BOB, consider installing a voltage reducing resistor in the power supply line to your bilge pump - it may well be that reducing CFM slightly will still get the cooling job done, while substantially reducing blower noise...
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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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I hope the TDR does an article on this experimentation you all are doing. I look forward to reading how this is all taking place. Maybe when its all said and done you can sell a set-up we can use and install on our trucks. All this electrical stuff with the blower and wiring, resistors, ect..... wont do me any good as ... . I am electronically challenged :-laf
10/19 to work, & home from work, 10/20 to work
The pattern that is developing is:
prior to engine start:
underhood temp on the EBC = OAT +5* consistantly in the morning cold soak over night, and in the evening before going home heat soak all day.
engine start:
EBC temp quickly goes to OAT
drive time:
EBC temp gradually rises to OAT +13*. You can look at OAT before EBC stabilizes and predict the temp the EBC will stabilize before it gets to that temp. I have been driving the engine very gently and will try to work in some WOT accelerations and faster cruise speeds and RV towing to see what that does to the EBC. I wanted to keep every variable as much the same as possible (ie acceleration style, driving style, cruise speed, roads traveled, traffic density) to try to establish a predictable pattern. Now I will vary some of the parameters.
engine shutdown:
Typically the EBC temperature will rise 3* - 5* (OAT + 16* - 18*) before the cooling air gets the EBC starting to fall. The engine is fully warmed up and had been running at a stable temp for about 15 minutes (ie the thermostat was closed, water temp went slightly above thermostat temp, thermostat opens, water temp drops to thermostat temp, and stabilizes). The OAT cooling air flow over the VP44 seems to drop the VP44 EBC about 6* - 8* per HOUR. The timer is set to 128 minutes of run time after engine stop. The EBC does generally drop about 15* back to OAT.
The bilge blower I use (Atwood) is very noisy and reports I read say they do not last very long. I did some research on bilge blowers and A/C duct blowers and there are A/C duct blowers that are much more quiet but take 120V and would require a reducer from their 4" to the 3" duct to the VP44. There are some bathroom vent fans (3" duct) (120v) that are quiet and probably could be used, but the same 120v issue. There are bilge blowers more squirrel cage like that are 10,000 hour motor MTBF (avg drive mph of 45 mph = 450,000 miles) (MTBF=mean time between failure) and 12 volt (11amps vs the 2. 7 amps the current bilge blower I am using). The longer lasting blowers are parts replaceable and I think (not sure) would fit behind the bumper and before the wheel well where the current blower is. I have not checked price of the long MTBF units yet. The Atwood I am using was about $28.
I do notice that with 128 minutes of run time when I startup after the fan has run the voltmeter on the dash cluster is down at about 11 volts. Supposedly the blower has only used 5. 76 amps (128 minutes * 2. 7 a/hr) but I find the startup voltage is obviously lower and the starter spin is slower than if the blower has not run. I have not had any problem starting yet, but I would think you could if your CTD did not start right up. Weather temperature could have a influence here. I do not know what would happen if the OAT were 0*, but then you could turn off the blower system and not use it because cooling should not be an issue.
There might be some consideration like stated above about WHEN to run this forced air system. It may be ony applicable to warm (above 70*) to hot OAT.
I do think this approach of forced air cooling of the VP44 does definitely have merit during those OAT times you want to keep the EBC of the VP44 cooler.
Here in florida I am going to run mine year around to see what happens to the engine start ability during cooler weather this winter and will report back on that. Also will report back if this blower fails and has to be replaced.
That's it for now,
Bob Weis
The pattern that is developing is:
prior to engine start:
underhood temp on the EBC = OAT +5* consistantly in the morning cold soak over night, and in the evening before going home heat soak all day.
engine start:
EBC temp quickly goes to OAT
drive time:
EBC temp gradually rises to OAT +13*. You can look at OAT before EBC stabilizes and predict the temp the EBC will stabilize before it gets to that temp. I have been driving the engine very gently and will try to work in some WOT accelerations and faster cruise speeds and RV towing to see what that does to the EBC. I wanted to keep every variable as much the same as possible (ie acceleration style, driving style, cruise speed, roads traveled, traffic density) to try to establish a predictable pattern. Now I will vary some of the parameters.
engine shutdown:
Typically the EBC temperature will rise 3* - 5* (OAT + 16* - 18*) before the cooling air gets the EBC starting to fall. The engine is fully warmed up and had been running at a stable temp for about 15 minutes (ie the thermostat was closed, water temp went slightly above thermostat temp, thermostat opens, water temp drops to thermostat temp, and stabilizes). The OAT cooling air flow over the VP44 seems to drop the VP44 EBC about 6* - 8* per HOUR. The timer is set to 128 minutes of run time after engine stop. The EBC does generally drop about 15* back to OAT.
