High Fuel Temp

[dripley]

I have never had to worry gelling for the most part, just not in that cold of climate 90% of the time. I have seen near 0 temps with no problems for some trips. I have wondered about the fuel temps with both return lines going to the fuel basket and the fact I have always run my tank low on road trips both winter and  summer. Just never have had filters clog  prematurely or any other side effects that i know of.

[KATOOM]

22 hours ago, Dieselfuture said:

I would be getting a better higher flow fuel pump if it was me, then it be much better, jmo.

 

Any aftermarket fuel pump will push more than enough fuel since the whole premise behind fuel lubricating and cooling the VP is having more fuel pass through it than the engine needs.  The limiting factors will always be what fuel volume can pass through the VP at any given time.  Even the air separation fuel pump systems which have their own return still offer no additional benefit to fuel volume through the cooler since their return fuel is dumped directly into the fuel tank inlet.

 

A thermo bypass, built in thermostatically controlled, heat exchanger would probable by ideal in one of these situations.

[Mopar1973Man]

Return from the VP44 is very limited anyway... Return on the left and supply on the right. No matter what you do for pressure the volume is limited to that small port drilled in the body of the pump. This why I never suggest pressure beyond the standard 14-20 PSI. There is nothing gained going to higher supply pressures. 

 

Edited July 18, 2018 by Mopar1973Man

[Dieselfuture]

10 psi wot doesn't sound too healthy after all I've read

[KATOOM]

2 hours ago, Mopar1973Man said:

Return from the VP44 is very limited anyway... Return on the left and supply on the right. No matter what you do for pressure the volume is limited to that small port drilled in the body of the pump. This why I never suggest pressure beyond the standard 14-20 PSI. There is nothing gained going to higher supply pressures.

 

Correct, except that the VP return is only part of what volume makes its way to the fuel tank.  The rest is excess fuel at the injectors.  And thats actually the HOTTEST fuel as its flowing out the back of a 200*+ cylinder head.

[Clunk]

This was a hot topic on another site about 14 years ago and ideas for addressing VP heat was varied & very interesting.

[Mopar1973Man]

2 minutes ago, Clunk said:

This was a hot topic on another site about 14 years ago and ideas for addressing VP heat was varied & very interesting.

 

I've seen everything... 

• CPU heatsink and CPU fan mounted on top
• Bulge blower tube routed to blow air over the VP44
• Even air dam tubing created to blow air over the VP44
• Transmission cooler use for cooling fuel

The list goes on...

 

The funny part is the aluminum cover is a just protective shield to the PSG electronics and will not absorb any heat. The electronics are actually heat sunk to the fuel below. The electronics are attached to the aluminum body facing the fuel. All the air and heatsink methods do nothing.

 

As you can see there is an air gap between the plastic cover and the electronics. 

 

Without the aluminum cover...

[Clunk]

Looks like it's sunk in gell too.

I guess the lift pump could be run when the VP temp. got too high after engine shutdown but some pumps draw alotta current. Mine is rated at 4 amps.

Edited July 19, 2018 by Clunk

[Mopar1973Man]

8 minutes ago, Clunk said:

Looks like it's sunk in gell too.

 

Correct. I'm assuming the gel help pull the heat back into the fuel plate below. You can see where I use my blow gun to attempt to blow off a chip of plastic when I pried the PSG open and it dropped on the gel. The gel is like a thick clear grease just about.

[KATOOM]

The only viable attempt I've seen someone do to keep the VP cooled down a bit is having cool air blowing over the entire VP.

 

Aside from its own heat generation... The VP hangs out in the open and is subject to heat transferred through the mounting base and whatever radiant heat from the motor.  So speculation would suggest any air blowing over it should help.

 

That said, a fuel cooler would seem like the most logical option.  Funny too how these topics cycle too.....

 

[greed]

I don't know if this helps my VP44 from radiant engine heat or not, but I draped a Chevy starter heat shield from the air horn to as far behind the VP44 as I could get it.

[KATOOM]

6 minutes ago, greed said:

I don't know if this helps my VP44 from radiant engine heat or not, but I draped a Chevy starter heat shield from the air horn to as far behind the VP44 as I could get it.

 

I've thought about trying that too but I was more concerned about heat being held in.  You have any pictures?

[Mopar1973Man]

8 hours ago, KATOOM said:

 

I've thought about trying that too but I was more concerned about heat being held in.

 

Exactly. Good fuel pressure is the biggest thing. As long as the fuel pressure is in the range of 14 to 20 PSI you should be fine. 

[greed]

Katoom, no, I don't have any pictures. As far as holding heat in, while moving or engine running, the fan should move enough air to help cool. After shutdown, the blanket should (I hope) keep radiant engine heat off the VP44 as it is between the VP44 and the block. The VP44 computer, fuel lines are still exposed to open air. I used a large hose clamp and clamped the top side of he blanket to the air horn.

[KATOOM]

You should check and see if the blanket is keeping the VP cooler.  Take some temperature readings while the engine is running and then about an hour or so after you shut the engine off.  If the blanket is working then the VP will not be as hot as the neighboring engine and bay temperature.  You certainly dont want to cause an opposite effect.

[greed]

Good idea. I have an IR temp gun. It is pushing 100 deg here, so I should be able to get a fairly good idea if it works.

[Mopar1973Man]

Would be better to see the fuel temp sensor inside the pump core. Either Edge Juice or Quadzilla display this value.

[015point9]

My (uneducated) thinking is the cooler the fuel, better for the electronics inside pump control unit?

[SavageTusk]

I had an interesting thought about temp readings.  I have my fuel sensor located on my fuel filter cap.  I wonder it it picks up extra temp from the filter housing.  Maybe a 1/2" online before the vp44 would be a more accurate reading. 

Interesting result just now.  It's about 104* out and was sitting, engine on, eating a quick bite. IAT is about 174* and fuel temps began to rise from ~130* to 154*.  I had 1/2 tank of fuel so drove to filler up.  After filling I started the truck and fuel temp was at 161*!  About 3 min later I was reading 134* and is at 132* now with IAT at 176*.  Maybe that hot fuel return really is the issue with this blasted heat! 

[Mopar1973Man]

Fuel pressure sensor does not pick up the temperature. Only pressure readings...

 

Fuel temperature is measure INSIDE the VP44... The black tone wheel pickup on the right side of the picture is what gets the fuel temperature measurement for the Quadzilla. It's buried inside the VP44.