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

[rweis]

Did you ever move to Tampa? I could drive over and demonstrate the differences.



Bob Weis

 

[Texas Diesel]

Not yet. We were just in Tampa 3 weeks ago and through Wintergarten (SP?). As I drove through I wished I would of had your number.



Current plans are to move to Tampa next April. I wish it was sooner... :{

 

[rweis]

I'm in the TDR Companion. I keep that in the van and the truck ALL the time. Let me know when you are this way and we'll do lunch and a brew.



April is just in time for hurricane season. BE CAREFUL about the home insurance you get. Be SURE you can get it first BEFORE you committ to move. Some owners can not get home owners insurance and have to go through the State of FL insurer of last resort and the rates are like 5x what you would normall pay. Many along the coast are selling and moving inland because the insurance is SOOOOOOOOO expensive along the coast.



NO HOME INSURANCE = NO MORTGAGE LOAN unless you pay cash then YOU are totally liable for losses.



My insurance company raised the rates 75% if you live from the coast to 30 miles inland, 50% if you live from 30 miles to 50 miles inland, 6% for the everyone else. Many companies will NOT write insurance in certain zones or in the state AT ALL.



CHECK FIRST before you committ so you do not have a rude surprise.



Taxes along the coast are another problem. Property values have skyrocketed and so to, the taxes.



Bob Weis

 

[Texas Diesel]

Rats! I had the TDR TC in the truck but never thought of looking there :{



We are bringing our home with us (04 Holiday Rambler 35' triple slide) and plan to tow it out before any storms hit. But we still need to verify coverage since we full time and they ask where it is parked, glad you brought that up!



We noticed it is nice and quiet there inspite of the doom and gloom forecasts for hurricanes.



Hopefully we'll see you soon!



(my first VP replacement is will be here tomorrow )

 

[rweis]

On the VP replacement IF



You can shim the VP mounting AT ALL from the timing cover with even the thinest of fiber like shiming material it MIGHT possibly help in VP temperature control. Something like transmission pan gasket might do. Might not be worth the risk of non standard mounting with gear alignment etc, BUT IF it were feasiable it might be of value.



We are looking at FT in about 3 years.



There are a lot of really nice RV parks left (some did not make it through 04 and survive). We have a '04 35' Alfa 5er and pull within 100 miles of home base regularly (W-(gulf (100 miles)) to E- (atlantic (100 miles)) S- (Ocochobee (100 miles)) N- (Ocala (100 miles)). We like to go at least once a month, so call ahead when you come down and we'll meet you on the way in and help with getting you settled.



Bob Weis

 

[Gary - K7GLD]

Bob - and others following this thread - here's some shots of the latest "evolution" of my air system supplying outside air to my VP-44. I'm using a larger entry scoop similar to what Bob proposed a few posts earlier, and will now see what - if any - gains there are in cooling performance with the truck in motion do to ram air effect.



Here's the raw scoop and lower duct:



#ad




You will notice the "lip" at the upper edge of the scoop portion - that clips to the lower lip of the air dam on my truck.



Here's an underside view of the installed new scoop:



#ad




Pretty neat mount - with a single wire tie for insurance.



Here's a view from the front:



#ad




YUP, sorta ugly!



BUT, main issue, is it effective? Time and miles will tell if there is any improvement over the smaller scoop originally used - and this one CAN always be relocated back more out of sight under the truck, and still get good airflow.



REALITY CHECK!



Those who have followed this thread, have mostly done so out of curiosity and vague thoughts of MAYBE trying some of the ideas offered here on their own trucks, if the test results seem to prove out - MOST will simply read here, and do nothing.



Speaking for myself, but I suspect Bob feels the same way, I have NOTHING to sell, and whether or not any readers apply anything presented here is purely up to them - I don't profess, or plan to "prove" anything to anyone, other than by various test results and readings freely provided in this thread - if some here think these efforts are a waste of time, FINE - then don't use any of them!



