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Turbo Boost Pressure


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5 replies to this topic

#1 LloydW

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Posted 09 December 2012 - 07:54 AM

What should the turbo boost pressure be when going up a steep hill at approx 6500 ft elevation? My C9 cat recently suffered a real loss of power, no black smoke, but the turbo boost was only 18%.

.Any suggestions, I have already changed both fuel filters, the air filter gauge showed 15% it red lines at 25%.
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#2 desertdeals69

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Posted 09 December 2012 - 08:16 AM

Depends on the rpm. Boost is measured in pounds per square inch, psi. The air at 6500 feet is pretty thin, My guess is somewhere around 15-20 psi. You are not going to get the power at elevation as at sea level. How does it run at lower altitudes?
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#3 LloydW

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Posted 09 December 2012 - 08:37 AM

Thanks for the reply. We had just left the sea level area and it was runnig fine.
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#4 wolfe10

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Posted 09 December 2012 - 09:03 AM

Lloyd,

Please check again for what unit you are expressing boost in. It could be in PSI or in column inches of HG. Very unlikely to be a percent.

You can call the Caterpillar RV Hotline at 877 777-3126 with your engine serial number to find out exactly what boost your engine should produce (as well as what boost it did produce on a dyno before leaving Caterpillar).

Next question: is this lower boost than it has been in the past? Sudden drop or gradual? At 6,500' you should be generating full boost-- that is the beauty of a turbo.

Looking for causes of a drop in boost pressure would begin with:
1. Leak between exhaust manifold and head or exhaust manifold and turbo-- look for any black (soot) at those locations.
2. A leak in a hose between turbo and tube going to CAC, tube to CAC, leak in a hose between the CAC and tube going to the engine and leak in hose at the engine intake manifold.
3. Leak in the CAC itself.
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Dianne and Brett Wolfe
1997 Safari Sahara 3540
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#5 DickandLois

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Posted 09 December 2012 - 01:19 PM

Lloyd, Brett is correct . If you have a spray bottle that you can put some soapy water in and spray around the Turbo air lines and the connections( these couplers are often Blue or Red in color) Look for bubbles and listen for air leaks.
Work safe around the engine.

Rich.
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#6 LloydW

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Posted 09 December 2012 - 04:55 PM

Thanks Brett and Rich.

I am going to be tied up tomorrow but will see what I can find the next day.
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