fruit" and decided to try to wrap this thread up, at least for me.
THe following are as I remember them, so take it with a grain (or pound) of salt.
OEM ff removal about -15*
VP return line back to the tank filler about -10*
Input to VP fuel cooler (mine with fan) about -10*
Fuel coolers on return line about -7*
Low pressure fuel pressurization system about +3*
VP presurization system about +5* ( the higher the engine rpm the higher the VP differential temperature in my case about 1* / 100 rpm)
The fuel tank seems to be about OAT+10 and fairly consistantly. Not sure why.
Towing does not seem to make much difference, mainly the difference in engine rpm.
Misting fuel coolers about -5*
With my previous system I had gotten the input fuel to OAT +10* and the EBC to about OAT + 13*. With misting the fuel feed cooler and the fuel return cooler the input fuel is OAT +5* and the EBC is about OAT + 8*. About the same relative temperature as before (just 5* cooler).
I drove for 2 hours in OAT 95* - 99*this afternoon. Fuel feed was right at 100* - 104*. EBC was right at 103* - 107*. One difference now speed seems to have more effect on better cooling. The 1* / 100 RPM starts to lessen over about 60 mph.
I got stopped by a phosphate train (80 cars long) for about 1 hour at OAT 98*. The fuel input temp went as high as 110* (12 differential) and the EBC went as high as 122* (24* differential). I think this tells me that frontal ram air under the hood is very important. My engine temperatures stayed at 180* so the engine fan never came on. I would liked to have been able to turn the engine fan on to see what that would have done. However if 110* is maximum fuel input temp and 122* is max EBC temperature then I am pretty satisfied with that. I figure the PSG is somewhere between those two values. (maybe a functioning hood scoop / vent could be very beneficial to lower heat?)
I put a 21 gallon commecial agriculture water tank in the bed and connected the pump and filter and misters described in a earlier post. The install was not bad. A little tight in some places, but over all not bad (of course if you go this route your own setup depends where you locate your components).
I am going to drive this for a while (several weeks) and see how it acts and reacts and see how the coolers load up or do not load up with road dirt.
I think this about finishes my quest for cooling the fuel. I can feed the VP with not much more than OAT degree fuel and that should keep the VP running well (I hope
), and that was the orgional objective.
I think overall what I found is no one thing is the silver bullet, but each thing contributes something.
I still totally endorse the after shutdown blower concept. When I got home tonight, OAT 98*, fuel temp 103*, EBC 106*, shutdown, max EBC temp went to 112* and started slowly cooling in about 20 minutes. The final EBC temp was OAT, but it only spiked 6* from run temperatures. I run it, I see it, I know in my case it works.
Good luck for others that try the same thing. I think I proved it could be done, but it sure took strange turns and you may not want to do add the water misting for only 5*, but at least we know about what the misting gain can be if you do that.
Good luck, Good hunting, I'll sit back and see if, or how, this thread develops. Who knows, maybe a totally different direction with someone's different ideas.
THANKS for ALL the inputs, everyone's thoughts and ideas, made this effort a very sygeneristic effort,
Bob Weis
THe following are as I remember them, so take it with a grain (or pound) of salt.
OEM ff removal about -15*
VP return line back to the tank filler about -10*
Input to VP fuel cooler (mine with fan) about -10*
Fuel coolers on return line about -7*
Low pressure fuel pressurization system about +3*
VP presurization system about +5* ( the higher the engine rpm the higher the VP differential temperature in my case about 1* / 100 rpm)
The fuel tank seems to be about OAT+10 and fairly consistantly. Not sure why.
Towing does not seem to make much difference, mainly the difference in engine rpm.
Misting fuel coolers about -5*
With my previous system I had gotten the input fuel to OAT +10* and the EBC to about OAT + 13*. With misting the fuel feed cooler and the fuel return cooler the input fuel is OAT +5* and the EBC is about OAT + 8*. About the same relative temperature as before (just 5* cooler).
I drove for 2 hours in OAT 95* - 99*this afternoon. Fuel feed was right at 100* - 104*. EBC was right at 103* - 107*. One difference now speed seems to have more effect on better cooling. The 1* / 100 RPM starts to lessen over about 60 mph.
I got stopped by a phosphate train (80 cars long) for about 1 hour at OAT 98*. The fuel input temp went as high as 110* (12 differential) and the EBC went as high as 122* (24* differential). I think this tells me that frontal ram air under the hood is very important. My engine temperatures stayed at 180* so the engine fan never came on. I would liked to have been able to turn the engine fan on to see what that would have done. However if 110* is maximum fuel input temp and 122* is max EBC temperature then I am pretty satisfied with that. I figure the PSG is somewhere between those two values. (maybe a functioning hood scoop / vent could be very beneficial to lower heat?)
