Boost pressure????

wtbuck12 · 02-06-2021, 07:16 PM

Just curious, on my 06 Charleston with an MBE926 engine, I run 25 to 30 psi of boost cruising at 50 mph. With any acceleration at all, boost jumps to 48 to 49 psi. I just figured the guage was wrong, so I installed a Scan Guage D and it reads the same. This seems high to me, I am just wondering if this is normal or do I have a problem?
Thanks
Ronnie

edgewant · 02-07-2021, 11:39 AM

I’m not familiar with your engine but on my Cummins ISB 6.7L 360hp my boost at cruise on a level road is very low (guessing 5 psi). Under heavy load uphill boost jumps to 25 to 30 psi.

wtbuck12 · 02-07-2021, 01:27 PM

Kind of what I was expecting. That's why I didn't believe my boost guage, but now the ScanGuage D is reading the same thing. That's why I was hoping to hear from other MBE926 owners.
Ronnie

**Bama Rambler** · 02-07-2021, 07:02 PM

Do you know if a "tune" has ever been loaded into the computer? If so, that could give you erroneous boost readings.

wtbuck12 · 02-07-2021, 08:22 PM

No tune as far as I know, I bought it with 42K miles on it. I guess a mechanical guage is the answer.
Thanks
Ronnie

dave-g · 02-08-2021, 05:41 AM

I did a google search on your motor- I could not find the Normal boost but did find several wright ups on the gauge being absolute pressure not gauge pressure. Also it may not be psa but kpa. Lots of miss information.

I would call factory frieightliner in Gafney

wtbuck12 · 02-08-2021, 07:15 AM

Thanks, I did the same search and got the same results. Guess I will try a mechanical guage and confirm the readings then call FLCCC.
Ronnie

**Bama Rambler** · 02-08-2021, 07:59 AM

If it is absolute pressure just subtract 14.7 PSI from the readings and you have PSIG. If you do that, the readings you're seeing make more sense.

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