Does adding pressure indirectly advance timing?

[JDiepstra]

Like the title says, does adding rail pressure advance timing in anyway?



I guess I ask this because doing something like going to a bigger injector indirectly advances timing, so I have to wonder what else does?



With people on the forums talking about too much timing melting motors (improper stacking and other causes) I would like to get a better understanding of how all the mods work together.

 

[CKelley1]

sort of. the 04. 5 up had to do bad things to the motor to meet the new epa regs it uses what cummins calls in cylinder egr, they retard the timing to keep the peak pressure down, use small orifice nozzles to lengthen duration again yo keep peak down added a third pulse that is very late in the cycle the cam lobe on the exhaust valve was changed to keep the valve closed way to long to achieve the effect to achieve the effect needed, the smarty jr is the best at returning timing to where it needs to be marty figured out some of the code and his timing is dynamic for best results. no one else has this. to shorten the duration and get more fuel in the 1st and 2ond pulse and less in the third (the third pulse is variable between none at light load to large at heavy load) can be done two ways either increase fuel pressure or increase nozzle hole size. the best way is the nozzle change because the pressure way is directly proportion to injector life. even stock pressure cuts the injector nozzles that is why the trucks get better fuel milage after about 75,000 miles. like every thing it is easy to get to much of a good thing if you go over 50 hp injectors it hurts because it does not atomize the fuel as well the only way to correct the valve timing is to replace the cam. the best thing to do is to change the cam and nozzles at the same time it will save 90% of the labor on the injectors by combining the three you will lower your egt 250* and increase your mpg about 4. 5 mpg if marty can figure out how to move the third pulse up next to the second you will pick up another 1 mpg and with each step the oil gets cleaner. we tow and i like the pdr cam and ddp nozzles. the above is way over simplification of a complicated process but gives a understandable view

 

[JDiepstra]

Only 1 response (thanks by the way)? Nobody knows or nobody cares? Take a guess at least!

 

[AClayton]

Only 1 response (thanks by the way)? Nobody knows or nobody cares? Take a guess at least!

I certainly can't answer your question but I can suggest posting in the 3rd Gen. Engine and Trans Topic... you may generate more interest there.



Alan

 

[fox]

The start of ignition is the same time.

But, more fuel is delivered quicker-with bigger injector flow--, so pressures in the combustion chamber rise quicker, as earlier time would do.

 

[CKelley1]

thanks fox that is what i was trying to say. kiss, keep it simple stupid

 

[Pistazie]

sort of. the 04. 5 up had to do bad things to the motor to meet the new epa regs it uses what cummins calls in cylinder egr, they retard the timing to keep the peak pressure down, use small orifice nozzles to lengthen duration again yo keep peak down added a third pulse that is very late in the cycle the cam lobe on the exhaust valve was changed to keep the valve closed way to long to achieve the effect to achieve the effect needed, the smarty jr is the best at returning timing to where it needs to be marty figured out some of the code and his timing is dynamic for best results. no one else has this. to shorten the duration and get more fuel in the 1st and 2ond pulse and less in the third (the third pulse is variable between none at light load to large at heavy load) can be done two ways either increase fuel pressure or increase nozzle hole size. the best way is the nozzle change because the pressure way is directly proportion to injector life. even stock pressure cuts the injector nozzles that is why the trucks get better fuel milage after about 75,000 miles. like every thing it is easy to get to much of a good thing if you go over 50 hp injectors it hurts because it does not atomize the fuel as well the only way to correct the valve timing is to replace the cam. the best thing to do is to change the cam and nozzles at the same time it will save 90% of the labor on the injectors by combining the three you will lower your egt 250* and increase your mpg about 4. 5 mpg if marty can figure out how to move the third pulse up next to the second you will pick up another 1 mpg and with each step the oil gets cleaner. we tow and i like the pdr cam and ddp nozzles. the above is way over simplification of a complicated process but gives a understandable view

Thanks for the very informative "ah-ha!" post... that is a good tip doing the nozzles and the cam at the same time.

 

[JDiepstra]

Thanks for the very informative "ah-ha!" post... that is a good tip doing the nozzles and the cam at the same time.

Finally made it to TDR huh... good job. This is where you go for the correct answers to tough questions. CF is mostly just for fun and answers to questions like "what's a good intake?" :-laf

 

[Pistazie]

haha, yep. , I'd have to agree... the TDR mag is awesome too... . you always ask the good questions