billet 66mm wont spool help

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Blue01Cummins

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I have a 2001 24v with a steed speed manifold t4 with a bw s366 with the 11blade billet wheel the turbo is a t4 I believe it is a 66/68/.81ar I don't know exhaust housing size doesn't look huge.. I have a drag comp along with mach 6s that are set for p pump pressure could that be a problem??? and the truck does have a airdog.. it will only make bout 21psi it starts to spool good but then it plains off at 21psi...and I have check for exhaust leaks before the turbo cant find any and all intercooler piping is good to.. before I did all this the truck had a hx35 and 150s and ran great... I cant figure out what is wrong any help would be greatly appreciated thanks...
 
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Is the exhaust housing wastegated? If not id say you have a leak in the IC or the piping. It may "look good", but that means nothing really. Pressure test it.
 
it is not wastegated and should I block off the pipe that goes into the intake and get like a rubber pluming to pressure test it??

I bought them use I was wanting to p pump the truck in the rear future so I just put them in...


the truck starts to make boost around 1800-1900 and gets to pretty fast but then that's when it plains off

the truck is a 6 speed so even if I brake boost it from a roll it still wont go over 21 it's like its wastegated at 21 its weird
 
You can build a plug for the inlet of the turbo, it'll lose a little through the rings but you'll hear any other leaks. Mach 6 ' s aren't real big to be trying to spool a t4 .81.
*edit
I didn't see that it was only a 68 turbine. It should light okay but I bet it's going to surge a lot.

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Most likely it is a 66/73m with a T4 0.91AR housing, the opening pressure on the injectors is of no concern.
 
I was gonna do the 66/74 but he told me he could do 66/68 and its a .81 or 80 something ar and I haven't had to deal with any surging yet but its not my daily driver.. but when will I get surging...
 
If it is actually a 68mm turbine, then most likely it has the 0.83AR housing.
 
check your boost gauge reference line, could be cracked at the ferrule fitting.
 
Cover the basics first.
Boost leak test( reference google and youtube for boost leak testing)
Drive pressure leaks ( look for soot everywhere, rev on engine to look for puffs in engine bay)
Check gauge against another.

If turbo is cleaning up smoke completely, add more fuel, you should be seeing xlose to 45 psi with that setup.
That ought to cover it.
 
take a PVC pipe cap and thread an air hose fitting to it. then use a fernco or rubber band boot and clamp it down tight to your turbo inlet.

it is also a good idea to a add an inline air pressure regulator to your new jig. the pressure leaving your compressor will not be the same at the end of your air hose. start low, around 5-10 psi and bring it up slow till you hear the leak.
 
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