I put a 21 gallon commecial agriculture water tank in the bed and connected the pump and filter and misters described in a earlier post. The install was not bad. A little tight in some places, but over all not bad (of course if you go this route your own setup depends where you locate your components).
I am going to drive this for a while (several weeks) and see how it acts and reacts and see how the coolers load up or do not load up with road dirt.
I think this about finishes my quest for cooling the fuel. I can feed the VP with not much more than OAT degree fuel and that should keep the VP running well (I hope
), and that was the orgional objective. I think overall what I found is no one thing is the silver bullet, but each thing contributes something.
I still totally endorse the after shutdown blower concept. When I got home tonight, OAT 98*, fuel temp 103*, EBC 106*, shutdown, max EBC temp went to 112* and started slowly cooling in about 20 minutes. The final EBC temp was OAT, but it only spiked 6* from run temperatures. I run it, I see it, I know in my case it works.
Good luck for others that try the same thing. I think I proved it could be done, but it sure took strange turns and you may not want to do add the water misting for only 5*, but at least we know about what the misting gain can be if you do that.
Good luck, Good hunting, I'll sit back and see if, or how, this thread develops. Who knows, maybe a totally different direction with someone's different ideas.
THANKS for ALL the inputs, everyone's thoughts and ideas, made this effort a very sygeneristic effort,
Bob Weis
Good effort Bob - I enjoyed both the thread contact, as well as the behind the scenes direct MSM mic/video ones - helped learn some deeper VP-44 operation stuff, and looking forward to what additional you pick up on your next Bosch visit.
My own blower upgrade is doing all I want/need so far in our climate, unless our RV trip day after tomorrow surfaces need for more cooling - but I doubt it.
Now all I need is a quieter blower that will deliver somewhere in excess of 125 CFM or so - as it now stands with the one I have, when I pass a Ford or GM in the grades, they'll turn to their passenger and ask, "Who WAS that masked man who just passed us driving the rocket-powered Hoover?"... :-laf :-laf
My own blower upgrade is doing all I want/need so far in our climate, unless our RV trip day after tomorrow surfaces need for more cooling - but I doubt it.
Now all I need is a quieter blower that will deliver somewhere in excess of 125 CFM or so - as it now stands with the one I have, when I pass a Ford or GM in the grades, they'll turn to their passenger and ask, "Who WAS that masked man who just passed us driving the rocket-powered Hoover?"... :-laf :-laf
Yeah, today when I made stops with the mister installed I had 3 different guys tell me I had a leak under my truck. I told them I had a "swamp cooler" installed. You get very puzzled looks.
It was a little weird tonight checking the water tank level for next weeks drive to work. Check the fuel, check the water. Reminds me of my Model A Ford.
At one point during the drive today I stopped and put 4 bags of ice in the water tank to see what that would do to fuel input temps. Actually not much.
When this inline blower reaches it's MTBF I am going to try the JABSCO squirrel cage. It is the only CONTINUOUS duty blower I found.
Definitely good msn'ing. I'll find a way to spend some time on the rebuild line at the SouthEast Power Orlando where they rebuild the VP44's. I want to see one throughout the entire tear down and rebuild process. Inquiring minds want to know, lol.
Bob Weis
It was a little weird tonight checking the water tank level for next weeks drive to work. Check the fuel, check the water. Reminds me of my Model A Ford.
At one point during the drive today I stopped and put 4 bags of ice in the water tank to see what that would do to fuel input temps. Actually not much.
When this inline blower reaches it's MTBF I am going to try the JABSCO squirrel cage. It is the only CONTINUOUS duty blower I found.
Definitely good msn'ing. I'll find a way to spend some time on the rebuild line at the SouthEast Power Orlando where they rebuild the VP44's. I want to see one throughout the entire tear down and rebuild process. Inquiring minds want to know, lol.
Bob Weis
Update: OAT 77* (morning)
The fuel cooler misting is going well. Temps are much better. The hottest I have had the VP44 body with 95* OAT is 125* during a LONG freight train that had the crossing closed for about 30 minutes (ie no ram air for 30 minutes)
As another experiment I put a mister on the Vp44 OAT blower ducting down by the blower (behind the front bumper drivers side). Dropped the EBC by 7* (which is a LOT, most projects it only effects the temp 2* - 3*). I thought since the VP is just one large aluminum heat sink so why not try to cool the whole VP with the OAT blower and mist it. The OAT blower discharges up by the electronic bay, but dumps air around the entire VP44 (the air exits out the thermal blanket on the injector line side (ie the rear fo the VP44 is completely open to the engine compartment)).
