If they roll coal, they really shouldn’t be complaining about fuel prices anyway since the “coal” is purposefully unburnt fuel that doesn’t give the truck any extra power or anything. One could easily improve fuel economy by undoing the crappy coal-rolling tune. Hell, just run a tune that doesn’t run overly rich and you can have more power than stock and better fuel economy than either the coal rollers OR the stock folks.
I hate rolling coal but running rich is used to protect an engine under high power output conditions. Mostly in forced induction setups. Extra fuel lowers cylinder and exhaust temperatures because it vaporizes without combusting, pulling heat out of the air fuel mixture during the compression stroke. Leaning out too much is death to an engine.
Untrue for diesel EGTs where a very rich mixture will in fact cause high temps as it will still be doing some burning while it’s out of the cylinder already.
Wrong. No oxygen is left so it can’t burn. It exits the exhaust as unburnt fuel exactly as you stated in your original comment.
Extra fuel in a diesel cycle is used as coolant just like in any of the gas cycles. Gas is see through when it vaporizes, diesel isn’t. A turboed gas engine rolls coal too but it only smells bad if it lacks emissions systems.
I still see them rolling coal, but the prices haven’t hit my state hard yet since we refine it.
If they roll coal, they really shouldn’t be complaining about fuel prices anyway since the “coal” is purposefully unburnt fuel that doesn’t give the truck any extra power or anything. One could easily improve fuel economy by undoing the crappy coal-rolling tune. Hell, just run a tune that doesn’t run overly rich and you can have more power than stock and better fuel economy than either the coal rollers OR the stock folks.
I hate rolling coal but running rich is used to protect an engine under high power output conditions. Mostly in forced induction setups. Extra fuel lowers cylinder and exhaust temperatures because it vaporizes without combusting, pulling heat out of the air fuel mixture during the compression stroke. Leaning out too much is death to an engine.
Untrue for diesel EGTs where a very rich mixture will in fact cause high temps as it will still be doing some burning while it’s out of the cylinder already.
Wrong. No oxygen is left so it can’t burn. It exits the exhaust as unburnt fuel exactly as you stated in your original comment.
Extra fuel in a diesel cycle is used as coolant just like in any of the gas cycles. Gas is see through when it vaporizes, diesel isn’t. A turboed gas engine rolls coal too but it only smells bad if it lacks emissions systems.