We have been told directly by Bosch reps that these VP-44's rely upon fuel flow for both cooling and lubrication - but what PART of the VP-44 NEEDS to be "cooled"? Certainly the metal components don't need any unusual cooling - the difference between 50 degrees or 150 degrees is no big deal!



Some of the seals MIGHT like temps lower on the temperature scale - but still probably not unusually sensitive in the ranges normal in typical truck operation...



The internal computer, however, is another story!



A LARGE percentage of VP-44 failures occur, not mechanically, but purely ELECTRONICALLY - to the point we have seen several significant Bosch upgrades to the electronics in an effort to reduce heat related failures in those components.



The temperature sensitive solid state components inside the VP-44 are, in my opinion, by FAR the most temperature sensitive in the whole Cummins fuel system - and stand to benefit most by controlling cooling fuel temperatures - or any OTHER contributing cooling that might be supplied.



Fuel coolers installed to provide and maintain cooler fuel temps are easily recognized and understood - they work, and properly done, work well - but the remaining issue of under hood heat soak and radically elevated temperatures after engine shutdown are NOT improved by fuel coolers alone!



THAT, is where applying a cooling stream of outside air during, and for a measured period of time AFTER engine operation comes into play! And yes, I am firmly and fully convinced that cooling the OUTSIDE of the VP-44 will as effectively cool the internals, just as applying heat to the OUTSIDE of a pan of water will cause it to boil, or applying freezing air to the outside of a container of that same water will cause it to freeze!



Certainly, air is NOT as effective or fast a temperature controlling medium as fuel or other liquids, and takes more volume and flow, but it IS effective, or the cooling systems in our trucks are ALSO a waste of time, since the radiators and coolant are cooled totally by circulating air flow!



Thus, my approach with the air cooling system I am using - I've thoroughly measured operating temperatures of the VP-44 body under widely varying conditions, as well as the fuel lines entering and leaving the pump - the application of good cooling airflow has displayed a substantial and predictable cooling effect to the VP-44, and the measurable elements going in and coming out of it - it hardly seems logical or sensible to assume there is no related benefit to the internal electronics as well...



But like I said, if'n ya don't believe it, don't DO it - most wouldn't anyway, and I only post this stuff as info for those sharing my interest!



Now, the testing continues! Oo.

 

[rweis]

I am still seeing the cooling affect of the ram air (~60 mph) has on cooling the external body of the VP44 and the internal fuel loop has a certain cooling load taken OFF of it and seems to be running cooler itself.



I never thought that cooling the external body of the VP44 would have any effect on the internal fuel temperature, but it does.



I can run slower (25 mph) let the fuel temp stabilize, run faster (higher rpm = hotter VP44) and the fuel temps should go up, however they go down I think because the case of the VP44 cools to below the fuel temp and the case is absorbing the heat faster than the fuel and the case heat is being exhausted.



Gary, my opening is 6" diameter = ~ 28 sq ", what is yours?



Ram air seems to kick in about 45 mph and the faster the more obvious it is. Up around 70 mph I can actually cool the VP body to less than OAT because of the mist evaporation I think.



I am going to move the mist from the blower to directly on the VP itself. At slower speeds the air is not flowing fast enough to get the mist up to the VP44 I think. Misting the Vp44 directly might help more than misting the air. RustyJC's concern with scaling may not be a problem with the temperatures of the VP44 down in the 100*- range.



I am also going to move my H7B fuel cooler with fan back to the fuel return circuit instead of the fuel feed circuit to reduce the number of fittings and make the fuel feel loop a little simplier. I will have enough date to compare the then (fuel return circuit) temps to the now (fuel feed circuit) and see any differences. I am thinking that the input fuel temp is so close to the outside air temp that fuel cooling is minimal. Maybe on the return loop it might have somewhat hotter fuel and be easier to get some more heat out of the fuel.



