x2
Would be much easier to ask. If not, could at least explain on paper why the conclusion.
Melting pistons.
- Thread starter McRat
- Start date
x2
Would be much easier to ask. If not, could at least explain on paper why the conclusion.
http://www.duramaxdiesels.com/forum/attachment.php?attachmentid=10590&stc=1&thumb=1&d=1248518842
http://www.duramaxdiesels.com/forum/attachment.php?attachmentid=10591&stc=1&thumb=1&d=1248518883
The last two pics are after being cleaned and somewhat scrubbed. Not sure if this is a before, with lots of timing " to us ", or marks through carbon/soot over time? Early on the engine was subject to tunes with 40* at 2500rpm with huge amounts of fuel and what we thought was not enough boost. Who knows but if you do, please share.
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No not looking for info, i just came to a conclusion that i know will work based on prior dodge tuning and looking at d-max failures.
I feel strongest about long duration and high RP being the main contributing factors in melted pistons. Heat kills any engine combo, and those two together, coupled with RPM will make big heat and holes in the pistons
Higher timing would lower EGT' and help the engine accel faster
Lower duration would create less EGT and heat soak in the piston at RPM, again making things more effiencient
Lower (about 25-26kpsi) RP would reduced the yeilding of the aluminum piston crowns at high heat and RPM, really there is no need for RP higher than 25-26k, beacuse once the fuel is atomized thats all you need....
Just a thought.
I feel strongest about long duration and high RP being the main contributing factors in melted pistons. Heat kills any engine combo, and those two together, coupled with RPM will make big heat and holes in the pistons
Higher timing would lower EGT' and help the engine accel faster
Lower duration would create less EGT and heat soak in the piston at RPM, again making things more effiencient
Lower (about 25-26kpsi) RP would reduced the yeilding of the aluminum piston crowns at high heat and RPM, really there is no need for RP higher than 25-26k, beacuse once the fuel is atomized thats all you need....
Just a thought.
Increasing pressure increases quantity in identical times or should we go back to 1850psi?
Long duration increases burn time and torque over time?
Long duration increases burn time and torque over time?
Increasing pressure increases quantity in identical times or should we go back to 1850psi?
Long duration increases burn time and torque over time?
Would 1850psi atomize??
Long duration chases the piston down the bore, soaking the piston with heat, AND giveing the fuel system less time to recouporate for the next injection cycle..........Would you like to turn more RPM's?
Find a way to speed up the burn and make it more effiecient, that will give you room to make more RPM and HP.
A engine is a engine, quickest in and quickest out makes the most HP, anyday of the week!
A engine is a engine, quickest in and quickest out makes the most HP, anyday of the week!
I guess this is all before tdc? Titanium rods, inconel pistons w/two inch wrist pins and a crank twice the diameter of your dodges? Oh ya, what part of the compression stroke are you wasting? An engine is an engine run some gas through it and repeat.
No not looking for info, i just came to a conclusion that i know will work based on prior dodge tuning and looking at d-max failures.
I feel strongest about long duration and high RP being the main contributing factors in melted pistons. Heat kills any engine combo, and those two together, coupled with RPM will make big heat and holes in the pistons
Higher timing would lower EGT' and help the engine accel faster
Lower duration would create less EGT and heat soak in the piston at RPM, again making things more effiencient
Lower (about 25-26kpsi) RP would reduced the yeilding of the aluminum piston crowns at high heat and RPM, really there is no need for RP higher than 25-26k, beacuse once the fuel is atomized thats all you need....
Just a thought.
You keep saying you are tuning Dodge? What software are you useing? As far as I know even the Smarty sytems are a box tuner.
It just seems to me injecting fuel early increases the time the piston has to heat up and actually decreases recovery time?
Some food for thought.
X amount of fuel generates Y BTUs.
Y BTUs raises a given mass of gas Z degrees independent of pressure.
For all intents and purposes, the mass of the gas in the chamber is fixed during the stroke.
Increasing the starting pressure in a chamber prior to the compression stroke (boost) does NOT increase the chamber Temperature from compression.
Increasing boost DOES increase the mass of the air in the chamber as well as the peak pressures in the chamber.
X amount of fuel generates Y BTUs.
Y BTUs raises a given mass of gas Z degrees independent of pressure.
For all intents and purposes, the mass of the gas in the chamber is fixed during the stroke.
Increasing the starting pressure in a chamber prior to the compression stroke (boost) does NOT increase the chamber Temperature from compression.
Increasing boost DOES increase the mass of the air in the chamber as well as the peak pressures in the chamber.
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Well said Jon. But me little mind is still hungry. Do you have some more with calories?
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Exactly thanks you.
Does your CP sensor read low enough to see boost in the chamber too?
compression stroke is BEFORE TDC, nothing wasted there.....this is where pilot and main injection start, should NOT be any ignition yet....
only if the fuel is igniting would it heat up, but on the compression stroke the fuel begines to compress with fuel and will try to expand towards the top, once TDC is reached the PSI is so great that the fuel explodes and expels energy that pushes our pistons down the bore creating the power stroke.
All the heat is created on the power and exhaust stroke, the intake and the compression run much cooler.
Ever wonder why every smarty box, or whatever box dont produce the same out put on similar trucks?? these modern dodge DL's and adjustable boxes allow independent timing, duration and FP adjustments, whaile everyone has the same adjustments it's up to the USER or TUNER to figure out what will work best and make HP,this is why so many dodges are melting pistons lately
Software is getting much better, still not what the d-max guys have, but it does and allways did need a good tuner. plug and go is for the non CR trucks...
Let me ask you guys this. Going back to the timming part of this thread where it's said lowering timming creates higher egts. Is the egts from the unburnt fuel in the exhaust system like the manifold where the reading is takin place hotter than the combustion chamber? By this I'm asking is the unburnt fuel that leaves the combustion chamber throught the exhaust stroke still burning as it enters the manifold thus giving a higher reading of egts than whats actually happening? Hope this question makes sense.
Dude, you really need to stop the expert routine and just ask questions.
The fuel burns as it's being sprayed in. Any delay results in knock, and a big delay will cause bursting.
Yes, the fuel will still be burning when the exhaust valve opens. Some race diesels blow flames out the pipe.