The bilge blower I use (Atwood) is very noisy and reports I read say they do not last very long. I did some research on bilge blowers and A/C duct blowers and there are A/C duct blowers that are much more quiet but take 120V and would require a reducer from their 4" to the 3" duct to the VP44. There are some bathroom vent fans (3" duct) (120v) that are quiet and probably could be used, but the same 120v issue. There are bilge blowers more squirrel cage like that are 10,000 hour motor MTBF (avg drive mph of 45 mph = 450,000 miles) (MTBF=mean time between failure) and 12 volt (11amps vs the 2. 7 amps the current bilge blower I am using). The longer lasting blowers are parts replaceable and I think (not sure) would fit behind the bumper and before the wheel well where the current blower is. I have not checked price of the long MTBF units yet. The Atwood I am using was about $28.
I do notice that with 128 minutes of run time when I startup after the fan has run the voltmeter on the dash cluster is down at about 11 volts. Supposedly the blower has only used 5. 76 amps (128 minutes * 2. 7 a/hr) but I find the startup voltage is obviously lower and the starter spin is slower than if the blower has not run. I have not had any problem starting yet, but I would think you could if your CTD did not start right up. Weather temperature could have a influence here. I do not know what would happen if the OAT were 0*, but then you could turn off the blower system and not use it because cooling should not be an issue.
There might be some consideration like stated above about WHEN to run this forced air system. It may be ony applicable to warm (above 70*) to hot OAT.
I do think this approach of forced air cooling of the VP44 does definitely have merit during those OAT times you want to keep the EBC of the VP44 cooler.
Here in florida I am going to run mine year around to see what happens to the engine start ability during cooler weather this winter and will report back on that. Also will report back if this blower fails and has to be replaced.
That's it for now,
Bob Weis
The get home temperature yesterday (10/26, 1800 EST) was 65*. I was courious to see what would happen if I did not do the shutdown cooling air to the VP44. In the past the difference was as generally about 50* above OAT.
The highest post shutdown VP44 EBC temp was 112*. It does not appear to matter how cool (cold to us in FL) the post shutdown OAT is, the underhood temps still run about OAT +50*.
I was thinking that if the temperature difference was less, that might be one reason not to run the post shut down air cooling.
Of course because the OAT is significantly less there is less need to do the post shut down air flow with cooler temperatures.
Bob Weis
The highest post shutdown VP44 EBC temp was 112*. It does not appear to matter how cool (cold to us in FL) the post shutdown OAT is, the underhood temps still run about OAT +50*.
I was thinking that if the temperature difference was less, that might be one reason not to run the post shut down air cooling.
Of course because the OAT is significantly less there is less need to do the post shut down air flow with cooler temperatures.
Bob Weis
Towed this weekend,
OAT 65*
EBC OAT+30* (Normally empty OAT*+15*)
I could not run the shutdown fan the first night (long story) highest was OAT*+60* (ie 30* above shutdown temp, parallels empty shutdown with no fan). In this case 125* at the EBC + whatever the internal temp is (probably +20*)
I think this really means
1. Towing VP44 temps higher than empty by about 15* (sounds reasonable).
2. If the OAT is more than about 70* you need to run post shutdown cooling to protect the VP44. You guys in the north (north of florida
) have an advantage with this I think.
The higher the running temps the more important it is because the less margin you have to overheating the electronics board (I think). The increase in temps seem to be in the OAT + 50* range without a post cooling fan and empty, seem to be in the OAT + 60* range without a post cooling fan and towing. (so far)
You would have to add another 20* (?) to determine what the internal VP44 temps are. The above temps are only at the EBC (electronics bay cover).
Bob Weis
OAT 65*
EBC OAT+30* (Normally empty OAT*+15*)
I could not run the shutdown fan the first night (long story) highest was OAT*+60* (ie 30* above shutdown temp, parallels empty shutdown with no fan). In this case 125* at the EBC + whatever the internal temp is (probably +20*)
I think this really means
1. Towing VP44 temps higher than empty by about 15* (sounds reasonable).
2. If the OAT is more than about 70* you need to run post shutdown cooling to protect the VP44. You guys in the north (north of florida
) have an advantage with this I think. The higher the running temps the more important it is because the less margin you have to overheating the electronics board (I think). The increase in temps seem to be in the OAT + 50* range without a post cooling fan and empty, seem to be in the OAT + 60* range without a post cooling fan and towing. (so far)
You would have to add another 20* (?) to determine what the internal VP44 temps are. The above temps are only at the EBC (electronics bay cover).
Bob Weis
I changed the fuel cooler from a -cool the return line to a -cool the feed line right out of the tank. Differences are:
MINOR variations, not significant. The VP44 input fuel temperatures are approximately the same, the VP44 EBC temperatures are approximately the same.
From what I can tell at this point the key points to this thread are:
It is VERY IMPORTANT to supply OAT cooling air to the VP44 AFTER engine shutdown to keep it from heat soaking. The heat soak temperature is approximately OAT + 50* on the EBC, plus whatever you think the additional actual internal temperatures are. These temperatures take approximately 2 hours to start to drop due to (I think) the mass of the metal under the hood.
