Engine/Transmission (1998.5 - 2002) Modifying fuel system so temperature input to VP44, 80* - 100*, your inputs.

[Fishin Guide]

I would love to see a passive cooler with a thermostatic bypass. Also, it would be easy to configure an electric fan driven off of temp.



The reason that the cooler will work well on the return line is that it is constantly heated by the returning fuel from the VP. It could potentially be mounted right up front and simply blocked off by a crude plastic/ cardboard cover. Simple, effective and the gains will be measureable.



Remeber, when you start to over-engineer an additional system, you are asking for trouble. Remeber the KISS rule! Keep It Simple Stupid!



I think that adding an active cooling system is just one more thing to break down on us down the road. Try what's easy and make small changes to gauge your progress. I am a big fan of the cooler in the return line option. If the fuel in the tank is cooler, it will help pull additional heat away from the VP.



One of the most important things that I think is overlooked is the fact that many of our pumps cannot keep the bypass open. Bob, set your pressure high enough on the RASP so that you have a full time return of fuel to the tank. You don't need 20 psi here. Just enough to always bypass fuel and avoid a static condition in the fuel. I know, I know, as long as it's running there is always fuel moving. We just want to be sure there is enough flow to take the heat with the fuel. Also, very high fuel pressures will not help to this end as it will move so quickly, it will not transfer any heat before flushing through the system.



JMHO



Dave

 

[Mundgyver]

So why not cool the fuel just before it enters the VP with a cooler in the slip stream of air. Seems like that would be pretty simple

 

[rweis]

To add to the confusion I borrowed the infarred thermometer today from work and went for a little ride. I had about 1/8 tank before the start, filled up enroute, and finished at home. I am posting the numbers as read, some of them do not make a lot of sense. I'll comment on those later in this post.



Engine Infared Fuel Temperatures



The table did not come out in the post so I will seperate the data with ,

#1 condition, #2 fuel tank amount on line 1 & 7, #3 VP fuel inlet, #4 VP Electronic cover, #5 VP Return, #6 VP Body, #7 Odometer





5 min Idle,last 1/8,105,101,115,110,55748

60 - 65,135,133,137,133,55761

60 - 65,153,134,135,140,55768

Stop pre gas stop,133,135,137,151,55772

Gas Stop pre fuel,156,135,139,139,55773

Gas Stop post fuel,158,149,151,152,55773

60 - 65,full,165,131,130,152,55780

60 - 65,156,135,136,150,55795

Residential,157,137,137,151,55797

5 min idle,160,133,140,148



Average,153,136,138,146



How do you build an excel table in a post?



The fuel inlet I was shooting at my full flow fitting on the VP inlet. I think I got a lot of the engine block in the reading.



Looking at post fueling and the VP electronics cover, seems latent buildup heat after the engine is off is definitely something to be factored in.



VP return was the VP banjo fitting on the return line as it comes out of the VP.



VP body was the VP body lower than the electronics by about an inch and toward the front of the VP toward the mate to the engine.



This is only a single run just messing around to see what it yielded. Far from a scientific study, just some numbers.



Truck was unloaded, outside air 97*, level terrain, driven reasonably gently.



As I get more data on different days maybe the picture will become more clear.



On the surface seems like 135* - 150* is the unloaded operating range of the VP body.



I will try to get a longer (50 miles) interstate run in tommorrow.



Bob Weis



Need more guys with infared temp guns gathering data.

 

[Texas Diesel]

Someone posted a picture of a large heatsink on the side of the VP-44, who was that?



Bob, great reading, keep posting more.

 

[Gary - K7GLD]

"Need more guys with infared temp guns gathering data.



I've been wanting one - but the local Radio Shack didn't have one when I was there last - will try to pick one up tomorrow. The possible effect of different mod levels could be an interesting factor as well...

 

[Gary - K7GLD]

SO, wonder how much affect from ambient temps need to be factored into Bob's readings - if you subtract his 97 degree ambient from those readings, temp rise at the worse is about 60 degrees...

