Fuel temp

[KansasIDI]

So I am wondering, how hot is our fuel supposed to get? I feel like I might be getting my fuel too hot somehow… so I was wondering if anybody else has noticed anything like this. My fuel filter will get up to about 200*, while the engine itself is at 185-190*. I would think our fuel would get warm, but not this scalding insanity. I pointed my laser temp gun at my rear tank after a couple hours of highway driving, 170ish degrees.


I would think that if this is a problem, then adding what would basically be a trans cooler along the fuel line somewhere would be a viable solution.

Could this have an effect on the IP, since they are lubed and cooled by the fuel? I would think so…


I’d be curious to hear what everyone else thinks about this…

 

[Nero]

I'm sure it has some sort of effect.

In older VW's, automatics had a larger injection pump than the manuals. They were also equipped with a fuel cooler on the return side, whereas the manuals with the smaller pumps did not.

Unsure if it made any difference, but if engineers went out of their way to make an automatic specific fuel cooler... I'm sure there was enough justification.

 

[Kdo58]

I ran all new fuel lines, near the motor I ran it through old heater hose, to protect and insulate it.

 

[tradergem]

While cooling the fuel in hot weather will improve fuel density and could therefore improve engine performance, in cold weather it could increase the posibility of fuel gelling needing anti-gel treatment. I think it would really be nice to have both cooler intake air and cooler fuel during the hot weather here in the desert though.

 

[KansasIDI]

While cooling the fuel in hot weather will improve fuel density and could therefore improve engine performance, in cold weather it could increase the posibility of fuel gelling needing anti-gel treatment. I think it would really be nice to have both cooler intake air and cooler fuel during the hot weather here in the desert though.

That’s something that I had considered about the gelling. Having some sort of plate to put over the cooler should suffice. And yes, in the summer I would think a fuel cooler would be a worthwhile thing to have.

 

[KansasIDI]

So would cooling the return fuel be the best bet? Or would it really matter much at all whether it was return or supply line getting cooled? Currently I am guessing that the return side would be better to do that to.

 

[Cubey]

I wouldn't worry. The fuel filter on vans is much closer to the radiator, and faces it. It probably gets hotter than trucks and it's fine.

 

[IDIBRONCO]

I wouldn't worry. The fuel filter on vans is much closer to the radiator, and faces it. It probably gets hotter than trucks and it's fine.

This could explain why the fuel filter is hotter than the tank itself.

 

[Cubey]

This could explain why the fuel filter is hotter than the tank itself.

And the tank gets some air flow cooling underneath.

I never tried taking a temperature reading on the RV but it never had fuel system issues, aside from the usual return o-rings when I first got it, and a weeping lift pump within the first year.

 

[The_Josh_Bear]

So would cooling the return fuel be the best bet? Or would it really matter much at all whether it was return or supply line getting cooled? Currently I am guessing that the return side would be better to do that to.

If you're going through the trouble of cooling the fuel, I'd do the supply side since the secondary job of the fuel is to cool the IP, I figure cooling it before entry is best. But that's me personally.

@Thewespaul has a bunch of good posts about all manner of things, one thread he started was about fuel cooling. Since he had the equipment, he found out that our engines actually suffer from max fuel delivery with hot fuel as it thins out. I don't remember the numbers, but 200*F sounds a little too hot to me. He lives in Texas and is well acquainted with the heat.
I think in the end he decided it wasn't worth it for most people, but it does make a difference!

I've noticed that when I'm climbing a grade and heat-soaked that I loose power. I've never been able to put my finger on it, but hot fuel is probably part of it. I'm sure a big part is the charge air cooler being heat-soaked and can't reject enough heat, since I just have e-fans.

Wes also mentioned that removing the check ball inside the return fitting in the IP gives 5% more max fuel, and I'm pretty sure more fuel flow through the IP for cooling. I haven't read up on it in years though.

I searched around a bit but I'm not finding that thread. Probably a side-track in one of this other threads. Gah

 

[03wr250f]

yes cooler fuel is better for the ip
so if I was going to cool it would be pre ip
I did my own research previous to wes's write ups and found much the same it helps, but not enough for most people to notice especially considering the cost.
if you live in colder climates I would not cool the return side as one of the jobs of the fuel is to take heat from the up, but it also warms the fuel in the tank to help prevent gelling. and as stated the tank is already subject to road speed wind removing heat .

now if you want to go for it, go for it! I'm sure you will see an improvement, how noticable will be up for debate
many semis have fuel coolers, as do 6.4 psd and Duramax

 

[KansasIDI]

After some research, I found a few sources saying that 140° should be max fuel inlet temp for the 6.5 GM diesel, which uses a fairly similar injection pump.

Aaand now it’s time for me to order a fuel cooler lol

 

[Nero]

So do you put the fuel cooler before or after the intercooler....?

Just to throw it out there, semi's that have fuel coolers are usually a single loop with fins on it mounted below the radiator. I only ever see them on the bigger engined chassis.

 

[KansasIDI]

So do you put the fuel cooler before or after the intercooler....?

Just to throw it out there, semi's that have fuel coolers are usually a single loop with fins on it mounted below the radiator. I only ever see them on the bigger engined chassis.

I am going to put a very small trans cooler below the intercooler. Probably with an electric pusher fan that I will connect to the same fan controller that the Workhorse Customs (@03wr250f) engine fan is operated by.

 

[Cant Write]

As @Nero mentioned earlier about VW’s. My TDI (‘05 Passat Wagon, BHW) will retard timing once my fuel temp gets so high. It has fins on the return line on the bottom of the car to cool fuel.

Oh and it will set a CEL as mine is currently on for failed fuel temp sensor.

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The long black thing ( ) is the fuel cooler.