Using forced air cooling for 2 hours, the VP44 EBC gains about 5* from running temperatures and then begins to cool at the rate of 7* per HOUR.
The VP44 EBC generally gains right at 15* above the OAT (as displayed on the overhead console) running empty, about 20* towing 13K RV in flat Florida. There is a definite correlation of engine rpm to Vp44 EBC temperature. 1400 rpm changing that to 2000 rpm (empty) would add about 7* to the EBC steady state (running at the new rpm for an extended period of time (1 hr +))
IF you desire to cool the VP44 input fuel it does not seem to be much difference between cooling the return fuel to cooling the input fuel (at least on my setup - fuel returned to the vent line, no OEM ff, insulated fuel lines in engine compartment, RASP, running VP input psi = 17.
The VP44 (and injector return) adds approximately 15* to the VP44 input fuel temp. It takes a pretty large heat exchanger to dump 15* of a ready heat source. I am using a large transmission cooler + an inline cooler (18") and still get some slight temp rise (ie I am not dumping all 15* yet) over time. However, as the tank gets above the OAT there is probably SOME heat disipation with the tank in the slip stream. I have not run at close to empty tank yet to see what that does to the heat dissipation / heat increase of a small quantity of fuel in the tank.
The fuel tank seems to run 10* above the OAT consistently except on overnight cooling soaks. However it quickly (30 minutes - 1 hour) comes up to OAT +10*. Afternoon trips home the fuel tank is at OAT +10* from the ambiant heat of the day.
I am going to now take the track of providing better forced cooling to the VP while running and +2 hours. Right now th fan (bilge fan) I am using is excessively loud after engine shutdown. Gary and I are experimenting with Pulse Width Modulation (PWM) DC motor controllers to see if we can find a happy medium of cool air and quiet. Each is testing a different fan system.
As winter passes and summer approaches I'll revisit this thread and report where we are and how the VP44 cooling concept is comming and the changes up to that point.
The focus remains to keep the VP44 cool and elimanate the failure of the Vp44 due to overheated electronics.
Bob Weis
MINOR variations, not significant. The VP44 input fuel temperatures are approximately the same, the VP44 EBC temperatures are approximately the same.
From what I can tell at this point the key points to this thread are:
It is VERY IMPORTANT to supply OAT cooling air to the VP44 AFTER engine shutdown to keep it from heat soaking. The heat soak temperature is approximately OAT + 50* on the EBC, plus whatever you think the additional actual internal temperatures are. These temperatures take approximately 2 hours to start to drop due to (I think) the mass of the metal under the hood.
Using forced air cooling for 2 hours, the VP44 EBC gains about 5* from running temperatures and then begins to cool at the rate of 7* per HOUR.
The VP44 EBC generally gains right at 15* above the OAT (as displayed on the overhead console) running empty, about 20* towing 13K RV in flat Florida. There is a definite correlation of engine rpm to Vp44 EBC temperature. 1400 rpm changing that to 2000 rpm (empty) would add about 7* to the EBC steady state (running at the new rpm for an extended period of time (1 hr +))
IF you desire to cool the VP44 input fuel it does not seem to be much difference between cooling the return fuel to cooling the input fuel (at least on my setup - fuel returned to the vent line, no OEM ff, insulated fuel lines in engine compartment, RASP, running VP input psi = 17.
The VP44 (and injector return) adds approximately 15* to the VP44 input fuel temp. It takes a pretty large heat exchanger to dump 15* of a ready heat source. I am using a large transmission cooler + an inline cooler (18") and still get some slight temp rise (ie I am not dumping all 15* yet) over time. However, as the tank gets above the OAT there is probably SOME heat disipation with the tank in the slip stream. I have not run at close to empty tank yet to see what that does to the heat dissipation / heat increase of a small quantity of fuel in the tank.
The fuel tank seems to run 10* above the OAT consistently except on overnight cooling soaks. However it quickly (30 minutes - 1 hour) comes up to OAT +10*. Afternoon trips home the fuel tank is at OAT +10* from the ambiant heat of the day.
I am going to now take the track of providing better forced cooling to the VP while running and +2 hours. Right now th fan (bilge fan) I am using is excessively loud after engine shutdown. Gary and I are experimenting with Pulse Width Modulation (PWM) DC motor controllers to see if we can find a happy medium of cool air and quiet. Each is testing a different fan system.
As winter passes and summer approaches I'll revisit this thread and report where we are and how the VP44 cooling concept is comming and the changes up to that point.
The focus remains to keep the VP44 cool and elimanate the failure of the Vp44 due to overheated electronics.
Bob Weis
rweis said:
How much would this drain the battery... or are you using another power supply to run the fans after you shut down.
