5.9L 24V Performance Discussion of 24 Valve 5.9 Liter Dodge Cummins Diesels with VP44 Injection Pumps Related To Performance And Longevity

Wastegate or tune?

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Old 05-26-2011, 11:52 PM
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Default Wastegate or tune?

Hey quick ?... Truck in my sig, noticed lately at WOT it runs nice and smooth up to about 50 psi, then once it hits the 50 psi mark it bogs down and fluctuates a little. Boost drops to about 42 and fluctuates between 40-43 psi. Still WOT. Now this is with the EJWA on hot unlock lvl 6, or lvl 5. If I take it to lvl 1, it runs smooth up to 40 psi and stays smooth. Now obviously it'll make less boost with less fuel. Does it sound like the wastegate is opening at about 45-50 psi to you guys or does it sound like something different. Thought maybe the juice was defueling, on lvl 6 WOT I can break 1500 degrees egt, maxes out about 1550*. The max egt setting on the juice only goes to 1500, but I believe backdown is off. Help me think here. I like to think aloud. Thanks everyone
 
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Old 05-27-2011, 07:22 AM
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A quick easy way to tell is pich/block off the wastegate hose. You could also disconnect or pull your pyro probe out to see if that is the limiting factor.
 
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Old 05-27-2011, 07:44 AM
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Default Wastegate or tune?

Originally Posted by RAWilliams
A quick easy way to tell is pich/block off the wastegate hose. You could also disconnect or pull your pyro probe out to see if that is the limiting factor.
True. I'll try both and see what happens. If it's the gate opening, the wastegate rod needs to be turned clockwise for more boost correct?
 
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Old 05-27-2011, 07:48 AM
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I guess that would depend on what type of thread the rod has. I have yet to see left hand thread on a wastegate actuator rod, only right hand. Clockwise will shorten the length of the rod.
 
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Old 05-27-2011, 11:33 AM
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are you running stock valve springs? ive heard of some pushing alot of boost such as yours, actually partially opening the intake valves allowing the boost to drop and flutter around.
 
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Old 05-27-2011, 01:17 PM
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Default Wastegate or tune?

Originally Posted by D-LUX
are you running stock valve springs? ive heard of some pushing alot of boost such as yours, actually partially opening the intake valves allowing the boost to drop and flutter around.
I thought about that too. Yea they're stock. I should probably check my valve lashes anyway... The thing that made me think otherwise was because my 64/71/14 I had on there before ran 54psi without any problems at all.
 
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Old 05-27-2011, 03:57 PM
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that is true. I would try the easy stuff first and see where it gets ya
 
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Old 05-27-2011, 08:06 PM
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Stock 24v springs allow the intake valve to blow open at 50psi on the bench. This is a major problem and it is intensified as rpm increase. With high drive pressures your engine might even be experiencing reversion, when the exhaust valve blows open on the intake stroke contaminating the intake charge. Aftermarket retainers are needed on 24v engines that rev over 4,000rpm.
 
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Old 05-27-2011, 08:37 PM
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then once it hits the 50 psi mark it bogs down and fluctuates a little. Boost drops to about 42 and fluctuates between 40-43 psi
I can't see this situation with valve float. If it started at 45 psi, and got worse and worse up to 50, yes. My boost gauge fluctuates after 48psi and gets worse to 57. I am very confident my valves are starting to float, but his situation reeks off wastegate, or a backdown.
 
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Old 05-27-2011, 08:50 PM
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Originally Posted by RAWilliams
I can't see this situation with valve float. If it started at 45 psi, and got worse and worse up to 50, yes. My boost gauge fluctuates after 48psi and gets worse to 57. I am very confident my valves are starting to float, but his situation reeks off wastegate, or a backdown.
Ture,I'm also wouldering what his fuel pressure is a WOT. As I seen with the VP trucks with heavy mods. Below 17 psi (WOT) at the VP starts to loss HP on the DYNO.
 


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