Letting the fuel level get low in the tank...Bad?

[FasNuf]

https://youtu.be/p8hW5ShKJ5Q?si=kWmMK7fcUnbekN9X

No cooling is not 100% when there isn’t much fuel in the tank. The pumps will heat the fuel and if there’s a lot of fuel, then there is a lot of dissipation, less fuel, less heat dissipation. If you have fuel returning to tank, then heat from the engine bay also heats the returning fuel. More fuel is better in any setup.

The video above is the OEM ZL1 pump and bucket.

[FasNuf]

Originally Posted by econ

What would you say to the theory that since the fuel pump draws from the bottom of the fuel tank and debris/water being heavier than the gas causes the debris/water to settle towards the bottom, the fuel pump will pick up an equal amount of debris/water with a full tank as it would with a near empty tank?

Yea I believe it would. Seriously though if you have crap in your fuel then it’s time to service the tank.

[The_bald_eagle_machine]

When I go below a 1/4 tank and mash the pedal, I hit a fuel cut. But that could be from the amount of power I'm making. She does snap pretty hard. I never go below half unless I am cruising the highway on a long trip

[Rusty Shackleford]

Originally Posted by econ

What would you say to the theory that since the fuel pump draws from the bottom of the fuel tank and debris/water being heavier than the gas causes the debris/water to settle towards the bottom, the fuel pump will pick up an equal amount of debris/water with a full tank as it would with a near empty tank?

I would agree with this assessment. Water is heavier than gasoline, most debris is as well. The pump draws fuel from the bottom of the tank. So your statement above would hold true. It would pull in those contaminants whether the tank was full, or near empty.

[econ]

Originally Posted by FasNuf

https://youtu.be/p8hW5ShKJ5Q?si=kWmMK7fcUnbekN9X

No cooling is not 100% when there isn’t much fuel in the tank. The pumps will heat the fuel and if there’s a lot of fuel, then there is a lot of dissipation, less fuel, less heat dissipation. If you have fuel returning to tank, then heat from the engine bay also heats the returning fuel. More fuel is better in any setup.

The video above is the OEM ZL1 pump and bucket.

Perhaps I should have worded my question differently.

What I meant to say is this...

Is it true that as long as the bucket is full and that no part of the pump is exposed to air, the pump temps will stay out of the "danger zone" even though with more fuel you get more heat dissipation? I get that more heat dissipation is better, but is the bucket volume enough to keep the pump safe? I assume that the buckets purpose in life is to keep the pump submerged in fuel even as the fuel level gets very low. I have to also assume that the buckets volume was calculated to assure a certain amount of cooling capacity and that would be enough capacity to keep the pump safe. Wouldn't make much sense to design a bucket that is not big enough to do it's job.


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Side note:

The reason I am thinking about this is because I don't drive my 2013 SS very much and as such I tend to prefer to keep the gas level on the low side. My theory up till now has been that keeping less gas on hand is better because gas can and will go stale after a certain amount of time and having large amounts of fuel in the tank would mean that said gas would be sitting for some time before it gets burned, potentially going stale. With less fuel on hand, the gas that is on hand in the tank will be fresher. Adding small amounts of fuel more frequently seems better than having large amounts of fuel and adding less frequently, from a gas freshness standpoint. Something like that anyways.

It recently occurred to me that the pump might be better off with larger volumes of fuel in the tank.

[0stones0]

Originally Posted by econ

Perhaps I should have worded my question differently.

What I meant to say is this...

Is it true that as long as the bucket is full and that no part of the pump is exposed to air, the pump temps will stay out of the "danger zone" even though with more fuel you get more heat dissipation? I get that more heat dissipation is better, but is the bucket volume enough to keep the pump safe? I assume that the buckets purpose in life is to keep the pump submerged in fuel even as the fuel level gets very low. I have to also assume that the buckets volume was calculated to assure a certain amount of cooling capacity and that would be enough capacity to keep the pump safe. Wouldn't make much sense to design a bucket that is not big enough to do it's job.


----------------------------------


Side note:

The reason I am thinking about this is because I don't drive my 2013 SS very much and as such I tend to prefer to keep the gas level on the low side. My theory up till now has been that keeping less gas on hand is better because gas can and will go stale after a certain amount of time and having large amounts of fuel in the tank would mean that said gas would be sitting for some time before it gets burned, potentially going stale. With less fuel on hand, the gas that is on hand in the tank will be fresher. Adding small amounts of fuel more frequently seems better than having large amounts of fuel and adding less frequently, from a gas freshness standpoint. Something like that anyways.

It recently occurred to me that the pump might be better off with larger volumes of fuel in the tank.

Another good reason to keep the tank full is less area of the tank is exposed to deterioration.

