To do or Not to do

scooterbob · 04-01-2016, 08:02 AM

When driving under normal driving conditions, how many people leave the exhaust brake on ?

daledrob · 04-01-2016, 08:15 AM

I do unless there are too many hills up down up down in which case it's always kicking off my cruise control. On large meals most definitely.

Ranger Smith · 04-01-2016, 08:25 AM

Mine is usually off

TonyMac · 04-01-2016, 08:41 AM

My exhaust brake kicks off the cruise, so I modulate its use. I like my cruise! I can go a long time without touching any pedals, just setting and trimming the cruise and using the exhaust brake. Cruising with the semis, getting passed by everyone else. Life's good......

Hikerdogs · 04-01-2016, 11:39 AM

I noticed on our last trip more and more tour busses have exhaust brakes that illuminate the brake lights whenever the driver let's their foot off the accelerator.

The first time I saw it I almost had a heart attack. We were doing about 65 mph in heavy traffic around Nashville. A bus going a good 10 mph faster passed us and cut in short. The bus was no sooner in front of us and the brake lights came on. I moved to the next right lane knowing full well I wouldn't be able to stop with the distance between us. That's when I saw the lane in front of the bus was clear.

I didn't understand what had happened until another bus pulled in behind the first. Eventually there were four busses in a line going a good 75 mph. Every time a driver would let off the accelerator the brake lights would come on. The brake lights on all four busses were continually flashing on and off for the entire time they were in sight.

While having the exhaust brake turn on the brake lights may be all well and good when descending hills it certainly needs to be used with some discretion on relatively level ground and in heavy traffic.

noserider · 04-01-2016, 11:57 AM

I leave mine off and just switch it on when needed. My approach to driving is to make everything shift and brake smoothly during highway type driving. While I use it often, there are times in stop and go traffic and others where leaving it on results in additional shifting that seems more of a nuisance than a necessity. Try it both ways and see how your rig behaves. I think the answer will come naturally to how you like the rig to respond under varying road and traffic conditions. To be clear, I leave it on all the time while climbing and descending big grades.

TonyDi · 04-01-2016, 12:21 PM

I leave mine off and just turn it on when it is needed.

Bigd9 · 04-01-2016, 01:00 PM

Quote:

Originally Posted by noserider

I leave mine off and just switch it on when needed. My approach to driving is to make everything shift and brake smoothly during highway type driving. While I use it often, there are times in stop and go traffic and others where leaving it on results in additional shifting that seems more of a nuisance than a necessity. Try it both ways and see how your rig behaves. I think the answer will come naturally to how you like the rig to respond under varying road and traffic conditions. To be clear, I leave it on all the time while climbing and descending big grades.

mel s · 04-01-2016, 01:32 PM

Quote:

Originally Posted by scooterbob

When driving under normal driving conditions, how many people leave the exhaust brake on ?

scooterbob
I always leave my PacBrake switch in the ON position.

The way my coach is "wired":
1.) If/when the Pacbrake switch is in the ON position the Pacbrake automatically (and always), comes on when I press the service brake pedal.
2.) If I touch the throttle pedal the PacBrake turns OFF and the coach "coasts".
3.) If I leave the PacBrake switch in the OFF position the PacBrake doesn't come on at all.

(Your coach may be wired differently)
Mel
'96 Safari

Bigd9 · 04-01-2016, 01:34 PM

Quote:

Originally Posted by Hikerdogs

I noticed on our last trip more and more tour busses have exhaust brakes that illuminate the brake lights whenever the driver let's their foot off the accelerator.

The first time I saw it I almost had a heart attack. We were doing about 65 mph in heavy traffic around Nashville. A bus going a good 10 mph faster passed us and cut in short. The bus was no sooner in front of us and the brake lights came on. I moved to the next right lane knowing full well I wouldn't be able to stop with the distance between us. That's when I saw the lane in front of the bus was clear.

I didn't understand what had happened until another bus pulled in behind the first. Eventually there were four busses in a line going a good 75 mph. Every time a driver would let off the accelerator the brake lights would come on. The brake lights on all four busses were continually flashing on and off for the entire time they were in sight.

While having the exhaust brake turn on the brake lights may be all well and good when descending hills it certainly needs to be used with some discretion on relatively level ground and in heavy traffic.

Funny this subject came up when it did. We were just returning from a nice trip and and had successfully crossed a mountain chain when we decided to stop in a rest area for a break. As I was walking the dog a guy came up to me and said "I followed you all the way down the mountain and I just wanted to warn you that you are going to kill someone someday!" That got my attention and I spun around seeing who he as talking to. Imagine my surprise when I realized he was looking at me and said "I have driven big rigs for millions of miles and I can tell you you will burn out your brakes by dragging them all the way down the mountain like that. Stab and realise, stab and realise is the way to do it. Didn't you learn anything in CDL school?"