 

[GBobbitt]

The local auto parts store may be a cheaper source Radio Shack for an infared temp gun. I bought mine used from my Snap-On dealer for $30. 00, new ones are a lot cheaper than they uised to be.

Several have mentioned cooling the fuel that returns to the tank, this could be very helpful when the fuel level is low. Mine has been below 1/2 tank only 2 or 3 times in the last year, I have always tried to follow the TDR's advice concerning fuel level and pump life. Could heat be the real issue instead of fuel level?

 

[rweis]

I have a full tank today and the weather is suppose to be the same about 97*. I'll do some more readings. I want to do a unloaded long cruise (50+ miles) reading.



The problem with having at least 1/2 tank when you are towing you are stopping every 130 miles for fuel (full tank = 26 gallons, 10 mpg).



I think there is definitely a correlation between tank level, day temperature heat level, VP heat level, especially at lower tank levels.



I want to do more readings tuesday because I am taking vacation wednesday & thursday to do the fuel cooler install. Then take more readings. I might try to go get the RV and run it a little bit (ie a load in hot weather).



Bob Weis

 

[Gary - K7GLD]

Bob, to better isolate readings, consider making a foil "shield" to more precisely isolate the area you REALLY want to measure - perhaps mount the foil to a piece of cardboard for better rigidity and durability...

 

[AJ]

15-16 months ago I converted the transmission cooler to fuel cooler after geeting bit by the 216 bug, at the same time drilled out fuel filter and tapped to 1/4npt and run 1/2" ID hose all the way from the two carters(7+15 psi units) Bought a new VP-44 but drove 10 months(40k) before changing it.

On a side note, at the same time bought the biggest transcooler I could find

and mounted it in between the intercooler and radiator, centered to the fan.

Noticed less smoke probably for not dumping all the heat at the end of the intercooler. Also noticed more fan cycling...

I have not measured temps(fuel or VP), but due to the size of the oem trans cooler, the fuel must be very close to ambient while in motion.

 

[rweis]

FYI

This morning



Conditions,tank,VP fuel,VP electronics,VP return,VP Body,mileage,OAT(added)

65-70,full,116,107,109,121,55821,80*



I do not think I am getting a good reading on VP fuel in temp, so not addressing that reading



Different than yesterday's average

(Yesterday's averages VP in 153*,VP elec 136*,VP return 138*, VP body146*)

VP Electronics 29*cooler

VP Return 29* cooler

VP Body 25* cooler

OAT is 17* cooler.



This afternoon I will do a long (100 mile) Interstate run and post that tonight.



Bob Weis

 

[McDowra]

Someone posted a picture of a large heatsink on the side of the VP-44, who was that?



Bob, great reading, keep posting more.

You talking about this one?



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[Gary - K7GLD]

Keep in mind that as I understand it, the heatsink pictured above is NOT to directly cool the fuel or VP-44 housing, but rather, is the heatsink for the solid state refrigeration chip mentioned earlier in this thread.



This is a very interesting concept I plan to watch closely in hopes progress is made.



Face it, the absolute BEST heat reduction we can ever achieve with added external coolers is outside ambient temperature - which CAN be significant in many locations in the summer - and those coolers do NOTHING to reduce underhood heat soak when the engine is shut down.



The refrigeration approach, on the other hand, CAN reduce temps below ambient, AND be designed to continue operation AFTER the engine shuts down to provide continued protection.



The unknown - at least to me - is whether sufficient cooling capacity is available in a compact enough size to actually make that approach practical. Further, I am thinking that cooling the FUEL flow to the VP-44 with that technology would be easier, less intrusive to the VP, and more effective to the VP overall than trying to tightly isolate the cooling effect only on the VP electronics...