Well, so far the battery drain for the fan is 3 Ah x 2 hr. It is noticable on engine start the next morning that the surface charge is drained off the batteries.
I have a brake controller that reports the battery voltage and the following morning battery voltage is generally 12. 6 volts from 13. 2 volts at shutdown.
Generally on engine start the next morning the charge is restored fairly quickly.
One of the concepts of the Pulse Width Modulation (PWM) is that for motor speed control they pulse the motor to control the motor speed. This means there is a short period of zero voltage prior to the next pulse to drive the motor. I do not know if the period of no voltage will have any real effect on the battery voltage draw down.
We are not using a secondary fan power source at this point.
We will have to see where the motor experimentation takes us.
Bob Weis
I have a brake controller that reports the battery voltage and the following morning battery voltage is generally 12. 6 volts from 13. 2 volts at shutdown.
Generally on engine start the next morning the charge is restored fairly quickly.
One of the concepts of the Pulse Width Modulation (PWM) is that for motor speed control they pulse the motor to control the motor speed. This means there is a short period of zero voltage prior to the next pulse to drive the motor. I do not know if the period of no voltage will have any real effect on the battery voltage draw down.
We are not using a secondary fan power source at this point.
We will have to see where the motor experimentation takes us.
Bob Weis
Bob, think about this. What you are doing by blowing air on the VP-44 is like trying to cool your computers CPU by blowing air on the outside case. There is no connection.
I'm still not sure that heat in the electronics bay is an issue. The Cummins ECU (below the VP-44 and mounted directly to the block) does just fine, have you ever heard of one of them failing?
I think the blower is a feel-good step that doesnt effect the internal temp of the VP-44 much, if at all. As you cool the side of the VP-44 facing your fan the engine is sinking much more heat right back in.
I'm not trying to rain on your parade, just something to think about.
I'm still not sure that heat in the electronics bay is an issue. The Cummins ECU (below the VP-44 and mounted directly to the block) does just fine, have you ever heard of one of them failing?
I think the blower is a feel-good step that doesnt effect the internal temp of the VP-44 much, if at all. As you cool the side of the VP-44 facing your fan the engine is sinking much more heat right back in.
I'm not trying to rain on your parade, just something to think about.
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Well, not sure about the correlation.
1. Keeping the fuel cool I think helps keep the Vp44 cooler. I can let the fuel temp go up and the VP44 EBC temp goes up eventhough the rpm and forced air stay the same.
2. After engine shutdown with no forced air the VP case will heat soak significantly higher than with forced air. I think that what the forced air on shutdown is doing is keeping the block heat OFF the VP44.
With forced air the case temp rises 5*, without forced air the case temp rises 30*.
Let's say you run your computer in an enclosed desk enclosure with the door shut and no outside air. The heat given off can not dissipate and the case and internal CPU gets hotter and hotter because it is heating the air faster than the desk can absorbe the heat. This happens at work all the time. We drill holes in the desk back to vent the air, and in some desk install forced air fans.
I see less temperature rise in the VP44 (and injector) fuel output temperature with case cooling than without case cooling. With case cooling I see less case temperatures, which I think would get temperatures to migrate from the inside to the outside of the VP44 to try to equalize the temperatures.
If the VP44 outside were higher temperatures than the inside then the temperatures would migrate from the outside to the inside of the VP44.
... "I think the blower is a feel-good step that doesnt effect the internal temp of the VP-44 much, if at all. As you cool the side of the VP-44 facing your fan the engine is sinking much more heat right back in... "
Not necessarily so,
Flooding the VP44 with OAT helps keep the engine block temperatures from migrating to the VP44 by providing a cooler forced air buffer around the VP44.
Try puting a temperature sensor on your VP44 right at the inlet. Measure the input fuel temperatures. Now go to the fuel return line and measure the return fuel temperatures. Now measure the Vp44 internal temperature (not sure how to do this). Now see what temperatures you are reading. We will compare OAT, empty, loaded, terrain. That should tell us if the forced cooling makes a difference.
I know when I have turned off the forced air everything else the same, the VP outlet fuel temperatures were higher (ie there was more heat internally being picked up by the fuel), the VP case temperatures were higher (maybe due to picking up engine block temperatures, not sure).
Turn on forced air, cooler, off, higher. The VP was doing the same work (rpm, load, gearing, fuel level).
Now if we could actually measure the internals of the VP44 that would be great. That is why I guesstimate about maybe somewhere around +20* to the case temperature to be the internal temperature. If anyone knows what the VP44 internal temperatures to the case temperatures are that would be great.
I have never heard of a ECU failing due to temp and it is mounted right on the side of the engine. Maybe designed correctly to handle the actual temperatures?
I have heard of VP44's failing. One vendor speaks of a redesigned electronics boards to try to prevent heat cycles. When my VP44 failed, run easily, no problem, run hard, problem. Everything was the same except higher rpm's and heat. I can see even now higher rpm's = higher case heat and I think I would extrapolate that to higher internal heat. If I can keep case heat low, then the higher internal heat should migrate toward the lower case heat.
