Winter tune

Diesel fuel economy tends to drop off dramatically when the temperatures plummet. I'd like to have one of the tunes on my CSP5 a winter tune. Has anyone ever attempted to compensate for cold temperatures? Would you add more post injection? More pre-injection or both, neither? Retard the timing a bit?

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Originally Posted by cjowett

Diesel fuel economy tends to drop off dramatically when the temperatures plummet. I'd like to have one of the tunes on my CSP5 a winter tune. Has anyone ever attempted to compensate for cold temperatures? Would you add more post injection? More pre-injection or both, neither? Retard the timing a bit?

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You are Moreso fighting fuel quality.

So anti-gelling additives and the like are the culprit?

To sum it up, winter blend fuel has less BTUs than summer fuel. Less BTUs equal less energy for a given amount of fuel. So, more winter fuel must be used to create the same amount of power as summer fuel, which equates to less miles traveled per gallon of winter fuel used.

A few other contributing factors for lower winter fuel economy: Idle time - many people let their trucks idle for a while to "warm up" when it is cold. Fuel is being burned but no miles are being traveled. All of the oils in the truck are going to be more resistant to flow when cold causing increased resistance and the motor to work harder, burning more fuel. Turning the defroster on high, seat heaters on, etc will create more of a load on the alternator and the engine which burns more fuel. Cold air is more dense than warm air which actually hurts aerodynamics so to speak (more so at highway speeds). The engine takes longer to get up to operating temp with cold ambient air temps, and since the engine is not as efficient when cold MPGs will be slightly lower. Running in 4x4 burns more fuel, driving through snow and slush burns more fuel....

I know that this doesn't help with your tuning, but hopefully it helps with understanding the MPG loss.

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Originally Posted by ATPCummins

To sum it up, winter blend fuel has less BTUs than summer fuel. Less BTUs equal less energy for a given amount of fuel. So, more winter fuel must be used to create the same amount of power as summer fuel, which equates to less miles traveled per gallon of winter fuel used.

A few other contributing factors for lower winter fuel economy: Idle time - many people let their trucks idle for a while to "warm up" when it is cold. Fuel is being burned but no miles are being traveled. All of the oils in the truck are going to be more resistant to flow when cold causing increased resistance and the motor to work harder, burning more fuel. Turning the defroster on high, seat heaters on, etc will create more of a load on the alternator and the engine which burns more fuel. Cold air is more dense than warm air which actually hurts aerodynamics so to speak (more so at highway speeds). The engine takes longer to get up to operating temp with cold ambient air temps, and since the engine is not as efficient when cold MPGs will be slightly lower. Running in 4x4 burns more fuel, driving through snow and slush burns more fuel....

I know that this doesn't help with your tuning, but hopefully it helps with understanding the MPG loss.

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^^^ This.

BTU loss due to the blending of #1 Diesel(Essentially Kerosene with lube) with #2 to combat gelling is the main culprit along with greater idling times to "warm up" the truck or keep it warm.

All good points Mike. I suspect in my case the biggest culprit is the fuel blend. I definitely see the others as contributors but in our climate only intermittently. My old IDI ford was brutal in the winter. I would get 800 to as much as 900 km per fill in the summer and drop to 600 or less in the winter without seeing snow and slush. I could improve it a bit by removing the air hose from the duct and let it breath warm air from behind the rad.