This ram air thing was totally a surprise. Sort of makes sense if you flood 70 mph (hurricane force) air on something you are going to get some of its heat off of it. Part of the reason I am going to move the air flow mister to the VP44. I think that at lower speeds the moist air is not getting to the VP44 because of lack of air volume. At higher speeds I might be seeing more of the mist getting to the VP44 because of the shear volume of air and its speed. Moving the mister to the Vp body should confirm this.



Today was 103* driving home, I made all the lights (constant higher velocity ram air flow) and the VP got down to 98* and the fuel never went over 103* where it normally would go to about 110* (OAT+7* or so). (Windows slightly down while parked, thermal winshield inside sun screen up, inside cab temps at departure were 135*. VP case temp at start up was 130*, quickly dropped to 105* and then ram air (65 mph) effect started to have effect)



I am starting to think the heat related problems of the stock Vp44's is due to air flow design (or lack of) in the later 2nd gens (2001, 2002) as the area around the engine compartment became tighter and tighter (ie more air flow restrictive). I tend to think the very best heat related mod is a large functional hood scoop dumping directly right on top of the VP44 and let the ram air cool the VP44 so the fuel never gets hot to start with.



Still "tinkering", but getting a better understanding of how it works,



Bob Weis



Oh, the after shutdown blower, I TOTALLY believe it helps. My VP case temps only rise about 2* from shutdown temp (98 to 100 or so). One day this week I will disable the after shutdown blower and take the temp rise reading again just to document that aspect.

 

[Texas Diesel]

Bob, a thin gasket between the VP and timing cover is possible. I looked at this closely during my VP transplant yesterday. This truck had 120k when i bought it and the VP died at 152k. Internal timing failure. I drove it two more weeks. During those two weeks I added extra (~100:1) two cycle oil and never had the code reset itself after adding the extra oil.



This might be useful knowledge for those away from home with a internal timing code/dead pedal. It set the code 3 times before the extra oil then not at all after the extra oil.



Next step is to find a suitable gasket material and install it. Since the timing gears are helical cut, the gasket needs to be thin but strong enough not to squeeze out.



I think this has real potential to keep the heat gain to a minimum.



On another note, I've beem leaving my hood raised 4" after a hot drive to let the heat out. The engine cool down time is shortened by HOURS with the hood opened slightly.

 

[Gary - K7GLD]

Bob, the dimensions of my new intake are 8. 5 x 3 inches - 28 sq. inches like yours - mine in the rectangular shape is ugly enough, hate to think what a 6 inch diameter one would be, mounted where mine is! :-laf



But my ducting is only 3 inch, and I think yours is still 4 inch?



As mentioned earlier, liquids cool better than air, but the difference in cooling volume and flow between a 3 inch diameter duct at 70 MPH WILL sorta overcome the advantage of a liquid at far lesser flow in a 3/8 diameter tube...



On another note, I just yesterday received the new inside/outside thermometer I ordered - it is newer and more sophisticated than the one I've been using, and provides the expected inside/outside temps, plus the inside temp will toggle for a clock function if desired instead of the temp - it also has humidity, and holds the high/low temps from last reset - great for getting the absolute highest VP-44 temps after shutdown without having to constantly visually monitor it.



I kept the old unit mounted in the cab, and moved it's sensor over to the fuel return line from the VP-44, and installed the new sensor as high on the metal portion of the VP-44 as possible, directly to the segment it appears the electronics assembly is attached to. This will give me instantaneous and constant monitoring of both the VP-44 case directly at the electronics bay, as well as return fuel temperature - should get some good info regarding typical down-the-road temperature variations between the two probe points:



#ad




Now to do some more driving! :-laf

 

[McDowra]

he internal computer, however, is another story!



A LARGE percentage of VP-44 failures occur, not mechanically, but purely ELECTRONICALLY - to the point we have seen several significant Bosch upgrades to the electronics in an effort to reduce heat related failures in those components.



The temperature sensitive solid state components inside the VP-44 are, in my opinion, by FAR the most temperature sensitive in the whole Cummins fuel system - and stand to benefit most by controlling cooling fuel temperatures - or any OTHER contributing cooling that might be supplied.



