I was wondering if someone here could answer this question as I can't quite figure it out myself.I've seen pictures/videos of the big compounds (100+ psi) on the 5.9's and Instead of plumbing the secondary's wastegate to feed the primary they have the waste energy venting to atmosphere.I understand that they are still just regulating the output of the secondary but why do they choose not to use this energy?


So far I've seen 3 pulling trucks use this wastegate configuration, 2 cummins and 1 PSD all pushing massive boost.

 

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they have enough fuel they dont need to use the energey. they vent it to the atsmosphere to try and get rid of some of the drive pressure. in some cases the mod trucks are pushing in excess of 200 psi of drive press..

 

Thanks for the reply stuckey,That sounds like a good explanation to me.The reason I'm asking is that I'm thinking about using the same idea on my VW diesel with compounds to keep the drive pressure down.The primary gets driven hard enough to not need that extra energy so I might do the same thing.

I guess If you can get the primary to work well without being fed from the secondary's wastegate then your best to bypass the primary.I would not be too suprised to see more compounds "pushing over 60 psi" in the future to be set up this way.

Anyone else's input on this would be apreciated.

 

if you do it that way i would plumb the waste gate in the down pipe behind the primary. instead of venting it to the atsmophere.