efi fuel cooler ?
07-25-2007, 06:58 PM
#4
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Originally Posted by 2002_Z28_Six_Speed
Why? I thought you would want to heat the fuel up for performance? That is done in a lot of gas turbines and other applications.
07-26-2007, 09:24 AM
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that is a jet engine where they are high in the sky and its alot colder the higher they get so the fuel would be to cold, so they heat it up. but on the surface its alot hotter so we cool the fuel.
hopefully that made since. oh and they use different fuel, but i dont know if that has anything to do with it or not
hopefully that made since. oh and they use different fuel, but i dont know if that has anything to do with it or not
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07-27-2007, 03:54 AM
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The reason you only see them on Carb cars is because that's the only place they need to be used.
In a carb car the fuel is normally static (dead headed) and low pressure, from mechanical FP to carb. This leads to fuel percolation (boiling) from the fuel setting in the lines in all the underhood engine heat. Even on a carbed car with electric fuel pump - you still have the large chunk of metal (carb) setting on an even larger chunk of metal (intake) soaking up all the heat & tranferring it to the fuel in the lines and in the float bowls of the carb. This fuel boiling takes place even faster the more the car sets at idle in hot outside temps, or after numerous WOT blasts. Once the fuel starts to percolate - the car runs like ****.
Therefore, a cool can is used to cool the fuel down as much as possible before it goes into the carb (if it starts at a low temp - it won't have as much chance of going to percolation before it is used by the carb)
In a fuel injected car of nowadays, the fuel usually flows in a continuos path - IN from high pressure fuel pump, thru rails & injectors - while the excess fuel continues to flow thru the loop back to the tank. Because of this, the fuel is continously flowing thru the loop with fresh, cool fuel being delivered all the time. On top of that, most of the new intakes on production cars are plastic (no heat soak whatsoever) & there is no carb to act as a heat soak point either - fuel is delivered thru injectors directly into cylinder - there is no time for the fuel to get hot in a fuel injection system.
Using a cool can on a fuel injection engine is a waste of time and $$
In a carb car the fuel is normally static (dead headed) and low pressure, from mechanical FP to carb. This leads to fuel percolation (boiling) from the fuel setting in the lines in all the underhood engine heat. Even on a carbed car with electric fuel pump - you still have the large chunk of metal (carb) setting on an even larger chunk of metal (intake) soaking up all the heat & tranferring it to the fuel in the lines and in the float bowls of the carb. This fuel boiling takes place even faster the more the car sets at idle in hot outside temps, or after numerous WOT blasts. Once the fuel starts to percolate - the car runs like ****.
Therefore, a cool can is used to cool the fuel down as much as possible before it goes into the carb (if it starts at a low temp - it won't have as much chance of going to percolation before it is used by the carb)
In a fuel injected car of nowadays, the fuel usually flows in a continuos path - IN from high pressure fuel pump, thru rails & injectors - while the excess fuel continues to flow thru the loop back to the tank. Because of this, the fuel is continously flowing thru the loop with fresh, cool fuel being delivered all the time. On top of that, most of the new intakes on production cars are plastic (no heat soak whatsoever) & there is no carb to act as a heat soak point either - fuel is delivered thru injectors directly into cylinder - there is no time for the fuel to get hot in a fuel injection system.
Using a cool can on a fuel injection engine is a waste of time and $$
07-27-2007, 06:31 PM
#11
2 PA guys in a row...... thought I would make it 3.
The above 3 posts pretty well sum it up.
To add to this, a carb float bowl does not hold fuel under pressure, which allows it to boil easier. Typically 1lb. of pressure will raise the boiling point by 3 degrees, hence the reason cars also run pressurized cooling systems. Typical EFI system pressures prevent vaporization from happening on the typical engine.
The lightest hydrocarbons in regular fuels start to vaporize around 130-160degs. Given a 190deg motor, you could see the problem with a carb motor as airflow is the only cooling mechanism.
On the other hand, fuel coolers are made for the fuel return system so that engine heat is not returned to the tank. This can prevent cavitation of the fuel pump under long term usage of large race type pumps on the street.
The above 3 posts pretty well sum it up.
To add to this, a carb float bowl does not hold fuel under pressure, which allows it to boil easier. Typically 1lb. of pressure will raise the boiling point by 3 degrees, hence the reason cars also run pressurized cooling systems. Typical EFI system pressures prevent vaporization from happening on the typical engine.
The lightest hydrocarbons in regular fuels start to vaporize around 130-160degs. Given a 190deg motor, you could see the problem with a carb motor as airflow is the only cooling mechanism.
On the other hand, fuel coolers are made for the fuel return system so that engine heat is not returned to the tank. This can prevent cavitation of the fuel pump under long term usage of large race type pumps on the street.
