Why no lean burn?

[403turbo]

After watching the TRUCKS! special about the D/A mods I have had a nagging question in my mind that I haven't been able to answer......so I figured I would ask it here.

Why is it that a diesel can't be run too lean? It seems just the oposite of gassers....too much fuel in a diesel causes problems while too lean in a gasser can lead to burnt guts. Why is this?

I'm sure its a simple thing that I'm just not thinking about but its just way too easy to get info here to not post it.

I did look for threads for this but no luck...

Thanks All

[DmaxMaverick]

A Diesel engine has only one "regulator" for power and rpm. It's the fuel delivery rate. The air is not regulated in any manor. More fuel, more rpm/power. Lean a Diesel and it just slows down.

The problem with piston burning is the injector itself. If one cylinder is injecting more fuel than the others, the combustion temps will rise. It is burning more fuel than the others, but is getting the same amount of air. This can happen on all cylinders at the same time, and is called lugging. Lugging is when you apply more fuel and your forward motion does not increase, or decreases. This is a bad thing. Another issue with the injector is the spray patern. In order for the fuel to burn completely at the right time, it has to be uniformly atomized. If you have too large of droplets, the fuel will combust later than the optimal event timing, and create hot spots within the combustion chamber, usually at the same place at each combustion event.

Hope this answers your question. Cheers.

[403turbo]

Thanks!

That does answer my question, and it makes sense too! smile.gif