1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

drive pressure

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Old 04-20-2010, 10:54 PM
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Default drive pressure

Anyone wanna explain drive pressure to me? whats good, whats bad, and how do ya change it cuse im lost on the subject.
 
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Old 04-21-2010, 01:08 AM
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Originally Posted by TTipsword
Anyone wanna explain drive pressure to me? whats good, whats bad, and how do ya change it cuse im lost on the subject.
well a 1 to 1 is good if that helps
 
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Old 04-21-2010, 01:16 AM
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Are you talking about adjusting pressure in the drive housing?
 
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Old 04-21-2010, 01:24 AM
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for every psi of boost thnere should be an equal amount of cylinder pressure
 
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Old 04-21-2010, 11:51 AM
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i think he wants to know what drive pressure actually is. yes 1 to 1 is a good start, but it does no good if you dont know what one of the 1's even means. i think he wants someone to explain to what "what" drivepressure is, not what a correct ratio is
 
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Old 04-21-2010, 03:03 PM
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If you have 35 psi boost on the intake side and 35 psi drive pressure ( exhaust manifold pressure ) then thats good. Thats what they mean by 1 to 1 ratio. I bet my H1C with a 16 cm and a 60 mm GDS is not near 1 to 1. I am putting out 45 psi and I bet my drive pressure is much higher. A good turbo with a 4 inch outlet and a waste gate should be closer to the 1 to 1 ratio. There is much more involved that is way over my head, but, that is the basics as I understand them. So, in short, drive pressure is the PSI that is backed up in the exhaust manifold or pre turbo on the hot side.
 
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Old 04-21-2010, 06:46 PM
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It's not possible to have less than a 1:1 ratio is it?
 
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Old 04-21-2010, 06:49 PM
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so basically it is good to have as much coming in as going out? tAnd to much drive pressure would also result in i dunno maybe head gasket problems or valve float?
 
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Old 04-21-2010, 08:18 PM
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Originally Posted by hotcummins
for every psi of boost thnere should be an equal amount of cylinder pressure
If that's all the cyl pressure you have you wont have a running truck..

Quick explination...

Drive pressure should ideally be 1;1 when against boost pressure. Pretty much what you are measuring is the efficiency of your turbo. When your drive pressure go up way above 1:1 you are trying to push the turbo to hard and its out of its map. You pretty much have a backup of gasses that is hurting things like head gaskets and turbo parts.
 
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Old 04-21-2010, 09:12 PM
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Originally Posted by RSWORDS
If that's all the cyl pressure you have you wont have a running truck..

Quick explination...

Drive pressure should ideally be 1;1 when against boost pressure. Pretty much what you are measuring is the efficiency of your turbo. When your drive pressure go up way above 1:1 you are trying to push the turbo to hard and its out of its map. You pretty much have a backup of gasses that is hurting things like head gaskets and turbo parts.
so if you were to install a drive pressure gauge, where would you put it? one in the intake manifold for boost and one in the exhaust manifold for drive pressure?
 


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