Preventing vapor lock

[J-440]

The controller is set to go full blast at 3500rpm. Voltage is fine. Forgot to mention that the pump temp was at 175 degrees when everything else was at 250.

[dhutton]

Originally Posted by J-440

The controller is set to go full blast at 3500rpm. Voltage is fine. Forgot to mention that the pump temp was at 175 degrees when everything else was at 250.

So you don’t know what your reduced voltage is? Haven’t you measured it?

If the heat sunk exterior of the pump is 175 you can bet the internal pump components are considerably hotter. If I had to guess I would say in excess of 300 degrees. This is based on 35 years of hardware design and countless thermal analyses and calculations....

Don

[J-440]

Voltage is right at 9. I used the instructions on the Aeromotive website.

[dhutton]

Pretty sure that pump is cooking your fuel if the external temperature is 175 degrees. What is the temperature of the fuel lines connections in and out of the pump? If the output side is much higher than the input side then that would show it is heating the fuel...

Don

[GregWeld]

Just copied off the internet -- not my personal knowledge -- but trying to find something helpful.



Gas doesn't typically "boil", but it does vaporize (evaporate) at anything over 93 degrees F or so. As I understand it, the "boiling point" of regular 87 unleaded is about 181 degrees...but this will differ depending on pressure and what additives are in the gas

[J-440]

I’ll check the line temps. But dam, is this normal for this pump? I’ve got it lower than the tank like Aeromotive said and all the lines are well insulated past the header collector.
Let’s say I use an in tank pump without changing anything. About how cooler would the fuel be? I’ve got some lava header wrap coming in the meantime. It’s more of a do it yourself shield like you see on LS motors. Trial and error I guess. Thanks for all the help.

[GregWeld]

I don't need an answer -- I'm just THINKING OUT LOUD --- so to speak.


Fuel "boils" when under vacuum (suction) --- so since the pump is external to the tank and pick up --- What size is the pick up tube?? And do you have any sharp 90's on the INLET side from tank to pump.... I try to use 90* "sweeps" instead of hard 90's or GO UP IN SIZE on the pick up and plumbing to the pump to avoid that. IDK.

[dhutton]

Originally Posted by J-440

I’ll check the line temps. But dam, is this normal for this pump? I’ve got it lower than the tank like Aeromotive said and all the lines are well insulated past the header collector.
Let’s say I use an in tank pump without changing anything. About how cooler would the fuel be? I’ve got some lava header wrap coming in the meantime. It’s more of a do it yourself shield like you see on LS motors. Trial and error I guess. Thanks for all the help.

Depends on the pump you use and how you control it. I’ve used several Vaporworx controllers without a hitch. The beauty is the pump never runs any harder than it needs to. Keeps heat to an absolute minimum. No return line to mess with.

Interested to see those input and output fitting temperatures.

Don

[Zspoiler]

Have you tried a heat shield under the fuel injection?

[J-440]

I’ve seen fuel rail heat wrap but never a shield under the injection rail. How would that work?