The lowest I have been able to get the fuel temp is ~ OAT +10* and the EBC ~ OAT +15*. With one drive this morning the fuel temps were ~OAT +7* and the EBC was ~ OAT + 9*. Temp rise was very very slow to the final stable temperature. The VP44 misting does carry off a good bit of heat.
A significant reduction in temps and well within usable range of not more than about 100* on either input fuel or EBC. Getting very very close to the objective of 100* max on the VP44.
I am going to go for a drive this afternoon (OAT 97*) and see if the really hot part of the day makes any difference.
The only down side is adding a water system to do the misting means another whole sytem and maintenance for another whole system. However it does seem to make a pretty good difference in controlling the VP44 heat. The mist is really really small dropplets 55um as I recall.
More later.
Later:
Afternoon OAT 93* - 97*
Town / Interstate (70 mph) total trip was 80 miles.
The EBC NEVER got over 100*! The fuel temp NEVER got over 100*! (full tank)
Sometimes the VP EBC was actually a degree or two cooler than the fuel temperature. Of course the relationship of rpm to VP EBC temperature held true (higher rpm, more VP temperature, ~ 1* / 100 rpm both + & -).
I stopped and let it idle for a little while and see what no ram air would do. Neither got over 100*. I took the aft end temperature of the VP44, the EBC and fuel were 100*, the aft end (where the solenoid is) was 120* (no real fuel cooling there). Which I think means that the entire VP body should not be much more than 120* if at all. I could touch under the thermal blanket anywhere, and warm, yes, but not hot. Took VP output fuel temp, same 5* increase because of what the VP44 does going into the rail fuel coolers (105* going in, 100* comming out into the tank (this might need a tiny bit of tweaking ot get a little more fuel temperature OUT before the tank.
Back on the interstate, same temperature relationships as before OAT 95* EBC 98* - 100* Fuel temp 99* - 100*. Got off the interstate to change the rpms. EBC cooled right down with the 1* / 100 rpm ratio. The fuel temp took a little while before it started to cool down eventually to 98*.
Got home, let's see if the same max EBC rise is 5* from EBC shutdown temp. Yep, and a little quicker to start the temp down from max. I think the entire VP44 is now a little cooler with the misting of the OAT blower air. Less heat, easier to cool down. There is no evidence of moisture around the VP44 or associated engine compartment (there is about 3' of semirigid 3" aluminum ducting (mixing chamber) to get from the blower to the VP44). I think there is a good bit of warm to hot air that any mist that is not evaporated by the VP is instantly evaporated in the engine compartment.
Well, I am going to run this for a long time and see what happens with towing etc. However, I think the VP temperature problem is done as far as I am concerned. Of course the VP44 can and will fail for a bunch of other reasons, but not because of temperature here.
I REALLY REALLY REALLY appreciate ALL the inputs from everyone and that you followed the thread as it unfolded. I hope this helps someone else avoid some of the mistakes I made.
Oh, BTW I took off the copper tube front cooler. It was a major fuel heat source IF YOU WERE NOT MOVING. Moving it assisted with cooling a couple of degrees, NOT moving it contributed about 10* - 20* to the fuel temp.
I summarized above with respect to each individual change. The misting especially of the VP44 seems to be a fairly significant heat reduction. You have to thermal insulate it etc etc, but misting the OAT blower air I think helps get the entire VP44 aluminum heat sink cooler.
Cooler fuel going in, cooler VP body to start with and I think there is significant reason to think there is something to this cooling approach.
Bob Weis
The fuel cooler misting is going well. Temps are much better. The hottest I have had the VP44 body with 95* OAT is 125* during a LONG freight train that had the crossing closed for about 30 minutes (ie no ram air for 30 minutes)
As another experiment I put a mister on the Vp44 OAT blower ducting down by the blower (behind the front bumper drivers side). Dropped the EBC by 7* (which is a LOT, most projects it only effects the temp 2* - 3*). I thought since the VP is just one large aluminum heat sink so why not try to cool the whole VP with the OAT blower and mist it. The OAT blower discharges up by the electronic bay, but dumps air around the entire VP44 (the air exits out the thermal blanket on the injector line side (ie the rear fo the VP44 is completely open to the engine compartment)).
