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Author Topic: Turbo boost pressure for series 60  (Read 1830 times)
H3Jim
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1995 Prevost H3-41, series 60, B500 Allison




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« on: July 19, 2007, 09:00:14 PM »

Does anyone know what a good turbo boost pressue is for a 12.7 series 60?

I am reading about 25 lbs under full load using the silverleaf PC product.  It seems that should be ok, but I am down a little in power lately. 

Fuel filters changed.  I have added weight, but I didn't think I added that much.  up to about 39,000 lbs so far.
« Last Edit: July 20, 2007, 09:42:42 AM by H3Jim » Logged

Jim Stewart
El Cajon, Ca.  (San Diego area)

Travel is more than the seeing of sights, it is a change that goes on, deep  and permanent, in the ideas of living.
TomC
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« Reply #1 on: July 19, 2007, 09:45:21 PM »

At 39,000lb, it should move effortlessly, considering the same engine is used in trucks to move 80,000lb.  25lbs is fine for the older engines.  New ones are getting towards 40psi.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Sojourner
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« Reply #2 on: July 20, 2007, 03:51:35 AM »

Other than what TomC posted…..is your Allison transmission’s oil temp normal? Higher temp than normal is possible that transmission system not in good working order:
1) Smell & color of transmission oil.
2) Torque converter lock-up is slipping or not on.
3) Multi-disc clutches is slipping.
4) Torque converter is damaging internally.
5) Transmission’s pressure circuit is low.
6) Retarder is dragging

To all bus nut…..If you don’t already have two transmission temp gauge in driver compartment…than for your peace of mind (if you want to) is to install them properly. 
1) Thermocouple (welded tip for quicker respond) tap in converter’s outlet line where it begin…..the one that go to cooler.
2) Thermocouple tap in transmission’s oil sump pan.
PS…your electronic DDEC may already connected to perform the above.

When you are in lock-out while accelerating….the converter’s out temperature will  go 40°F higher quickly and the longer you continue to heavy accelerate….the higher still…..bottom line is  to never go higher than 300°F for longer fluid life. It like having a performance indicator in regard to converter. However while in lock-up, there will be no rapid change of increase temperature.

Pan’s temperature should be around 260°F or less but never over 300°F while heavy climbing or you will shorten transmission’s oil & transmission’s life.

Link:
http://allisontransmissionparts.com/AllisonTransmissionPartsHD4000-B500.html

You don’t have to have them but it a peace of mind at your disposal.

Otherwise lost of power….your increase (depend how much) pay load is your reason if all (other than trans) else is OK. Or it just getting use to it after many driving miles…thinking it not the same performance as before.

FWIW

Sojourn for Christ, Jerry
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H3Jim
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1995 Prevost H3-41, series 60, B500 Allison




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« Reply #3 on: July 20, 2007, 07:36:22 AM »

Thanks,

its the B500 world tranny.  I use the Silverleaf software and a PC to read all available sensor readings.  Ths last trip, the tranny temp normally runs around 205, with about 218 max.  I run Transynd.  Engine oil temp is about the same or 10 degrees lower.
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Jim Stewart
El Cajon, Ca.  (San Diego area)

Travel is more than the seeing of sights, it is a change that goes on, deep  and permanent, in the ideas of living.
edroelle
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1998 Royale Prevost




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« Reply #4 on: July 20, 2007, 09:37:13 AM »

In 5th and 6th gear, my Series 60 DDEC 3 turbo reaches approximately 25 PSI while cruising and I come to a steep hill.   I had thought that it went substantially higher in 1st and 2nd gear, but I don't watch it in those gears often.

Ed Roelle
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