diesels and turbos/superchargers:

[LTZ C20]

Didn't know that, I "spool" it.

Hahahaha, get it.

LMAO, I see what you did there.

[hatzie]

When you turn up the fuel and air little things like exhaust gas temps become real important. 
You can melt your pistons even with the mild Banks turbos.

From orbit on my Android.

[1967KaiserM715]

Too get into it a little more, when you turn up the fuel, you turn it up throughout the whole throttle range, the advance cam in the pump will meter out a little of that extra fuel at partial/ no throttle.

But a diesel doesn't work like a gas motor. It takes in as much air as it wants/needs(boost adds air), it is the fuel intake that varies the rpms, the less fuel, less rpms and less power. More fuel is more power and rpms, too much fuel will be unburnt but cause high temps(monitor egts)

A gas motor needs a specific amount of air and fuel to increase rpm and power, too much of one or another alters a lot plus gas motors are a lot more picky with timing, a diesel is pretty much set once, adding a turbo should not have any affect on timing advance/retard

At any time you do any fuel or air intake work, an egt gauge is a must. Shoot for 900 degrees max on longer durations(say 10 min pulling uphill) I would say 1200 absolute max for less then 2 minutes

Hopefully helps a little


Sent from my iPhone using Tapatalk

[fitz]

Didn't know that, I "spool" it.

Hahahaha, get it.

Irish,
If I had a Cummins in my truck, I would also be laughing at us 6.2 owners.

[Stewart G Griffin]

Too get into it a little more, when you turn up the fuel, you turn it up throughout the whole throttle range, the advance cam in the pump will meter out a little of that extra fuel at partial/ no throttle.

But a diesel doesn't work like a gas motor. It takes in as much air as it wants/needs(boost adds air), it is the fuel intake that varies the rpms, the less fuel, less rpms and less power. More fuel is more power and rpms, too much fuel will be unburnt but cause high temps(monitor egts)

A gas motor needs a specific amount of air and fuel to increase rpm and power, too much of one or another alters a lot plus gas motors are a lot more picky with timing, a diesel is pretty much set once, adding a turbo should not have any affect on timing advance/retard

At any time you do any fuel or air intake work, an egt gauge is a must. Shoot for 900 degrees max on longer durations(say 10 min pulling uphill) I would say 1200 absolute max for less then 2 minutes

Hopefully helps a little


Sent from my iPhone using Tapatalk

i guess i should back up and ask if the turbo on a diesel is making boost all the time since fuel input/throttle position is what seems to determine rpm----but not always---as in the going downhill case?

[Irish_Alley]

no, they afaik they work just like a gas turbo. when im at idle im at 0 psi. depending on how hard i get on it generally im only making 20 psi if i really get on it im up to 40 psi and when im cruising it depends on what speed but at 65 im usually around 10. the more PSI you make the hotter the air gets and it will from what i understand anything above 40 is pointless cause of how hot the air gets. one bad thing about diesels is when they want to "run away" this is caused when the oil seal in the turbo goes bad and instead of burning fuel you are burning oil and since we have no way of shutting of the spark like a gas you either have to wait till you run out of oil at extremely high rpms or you have to block the air from getting to the turbo

[LTZ C20]

Turbo and Superchargers, just like an intake manifold or camshaft, have an operating range.

[1967KaiserM715]

i guess i should back up and ask if the turbo on a diesel is making boost all the time since fuel input/throttle position is what seems to determine rpm----but not always---as in the going downhill case?

like Irish_Alley said, works just like a car, rpms increase, turbo makes more boost, less rpms, less boost-an ideal turbo would make no boost at idle, but steadily progress through the rpm range, alas, that is not completely true-hence turbo lag, but anyways,

in a going downhill case it is pretty much like a gas engine, since the rpms are low, the fuel supply is less, and boost if so equipped, is also low. I would say to really oversimplify it, is a gas engine requires extra timing(advance or retard) to help with boost as the spark timing is what determines how the engine runs; a diesel does not require additional timing throughout the rpm range, as it runs off of the compression, not spark. now a gas motor is actually much more difficult to boost then a diesel IMO

also with turbos and supercharger, one can use a inter cooler to cool the air, thus being able to make more boost(beyond 40 sometimes), but on a 6.2 or 6.5 diesel I think no more then 15 comfortably, as far as operating range, yes, different ratios(and sizes) to the turbo housing(or supercharger) can dictate when, and how much boost one can make.

[Irish_Alley]

also i can this if theres no resistance on the motor (in neutral) and you floor it you will make no boost. if you try and power brake you will build up some boost then you can take off with boost

[hatzie]

The 6.x AMG/Detroit isn't an engine I would boost past 15psi or so.   The block webs are not up to the task.
The 6.5 cracks on stock boost.

From orbit on my Android.

[Stewart G Griffin]

Anyways, here's the video that sparked my question in the first place:

https://www.youtube.com/watch?v=-INMo8fyTQE

[ehjorten]

Yes...as Irish said...you do not make boost by simply increasing the RPMs.  You make boost by increasing the load on the engine.  So...you can't make boost simply by reving the engine.