The lowest I have been able to get the fuel temp is ~ OAT +10* and the EBC ~ OAT +15*. With one drive this morning the fuel temps were ~OAT +7* and the EBC was ~ OAT + 9*. Temp rise was very very slow to the final stable temperature. The VP44 misting does carry off a good bit of heat.
A significant reduction in temps and well within usable range of not more than about 100* on either input fuel or EBC. Getting very very close to the objective of 100* max on the VP44.
I am going to go for a drive this afternoon (OAT 97*) and see if the really hot part of the day makes any difference.
The only down side is adding a water system to do the misting means another whole sytem and maintenance for another whole system. However it does seem to make a pretty good difference in controlling the VP44 heat. The mist is really really small dropplets 55um as I recall.
More later.
Later:
Afternoon OAT 93* - 97*
Town / Interstate (70 mph) total trip was 80 miles.
The EBC NEVER got over 100*! The fuel temp NEVER got over 100*! (full tank)
Sometimes the VP EBC was actually a degree or two cooler than the fuel temperature. Of course the relationship of rpm to VP EBC temperature held true (higher rpm, more VP temperature, ~ 1* / 100 rpm both + & -).
I stopped and let it idle for a little while and see what no ram air would do. Neither got over 100*. I took the aft end temperature of the VP44, the EBC and fuel were 100*, the aft end (where the solenoid is) was 120* (no real fuel cooling there). Which I think means that the entire VP body should not be much more than 120* if at all. I could touch under the thermal blanket anywhere, and warm, yes, but not hot. Took VP output fuel temp, same 5* increase because of what the VP44 does going into the rail fuel coolers (105* going in, 100* comming out into the tank (this might need a tiny bit of tweaking ot get a little more fuel temperature OUT before the tank.
Back on the interstate, same temperature relationships as before OAT 95* EBC 98* - 100* Fuel temp 99* - 100*. Got off the interstate to change the rpms. EBC cooled right down with the 1* / 100 rpm ratio. The fuel temp took a little while before it started to cool down eventually to 98*.
Got home, let's see if the same max EBC rise is 5* from EBC shutdown temp. Yep, and a little quicker to start the temp down from max. I think the entire VP44 is now a little cooler with the misting of the OAT blower air. Less heat, easier to cool down. There is no evidence of moisture around the VP44 or associated engine compartment (there is about 3' of semirigid 3" aluminum ducting (mixing chamber) to get from the blower to the VP44). I think there is a good bit of warm to hot air that any mist that is not evaporated by the VP is instantly evaporated in the engine compartment.
Well, I am going to run this for a long time and see what happens with towing etc. However, I think the VP temperature problem is done as far as I am concerned. Of course the VP44 can and will fail for a bunch of other reasons, but not because of temperature here.
I REALLY REALLY REALLY appreciate ALL the inputs from everyone and that you followed the thread as it unfolded. I hope this helps someone else avoid some of the mistakes I made.
Oh, BTW I took off the copper tube front cooler. It was a major fuel heat source IF YOU WERE NOT MOVING. Moving it assisted with cooling a couple of degrees, NOT moving it contributed about 10* - 20* to the fuel temp.
I summarized above with respect to each individual change. The misting especially of the VP44 seems to be a fairly significant heat reduction. You have to thermal insulate it etc etc, but misting the OAT blower air I think helps get the entire VP44 aluminum heat sink cooler.
Cooler fuel going in, cooler VP body to start with and I think there is significant reason to think there is something to this cooling approach.
Bob Weis
Last edited:
We've only completed about half of our 3 week, 2000 mile RV trip with my setup - which is the insulated strips between the stock fuel filter and intake manifold, aluminum heat barrier between the engine block and VP-44, the added Frantz fuel filter with the installed finned outer cover, and the 140 CFM 3 inch marine bilge blower directing air from under/behind the front bumper pretty much all around the VP - plus my added PC microprocessor heatsink on the EB cover.
Temps on the trip down here to the Lodi area of N. Central California were pretty cool - in the mid to upper 80's, and in the upper 80's to low 90's since we've been here.
All the way here pulling the 5er - a GCW of over 14,000 lbs, temp of the VP-44 never got above 98 degrees - and instantly began to drop as speed was reduced as we went thru towns, and also when stopped or when the engine shut down. I've been able to reduce the Marine blower time from just over 2 hours, down to 80 minutes with the newer and more powerful blower, and overall VP temperature control has been vastly improved.
All in all, I rarely see over 100 degrees at ANY time as measured down on the main body of the VP-44, right between and slightly above the VP inlet and outlet ports.
