Fuel cooler?
That leaves fuel pressure and boost pressure. Fuel pressure sounds ideal, but it also sounds like it would always be playing catch up. Boost pressure seems like it could more reliably predict fuel pump needs without unnecessary fluctuations in pressure, and only the minimal amount of excess drive to heat up the fuel. Also, map sensors of various bar values are already familiar to everyone using boost. You ever pick up some hot hippie chick, though, you will feel bad about discounting my "moon phase" controller, lol.
That leaves fuel pressure and boost pressure. Fuel pressure sounds ideal, but it also sounds like it would always be playing catch up. Boost pressure seems like it could more reliably predict fuel pump needs without unnecessary fluctuations in pressure, and only the minimal amount of excess drive to heat up the fuel. Also, map sensors of various bar values are already familiar to everyone using boost. You ever pick up some hot hippie chick, though, you will feel bad about discounting my "moon phase" controller, lol.
OEM's use fuel pressure sensors in a returnless manner. Every Gen5/6, CTS-V2/3, Hellcat, Demon, GenI/II/III Coytote Mustang (and a bunch of earlier versions), GM Trucks for about the last 10 years, etc. Port and DI systems. There's no timing/lag issue either with the OEM or the VaporWorx stand-alone systems. Any other PWM system requires the use of a mechanical regulator to control fuel pressure. I've seen that type used in OE Ford products that likely will not be seeing horsepower mods (work trucks), and since the setup does not require a fuel pressure sensor, it saves $$$$ over time.
There's no practical way to predict fuel pump needs in a returnless system. Doing so would result in pressure over/under-shoots. For a return system using PWM it's not needed since the fuel flowrate has to be more than what the engine needs in order to sufficiently deploy the mechanical regulator.
We already make MAP and TPS based PWM controllers for use in mechanically regulated systems. 1-4 BAR are the standard offerings but we can tweak them to any sensor as long as we have the output data. For a typical single 525lph pump/regulator setup, the power reduction during idle/cruise is 58% vs. running full speed. With pumps being about 1/3 efficient, that's a significant reduction in heat added to the fuel load.
Reduce the pump power at idle/cruise by 58% and turn the system into a dead-head arrangement and fuel system overheating problems pretty much go away. Fuel boiling typically does not happen on a high-pressure EFI systems past the pump, but it is a very real problem at the pump inlet when full re-circulation + hot engine compartments + full speed pumps come into play. The suction created at the pump inlet lowers the boiling point of the fuel, so when the liquid is hot, that's where trouble occurs. On hot days with a full recirculating system the fuel tank will get very warm, to the point where I can't leave my hand on it. Nothing good comes from that. That's where the nasty noises come from when hot pump(s) + liquid happen to meet.
I sat in lines for nearly an hour on blacktop at Bondurant in Phoenix in 116* heat in a Dodge Hellcat widebody with the windows up and the AC blowing cold. The pump in the fuel module used in those cars is a TI Automotive/Walbro 450lph in a full returnless system. There were at least 30 others doing the same. Zero issues. How many modern cars have fuel boiling problems? Heck, any kind of fuel problems?
Here's Greg T's car. He has another C2 as well. Both with VaporWorx PWM returnless systems. https://ls1tech.com/articles/from-ga...ecked-carcass/
Last edited by CarlC; Jul 5, 2022 at 01:28 AM.
If I can't dazzle her with my brilliance, I'll get her with by BS moon phase controller ;-)
OEM's use fuel pressure sensors in a returnless manner. Every Gen5/6, CTS-V2/3, Hellcat, Demon, GenI/II/III Coytote Mustang (and a bunch of earlier versions), GM Trucks for about the last 10 years, etc. Port and DI systems. There's no timing/lag issue either with the OEM or the VaporWorx stand-alone systems. Any other PWM system requires the use of a mechanical regulator to control fuel pressure. I've seen that type used in OE Ford products that likely will not be seeing horsepower mods (work trucks), and since the setup does not require a fuel pressure sensor, it saves $$$$ over time.
There's no practical way to predict fuel pump needs in a returnless system. Doing so would result in pressure over/under-shoots. For a return system using PWM it's not needed since the fuel flowrate has to be more than what the engine needs in order to sufficiently deploy the mechanical regulator.
