ayousef

Well, might sound like a noob question, but there is a reason for me to ask, im working on something and can use some feedback.

What heats up the fuel when using an external pump, is it the pump itself, or the fact that the fuel has to pass through the rails (hot) and return and so on so forth?

rwb

When the pump sits in the gasoline, the gas keeps it cool by dispersing the heat into the gas. An external pump only has the air to cool it so the heat tends to soak into the gas that is pumping through it. So basically the pump heats up the gas.

ayousef

thats true, but can the pump itself be the cause of such increased heat?

Is the heat coming from somewhere else? As I previously mentioned since the fuel passes over the rails and is then returned, the rails are quite hot if you ask me

rwb

It is the pump and the fact that you are pumping volume through a small tube at high pressure. Plus the fact that you are in Dubai where it is probably hot outside anyway. Ok just kidding about where you are. On a mopar that I built years ago the fuel was always hot after we put an electric external pump on.

onfire

iTrader: (17)

It's just plain physics folks...doesn't really matter if the pump is in the tank or inline. A hot pump in the tank will transfer the heat directly to the fuel...but it's not the cause...

The more pump you have, the more volume you pump,,,,at high pressure ....creates heat...so if you have one small pump that pumps 35 gallons per hour it's going to transfer x number of BTU's to the gas tank. Now go to a big single or twin's and you're at 70 gallons per hour and you have doubled the BTU's
added to the fuel in the tank....now add a smaller tank/cell or run your stock tank at 8 gallons and you have 50% of the fuel to cool/absorb the addition BTU's and it's getting hotter and hotter.

chevyz2801

iTrader: (20)

Can a fuel cooler be added something like a tranny or oil cooler. Are there any benefits of doing this?

ayousef

I know a few who have done this, something called a fuel catch-tank, also someone on the forum recommended a fuel-air cooler, so its definitely an option.

I would think with the fuel heating so much and being introduced into the combustion chamber could easily release all the heat contained within into the air and....? but thats just my guess, all in all "overheating" is not a motor's friend.

onfire

iTrader: (17)

Those do help. Or you can run twin pumps and have one activated by a Hobbs switch. Normally only one pump runs while your driving around town at part throttle....when you need the flow at wot the second pump activates.

I had to do that because two 044 Bosch pumps running all of the time and 8 gallons of fuel in the tank caused too much heat in the fuel. Excessive heat caused the fuel to cavitate.

C5Fire

This is a false statement. The pump will make some heat but not enough to cause any issues. Here is a post I made a while back explaining where heat comes from. There is some extra stuff in there but it's a good read.

This is what just blows me away. You just stated that the main reason why my pump has lived so long is because i'm running a 10AN feed line. Imagine that, I followed the instructions and my pump works!!!! Now onto the rest of your statement that the 10AN line keeps the pump cool. The line size has nothing to do with keeping the pump cool but it does keep the pump from working over time to pull fuel through a smaller line (smaller line = more restriction). Now here is a Mr. Wizard lesson for everyone that wants to learn.
The fuel system in your car is a return style fuel system. Fuel is being pumped through fuel rails attached to a hot engine where heat is transfered to the rails. The fuel passes through the rails which takes the heat out of the rails and puts it in the fuel. This hot fuel is then returned to the tank. With the large volume of fuel the Aeromotive unit puts out, the more fuel that gets passed through the hot rail and back to the tank (2 gallons a minute). Now take your car on a 45min cruise. If you had 15 gallons in your tank when you started the cruise you put the contents of the tank through the engine bay every 7.5 minutes. So on your 45min cruise you recirculated the contents of your tank 6 times! And that's if you didn't burn any fuel. So it will be around 7-7.5 times in your 45min cruise. Now that we have established where heat in the system comes from, let talk about how it effects the pump and line size.
Here is where Mr. Wizard comes in handy. When a hot liquid is placed in a vacuum it lowers its boiling point (the point when it changes from liquid to vapor). All fuel pumps make vacuum to prime themselfs (some more than others). Now take that pump that makes vacuum, place a smaller restrictive feed line on it so it has to make move vacuum to over come the restiction and you now have turned your hot fuel into vapor (air). Now lets take and place a restrictive filter on a system that is already restricted and see what happens. The fuel pump has to make more vacuum to over come the restriction in the system. This in turn lowers the point in which fuel will turn to vapor. So you get less drive time before your pump vapor locks. Sorry for the long post but I just had to get some FACTS out there.

Rapin'Ya

iTrader: (1)

You know I have to disagree with this here. I ran the worlds worst pump (when installed incorrectly) on the street with no voltage controller (aeromotive A1000) and never once had a heat issue with my fueling or a cavitation issue.

I did however have my pump gravity fed right near the lowest part of the sump. If you install the pumps above the sump yet still have a cavitation issue, its not the pumps fault yet we all tend to want to blame it on the pumps volume. It is ALWAYS an installer issue whether its not lower than the sump or level with it or a wiring issue also causing a heating issue. Think about these things before you respond to my post. Generally, you will find it all to be true.

Old Geezer

iTrader: (3)

on the fuel/heat topic.
http://www.patentstorm.us/patents/58...scription.html

sultan(ZR-1)KSA

lestin my frind me ans you we r living in almost same wether aria , i live in saudi arabia so were close ,
i have on my car 2-044 bosche pumps one in tank and one external running all the time
i have never notced any heat in the fuel nor any stuff like that i am producing at the moment from my littel 347 671WHP ,700Wtq on hi boost and this is my daily driver ,
so in my point of vew there is no problems what so ever
and yes it ia a 2002 corvette C5 Z06

onfire

iTrader: (17)

You're disagreeing with physics....not me...

Compress a liquid and you create heat.

Compare the flow curve of a single Aero vs twin 044's for a hint.

You can have hot fuel and cav and not know it under certain conditions. My problem never stopped me from driving the car....just wasn't a good situation.

I've designed 450psi industrial pumping stations...probably not an install issue

My 044's are in a custom stainless tank with individual spiral baffles per pump with the inlets at the rear bottom of the tank. Twin 40amp relays with a dedicated 10ga wire per pump.

onfire

iTrader: (17)

Are the two pumps inline or parallel?