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domano

Turbo PSI - Cummins 340hp

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Curious those with the ISB 6.7 340hp Cummins what’s the maximum Turbo PSI they are receiving. My maximum is around 17, and Freightliner is telling me they feel that’s a little low.  I’ve noticed recently that climbing mountains, I’m just not getting the power I used to have.  

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Haven't had a 6.7 but my 5.9 would run 35+. What does Freightliner think the problem is? Have you checked the CAC for leaks or all the clamps on the airline/ducks in and out of the turbo? 

Bill

Edited by wildebill308

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On the waiting list to get it into Freightliner…. Was hoping someone here with the same engine can tell me their PSI…. I can’t find anything online with regards to a suitable range (ie. if typically it should be 30-35 and I’m running at 17, then I know I have a problem, but if 19-20 is typical, then it’s probably okay)… just trying to get feedback here if anyone knows.  

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14 hours ago, domano said:

On the waiting list to get it into Freightliner…. Was hoping someone here with the same engine can tell me their PSI…. I can’t find anything online with regards to a suitable range (ie. if typically it should be 30-35 and I’m running at 17, then I know I have a problem, but if 19-20 is typical, then it’s probably okay)… just trying to get feedback here if anyone knows.  

Why don't you call a couple of your local Cummins dealers and ask them?

Bill

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domano,

My first thought was, "have you ever had your Turbo serviced? It sounds to me like you may have a sticking Waste Gate Valve. It would also help to know the year of you RV and make.

Herman

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2017 Newmar Ventana LE 3709 340hp Cummins 6.7 ISB.  Never had it (turbo) serviced.  I’ll call Cummins tomorrow and ask then about what PSI I should expect on, say, a 6% grade rolling at 65mph. Right now I drop to about 30 before getting over the mountain. 

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On 2/28/2022 at 9:47 AM, wildebill308 said:

Are you manually downshifting to keep your rpm up? 

Bill

Bingo, when I manually drop a gear pulling a hill I get more boost vs allowing it to shift on its own.

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Yup, gauge in dash!

Don, you should have it on your dash also....Never had a DP that didn't.

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On 3/8/2022 at 9:54 AM, manholt said:

Yup, gauge in dash!

Don, you should have it on your dash also....Never had a DP that didn't.

Doug’s Allegro Bus NOPE!

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If its a FTL Chassis, its on the Light Bar Control Unit.  Turbo Pressure, Tranny Temp, Engine Temp, Etc, Etc.  No exhaust gas temp, darn it. 

The gauge measures in PSI.  

 

 

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