[econ]

Originally Posted by 0stones0

Another good reason to keep the tank full is less area of the tank is exposed to deterioration.

Isn't our gas tank sealed from the atmosphere, provided that the gas cap is properly threaded on?

If so, then there wouldn't be any ambient air getting in and thus no corrosion, right?

[FasNuf]

Originally Posted by econ

Isn't our gas tank sealed from the atmosphere, provided that the gas cap is properly threaded on?

If so, then there wouldn't be any ambient air getting in and thus no corrosion, right?

Gen 5 tanks are poly so they won’t corrode.

[FasNuf]

Originally Posted by econ

Perhaps I should have worded my question differently.

What I meant to say is this...

Is it true that as long as the bucket is full and that no part of the pump is exposed to air, the pump temps will stay out of the "danger zone" even though with more fuel you get more heat dissipation? I get that more heat dissipation is better, but is the bucket volume enough to keep the pump safe? I assume that the buckets purpose in life is to keep the pump submerged in fuel even as the fuel level gets very low. I have to also assume that the buckets volume was calculated to assure a certain amount of cooling capacity and that would be enough capacity to keep the pump safe. Wouldn't make much sense to design a bucket that is not big enough to do it's job.


----------------------------------


Side note:

The reason I am thinking about this is because I don't drive my 2013 SS very much and as such I tend to prefer to keep the gas level on the low side. My theory up till now has been that keeping less gas on hand is better because gas can and will go stale after a certain amount of time and having large amounts of fuel in the tank would mean that said gas would be sitting for some time before it gets burned, potentially going stale. With less fuel on hand, the gas that is on hand in the tank will be fresher. Adding small amounts of fuel more frequently seems better than having large amounts of fuel and adding less frequently, from a gas freshness standpoint. Something like that anyways.

It recently occurred to me that the pump might be better off with larger volumes of fuel in the tank.

I just put Stabil in my gas before storing the car for the winter.

Most OEM fuel pumps now are PWM, meaning they are computer controlled to only run enough to keep rail pressure up so they don't return to tank heating the existing fuel in the tank. Pumps submerged will always run cooler, but the buckets main advantage is not starving the pump of fuel when cornering or climbing. Some off-road and racing configurations use a fuel surge tank which basically does the same thing.

[0stones0]

Originally Posted by FasNuf

Gen 5 tanks are poly so they won’t corrode.

Did not know they are poly. Glad to know it now!

[econ]

Originally Posted by FasNuf

I just put Stabil in my gas before storing the car for the winter.

Most OEM fuel pumps now are PWM, meaning they are computer controlled to only run enough to keep rail pressure up so they don't return to tank heating the existing fuel in the tank. Pumps submerged will always run cooler, but the buckets main advantage is not starving the pump of fuel when cornering or climbing. Some off-road and racing configurations use a fuel surge tank which basically does the same thing.

Does the fuel pump shut off once the fuel gets down to a certain level or does the fuel pump keep going until the tank is dry?

[FasNuf]

Originally Posted by econ

Does the fuel pump shut off once the fuel gets down to a certain level or does the fuel pump keep going until the tank is dry?

I suppose it depends if you mean the OEM pump. I guess the fuel pressure sensor would see the drop in pressure and kick the pump on , but if it's sucking air the engine would quit. I imagine the ECM would stop signaling the pump at that point, but I'm not sure. It's not good for any cars pump to suck the tank dry.
Are you hell bent on running water, dirt and low volume through your pump? Consider your injectors too. They have to see all the trash the pump sends to them that the filter slips past.

[econ]

Originally Posted by FasNuf

I suppose it depends if you mean the OEM pump. I guess the fuel pressure sensor would see the drop in pressure and kick the pump on , but if it's sucking air the engine would quit. I imagine the ECM would stop signaling the pump at that point, but I'm not sure. It's not good for any cars pump to suck the tank dry.
Are you hell bent on running water, dirt and low volume through your pump? Consider your injectors too. They have to see all the trash the pump sends to them that the filter slips past.

I do mean OEM pump, OEM ECM.

I have no intentions of trying to run it dry.

I was just wondering if the ECM stops the pump once it reaches a certain fuel level to protect the pump and the rest of the fuel system. Or if no such protection exists and the pump will keep going until there is no more fuel to pump.

[FasNuf]

Originally Posted by econ

I do mean OEM pump, OEM ECM.

I have no intentions of trying to run it dry.

I was just wondering if the ECM stops the pump once it reaches a certain fuel level to protect the pump and the rest of the fuel system. Or if no such protection exists and the pump will keep going until there is no more fuel to pump.

No, I don't think the ECM is controlling that and I also don't think the first time you ran it dry it would kill the pump either. Pretty sure GM didnt see a need to invest the time to make it do that. Hope that helps.