Our return trip home in a week will see higher average OAT, and some steeper and longer grades than the trip here - and will be the final, worse-case scenario for the travels we normally see in our RV trips. I'll report results when we get back home.
All in all, for our truck usage and climate exposure, I'm extremely satisfied with my setup, and can't see any need for additional mods for our climates - plus, the setup that works for me requires no routine maintenance or attention, it all pretty well takes care of itself - obviously, Bob's higher average daily temps need more mods to obtain the same general results.
More later...
Temps on the trip down here to the Lodi area of N. Central California were pretty cool - in the mid to upper 80's, and in the upper 80's to low 90's since we've been here.
All the way here pulling the 5er - a GCW of over 14,000 lbs, temp of the VP-44 never got above 98 degrees - and instantly began to drop as speed was reduced as we went thru towns, and also when stopped or when the engine shut down. I've been able to reduce the Marine blower time from just over 2 hours, down to 80 minutes with the newer and more powerful blower, and overall VP temperature control has been vastly improved.
All in all, I rarely see over 100 degrees at ANY time as measured down on the main body of the VP-44, right between and slightly above the VP inlet and outlet ports.
Our return trip home in a week will see higher average OAT, and some steeper and longer grades than the trip here - and will be the final, worse-case scenario for the travels we normally see in our RV trips. I'll report results when we get back home.
All in all, for our truck usage and climate exposure, I'm extremely satisfied with my setup, and can't see any need for additional mods for our climates - plus, the setup that works for me requires no routine maintenance or attention, it all pretty well takes care of itself - obviously, Bob's higher average daily temps need more mods to obtain the same general results.
More later...
Slight variation emerging:
Cool the fuel to cool the VP44 from the inside. Duct significant outside air to saturate the VP44 mounting area to keep engine heat off the VP44 from the outside (the VP44 is just a large block of aluminum heat sink with internal parts).
Work on both the inside and outside of the VP44 with cooling.
The bilge blower (250 cfm) was moved from behind the bumper pocket to under the front bumper to get ram air head on. Ram air takes over from the electric blower noticably above about 40 mph.
The bumper inlet facia was removed to allow total frontal air flow into the front of the engine as unimpeaded as possible. Engine temperature rise to standard thermostat temperatures takes about twice as long as long as you are going 40mph+ during engine temperature rise time period. I think (no proof) that there is better under hood air flow.
Over 40 mph the EBC is cooler than the fuel input temps and remains so by about 5* until you decelerate below 40 mph. Long periods of slow speed (below 40 mph) driving the input fuel temps begin to swap place with the EBC temps as the cooler temp. Implies the fuel cooler is most effective at slower speeds (below 40 mph), ram air most effective at higher speeds (over 40 mph).
The combination seems to work reasonably well. VP EBC temp OR fuel input temp has not gone over OAT +8* for several weeks now with OAT between 90* - 100*. The combination of different ways to cool as one cooler system becomes less efficient the other system becomes more efficient may be a key ingrediant.
Recently the SE TDR club went to SouthEast Power Systems in Tampa and had extended VP questions. The DC approach to VP cooling is that the fuel tank fuel is the heat sink. I see the problem is as you use fuel you use the heat sink and make it less and less able to do its task, and hence WHY cooler fuel is needed especially when the fuel volume goes toward "E".
Bob Weis
Cool the fuel to cool the VP44 from the inside. Duct significant outside air to saturate the VP44 mounting area to keep engine heat off the VP44 from the outside (the VP44 is just a large block of aluminum heat sink with internal parts).
Work on both the inside and outside of the VP44 with cooling.
The bilge blower (250 cfm) was moved from behind the bumper pocket to under the front bumper to get ram air head on. Ram air takes over from the electric blower noticably above about 40 mph.
The bumper inlet facia was removed to allow total frontal air flow into the front of the engine as unimpeaded as possible. Engine temperature rise to standard thermostat temperatures takes about twice as long as long as you are going 40mph+ during engine temperature rise time period. I think (no proof) that there is better under hood air flow.
Over 40 mph the EBC is cooler than the fuel input temps and remains so by about 5* until you decelerate below 40 mph. Long periods of slow speed (below 40 mph) driving the input fuel temps begin to swap place with the EBC temps as the cooler temp. Implies the fuel cooler is most effective at slower speeds (below 40 mph), ram air most effective at higher speeds (over 40 mph).
The combination seems to work reasonably well. VP EBC temp OR fuel input temp has not gone over OAT +8* for several weeks now with OAT between 90* - 100*. The combination of different ways to cool as one cooler system becomes less efficient the other system becomes more efficient may be a key ingrediant.