We already make MAP and TPS based PWM controllers for use in mechanically regulated systems. 1-4 BAR are the standard offerings but we can tweak them to any sensor as long as we have the output data. For a typical single 525lph pump/regulator setup, the power reduction during idle/cruise is 58% vs. running full speed. With pumps being about 1/3 efficient, that's a significant reduction in heat added to the fuel load.
Reduce the pump power at idle/cruise by 58% and turn the system into a dead-head arrangement and fuel system overheating problems pretty much go away. Fuel boiling typically does not happen on a high-pressure EFI systems past the pump, but it is a very real problem at the pump inlet when full re-circulation + hot engine compartments + full speed pumps come into play. The suction created at the pump inlet lowers the boiling point of the fuel, so when the liquid is hot, that's where trouble occurs. On hot days with a full recirculating system the fuel tank will get very warm, to the point where I can't leave my hand on it. Nothing good comes from that. That's where the nasty noises come from when hot pump(s) + liquid happen to meet.
I sat in lines for nearly an hour on blacktop at Bondurant in Phoenix in 116* heat in a Dodge Hellcat widebody with the windows up and the AC blowing cold. The pump in the fuel module used in those cars is a TI Automotive/Walbro 450lph in a full returnless system. There were at least 30 others doing the same. Zero issues. How many modern cars have fuel boiling problems? Heck, any kind of fuel problems?
Here's Greg T's car. He has another C2 as well. Both with VaporWorx PWM returnless systems. https://ls1tech.com/articles/from-ga...ecked-carcass/
OEM's use fuel pressure sensors in a returnless manner. Every Gen5/6, CTS-V2/3, Hellcat, Demon, GenI/II/III Coytote Mustang (and a bunch of earlier versions), GM Trucks for about the last 10 years, etc. Port and DI systems. There's no timing/lag issue either with the OEM or the VaporWorx stand-alone systems. Any other PWM system requires the use of a mechanical regulator to control fuel pressure. I've seen that type used in OE Ford products that likely will not be seeing horsepower mods (work trucks), and since the setup does not require a fuel pressure sensor, it saves $$$$ over time.
There's no practical way to predict fuel pump needs in a returnless system. Doing so would result in pressure over/under-shoots. For a return system using PWM it's not needed since the fuel flowrate has to be more than what the engine needs in order to sufficiently deploy the mechanical regulator.
We already make MAP and TPS based PWM controllers for use in mechanically regulated systems. 1-4 BAR are the standard offerings but we can tweak them to any sensor as long as we have the output data. For a typical single 525lph pump/regulator setup, the power reduction during idle/cruise is 58% vs. running full speed. With pumps being about 1/3 efficient, that's a significant reduction in heat added to the fuel load.
Reduce the pump power at idle/cruise by 58% and turn the system into a dead-head arrangement and fuel system overheating problems pretty much go away. Fuel boiling typically does not happen on a high-pressure EFI systems past the pump, but it is a very real problem at the pump inlet when full re-circulation + hot engine compartments + full speed pumps come into play. The suction created at the pump inlet lowers the boiling point of the fuel, so when the liquid is hot, that's where trouble occurs. On hot days with a full recirculating system the fuel tank will get very warm, to the point where I can't leave my hand on it. Nothing good comes from that. That's where the nasty noises come from when hot pump(s) + liquid happen to meet.
I sat in lines for nearly an hour on blacktop at Bondurant in Phoenix in 116* heat in a Dodge Hellcat widebody with the windows up and the AC blowing cold. The pump in the fuel module used in those cars is a TI Automotive/Walbro 450lph in a full returnless system. There were at least 30 others doing the same. Zero issues. How many modern cars have fuel boiling problems? Heck, any kind of fuel problems?
Here's Greg T's car. He has another C2 as well. Both with VaporWorx PWM returnless systems. https://ls1tech.com/articles/from-ga...ecked-carcass/
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
I think that the easiest approach for me will be running both pumps (the new engine is going to be close to the limit of one) with a temperature sensor on the return line, at the regulator. Then I can add a fan cooled cooler later, if needed.