Fuel coolers installed to provide and maintain cooler fuel temps are easily recognized and understood - they work, and properly done, work well - but the remaining issue of under hood heat soak and radically elevated temperatures after engine shutdown are NOT improved by fuel coolers alone!

Under the hood heat soak is why we abandoned the solid state cooler we were experimenting with. In our testing where we actually put a temp probe on the electronics themselves the largest problem with heat is after the engine is shutoff. We could completely cool the electronics going down the road ( less than 50F) but after you shut power off to the cooling system the heat soak from the engine and the heatsink used itself would reheat the electronics. Well that led to an integrated heat activated always on controller which worked well for keeping everything cool but tended to be really hard on batteries.



If you are going to attempt to cool the electronics of the vp44 you must account for heat soak after shut off.

 

[Texas Diesel]

Tim, can you give any details on the setup you used to measure the electronics' actual temperatures inside the case?

 

[McDowra]

We cracked the case the black casing the electronics are in (not recommended instant warranty problems) and used 10K NTC temp sensor, from U. S. Sensor, I can give out the part numbers we used for the complete system, but if our information is used successfully to make a product for profit we would appreciate a look at the final design plans, and permission to use any modifications made.



-Jason

 

[Gary - K7GLD]

We cracked the case the black casing the electronics are in (not recommended instant warranty problems) and used 10K NTC temp sensor, from U. S. Sensor, I can give out the part numbers we used for the complete system, but if our information is used successfully to make a product for profit we would appreciate a look at the final design plans, and permission to use any modifications made.



-Jason

Jason, your info is extremely helpful - and as an associated point of interest, how closely did your testing show the electronics board to track the incoming fuel flow temperature - you mentioned 50 degrees in your earlier post, not sure exactly what you mean with that figure, but can you give any added relationship between incoming fuel temp and the electrionics temp - and/or the measured relationship in temp between the electronics bay cover and the electronics?



Obviously, I'm interested in learning how much effect my own timed air cooling and added heatsink should have in controlling the electronics temperature for heatsoak after engine shutdown.



Thanks.

 

[McDowra]

You mentioned 50 degrees in your earlier post, not sure exactly what you mean with that figure, but can you give any added relationship between incoming fuel temp and the electrionics temp - and/or the measured relationship in temp between the electronics bay cover and the electronics?

The 50 degrees is the temperature of the actual electronics inside the pump after extended use (30-45 minutes). We did not do any testing that involves fuel temperature. The electronics bay cover and the electronics typically were within 10 degrees of each other. It seemed during our testing that if you could keep the electronic bay cover and surrounding area cool then the electronics would stay cool as well.

 

[Mundgyver]

Wonder if you could put on an electronic peltier cooler run from a solar panel. That way after shut down the peltier is not draining the battery



FOOD FOR THOUGHT

 

[Gary - K7GLD]

The 50 degrees is the temperature of the actual electronics inside the pump after extended use (30-45 minutes). We did not do any testing that involves fuel temperature. The electronics bay cover and the electronics typically were within 10 degrees of each other. It seemed during our testing that if you could keep the electronic bay cover and surrounding area cool then the electronics would stay cool as well.

Absolutely GREAT news Jason, and a final verification of a number of temp readings at various VP-44 test points both Bob and I have taken since this thread started - I appreciate your input, and hope this puts criticism of the theory Bob and I share as to the effectiveness of cooling the electronics bay cover to it's final deserved rest...



Not many of us have the courage or re$ource$ to so aggressively violate a working VP-44 as you have done - your efforts and willingness to share info is greatly appreciated! Oo.

 

[rweis]

Well, that is really "cool" (pun intended). Finally we have verification that heat soak is a problem.



Now to what I have been up to:

I have been playing with water misting of the incomming air in the bilge blower. Below 40 mph it seems the water mist is too heavy for it to get to the VP44 effectively. Above 40 mph the ram air is enough to carry the mist to the VP44 and the cooling to the VP44 becomes better than the fuel cooling. I think even that the VP44 (above 40 mph) is cooling the FUEL rather than the other way around.