Recently the SE TDR club went to SouthEast Power Systems in Tampa and had extended VP questions. The DC approach to VP cooling is that the fuel tank fuel is the heat sink. I see the problem is as you use fuel you use the heat sink and make it less and less able to do its task, and hence WHY cooler fuel is needed especially when the fuel volume goes toward "E".
Bob Weis
The concept of fuel cooling below 40 mph and ram air duct cooling above 40 mph is holding up well.
Above about 60 mph the EBC is actually cooler than the outside air by ~ 2 degrees and the Vp44 seems to cool the fuel instead of the fuel cooling the VP44. Interesting concept.
I am going to put a 6" to 4" A/C duct reducer (on backwards so the 6" opening is forward and the 4" opening is mounted to the bilge blower) in front of the bilge fan blower to double the corss sectional area of the ram air input (pi x r**2, 3. 14 x 2x2 = 12. 56 sq inches, 3. 14 x 3x3 = 28. 26 sq inches). We'll see how this works.
Key point of the ram air is that you HAVE to be moving forward. Sitting at a stop light or in a traffic jam the EBC temp will start increasing with only ram air. That is where fuel cooling comes in and becomes the primary Vp44 cooling. Remember also that at idle the amount of fuel going through the VP44 is about zilch so little fuel cooling at idle (in traffic etc) as well. SO long periods of low rpm are NOT good for VP temperature control. That is where the blige blower helps a whole lot to keep the air moving over the VP44.
The after engine shutdown air blower (again thanks to Gary) is the key to STOP the heat soaking after shutdown.
Back to the testing,
Bob Weis
Above about 60 mph the EBC is actually cooler than the outside air by ~ 2 degrees and the Vp44 seems to cool the fuel instead of the fuel cooling the VP44. Interesting concept.
I am going to put a 6" to 4" A/C duct reducer (on backwards so the 6" opening is forward and the 4" opening is mounted to the bilge blower) in front of the bilge fan blower to double the corss sectional area of the ram air input (pi x r**2, 3. 14 x 2x2 = 12. 56 sq inches, 3. 14 x 3x3 = 28. 26 sq inches). We'll see how this works.
Key point of the ram air is that you HAVE to be moving forward. Sitting at a stop light or in a traffic jam the EBC temp will start increasing with only ram air. That is where fuel cooling comes in and becomes the primary Vp44 cooling. Remember also that at idle the amount of fuel going through the VP44 is about zilch so little fuel cooling at idle (in traffic etc) as well. SO long periods of low rpm are NOT good for VP temperature control. That is where the blige blower helps a whole lot to keep the air moving over the VP44.
The after engine shutdown air blower (again thanks to Gary) is the key to STOP the heat soaking after shutdown.
Back to the testing,
Bob Weis
Bob, has there been any uncovered evidence that there are actually reduced **internal** VP temps?
Blowing air on the VP is like blowing air on your computer case and assuming that the CPU is being cooled.
When you point your IR temp gun at the VP electronincs bay, all you are reading is **surface** temperature. The internal temp will be quite different and posssibly be uneffected by the mini windstorm you have with your bilge blower.
(Is it possible to measure exit fuel temperature to see if the air blast is having any dersired effect?)
I'm not trying to pick a fight but I just cant see how blowing air on the surface can have any effect on the internal temps.
Secondly, the heat sinking (heat gain) through the timing cover has to be far in excess of the BTU's of heat loss of a dozen or so square inches of aluminum plate [ the VP EB cover ].
Following this path, would setting up a 3" duct to blow air on the transmission pan cause the transmission temps to drop? Of course not, but you can see my point. You need to measure and record **internal** temps before any real testing can be accomplished or conclusions drawn.
Besides, most of the VP failures seem to come from lubricity, atleast according to the Bosch report I read. Galling, scoring, siezing and rapid wear are indicative of low lubricity. No doubt reducing temps might have a small effect (only if excessive temps were the original cause).
Blowing air on the VP is like blowing air on your computer case and assuming that the CPU is being cooled.
When you point your IR temp gun at the VP electronincs bay, all you are reading is **surface** temperature. The internal temp will be quite different and posssibly be uneffected by the mini windstorm you have with your bilge blower.
(Is it possible to measure exit fuel temperature to see if the air blast is having any dersired effect?)
I'm not trying to pick a fight but I just cant see how blowing air on the surface can have any effect on the internal temps.
Secondly, the heat sinking (heat gain) through the timing cover has to be far in excess of the BTU's of heat loss of a dozen or so square inches of aluminum plate [ the VP EB cover ].
