Engine/Transmission (1998.5 - 2002) question about in tank fuel return and pickup

[Todd T]

this is something that came up after talking with a guy over on the Ford site. on the fords they have a real crappy mixing chamber in the tank. this mixing chamber blends the returned fuel with the supply fuel and somehow uses the return fuel to wash the pickup filter clean. a long story, longer... through testing they have found the return fuel from a Ford PSD is between 80 and 120 degrees during normal operation. there is 8 gallons returned for about every 3 burned. the fords also have a real nice problem with bad connections sucking air into the liftpump. anyway... . a fix for this is to remove the mixing chamber and install new lines in the tank and at the lift pump along with an external prefilter. while they are in there, they route the return fuel across the tank as far away from the pickup as possible. (lightbulb over the head)



what do the Dodge tanks have and how close is the pickup from the return?



maybe this is a mod that is worth looking into on the Cummins. I have seen test data that shows hot fuel will bring down the performance of fuel.



what do you think? Discuss, Please.

Todd

 

[illflem]

The pickup and return on our Dodges aren't that far apart inside the module but I don't think it makes much difference as far as heat goes because the entire tank gets hot. I've measured the temp at the bottom of the tank with an infrared temp gun on winter day. The fuel went from 20°F to 105° in 50 miles.

I can't imagine it gets much hotter inside the module with the heat sink of the surrounding fuel.

Some folks have talked about fuel coolers, I don't think they're necessary if you keep your tank level up. In fact I think one of the reasons our fuel gauges were designed read empty with 7-10 gallons to go is to provide the additional cooling.

 

[Rob Thomas]

I agree with Bill. Our pick-ups are close to our return, but at the same time somewhat far apart. The pick-up is at the absolute bottom of the unit, between two screens, and is in noway connected to the canister, as far as sucking fuel goes.



The return on the otherhand, dumps into the the canister, and overflows through the slots cut into the sides of the canister, and thus flows out into the open tank, not directly to the pick-up.



Later, Rob

 

[Todd T]

i thought of a cooler at first too. but at that rate of return and feed do you think it would even have time to cool it any? your only chance would be through the return side. IMO



i'll have to dig out that study i read about the effects of heat on the fuel flash points. I usually slow down on the hot roddin once i get below 1/4 tank. call it weird, i just always felt it was bad to work it hard on hot (foamy) fuel.



i wonder if HVAC or anyone else has tried a cool can at the strip with any luck?



maybe a wrap or two of aluminum tubing around the rear air cold side hose, might be the trick

 

[illflem]

I read once where studies were done looking for the fuel temp that produced the highest efficency. Can't remember the temp but it was pretty high, like around 200°



Typical aluminum wire wound fuel cooler from an Audi gasser. The Bio-diesel guys use these strapped to the exhaust to heat their fuel.

On an Audi its under the car by the fuel tank on the return line, passing air from moving cools the fuel.



#ad

 

[illflem]

Here another from http://www.perma-cool.com/



1001 Two-Pass Power Steering/Fuel Cooler Kit

Coil size: 1-1/2" x 2-1/2" x 7-1/2"

1002 Cooler coil only with -6 AN male fittings



#ad