Fuel Cooler - Worth it on turbo gasoline engine?
Fuel Cooler - Worth it on turbo gasoline engine?
(OP)
I know that some drag teams run fuel coolers to cool their fuel to sub ambient temps prior to runs and get a HP gain out of this. I am building an all-out effort turbo 4-cyl.
My questions are these:
What is the average temperature increase on fuel in an EFI engine running around 45-75psi(fuel pressure) (using a Walbro 255l in tank)?
Have any of you guys run one a fuel cooler in a turbocharged (non-diesel)application and did you experience any performance gains?
Is a normal air cooled fuel cooler worth it or are sizable gains only seen by super-cooling the fuel?
My questions are these:
What is the average temperature increase on fuel in an EFI engine running around 45-75psi(fuel pressure) (using a Walbro 255l in tank)?
Have any of you guys run one a fuel cooler in a turbocharged (non-diesel)application and did you experience any performance gains?
Is a normal air cooled fuel cooler worth it or are sizable gains only seen by super-cooling the fuel?





RE: Fuel Cooler - Worth it on turbo gasoline engine?
If you do a site search with the google feature you will find this has already been covered in detail with all the math done to support the arguments.
Real rough ball park summary from memory.
a:f ratio 15:1 by mass.
Forget about specific heats as I can't remember them.
15 deg drop in fuel temp = 1 deg drop in charge temp, but evaporation rate is also hurt.
Net effect, two tenths of a gnats whisker power increase for a pound or two weight increase
Regards
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RE: Fuel Cooler - Worth it on turbo gasoline engine?
I have done multiple searches but "fuel" and "cooler" tend to return many unwanted results.
Does anybody have a link to this "detailed" thread, because I can't seem to find it. This is the only thread that I could find, but it isn't very scientific, and no real data to prove either side correct.
http://www
Just one note on turbocharged cars. They all run richer than required because they use excess fuel as an in-cylinder cooling agent. My theory is that any cooling done to the fuel prior to injection is a measurable benefit to performance since the fuel itself is used as a coolant.
It would be helpful to have information on the average injected fuel temp so I could see if it is worth the effort to make a air-cooled fuel cooler.
RE: Fuel Cooler - Worth it on turbo gasoline engine?
I guess you want me to search and find it for you.
I will see if I can find that amount of time tonight.
Regards
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RE: Fuel Cooler - Worth it on turbo gasoline engine?
RE: Fuel Cooler - Worth it on turbo gasoline engine?
You also have to realize that some set-ups run a lot of fuel through a pressure regulator and back to tank - which turns the pump energy into pressure and then into heat. (This is common on diesel injection pumps, the fuel is used as a coolant.)
"What is the average temperature increase on fuel in an EFI engine running around 45-75psi(fuel pressure) (using a Walbro 255l in tank)?" I would figure that ~80% of the energy the pump uses will end up heating the fuel, but then you have to consider the mass of fuel you are starting with (takes XX minutes to heat XX lbs of fuel XX degrees), the cooling affect of the metal fuel lines, heat absorption in the engine compartment, etc. Very difficult to predict. I suggest measuring the temp rise with a thermocouple during your debugging runs to see what the actual temp rise is and if it is worth "fixing."
ISZ
ISZ
RE: Fuel Cooler - Worth it on turbo gasoline engine?
Even with a straight fuel, as the mechanical fuel injection systems metre fuel by volume as the fuel expands the mixture goes richer if the air temperature remains constant.
Regards
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RE: Fuel Cooler - Worth it on turbo gasoline engine?
If the fuel was cooled down by 50 F, that would give 27 more BTU/lb or 21% more cooling or 6 F or 1.0% more air than before.
If you could just cool the air down by 6 degrees you would get the same effect (or close anyway) Drop the after cooler temp from 120 to 110 F and get the same effect.
With dragsters, the oxidizer is in the fuel, so cooling the fuel is also cooling the "air" too.
RE: Fuel Cooler - Worth it on turbo gasoline engine?
RE: Fuel Cooler - Worth it on turbo gasoline engine?
One of the more recent and lengthy threads started out under "Fuel Warming".
http://www.eng-tips.com/viewthread.cfm?qid=155457
RE: Fuel Cooler - Worth it on turbo gasoline engine?
"Even with a straight fuel, as the mechanical fuel injection systems metre fuel by volume as the fuel expands the mixture goes richer if the air temperature remains constant. "
Right principle, but you've stated the effect backwards, I think...
RE: Fuel Cooler - Worth it on turbo gasoline engine?
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RE: Fuel Cooler - Worth it on turbo gasoline engine?
RE: Fuel Cooler - Worth it on turbo gasoline engine?
This is like intercooling your exhaust to me.
RE: Fuel Cooler - Worth it on turbo gasoline engine?
Hot non pressurised fuel is much more prone to evaporative losses than hot fuel pressurised being injected into the intake tract. This hot fuel in the tank makes the fuel pump more prone to cavitation.
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RE: Fuel Cooler - Worth it on turbo gasoline engine?
Thanks for the input. I'm looking forward to reading more on the topic.
RE: Fuel Cooler - Worth it on turbo gasoline engine?
My fuel lines are hot to the touch with my car just idling and they are only physically attached to the engine via the rails, so most of the heat must be coming from the thermodynamics of pumping.
RE: Fuel Cooler - Worth it on turbo gasoline engine?
Cheers
Greg Locock
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