Question: best fuel temp

lotsofmiles

Father of the Van
Dec 4, 2008
3,097
0
0
Michigan
I had this thought, and it could come from too much time alone.....

Would it help cool the fuel to reroute the return line up into my aux fuel tank?


I've got the aux tank setup so I can pump on the fly, flip a switch on the dash to top-off the factory tank at any time. So the warm fuel would be sent into the aux tank, mix it with upto 115 gallons instead of 34. Seems like the 34 gallon factory tank would stay cooler.

Factory tank level would go down faster, but being able to refill without stopping it wouldnt be an issue.

This probably wouldnt be beneficial for a daily driver doing short trips back and forth to work. But for a truck like mine that hits the eway and runs all day (and into the night),
would it make any difference in performance/fuel economy?

Seems like in would be an easy mod to try
 

eds04max

New member
May 7, 2008
412
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0
Landis, N.C.
I installed a secondary fuel-cooler with a fan under the truck about 18-24 months ago. It dropped my temps about 30*. I'm down to about 130* now after the truck has been on the road for a while. The high rail pressure that we like so well adds to this high temp.
 

sweetdiesel

That's better
Aug 6, 2006
10,390
0
0
53
Thailand
I had this thought, and it could come from too much time alone.....

Would it help cool the fuel to reroute the return line up into my aux fuel tank?


I've got the aux tank setup so I can pump on the fly, flip a switch on the dash to top-off the factory tank at any time. So the warm fuel would be sent into the aux tank, mix it with upto 115 gallons instead of 34. Seems like the 34 gallon factory tank would stay cooler.

Factory tank level would go down faster, but being able to refill without stopping it wouldnt be an issue.

This probably wouldnt be beneficial for a daily driver doing short trips back and forth to work. But for a truck like mine that hits the eway and runs all day (and into the night),
would it make any difference in performance/fuel economy?

Seems like in would be an easy mod to try

I do that with my aux tank all the time....it works on long trips and you can actually watch your fuel temps go down

80-90 would be best:)

Stop and go would be nice to have a more efficiant cooler and maybe even the fan of some sort....Mike L did a bunch of stuff on this years ago
He could probably rig you up with a cooler and fan
 

NemesisDP

New member
Apr 20, 2008
520
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Bloomfield New Mexico
I set up a hot shot truck to return to the aux tank and auto fill the the truck tank with a check valve. This truck would run for days with out shutting off and pulling heavy. He added a fuel cooler and said that in 100 deg weather the fuel temp in the truck tank would be just a few degs warmer than outside temp.
 

lotsofmiles

Father of the Van
Dec 4, 2008
3,097
0
0
Michigan
sounds like i know what my next project is.


dont think anyone answered this yet, is there much pressure on the return line?
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
236
63
Fullerton CA
Fuel coolers with fans are your friend. There is a lot to be gained with cooler fuel IF yours is too hot because you will loose power IF your fuel is too warm.
I did a lot of testing a few years ago with infra red camera and learned a lot. A bunch of people laughed at this on DP so I dropped it.
 

lotsofmiles

Father of the Van
Dec 4, 2008
3,097
0
0
Michigan
interesting...

what I'm thinking is T the line after the cooler. Put in a couple valves (make it easy to switch from dumping into the aux tank vs factory) run a line up to the aux tank.


Maybe another cooler too?


Thanks for all the input!
 

lotsofmiles

Father of the Van
Dec 4, 2008
3,097
0
0
Michigan
Milke L, did you ever come up with a fuel cooler or were you just thinking it out?

The more I think about rerouting the return line into the aux tank got me wondering about the sun beating down on it warming it back up.


Maybe a fan on the cooler or an additional cooler would keep the temps down more.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
236
63
Fullerton CA
I developed a twin fan cooler that replaced the factory one. Got too much shit from the DP idiots and shit canned the whole project. I pretty much told everyone to FO.
 

racinmike77

New member
Sep 14, 2008
1,029
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MD
its a great idea but it would be good to be able to bypass this in the winter, dont want to make the diesel thicker than it already is.