Bob Weis
1. Keeping the fuel cool I think helps keep the Vp44 cooler. I can let the fuel temp go up and the VP44 EBC temp goes up eventhough the rpm and forced air stay the same.
2. After engine shutdown with no forced air the VP case will heat soak significantly higher than with forced air. I think that what the forced air on shutdown is doing is keeping the block heat OFF the VP44.
With forced air the case temp rises 5*, without forced air the case temp rises 30*.
Let's say you run your computer in an enclosed desk enclosure with the door shut and no outside air. The heat given off can not dissipate and the case and internal CPU gets hotter and hotter because it is heating the air faster than the desk can absorbe the heat. This happens at work all the time. We drill holes in the desk back to vent the air, and in some desk install forced air fans.
I see less temperature rise in the VP44 (and injector) fuel output temperature with case cooling than without case cooling. With case cooling I see less case temperatures, which I think would get temperatures to migrate from the inside to the outside of the VP44 to try to equalize the temperatures.
If the VP44 outside were higher temperatures than the inside then the temperatures would migrate from the outside to the inside of the VP44.
... "I think the blower is a feel-good step that doesnt effect the internal temp of the VP-44 much, if at all. As you cool the side of the VP-44 facing your fan the engine is sinking much more heat right back in... "
Not necessarily so,
Flooding the VP44 with OAT helps keep the engine block temperatures from migrating to the VP44 by providing a cooler forced air buffer around the VP44.
Try puting a temperature sensor on your VP44 right at the inlet. Measure the input fuel temperatures. Now go to the fuel return line and measure the return fuel temperatures. Now measure the Vp44 internal temperature (not sure how to do this). Now see what temperatures you are reading. We will compare OAT, empty, loaded, terrain. That should tell us if the forced cooling makes a difference.
I know when I have turned off the forced air everything else the same, the VP outlet fuel temperatures were higher (ie there was more heat internally being picked up by the fuel), the VP case temperatures were higher (maybe due to picking up engine block temperatures, not sure).
Turn on forced air, cooler, off, higher. The VP was doing the same work (rpm, load, gearing, fuel level).
Now if we could actually measure the internals of the VP44 that would be great. That is why I guesstimate about maybe somewhere around +20* to the case temperature to be the internal temperature. If anyone knows what the VP44 internal temperatures to the case temperatures are that would be great.
I have never heard of a ECU failing due to temp and it is mounted right on the side of the engine. Maybe designed correctly to handle the actual temperatures?
I have heard of VP44's failing. One vendor speaks of a redesigned electronics boards to try to prevent heat cycles. When my VP44 failed, run easily, no problem, run hard, problem. Everything was the same except higher rpm's and heat. I can see even now higher rpm's = higher case heat and I think I would extrapolate that to higher internal heat. If I can keep case heat low, then the higher internal heat should migrate toward the lower case heat.
Bob Weis
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Bob, you discovering exactly how hot the fuel is and WHERE most of the heat gain is taking place (fuel filter) is nothing short of genius. You have benefited the membership immeasurably with this discovery. Of course this applies to those who take action.
Clearly the VP has less than stellar performance :-laf
But blowing air across 8 square inches of aluminum surface is inconsequential compared the the mass of the iron block and head. Considering the VP is bolted directly to all that mass, well, I wish I could do what I did to the FF, and use an insulating washer between them to stop heat gain.
Playing the Devils advocate here, we need a way to measure the internal temp of the VP. I have a way but it is beyond what I can do with the hood raised in my yard. All that needs to be done is to remove the VP electronics bay cover and epoxy a thermistor to the circuit board and run the two wires through a silicone filled hole to a digital display in the cab.
This would solve the issue. I used to have a home built, thermistor based, contact thermometer that would be perfect, but it is long gone.
The reference you made to the redesigned circuit boards neglects one thing. Heat cycles and not heat gain. I would suspect that the heat gain you see is coming from two sources. Engine heat conducted to the VP and some forgotten law of physics that says when you compress a liquid it gets hotter.
Perhaps some of the outlet fuel temp decrease is because of the airflow over the metal injector lines and not actual internal temp decrease.
Back to the computer case idea. Yes ventilating the computer compartment works, I do the same thing here as well. But consider the BTU output of the CPU (very small compared to engine generated heat). Try putting the BTU equivalent of the engine inside your computer case. The amount of heat now would completely overwhelm the small fan. At least as I see it.
Your IR heat gun reads surface temp, right? And your fan blows are on the surface, right? So, IMO you are only seeing surface cooling and the lower discharge temps of the fuel is from surface cooling of the steel injector lines. And don't forget that some of the heat gain of the VP is due to pressurizing of the fuel. 0 PSI to 18,000PSI (guess) is quite an increase.
