does cold thick fuel=more power?
- Thread starter chris142
- Start date
79jasper
Chickenhawk
Cold timing advance?
Cold fuel keeping ip tolerances tight?
Cold fuel building more pressure?
Just some thoughts.
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Cold fuel keeping ip tolerances tight?
Cold fuel building more pressure?
Just some thoughts.
Sent from my iPhone using Tapatalk
fordf350man
Full Access Member
my truck does the same exact thing, i think its the cooler air because there isnt much engine heat in the engine bay for that short time, not really sure though, if i had the power like it does when its cold all the time i wouldn't be wanting to swap out the idi
JosieGallows
Full Access Member
Hmm not sure how cooler air could make more power. Don't diesels just love to compress air to the point it gets hot enough to auto-ignite fuel?
I thought diesels prefer hot air and hot coolant as they are compression engines.
Just a few thoughts.
I thought diesels prefer hot air and hot coolant as they are compression engines.
Just a few thoughts.
Michael Fowler
Registered User
I think it IS the air temp. Colder, denser air contains more Oxygen, and hence, more power. As the fuel is a liquid, it can't get denser; only more resistant to flow.
I think the fuel is the same as the air, the colder it is, the denser it is, the more BTUs packed into each squirt. Some drag racers used cool cans where they would run coils of fuel line through a coffee can with dry ice, or regular ice in it to cool the fuel to make it more dense. Same reason for cold air intakes I guess, to pull cooler air from somewhere other than right above the hot engine.
Ugly Moosling
Full Access Member
Fuel has higher viscosity when cold, so it's not able to sneak past worn parts as well. It's the opposite of what people with hard hot starts are seeing. Even an ip with no wear will see some internal 'leakage' past different parts. The more viscosity there is (colder fuel) the less leakage, which means more of the fuel is going where it's supposed to, like out to the injectors or moving the advance piston further.
Why do you think they put intercoolers on turbos? Answer: because cooler air carries more Oxygen. When any gas gets hot, it expands, cooler it contracts, hence it's more dense. Fog in the morning is a good example.
G. Mann
Full Access Member
To build a fire you need a fuel source [liquid diesel in our case] and and oxygen source. To make a bigger fire, add more oxygen until the fuel source is completely consumed [fanning a camp fire, for example, same fuel, more oxygen being fanned into the flame].
In our diesel engines, in cold weather, the charge air is more dense. Cold air has more oxygen molecules per square inch. Thus we get a "free boost" to the combustion with each stroke. Liquid diesel, to burn well, needs to be atomized into small droplets, a fine well dispersed mist, into the combustion chamber. Warm fuel atomizes more easily, cold fuel, near the "gell point" doesn't atomize well and makes large droplets, which take more heat energy to combustion flash point. [example, put a teaspoon of water in a frying pan over high flame, how long does it take to evaporate vs the pan completely full of water].
Ideal power development would be liquid fuel temp of 120 F with charge air temp of [cold, pick a temp, dense air] which would result in a cylinder charge of finely atomized fuel droplets well mixed with an oxygen dense air charge, quickly compressed to cause that combined charge to rise to ignition temperature.
Some days, we get most or part of that and feel it in our butt dyno... The closer we can get to that mix of fuel and oxygen, metered to the displacement of the cylinder, the more energy is released by the fire thus more heat, more expansion energy, more power to the rear wheel.
Suck, Squeeze, Bang, Blow .... repeat as necessary
In our diesel engines, in cold weather, the charge air is more dense. Cold air has more oxygen molecules per square inch. Thus we get a "free boost" to the combustion with each stroke. Liquid diesel, to burn well, needs to be atomized into small droplets, a fine well dispersed mist, into the combustion chamber. Warm fuel atomizes more easily, cold fuel, near the "gell point" doesn't atomize well and makes large droplets, which take more heat energy to combustion flash point. [example, put a teaspoon of water in a frying pan over high flame, how long does it take to evaporate vs the pan completely full of water].
Ideal power development would be liquid fuel temp of 120 F with charge air temp of [cold, pick a temp, dense air] which would result in a cylinder charge of finely atomized fuel droplets well mixed with an oxygen dense air charge, quickly compressed to cause that combined charge to rise to ignition temperature.
Some days, we get most or part of that and feel it in our butt dyno... The closer we can get to that mix of fuel and oxygen, metered to the displacement of the cylinder, the more energy is released by the fire thus more heat, more expansion energy, more power to the rear wheel.
Suck, Squeeze, Bang, Blow .... repeat as necessary
jaluhn83
Full Access Member
Cool humid air is the best for power.
Fuel temp is probably warmer than you think by the time it actually gets to the pump. The entire tank probably isn't warmed up much, but the fuel in the pump has a low flow rate and lots of time to pick up heat through the lift & injection pump, filter and lines....
Fuel temp is probably warmer than you think by the time it actually gets to the pump. The entire tank probably isn't warmed up much, but the fuel in the pump has a low flow rate and lots of time to pick up heat through the lift & injection pump, filter and lines....
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