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#1
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I am pulling the vacuum off the back of the intake. We smoked the entire intake yesterday and found a small leak on a weld in one of the intake pipes just before the intake manifold. The silicone is good quality and pretty small runs in between hard pipes. I am running 3" into the turbo and 2.5" from the outlet to the intake, which is a very short run.
These problems have been there since it went back together. There is nothing obvious jumping out at me about this. I even took the air filter out of the box, just in case that was a restriction. |
#2
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Good to fix the leak but it shouldn't cause boost to fall with higher RPM. Something about the way this setup breathes isn't right.
Are you able to check the boost pressure ahead of the IC? Eg from the wastegate signal line? You are sure the wastegate is seeing the same pressure signals the intake is? If there is restriction in the IC then that's going to cause the exact issue you are experiencing. Boost controller and wastegate the right parts installed the right way, correct spring choice, etc? The 3" inlet, is that direct from atmosphere or is the snorkel still in place? How recent is the fuel filter? If there is fuel system restriction causing retarded timing at high RPM, that can cause issues. Pinzgauers have a primary fuel filter under the body in addition to the main secondary filter on the engine, are both of them fresh? Tank pickup clean, tank vent OK, etc? Checked fuel inlet vacuum under load? How does it start and run otherwise, basics like cam timing and valve clearance are all right on?
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86 745 D24T/ZF 345k lifted 2.5" 83 764 D24T/M46 155k |
#3
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Photos of intake
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#4
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Wastegate stuck open possibility? Or something up with the boost controller?
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#5
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Nice looking setup. However we can't tell you much from the pictures unless you do some checks and get answers.
I suggest you start by plugging your boost gauge in somewhere ahead of the intercooler, best way may be to tap into the line running from the compressor housing to the wastegate. Take it for a drive and see if you are seeing the same boost response as you saw in the intake manifold. If you see no change, then you'll need to check the wastegate and boost controller for correct configuration or other issues, and check again for possible restrictions in the air inlet to the turbo, the exhaust, or the fuel system. If you do see different pressures from this test, then it means you have a restriction in the intake path between the turbo and the intake manifold, probably in the intercooler, the intake manifold inlet, or one of the hose connections. We'll be able to help you more once you have concrete answers to these questions, until then, we can only speculate.
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86 745 D24T/ZF 345k lifted 2.5" 83 764 D24T/M46 155k |
#6
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Is there still black smoke present when you have 10lbs of boost?
What is the EGT? Are you going to try the .48 AR turbine housing or stick with that large turbine housing?
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12mm pump heads, ARP stud kits and GTD nozzles available! http://d24t.com/showthread.php?t=1646 NA intake manifolds and 240 turbo pans for sale. Need d24 or d24t parts? PM me! Shipments done on fridays! 1982 242 D24+T/M46- Super pumped! Build thread: http://www.d24t.com/showthread.php?t=1545 1984 764 D24T/ZF build thread: http://www.d24t.com/showthread.php?t=1734 Diesel parts cars: 82 244,83 244, 84 244, 84 245, 85 745 Last edited by anders; 06-06-2017 at 03:12 PM. |
#7
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This is basic, but main fuel adjustment can have a huge influence boost behaviors. I won't pretend to fully understand why, just observed this from adjusting my pump over time. Have you played with the main fuel? From your specs it seems like you are familiar with the setup, but you didn't mention. Even a quarter turn can mean building 10 psi and bottoming out or building 20 quickly.
Backing out star screw (LDA, top of pump) really helped me with low rpm/boost smoke, at with noticeable change to overall power. No matter what power you're making, having that adjusted in fully will make clouds of thick black smoke with no real benefit in my experience.
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1985 744 D24T M46 49mm t3 @20psi 280k |
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