(Gary, I am using a 3" duct, that is a big as I could get snaked up to the VP44. The bilge blower is a 4" then I neck it down to 3". I am testing a 6" fitting out at the ran air end to the 4" blower then to the 3" duct to see what effect ram air speed has to do with anything).



I have been intentionally running without misting to verify that the differences I am seeing with misting are really true.



Next I am going to move the water misting from the air flow at the bilge blower to the VP44 itself so the water cooling will be effective at slow driving speeds as well (and even stopped in traffic congestion) and not dependent on ram air flow speed. This will take place after the current hurricane gets by I hope by the end of the week. Then I will run with that for the rest of the summer hot months.



My misting cooling of the input fuel is not as good as I had hoped. I am going to re plumb the input fuel cooler back into the fuel return line where I remember it did a better job of getting temperature out of the fuel. I am going to keep the misting on the (then) return fuel cooler and see what that does to the return fuel temperature.



I REALLY REALLY appreciate the comments from others about the temperatures of the electronics bay relative to the electronics temperatures them selves. In addition I am finding (I think) that you can use the VP44 as a cooling body itself for the fuel as long as you have gotten most of the heat out of the fuel to start with (the biggest heat culprit is the OEM ff I think, followed by the hot return fuel dump right back in the fuel pickup cannister).



I have been musing the last couple of weeks about what I would recommend to a new guy starting with the fuel cooling thing. As with the comment about leaving the hood open a little on shutdown to drastically reduce the heat soak time, a functional hood scoop right over the VP44 (pointing forward?) with a fairly large opening would do the same thing I think and would be more acceptable to most people. I can see ram air definitely having a very positive effect. A hood scoop would be a passive simple one time maybe fix (but pricey).



One interesting thing about the after shutdown blower pumping OAT onto the Vp44 is you feel the engine heat comming OUT of the front grill from the blower air dump under the hood. Turn the blower off and the air stops comming OUT from the front grill. Turn it on and hot air starts comming OUT from the grill. Not like slightly raising the hood by any means, but still a positive outflow. Hence the fascination with the functional hood scoop.



Has anyone ever LOCKED the engine fan clutch on to see what that would do to under hood cooling? Like take the fan clutch out and replace it with a spacer, then see what the cooling to the VP44 does.



I know when it comes on it really roars and that could be a problem, but is someone were willing to put up with the noise for a couple of weeks and measure the VP44 body temps to see what happens. Could be another simple fix without adding any extraneous coolers etc. I would guess the DC put a fan clutch on it for fuel mileage and noise purposes. Maybe a slightly different fan structure (less noise) but seriously imporved under hood cooling flow. I know it would not change the shutdown heat soak thing, but could be a better approach to improve the air flow to cool the VP44 than cooling the fuel to cool the VP44. I think that if the VP44 gets cooled enough itself, it will keep the fuel cool.



Ideas, ideas, ideas,



Bob Weis



Thanks for all the input and all the trials you guys are doing. Everyone working on something slightly different will vastly contribute to the solution.

 

[Texas Diesel]

Absolutely GREAT news Jason, and a final verification of a number of temp readings at various VP-44 test points both Bob and I have taken since this thread started - I appreciate your input, and hope this puts criticism of the theory Bob and I share as to the effectiveness of cooling the electronics bay cover to it's final deserved rest...



Not many of us have the courage or re$ource$ to so aggressively violate a working VP-44 as you have done - your efforts and willingness to share info is greatly appreciated! Oo.

Gary, I think you misread what he said. Jason never said that what you are doing is lowering the circuit board temps 50F.





What Jason said was that HIS ACTIVE setup (I assume using a peltier junction device) lowered the electronics temps by 50*. I dont know if that is 50*F or 50*F below OAT. An active, peltier junction device will be tremendiously more effecitive than what you are doing. And to assume that your results with blowing 100+F air on the case will give the same results as Jason achieved is silly.