Ok, I'll stop. I'm not trying to be insulting but instead trying to question what you are doing to make sure we stay on track. Hopefully you will understand that my efforts aren't to discredit you at all but to make sure everything is thought through. Because of your efforts and posting them here I have a fuel return cooler and an insulated fuel filter, to which I would'nt have without your experience.
Keep up the good work and I appreciate you not getting defencive or taking it personally when I ask for a reality check.
Keep up the good work, I follow every post you make.
Besides, I have to be nice, we're trying to relocate to Tampa and then we would be neighbors...
Clearly the VP has less than stellar performance :-laf
But blowing air across 8 square inches of aluminum surface is inconsequential compared the the mass of the iron block and head. Considering the VP is bolted directly to all that mass, well, I wish I could do what I did to the FF, and use an insulating washer between them to stop heat gain.
Playing the Devils advocate here, we need a way to measure the internal temp of the VP. I have a way but it is beyond what I can do with the hood raised in my yard. All that needs to be done is to remove the VP electronics bay cover and epoxy a thermistor to the circuit board and run the two wires through a silicone filled hole to a digital display in the cab.
This would solve the issue. I used to have a home built, thermistor based, contact thermometer that would be perfect, but it is long gone.
The reference you made to the redesigned circuit boards neglects one thing. Heat cycles and not heat gain. I would suspect that the heat gain you see is coming from two sources. Engine heat conducted to the VP and some forgotten law of physics that says when you compress a liquid it gets hotter.
Perhaps some of the outlet fuel temp decrease is because of the airflow over the metal injector lines and not actual internal temp decrease.
Back to the computer case idea. Yes ventilating the computer compartment works, I do the same thing here as well. But consider the BTU output of the CPU (very small compared to engine generated heat). Try putting the BTU equivalent of the engine inside your computer case. The amount of heat now would completely overwhelm the small fan. At least as I see it.
Your IR heat gun reads surface temp, right? And your fan blows are on the surface, right? So, IMO you are only seeing surface cooling and the lower discharge temps of the fuel is from surface cooling of the steel injector lines. And don't forget that some of the heat gain of the VP is due to pressurizing of the fuel. 0 PSI to 18,000PSI (guess) is quite an increase.
Ok, I'll stop. I'm not trying to be insulting but instead trying to question what you are doing to make sure we stay on track. Hopefully you will understand that my efforts aren't to discredit you at all but to make sure everything is thought through. Because of your efforts and posting them here I have a fuel return cooler and an insulated fuel filter, to which I would'nt have without your experience.
Keep up the good work and I appreciate you not getting defencive or taking it personally when I ask for a reality check.
Keep up the good work, I follow every post you make.
Besides, I have to be nice, we're trying to relocate to Tampa and then we would be neighbors...
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For those interested in fan cooling of the VP44:
I initially got the 3" Attwood bilge blower and connected that to a timer board. Well the sound pitch of the full power 3" blower is annoying. So I found a PWM DC motor controller to be able to adjust the pitch of the blower to an acceptable level.
Initially tonight I found about -1/3 from full power is an acceptable pitch. Now of course the air volume curves are probably not linear and -1/3 in motor speed is probably -1/2 in air volume. Which brings up the next point from the experimentation.
Probably the 4" blower is the correct one. It pushes 250 cfm at full power. So when you reduce the speed to get an acceptable pitch you probably still have probably 125 cfm. Earlier in an above post I found there is just enough room to get a 3" semi flexable duct (Home Depot) snaked up to the Vp44. I do not think a 4" would fit easily. However Home Depot also has a 4" to 3" A/C duct reducer to accomodate the 4" fan and get it onto a 3" duct. I will get the fan and reducer in a couple of days and make sure it all fits.
Tommorrow I will see what the reduced air flow does or does not do to the VP44 cooling temperatures.
Stay tuned,
Bob Weis
I initially got the 3" Attwood bilge blower and connected that to a timer board. Well the sound pitch of the full power 3" blower is annoying. So I found a PWM DC motor controller to be able to adjust the pitch of the blower to an acceptable level.
Initially tonight I found about -1/3 from full power is an acceptable pitch. Now of course the air volume curves are probably not linear and -1/3 in motor speed is probably -1/2 in air volume. Which brings up the next point from the experimentation.
Probably the 4" blower is the correct one. It pushes 250 cfm at full power. So when you reduce the speed to get an acceptable pitch you probably still have probably 125 cfm. Earlier in an above post I found there is just enough room to get a 3" semi flexable duct (Home Depot) snaked up to the Vp44. I do not think a 4" would fit easily. However Home Depot also has a 4" to 3" A/C duct reducer to accomodate the 4" fan and get it onto a 3" duct. I will get the fan and reducer in a couple of days and make sure it all fits.
Tommorrow I will see what the reduced air flow does or does not do to the VP44 cooling temperatures.
