Fading turbocharger boost

Discussion in 'Ask An Owner Operator' started by Lepton1, Dec 23, 2016.

  1. Lepton1

    Lepton1 Road Train Member

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    A few years ago my brother developed a leak in his charge air cooler that cascaded into a series of problems, including a crack in the turbocharger housing. When he replaced the turbocharger he also installed a boost gauge.

    Maximum boost with the brand new turbocharger was 28 psi. Now his maximum boost is about 18 psi. There doesn't seem to be any loss of performance, as in ability to accelerate or climb hills.

    I just bought a truck last month and it has a boost gauge. Maximum boost is about 18 psi as well. The truck has just shy of a million miles. The Cummins ISX pulls hills well.

    I'm just wondering whether actual boost deteriorates over time with a turbocharger. I also question why performance doesn't seem to be affected by the loss of psi. Any thoughts or experiences in this matter would be appreciated.
     
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  3. double yellow

    double yellow Road Train Member

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    put a boost gauge at the turbo outlet and another at the intake manifold. If you're losing more than a couple psi (normal for piping/CAC restriction to flow), start chasing leaks...
     
    Dave_in_AZ and Lepton1 Thank this.
  4. Ridgeline

    Ridgeline Road Train Member

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    Normally the boast gauges on the dash are electric so they seem to be just a general indicator. as Double mentioned, go get a couple boost gauges and put it on the outlet of the turbo, and on the inlet.

    ALSO get a vacuum gauge and put that on the inlet of the turbo. this will help you a lot more to monitor everything from the air filter to the CAC.
     
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  5. The Admiral

    The Admiral Heavy Load Member

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    A few years ago I bought a million mile truck from a friend of mine. The pyrometer was not working,boost was about 21#. I repaired the pyrometer and the gauge would go to 1150* like right now. I always owned new trucks so had little experience with charge air coolers. Anyway checked in on this forum and most everyone told me the cooler was bad. It was! Pulled all the piping and could see soot marks here and there. There was corrosion on the piping also. So, 1 severe service bar and plate cooler,cleaned corrosion off piping,replaced all boots and clamps. Boost is now at 31#.
     
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  6. Studebaker Hawk

    Studebaker Hawk Road Train Member

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    My 2000 Detroit 12.7 has a waste gate which limits the boost to 26psi. I am on my 3rd charge air cooler in 1.7 million miles. The first 2 OEM coolers gave it up at 500K. The symptom was exactly like you describe.
    I have had 3 turbos on the same truck through the same time frame. No loss of boost through the life of the turbo. They either work or they explode....lol
     
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  7. 77fib77

    77fib77 Road Train Member

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    Fuel mileage?
     
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  8. Lepton1

    Lepton1 Road Train Member

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    My brother's mpg has never been better, nor does there seem to be loss of power. He also replaced his CAC a couple of years ago, which was the beginning of a cascade effect which took out his turbocharger, exhaust manifold, etc.

    For my truck I seem to have plenty of power and mpg is good for the kind of work I do (run fast and plenty of dirt roads). My brother's a master plumber, so I will pass on the idea of adding exhaust manifold and turbo intake gauges.
     
  9. rollin coal

    rollin coal Road Train Member

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    If it is down 10 psi there is definitely a loss of power. It might have been a gradual thing and you didn't notice because you were accustomed to it. Like others say you have a leak somewhere and you will notice an improvement when you fix it.
     
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  10. Dave_in_AZ

    Dave_in_AZ Road Train Member

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    How come replacing the CAC destroyed the rest of the respiratory system on the engine?
     
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  11. double yellow

    double yellow Road Train Member

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    Since you are lacking symptoms, before I threw a ton of money solving what might not even be a problem, I'd check that boost reading against another gauge.
     
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