What is needed is someone to install a temp probe, like Jason did, and take some measurements using OAT to cool the VP electronics bay.



It is becoming obvious that with sufficient heat removal is possible to cool the electronics by cooling the electronics bay cover. What needs to be demonstrated is that ambient air will be enough to cool the pump brain.



And I never critized Bob's effort's. Simply pointed out that measuring the temps of the electronics themselves is necessary, and that cooling the case to OAT temp may or may not have sufficient effect on the actual electronics. A point that has not been verified yet. This is very interesting but someone will have to place a temp probe inside the VP like Jason did and use ambient air as the cooling source. If mine wasnt under warranty I would already be finding out how to place a probe on the pump brain.



I cant help but wonder if the new, so called, FedEx board revision of the pump brain will help (or solve?) this problem.



Bob, you are correct, raising the hood a little is not a practical solution. But atleast it shortens the heat soak times. A hood scoop would be expensive and not practical for a lot of folks.



I cant help but wonder if a peltier junction device thermal epoxied to the VP bay cover, and an outside air source to blow air over the heat sink of the peltier junction ONLY. This would use much less air (less noise) and may allow the peltier junction device to be PWM after shutdown to reduce battery drain. If a circuit could be designed (would be simple for an engineer) that would cycle the heat sink fan and peltier junction duty cycle to maintain a set maximum temp for the board itself. This would be most efficient (battery wise) setup. And not difficult to design.



Bob, a question, are you forcing air over the VP or do you have a heatsink mounted on your VP bay cover?

 

[McDowra]

The circuit I created works similarly to what you seem to want, It has a pot, that lets you adjust the temperature range the peltier device comes on at. However what happens after you shut the truck off and let it sit for a while the heat soak from the engine completly overwhelms the heatsink used to cool the peltier device, at which point it becomes a super heater, we looked at trying to simply go with a larger heatsink, however there is really not enough room for that to be effective. A fan operating on the same circuit forcing air over the heat sink would work if its feasible.



To be honest I kind of got burned out on this project a while back and have no real desire to pick it back up, and there is no one else here with both the free time and the ability to finish it for me.



I think some clarification on terminology is needed, by vp44 bay cover Im not talking about the metal piece with the 5 tamper proof bolts through it I am talking about the black casing that the electronics are actually inside of. If you are trying to cool the metal piece you will have to use some type of thermal putty between the metal piece and the black casing for heat transfer, yes putty not paste because the surface is actually convex and paste would not make contact.



Let me try and find our actual test data, with real temperatures and times, instead of trying to remember. Gary maybe a combination of our solutions would be the way to go, however something to remember a peltier cooling device uses a lot of energy so it might be a good idea to redesign the circuit a bit to let it come on at a different temp, when the truck is running versus off. I'll try to look at this sometime but no promises as I will be gone pretty much all of the next 2 weeks.

Wonder if you could put on an electronic peltier cooler run from a solar panel. That way after shut down the peltier is not draining the battery



FOOD FOR THOUGHT

Wow I just now read this, that could be a great idea, why didnt I think of that. I don't think you will be able to collect enough energy with a solar panel to run it without it looking really gaudy and adding to the cost, however it may be possible to convert some of the heat to energy to supplement the battery so while its hot under the hood (heat soak) you would have plenty of power and when things cool down you dont need the cooling anyway.



Dont really know how feasible this is yet, as I am not an engineer, just someone capable of doing research and working with new Ideas. I will look at this some though. We could possibly use thermionics technology to this end.



-Jason

 

[Texas Diesel]

Jason, give the the amount of current and voltage that your peltier junctions work at and I'll look into solar panel size.



As I recall the junctions are low voltage, high current devices. The ones I worked with were 3VDC @ 5 amps and would die instantly if the junction temp exceeded at set point.



It would be kind of interesting of we could use another set of peltier devices to generate power off of engine heat. Some solar powered homes use these devices on their wood stoves to convert heat into electricity.