My have things changed

valhalla360 wrote:

ShinerBock wrote:

Nope. You still seem to be confusing gas with diesels. What do you think the black smoke coming from diesels is? Un-burned fuel. Why? Because it does not have enough air to burn said fuel. This is why old N/A diesel blew puffs of black smoke just about all the time and turbo diesels blew a puff off the line until the turbo was pushing enough air to burn all the fuel being added which only took a second. Adding more air does improve efficiency in a diesel because it is able to use the fuel to more efficiently use the same amount of fuel to make more power instead of blowing it out as black smoke..


And I still don't believe your story. Not only, that, but none of the guys in this(LINK) 7.3L forum even say that 16 mpg is normal and if you look at fuelly.com here(LINK) it is even less than that.

Black smoke means you are pushing the engine outside of it's limits. For a couple seconds under hard acceleration, it's not harmful but if it's continuous as you are cruising down a level freeway, you are overloaded and that will kill efficiency in any engine type. Only difference with gas engines is the unburnt fuel isn't visible under similar conditions.

Believe what you like, it was pretty consistent over a long period of time.

No it does not. Black smoke from a diesel is uburnt fuel(i.e. not enough air for the amount of fuel being added).

How to reduce black smoke in diesel engines

Older N/A diesels used to blow black smoke all the time because they did not have enough air to burn the amount of fuel being added. That changed with the introduction of turbochargers and they mainly only blow black smoke when the turbo is not spooled up or there is a fuel issue.

A leaner air fuel ratio with the same amount of fuel will create more power therefore less fuel is needed to create the same amount of power meaning it needs less fuel to do the same amount of work.