Stay tuned,
Bob Weis
rweis said:
I'll also be interested in seeing what happens to current draw at reduced RPM PWM settings - try to get an analog meter reading if you can for a general average current indication.
Zero problem with getting Ah readings.
I still have to get the PWM board into an enclosure, so it is just sitting next to the timer board enclosure out in the open. I'll get Ah readings tommorrow after work.
All I have is a digital though, but can take readings over the 128 minutes.
Bob Weis
I still have to get the PWM board into an enclosure, so it is just sitting next to the timer board enclosure out in the open. I'll get Ah readings tommorrow after work.
All I have is a digital though, but can take readings over the 128 minutes.
Bob Weis
I am thinking that using a bypass regulator set to 14psi "helps" by sending most of the uneeded fuel back to the tank before it gets heated up by the VP? I am also thinking about using a piece of industrial floor mat (chemical/weld proof) between the filter and the head to insulate some of the heat.
Awesome research and reporting Bob!
Awesome research and reporting Bob!
more info on fan cooling (fairly long):
I put the PWM on the fan (3" attwood bilge blower). At full power it has an annoying whine (you can't hear it with the engine running) during the after engine shutdown. I adjusted the PWM controller from 100% to 66% to get a comfortable and acceptable blower whine. HOWEVER,
I think it reduced the airflow from 130cfm to about 60 - 70 cfm (about 50%, nothing is linear, lol). And the running EBC temperatures went up about 5* from the 130cfm. BUT the after shutdown temps went up (highest temp)about 10* from running EBC +5* (100% fan) to EBC +15*. The EBC is generally about OAT+15* running.
OAT yesterday going home 85*. EBC running 97*. EBC maximum after shutdown 102* (100% fan). With 66% fan EBC maximum after shutdown was 113*.
I use a WAG (wild *** guess) of internal VP temps = EBC + 20*. Now I have zero reason to use a 20* delta. Internal temperatures could be 50*, it could be 1* over (or actually under) the electronics bay cover (EBC) temp. If someone has a better guess I would sure like to hear it and probably use it because my guess is exactely that - a WAG, but I think it is a safe WAG operationally.
Getting back to the discussion - if the EBC max after shutdown was 113* (66% fan) +20* WAG = 133* and probably safe for the VP44, now that we are approaching winter. Let's say summer temps =100*. If all the temps go up by the same amount the VP44 max temp after shutdown goes to 148*. IS that still safe for the VP44? BUT we can lower that by 10* with the fan at 100% (2 paragraphs up), but we can not live with the wife and camping club because of the annoying sound for 2 hours.
So I bought a 240 cfm 4" Detmar bilge blower on EBay yesterday ($31. 20 delivered to my door vs ~$55 at the boat store) that will be here in 3 days. I intend to change out the 3" for the 4" and run it at 100% (240cfm vs 130cfm) to see what that does. Then to be livable, turn the 240cfm down from 100% to 66% (if the whine is the same, I am assuming here it will be), which will STILL give me 120cfm (an assumption that 66% lower PWM = 50% lower air delivery volume) that should still be enough to keep the engine shutdown EBC to approxmately OAT +15* (100* day running EBC (with 3" fan 100%) = OAT +15 (115*) and maybe about 5* more = 120* max EBC. Add the WAG of 20* internal VP temps and we are at 140* which I GUESS is safe.
I have thought of adding another fuel temp sensor on the VP fuel return line before the T with the injector fuel return. That would give us a difference between input fuel temp and output fuel temp, or VP44 work expended temp? So far I can heat gun measure the return line fuel fittings back at the tank filler. I generally get fuel input temp +15*, BUT that includes the injector return fuel. How much is the VP44 contributing to return fuel temps? That is why I am thinking of measuring the VP fuel return line BEFORE the T with the injector fuel return.
I DO KNOW that I can effect (lower or raise) the EBC temperature while driving by how hard I drive it (primarily RPM, not MPH). That is consistant with Texas Diesel's comments about heat is generated when the fuel is pressurized from 17 psi to 18,000 psi (guess). The more fuel you are pressurizing (rpm) the more temp the VP44 is generating (does not sound like rocket science). I have not taken the time to do much variation in driving rpm to see what the temperature correlation is. Nor have I taken much time to see what the temperature correlation is to driving hard (heavy) for long distances (more engine heat, empty I am running at 180* (180* thermostat, changed out from the 190* thermostat that came in the 2002 ETC)).
SO, the next step is changing the blower to get ~120cfm (???, acceptable whine on a 240cfm blower?) and be socially acceptable in a campground and be able to sleep in bed and not on the sofa at home.