 

[Fishin Guide]

We could always throw a cool can in the system too! All we would need is an ice maker mounted in the bed and stop about every 20 miles to refill the can. :-laf



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Dave

 

[Gary - K7GLD]

For the uninformed - and that largely applies to me - here's a pic of what LOOKS like a good candidate for use as a solid state cooling chip as I discussed above:



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This chip/assembly is about 1 1/2 inches by 1 3/4 inches in size, and as the specs indicate, will cool to about 70 degrees below ambient.



It draws pretty heavy current at full power, nearly 15 amps, and while ONE side gets cold, the OTHER side gets HOT - thus the cooling heatsink shown in the photo further above in this thread.



Other sizes and capacities are easily available - and I really don't have a clue as to WHAT size would be needed to do what is being discussed here.



These aren't cheap - the one displayed here sells for about $55 - but worth it if it could do the job...

 

[rweis]

I see the problem with electric cooling is that to cool a moving volume like fuel you are going to have to do a cooler that runs on 120 volts or the amps at 12 volts are going to be fairly significant. We have a couple of "coolers" we use camping. The larger coolers (ie 3 cases of cans) take a day to cool the mass down. Now there is only 1 heat exchanger for a large volume, but the volume is closed and not constantly adding more heat.



Ambient air can be 100+ in some parts of the country in the summer, but the fuel system is "designed" to not even use that, so I feel ambient air will definitely keep the fuel temperatures down below what they are now. My objective is to feed 80* - 100* fuel to the VP. The 1000 cfm fan may be difference in high ambient temperatures. Air cooling may not be it.



I will just have to see how this works. It HAS to get rid of some of the heat. If I can put not greater than 100* fuel in the tank, maybe the tank volume will get rid of another 10* or so. I can not see how it would not get rid of some of the problem, but I definitely do not have the answers.



Somehow the heat of the fuel has to be transferred to something else, ambient air, vehicle frame, a misting spray, water bath, just somewhere other than the cooling fuel volume. Now how do we do that?, and we do not want to make it so complicated that it is cost intensive, labor intensive, maintenance intensive, or cumbersome.



Bob Weis



Just saying "poor design" and buying VP44's every 50k is not acceptable either

Bob Weis

 

[rweis]

If you stop every 20 miles to replenish the cool can AND the driver, you may not get very far. Oo.



The driver would then NEED to stop every 20 miles to offload and refill, oh and don't forget about the cool can too



I can see a couple fo hazzards there. lol



Bob Weis

 

[Fishin Guide]

If you stop every 20 miles to replenish the cool can AND the driver, you may not get very far. Oo.



The driver would then NEED to stop every 20 miles to offload and refill, oh and don't forget about the cool can too



I can see a couple fo hazzards there. lol



Bob Weis

just think, it probably could be converted to a crude still for when things get really tough and the fuel gets too hot. Heck, set an Espar under it in the winter and you'll have a fuel heater and a bio-diesel plant all in one! :-laf :-laf

 

[RClark]

for Lsfarm- Do you have pictures of the air duct?

How did it help?

 

[Gary - K7GLD]

OK Bob - bought an infrared thermometer today, engine warmed up and at idle, 80 degrees ambient temp - engine block temp 185 degrees - 3/4 tank of fuel. .



fuel temp, taken at my Frantz fuel filter just ahead of the stock fuel filter - 105 degrees



VP-44 temp right at banjo fuel inlet fitting and most of the rest of the VP body, 120 degrees



temp at top cover of VP - 110 degrees



After running about 5 miles, ending in a quarter mile steep grade to our house



same locations



110

125

112





After shutting engine down, and heat soak for 15 minutes with hood closed



108

128

118



My temperature rise above ambient doesn't seem as high as Bob's - but this was a relatively short run with the truck unloaded - also, I suspect the added Frantz fuel filter, sitting at the front of the engine where it gets some cooler air at the edge of the radiator, might act as a sort of heat sink itself - I have NEVER seen it so hot I couldn't easily keep my hands on it, even after the longest, hardest runs...



Dunno what the actual fuel temp rise will be after more miles are driven and fuel tank level declines - will see as further measurements are taken...



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