Following this path, would setting up a 3" duct to blow air on the transmission pan cause the transmission temps to drop? Of course not, but you can see my point. You need to measure and record **internal** temps before any real testing can be accomplished or conclusions drawn.
Besides, most of the VP failures seem to come from lubricity, atleast according to the Bosch report I read. Galling, scoring, siezing and rapid wear are indicative of low lubricity. No doubt reducing temps might have a small effect (only if excessive temps were the original cause).
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Glad to see the update and keeping this thread alive Bob - thanks.
Been doing some minor revamping on my setup, and coincidentally also working on improving the "ram air" effect by much the same method you are working on. I'll post some updated pics when I get mine completed - probably sometime this next week.
Meanwhile, the highest VP-44 case temps registered right at the fuel input/output port area have not exceeded about 110 degrees, even in our latest heat spell with ambient temps at and slightly above 110 degrees as well - sure hate to think what the VP-44 temps would have been with underhood heat soak added without the mods made so far!
More later...
Been doing some minor revamping on my setup, and coincidentally also working on improving the "ram air" effect by much the same method you are working on. I'll post some updated pics when I get mine completed - probably sometime this next week.
Meanwhile, the highest VP-44 case temps registered right at the fuel input/output port area have not exceeded about 110 degrees, even in our latest heat spell with ambient temps at and slightly above 110 degrees as well - sure hate to think what the VP-44 temps would have been with underhood heat soak added without the mods made so far!
More later...
Texas Diesel - Well yes.
I measure the internal temperatures of the VP by what the temperature of the fuel to the VP does as it is returned to the tank and back to the VP44 over a long period of time (hours).
If the fuel coolers do not take more temp out of the fuel than the VP is putting in then the fuel tank input temps go up. IF there is no change to the fuel coolers and the input fuel temps were going up above the VP case temp then the VP was introducing more heat than the cooling system was taking out until there is enough temperature difference between the fuel and the ambiant air for the fuel coolers to reach equilibrium.
At some point there becomes an equilibrium with the fuel system. Even on the unmodified trucks, the heat in and the heat out will strike some sort of balance.
Only one run, so a couple of weeks fo data will hekp but, on the one run (1hr).
The only change was the larger heading of the ram air to the blower.
The fuel input temps did not go up the usual about 5* greater than the VP case temp. Why not?, what changed?, only the frontal cross section of the ram air.
The VP is basically a large aluminum heat sink internally or externally. Ideally the fuel will cool it from the inside and I do that. However, because aluminum is such a great heat sink I believe that if I also cool the outside it will remove some of the temperature and help in keeping the internals cooler and have less internal heat for the fuel to cool.
I think that MIGHT be the case in increasing the ram air volume in the latest modification. Time will tell, maybe yes maybe no.
You do experimentation to disprove the idea, I will do the experimentation to prove the idea. My fuel temp with the latest change = OAT, what does your fuel temp read? My Vp44 has not had a single day above 100* measured in case temp (external) and fuel temp (internal) how about yours?
On the computer cpu concept, why do they put cooling fans on the cpu's?, wht do they put cooling fans in the cases to expell heat?why do they blow ambiant air on the cpu mechanical structure? BECAUSE they mount a heat sink on the mechanical chip to get as much of the heat to migrate to the heat sink and then cool the heat sink trying to carry heat away from the mechanical chip. Some computers do not even put a fan directly on the cpu and use internal case air flow to cool the heat sink. Ever taken the heat sink off a cpu and turned the computer on? Put your finger on the cpu chip and turn the computer on and see how fast (1 or 2 seconds) before it gets too hot to leave your finger on the cpu. Now put the mechanical heat sink on the cpu and do the same but put your finger on the heat sink and you can leave your finger on it indefinitely. The heat sink is not cooling the internals of the cpu chip but is taking heat off the surface as some rate to keep the internals of the cpu chip at an acceptable temperature.
Somewhat the same with the VP44.
Cool what you can internally (and the fuel is indeed the primary means of cooling) and augment that with extracting heat from the surface of the Vp44 (big aluminum heat sink). Most of the heat comes off from internal cooling, some heat comes off from external cooling.
Watching what happens to the temperatures of the internal cooling fluid with a change of the external cooling rate of air flow with all other things the same I think will give some indication of that there is less heat being taken off by the internal cooling because the heat reduction to the external aluminum block caused the internal fuel return to not increase in temperature.
IF NOT - then where did the heat go? If you can tell me where the heat went (assuming it was not the increased ram cross section) then we may have another avenue to explore in keeping the Vp44 cool.
