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Discussion Starter · #1 ·
Somebody explain fuel temps and their effect on injection to me.

I'm not 100% on them.

Sorry if it's a newb question.
 

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Drink til she's cute
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I just read a Princeton University research paper on this subject:

Their study finds the following:

60* is the optimum temp of diesel fuel pumped into an engine. At 60* there is a specific amount of energy in diesel fuel and every degree above 60* they saw a drop in that variable.

At 60* a gallon of diesel fuel is 230 cubic inches with "x" amount of energy

At 90* a gallon of diesel fuel expands to 235 cubic inches with less energy to utilize... the study finds this is what leads to poor MPG's and decrease power.

The study did not publish the exact energy available at 60 and 90* only that is was a significant decrease.
 

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Discussion Starter · #3 ·
So, the hotter it gets the less energy it has?

I was kinda wondering about flow characteristics too.
 

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Nice post Thuggy. Don M had also suggested some interesting ideas back when the suggested if various injectors received fuel of different tempuratures that created imbalanced power between cylinders.
 

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Discussion Starter · #5 ·
Nice post Thuggy. Don M had also suggested some interesting ideas back when the suggested if various injectors received fuel of different tempuratures that created imbalanced power between cylinders.
If that's the case then, it would be yet another reason for a RR.

So one didn't have fuel sitting in the head being heated.
 

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What else?
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Either Bob Riley or [email protected] did fuel temperature testing a few years ago. I looked on both their sites for the information but I can't find it now.

Anyone have a link to that info still? It was quite in-depth from what I remember.

Dave
 

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Discussion Starter · #7 ·
Either Bob Riley or [email protected] did fuel temperature testing a few years ago. I looked on both their sites for the information but I can't find it now.

Anyone have a link to that info still? It was quite in-depth from what I remember.

Dave
Yeah that's what I was lookin for ^^^^

Maybe I'll just call Bob. He likes to talk lol.
 

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FORD..THE ROCK CRUSHER
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Discussion Starter · #9 ·
Good read but not entirely what I'm after. Thanks for diggin it up though!

Now, I don't have a temp gauge for fuel. I haven't gotten one, because I don't understand the effects (if any) of cold or hot fuel in the injection sequence.

The only area this would really have any critical bearing on my truck is probably sled pulling.

Option 1, my truck hitches a ride to the pull on a trailer. Usually gets started and placed at highidle as soon as we get there while I go register and/or BS. It runs until it's time to pull and oil temps are usually right about 180*.

Option 2, I drive my truck to the pull and leave it running while I register/BS. Truck never cools down and EOT is usually 190-205, depending on how long it sits at idle, and how long I was on the interstate getting there.

So, I could expect different fuel temps right along with the differing EOT's right? The difference would seem to be, driving the truck to the pulls would circulate more fuel, in addition to higher overall engine temps, and result in higher fuel temps than idling up to temp on arrival.

So, based on flow characteristics, do I want cold or hot fuel before I hammer on it? Based on the energy information I want cold fuel.

But based on EOT guidelines, I want things up to temp to make sure fluids flow when commanded. And nothing is tryin to happen before or after that.

Are the potential differences on an engine warmed up at idle, or just comin off the road, even large enough to make this a factor?
 

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The highway fuel temps will be considerably warmer if you have a regulated return.
 

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Discussion Starter · #11 ·
Right, because more fuel moves through the heads and goes back to the tank, raising the temps of the fuel feeding to the engine.

But what does that do to actual timing?

Injection pressures?
 

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Village Idiot
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i'd still call bob his system uses a cooler.
Usfull esp with the bigger fuel systems pumping and reciculating fuel, just heating it up.
 

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Does Bob's system run the fuel through both heads? I think that might just be a part of the reason he runs a fuel cooler.
 

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Yes, in from the back, out the front, across to the other head, in the front, out the back, to the reg, into the cooler, to the tank. But time in the head is about the same as if its split. A bit more but not 2x.

Regardless, the fuel is going thru the heads on all RRs. With the high flow rates the fuel is circulating with these HP pumps it can be running thru those heads a lot. Its getting reheated more frequently and given less time to cool. 100 GPH 27-44 gal tank when full. But I wonder if any temp testing is taking into account when you are running at 1/2 or 1/4 tank. That fuel is being turned over many times in one hour. Add in some traffic with lots of idle time.
 

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Lol I feel bad for you chvy, no one will answer your question.

Call bob or dennis and see if they have an answer and post back up here.
 

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Discussion Starter · #18 ·
Lol, try searchin for the answer for a couple hours. That's really frustrating.

I'll have to try to call tomorrow and see what I can find out.
 
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