Bob Weis
I put the PWM on the fan (3" attwood bilge blower). At full power it has an annoying whine (you can't hear it with the engine running) during the after engine shutdown. I adjusted the PWM controller from 100% to 66% to get a comfortable and acceptable blower whine. HOWEVER,
I think it reduced the airflow from 130cfm to about 60 - 70 cfm (about 50%, nothing is linear, lol). And the running EBC temperatures went up about 5* from the 130cfm. BUT the after shutdown temps went up (highest temp)about 10* from running EBC +5* (100% fan) to EBC +15*. The EBC is generally about OAT+15* running.
OAT yesterday going home 85*. EBC running 97*. EBC maximum after shutdown 102* (100% fan). With 66% fan EBC maximum after shutdown was 113*.
I use a WAG (wild *** guess) of internal VP temps = EBC + 20*. Now I have zero reason to use a 20* delta. Internal temperatures could be 50*, it could be 1* over (or actually under) the electronics bay cover (EBC) temp. If someone has a better guess I would sure like to hear it and probably use it because my guess is exactely that - a WAG, but I think it is a safe WAG operationally.
Getting back to the discussion - if the EBC max after shutdown was 113* (66% fan) +20* WAG = 133* and probably safe for the VP44, now that we are approaching winter. Let's say summer temps =100*. If all the temps go up by the same amount the VP44 max temp after shutdown goes to 148*. IS that still safe for the VP44? BUT we can lower that by 10* with the fan at 100% (2 paragraphs up), but we can not live with the wife and camping club because of the annoying sound for 2 hours.
So I bought a 240 cfm 4" Detmar bilge blower on EBay yesterday ($31. 20 delivered to my door vs ~$55 at the boat store) that will be here in 3 days. I intend to change out the 3" for the 4" and run it at 100% (240cfm vs 130cfm) to see what that does. Then to be livable, turn the 240cfm down from 100% to 66% (if the whine is the same, I am assuming here it will be), which will STILL give me 120cfm (an assumption that 66% lower PWM = 50% lower air delivery volume) that should still be enough to keep the engine shutdown EBC to approxmately OAT +15* (100* day running EBC (with 3" fan 100%) = OAT +15 (115*) and maybe about 5* more = 120* max EBC. Add the WAG of 20* internal VP temps and we are at 140* which I GUESS is safe.
I have thought of adding another fuel temp sensor on the VP fuel return line before the T with the injector fuel return. That would give us a difference between input fuel temp and output fuel temp, or VP44 work expended temp? So far I can heat gun measure the return line fuel fittings back at the tank filler. I generally get fuel input temp +15*, BUT that includes the injector return fuel. How much is the VP44 contributing to return fuel temps? That is why I am thinking of measuring the VP fuel return line BEFORE the T with the injector fuel return.
I DO KNOW that I can effect (lower or raise) the EBC temperature while driving by how hard I drive it (primarily RPM, not MPH). That is consistant with Texas Diesel's comments about heat is generated when the fuel is pressurized from 17 psi to 18,000 psi (guess). The more fuel you are pressurizing (rpm) the more temp the VP44 is generating (does not sound like rocket science). I have not taken the time to do much variation in driving rpm to see what the temperature correlation is. Nor have I taken much time to see what the temperature correlation is to driving hard (heavy) for long distances (more engine heat, empty I am running at 180* (180* thermostat, changed out from the 190* thermostat that came in the 2002 ETC)).
SO, the next step is changing the blower to get ~120cfm (???, acceptable whine on a 240cfm blower?) and be socially acceptable in a campground and be able to sleep in bed and not on the sofa at home.
Bob Weis
Last edited:
Fan info:
I installed the 4" blower (Detmar) last night. Interestingly, the mounting holes in the feet were EXACTELY the same place (as the Attwood 3"). I got the 4" to 3" reducer at Home Depot and used A/C foil water resistant tape to mate the reducer to the blower. The reducer was the exact same diameter as the fan housing at the 4" end of the reducer. The 3" semi rigid flex hose had to be split on each side where it goes on the reducer as the ID of the flex is a tad too large to fit over the OD of the reducer.
Preliminary observations:
The 4" fan is MUCH lower pitch at full speed than the 3" and therefore probably will have a faster run speed before it becomes objectionable, and therefore more air.
Not enough data to draw any conclusions yet.
Bob Weis
I installed the 4" blower (Detmar) last night. Interestingly, the mounting holes in the feet were EXACTELY the same place (as the Attwood 3"). I got the 4" to 3" reducer at Home Depot and used A/C foil water resistant tape to mate the reducer to the blower. The reducer was the exact same diameter as the fan housing at the 4" end of the reducer. The 3" semi rigid flex hose had to be split on each side where it goes on the reducer as the ID of the flex is a tad too large to fit over the OD of the reducer.
Preliminary observations:
The 4" fan is MUCH lower pitch at full speed than the 3" and therefore probably will have a faster run speed before it becomes objectionable, and therefore more air.
Not enough data to draw any conclusions yet.
Bob Weis
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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
TSB Updates
Dodge/Cummins Historical Overview
Cameron Collection
What Makes Us Tick?
Product Showcase
Advertising
