Still on his web site...
He may ( should) revise this.

Just saying

Hi Frank, to be fair, he doesn't explicitly claim all those parameters are met simultaneously.

To be fair, he isn’t going to carry 5 people in the current configuration or get 230 ktas @7 gph or sell it for $130k.

To be fair, he isn’t going to carry 5 people in the current configuration or get 230 ktas @7 gph or sell it for $130k.

Does anyone remember Dorf on Golf? This is turning into Dorf on Airplanes. Well you see Leonard, we’re going to add some icea packs righta here you see, to keepa everytinga nice anda cool.

that last video about boost was hard to watch. He has no idea what he is doing, His software background is giving him way too much confidence about this tuning. He thinks he can just follow the data and it's not that simple.

He keeps saying he does not want to reduce fuel because he will make less power. Dumping fuel out the tail pipe and looking at how much fuel you are putting in to get the HP is not how it works. If he is rich and leans it out to peak it will make more power. You cant just look at how much fuel is going in and tell how much power you are making.

I have very little diesel tuning experience but with gas engines its never that simple. Things don't always work the way you think they should. that why experience matters.

The crazy part is getting a good tuner is probably one of the easiest things he can do. But I think he is scared of them challenging his previous assumptions.

Mike

Hi Mike,

If I might make a polite suggestion, don't apply any spark-ignited engine thoughts to diesels. There is no "peak" on a diesel. Diesels by definition always run lean of stoich as measured by overall mass air flow - and considerably so. EGT/TIT is a limit, not a target.

Jeff,

Makes sense. and like I said I don't know much about diesels. I know when he says timing he is talking about fuel injector timing not ignition timing.

When I say peak I am talking about AFR. If you are rich you are not turning that fuel into power. And if you are lean you are not getting as much power as you could. But power is not the only metric that matters. Heat is a big part. If he is putting all that fuel into turbo heat he is not turning that heat (energy) into usable energy. Heating up the front compartment water tanks is not as useful as putting the heat into spinning the prop.

Mike

not exactly. There is no such thing as "rich". Diesels govern fuel limits, among other things, off a farc map, often called a smoke map. If you don't have enough air you won't be allowed to inject more than a certain amount of fuel. Or else your customer gets really aggravated when something like the below pic happens. Cold starts are a real bear to do cleanly because the relationship between air and fuel goes off the charts.

At the same time, you don't pump any more air than is necessary else all you make is heat. These days air is usually regulated by a VGT or more crudely by a wastegated turbo.

OK, not sure that makes sense, which again could be my lack of knowledge.

So you are saying you can dump twice the fuel into a diesel engine and have a ton of black smoke and thats the same efficiency as proper Air fuel and clean tail pipe?

Peter is calculating his HP by the amount of fuel he is putting in. A rich condition will not get all the power out of that same amount of fuel. That just seems to be basic with any combustion engine that uses any kind of fuel. Dump the fuel out the tail pipe and you are not using the energy that was in that fuel.

Wouldn't a ton of black smoke be putting too much fuel in for the available air? that to me is what Rich is. Air Fuel ratio seems to apply to any combustion engine. If there was no Rich then wouldn't you just put all the fuel you want and it magically makes more power? There has to be a relationship between air and fuel in a diesel engine.

Mike

No, I'm saying the opposite of that

Actually you can get more power with more fuel to a point. Go to a county fair tractor pull to see that in action. But you can't run an engine like that for extended periods.

Come to think of it, tractor pull engines and their midget cooling systems, are a pretty good analogy for what peter is trying to accomplish. Make as much power as possible for a brief period and try to finish the run before it over-heats.

I am confused too. The guys in jacked up trucks "blowing coal" would seem to be running rich. Doesn't seem like that is efficient. My moms Delta 88 diesel would blow coal when the fuel filter started getting clogged... but that's a different conversation (maybe)
Kevin

There are a few of ways to "roll coal," that is to use the combustion chambers to create a smokescreen. Running excessively rich is the obvious and easy one, incorrect injector timing can do it, something wrong with your injector/fuel nozzle that it doesn't spray right, damaged genes and chromosomes passed on by your parents are frequently the root cause though not the direct cause...

This is how I watch every video:

Michael,

The terms rich and lean really don't apply much to diesel engines. Gasoline only burns from around 12:1 up to around 16:1. These are our rich and lean limits.

Diesel isn't that way. Diesel will run over a drastically wider range of mixture. Older diesel engines did not limit airflow at all. There was no throttle butterfly. An engine idling was just extremely lean. An engine at full power was rich. The airflow only changed by rpm.

Putting a turbo on a diesel usually works really well. You are increasing the amount of airflow so you can then increase the fuel and make more power without smoke.

I'm sure that Jeff can go into much greater detail than I, but I think most people don't understand this whole rich-lean concept with diesels.