Does low rail pressure cause high EGT's?

[Alligator]

I am questioning this because now I am confused about the logic behind it. How does low rail pressure cause high EGT's, and how would adding more fuel cause lower EGT's?

My experience has always been that adding a lift pump will lower EGT's due to the ability to maintain rail pressure. But is that due to more fuel to drive the turbo, creating more boost, which in turn lowers EGT's...?

Please help, I know I'm not the only one confused...

 

[TrentNell]

I am questioning this because now I am confused about the logic behind it. How does low rail pressure cause high EGT's, and how would adding more fuel cause lower EGT's?

My experience has always been that adding a lift pump will lower EGT's due to the ability to maintain rail pressure. But is that due to more fuel to drive the turbo, creating more boost, which in turn lowers EGT's...?

Please help, I know I'm not the only one confused...

I have always viewed it as poor atomazation, and the droplets probably end up larger . this is my theroy ( educated guess:rofl: ) probably has a harder time entering the combustion chamber fast enough as well ends up trailing into the power stroke and out the tail pipe .

 

[bullfrogjohnson]

lower rail pressure causes poor fuel atomization, which causes big fuel droplets instead of a fine mist. The big droplets dont burn near as complete as a fine mist.

As for how those big droplets cause high EGT's i dont know. One would think that a less complete burn would be cooler than a full burn

 

[MMLMM]

i wasnt aware that a lift pump would increase rail psi, just maintain desired, and the lift pump not have anything to do with EGTS (so to speak)

 

[jonathancasey19]

I am questioning this because now I am confused about the logic behind it. How does low rail pressure cause high EGT's, and how would adding more fuel cause lower EGT's?

My experience has always been that adding a lift pump will lower EGT's due to the ability to maintain rail pressure. But is that due to more fuel to drive the turbo, creating more boost, which in turn lowers EGT's...?

Please help, I know I'm not the only one confused...

I thought that would raise egt's???

 

[paint94979]

I thought that would raise egt's???

more fuel cools EGT's

 

[TrentNell]

more fuel cools EGT's

more qauntity without more air will certainly raise them , better / faster injection process ( bigger injector , higher pressure )you could run more maybe at a cooler egt but just plain more will not .

 

[Idaho CTD]

Low rail pressure means poor atomization and late burning of the fuel. It can make a ton of boost but no hp. The late burning in the exhaust drives turbos really hard (high egt's) but doesn't push down on the piston as hard.

 

[Alligator]

i wasnt aware that a lift pump would increase rail psi, just maintain desired, and the lift pump not have anything to do with EGTS (so to speak)

I never said it would raise rail pressure, just maintain it.

My experience has always been that adding a lift pump will lower EGT's due to the ability to maintain rail pressure.

 

[Alligator]

Low rail pressure means poor atomization and late burning of the fuel. It can make a ton of boost but no hp. The late burning in the exhaust drives turbos really hard (high egt's) but doesn't push down on the piston as hard.

Thank you Nathan. That explanation helps quite a bit.