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Old 11-18-2013, 10:06 PM   #43
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Originally Posted by Ray,IN View Post
I have never seen that caveat on any of the signage. It just states NO engine brakes.
Then you've been looking at the wrong signs. Around here some of them do say "Unmuffled Exhaust Brakes". Besides, if they're muffled how will they know?
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Old 11-18-2013, 10:11 PM   #44
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Originally Posted by MSHappyCampers View Post
When I engage my PacBrake exhaust brake the Allison tranny automatically shifts down to 2, BUT at highway speed it doesn't actually go to 2nd gear until the speed drops way down to where it's safe for the tranny to be in 2nd! So even though it says it's in 2nd the tranny is not reducing the speed any if you are at higher highway speeds.
Allison calls that change from 6th to 2nd as a "preselect", meaning the trans is told to aggressively downshift to 2nd as fast as it can without harming the engine or trans.
BTW: on both a CAT 3126 and Cummins ISC the governed RPM is different under power then exhaust braking conditions. I've verified this with both Cummins and CAT over the years. On the ISC the under power RPM is 2,200 and with the exhaust brake active (not just turned on) it's 2,400.
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Old 11-18-2013, 10:14 PM   #45
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Then you've been looking at the wrong signs. Around here some of them do say "Unmuffled Exhaust Brakes". Besides, if they're muffled how will they know?
Mr D is completely correct. usually followed by max fine of-
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Old 11-19-2013, 08:07 AM   #46
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The issue with the various engine brake restrictions in municipalities around the country is all about noise. They don't want the loud "BBRRRAAAP" of an un-muffled Jake waking up the residents.

Like most diesel pushers, the Jake brake in my MH is muffled and doesn't make any noise. Consequently no one will hear anything if I use my Jake in town. So I pay no attention to those signs.

If the regulation is noise-based and the typical MH Jake doesn't make any noise, where's the problem?
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Old 12-01-2013, 09:02 AM   #47
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solution to downshift vs coast allison 3000

Quote:
Originally Posted by Mr_D View Post
Allison calls that change from 6th to 2nd as a "preselect", meaning the trans is told to aggressively downshift to 2nd as fast as it can without harming the engine or trans.
BTW: on both a CAT 3126 and Cummins ISC the governed RPM is different under power then exhaust braking conditions. I've verified this with both Cummins and CAT over the years. On the ISC the under power RPM is 2,200 and with the exhaust brake active (not just turned on) it's 2,400.
I have posted this elsewhere but U may have missed it for the operation of the exhaust (PAC) brake.Not sure if it will work for the jake engine brake. We have put on over 4000 miles of comfortable driving since the modification.

Here is the setup for the PAC brake, on all the time, but able to coast when letting off accelerator.
Operation:
􀂾 let up on pedal and coast, trans will not down shift and PAC will not operate, the dash light will
on. Press on accelerator pedal to continue. Going down hill vehicle will coast unless you wish to slow
down.
To Slow down - Depress brake pedal and relay will make contact and activates PAC and Downshift
􀂾 If ready to continue acceleration simply depress fuel pedal and PAC will release till next event.
􀂾 If you were in cruise then depress fuel and pull the cruise switch to resume previous speed.
􀂾 Alternative is to depress the foot switch (optional) and will return to normal PAC operations.
􀂾 Normal may be preferred in some traffic conditions.
􀂾 The computer will not allow your rig to have both brake and fuel at the same time.
This arrangement is for a 99 Freightliner Winnebago and may not function the same in other MH.
(created by Jerry Donofrio, 99 Chieftain, Willingboro, NJ 6093515172)
relay = simple low current single or double pole.
Foot switch= old fashion hi low beam switch
Both found in most automotive stores.

below is the diagram
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Old 12-03-2013, 05:54 PM   #48
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But it costs nothing to only turn on the exhaust brake when actually needed. A HDT shop told me my Spartan service brakes are designed to last about 200,000 miles anyway, so why run with the PAC brake on constantly.
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Old 12-03-2013, 07:08 PM   #49
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There is a HUGE difference between having the Exhaust Brake Switch on and ready for the Exhaust Brake to activate versus having the Exhaust Brake engaged ALL the time.

Most large bus motorcoaches will never wear out their brakes nor will they need to replace the shoes or pads during the time that most of us own our coaches.

This has been discussed so MANY times before and basically it is totally up to each owner how they choose to manage their Exhaust Brake or their Engine Brake.

Spartan chassis are a lot different than the Roadmaster chassis so for you I would stick with what Spartan states.

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