Certainly is an interesting subject because of the critical nature of the VP44 and somewhere the delicate nature of it.
Bob Weis
I think your analogy of blowing air on the case of a computer to cool the cpu is like blowing air on the sheetmetal exterior of the truck to cool the VP44, and that is not quite what we are doing.
The lubricity is easy, Stanadyne will do that, clean fuel is a little harder (change filters often), cool fuel is a little harder.
I measure the internal temperatures of the VP by what the temperature of the fuel to the VP does as it is returned to the tank and back to the VP44 over a long period of time (hours).
If the fuel coolers do not take more temp out of the fuel than the VP is putting in then the fuel tank input temps go up. IF there is no change to the fuel coolers and the input fuel temps were going up above the VP case temp then the VP was introducing more heat than the cooling system was taking out until there is enough temperature difference between the fuel and the ambiant air for the fuel coolers to reach equilibrium.
At some point there becomes an equilibrium with the fuel system. Even on the unmodified trucks, the heat in and the heat out will strike some sort of balance.
Only one run, so a couple of weeks fo data will hekp but, on the one run (1hr).
The only change was the larger heading of the ram air to the blower.
The fuel input temps did not go up the usual about 5* greater than the VP case temp. Why not?, what changed?, only the frontal cross section of the ram air.
The VP is basically a large aluminum heat sink internally or externally. Ideally the fuel will cool it from the inside and I do that. However, because aluminum is such a great heat sink I believe that if I also cool the outside it will remove some of the temperature and help in keeping the internals cooler and have less internal heat for the fuel to cool.
I think that MIGHT be the case in increasing the ram air volume in the latest modification. Time will tell, maybe yes maybe no.
You do experimentation to disprove the idea, I will do the experimentation to prove the idea. My fuel temp with the latest change = OAT, what does your fuel temp read? My Vp44 has not had a single day above 100* measured in case temp (external) and fuel temp (internal) how about yours?
On the computer cpu concept, why do they put cooling fans on the cpu's?, wht do they put cooling fans in the cases to expell heat?why do they blow ambiant air on the cpu mechanical structure? BECAUSE they mount a heat sink on the mechanical chip to get as much of the heat to migrate to the heat sink and then cool the heat sink trying to carry heat away from the mechanical chip. Some computers do not even put a fan directly on the cpu and use internal case air flow to cool the heat sink. Ever taken the heat sink off a cpu and turned the computer on? Put your finger on the cpu chip and turn the computer on and see how fast (1 or 2 seconds) before it gets too hot to leave your finger on the cpu. Now put the mechanical heat sink on the cpu and do the same but put your finger on the heat sink and you can leave your finger on it indefinitely. The heat sink is not cooling the internals of the cpu chip but is taking heat off the surface as some rate to keep the internals of the cpu chip at an acceptable temperature.
Somewhat the same with the VP44.
Cool what you can internally (and the fuel is indeed the primary means of cooling) and augment that with extracting heat from the surface of the Vp44 (big aluminum heat sink). Most of the heat comes off from internal cooling, some heat comes off from external cooling.
Watching what happens to the temperatures of the internal cooling fluid with a change of the external cooling rate of air flow with all other things the same I think will give some indication of that there is less heat being taken off by the internal cooling because the heat reduction to the external aluminum block caused the internal fuel return to not increase in temperature.
IF NOT - then where did the heat go? If you can tell me where the heat went (assuming it was not the increased ram cross section) then we may have another avenue to explore in keeping the Vp44 cool.
Certainly is an interesting subject because of the critical nature of the VP44 and somewhere the delicate nature of it.
Bob Weis
I think your analogy of blowing air on the case of a computer to cool the cpu is like blowing air on the sheetmetal exterior of the truck to cool the VP44, and that is not quite what we are doing.
The lubricity is easy, Stanadyne will do that, clean fuel is a little harder (change filters often), cool fuel is a little harder.
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Bob, thanks for the thoughtful reply. I am printing your response so I can read it over time and let it soak in. I'll get back with you later, I have no net at home, still waiting on the WiFi equipment. I have limited time at work to read personal stuff.
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Issue 128 – Digital Version
Digital Magazines
FREE!
TDR Test Drive - Digital Edition
Renew
Subscribe
Gift Subscriptions
Back Issues
Subscription Status
Address Change Form
Buyer's Guides
Ram Diagnostic Trouble Codes
The Perfect Collection
The Perfect Collection Vol. II
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Dodge/Cummins Historical Overview
Cameron Collection
What Makes Us Tick?
Product Showcase
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