I thanked him for his concern and replied "for your information I never touched the service brakes all the way down till I saw this rest area and the exit ramp. What you saw was the exhaust brake illuminating the stop lights, and secondly I don't need a CDL to drive this coach". He replied "that is about the must stupidest thing I ever heard of, you need to go back to drivers school before you kill someone, and I have a half of a mind to report you". I said "Thanks for the concern, but I need to leave now" and I turned to leave watching him storm over to his small 2 door economy car that was parked all by itself in a long truck parking area climb in and drive away.

bobmac · 04-01-2016, 06:57 PM

The standard configuration for the Brake was to activate if you take your foot off the throttle and it is switched on. There is a significant advantage to leaving it on from a quick stopping capability but not with it activating whenever the throttle is released.
I had Cummins change the activation criterion in the ECM to activate when the brake pedal is depressed. This allows you to take your foot off the throttle and coast - particularly desirable at low speeds in urban areas. I just tap the brake pedal to activate the brake and the throttle to release it. Works great. I cannot understand why this is not the default configuration for RVs. Cummins used their Insite software to make the change and charged one hours labor - well worth it in my opinion.

RVNeophytes2 · 04-01-2016, 07:02 PM

Quote:

Originally Posted by scooterbob

When driving under normal driving conditions, how many people leave the exhaust brake on ?

I cruise on open road with it off.

[To prevent burning up trailer brakes, I've pulled the exhaust brake light fuse.]

palehorse89 · 04-01-2016, 07:06 PM

Mine is on all the time, set up to work with the cruise control to maintain cruise set point..........makes long trips a lot easier.

Mr_D · 04-01-2016, 07:12 PM

Leave mine on most of the time but only on the "Low" setting, reserve "Med" for mountains and have yet to really find a need for "High".

mel s · 04-02-2016, 06:54 AM

Quote:

Originally Posted by Mr_D

Leave mine on most of the time but only on the "Low" setting, reserve "Med" for mountains and have yet to really find a need for "High".

Apparently you have a a "compression release engine brake", (aka: "Jake brake")...not an "exhust brake"?

daledrob · 04-02-2016, 08:26 AM

I am in the process of moving my exhaust break switch so that it is much more convenient. Then I can choose the time for it to kick on and off .

KoolBell · 04-03-2016, 06:38 AM

Quote:

Originally Posted by noserider

I leave mine off and just switch it on when needed. My approach to driving is to make everything shift and brake smoothly during highway type driving. While I use it often, there are times in stop and go traffic and others where leaving it on results in additional shifting that seems more of a nuisance than a necessity. Try it both ways and see how your rig behaves. I think the answer will come naturally to how you like the rig to respond under varying road and traffic conditions. To be clear, I leave it on all the time while climbing and descending big grades.

This is my recommendation as well. I use mine only in mountainous areas, or heavy rush hour traffic( which I try my best to avoid).

mel s · 04-03-2016, 10:00 AM

Quote:

Originally Posted by bobmac

I had Cummins change the activation criterion in the ECM to activate when the brake pedal is depressed. This allows you to take your foot off the throttle and coast - particularly desirable at low speeds in urban areas. I just tap the brake pedal to activate the brake and the throttle to release it. Works great. I cannot understand why this is not the default configuration for RVs. Cummins used their Insite software to make the change and charged one hours labor - well worth it in my opinion.

bobmac

On most, (all?), Caterpillar powered coaches the Exhaust Brake Mode in the Cruise Control Perimeters of the ECU can be electronically programed to "Coast", (rather than "Manual or "Latch")...which results in the same exhust brake action you describe.

BTW, in 2011 Fabco Cat, (now Fabick Cat), in Weston, Wisconsin programmed mine to "Coast" at no charge.

Mel
'96 Safari. 148k miles

doorguy · 04-09-2016, 09:48 AM

mel s, your sounds like it works like ours. I just have the one setting PacBrake. Several years ago, in the FMCA magazine, there was an an for a BrakeSwitch. I bought one and it is wired into the exhaust brake on the dash. If I have the ex. brake sw. "on", the exhaust brake does not activate until I touch the brakes. When I accelerate again, it releases. I leave it on the majority of the time and have gotten so used to it. I haven't seen it advertised since, I think the inventor/seller, a guy named Homer something or another kinda dropped out of the loop for some reason.

mel s · 04-09-2016, 10:38 AM

Quote:

Originally Posted by doorguy

mel s, your sounds like it works like ours. I just have the one setting PacBrake. Several years ago, in the FMCA magazine, there was an an for a BrakeSwitch. I bought one and it is wired into the exhaust brake on the dash. If I have the ex. brake sw. "on", the exhaust brake does not activate until I touch the brakes. When I accelerate again, it releases. I leave it on the majority of the time and have gotten so used to it. I haven't seen it advertised since, I think the inventor/seller, a guy named Homer something or another kinda dropped out of the loop for some reason.

doorguy
I believe Homer "dropped out of the loop" because the ECMs, (in both Cummins and Cat powered coaches with a Pacbrake), can now be electronically programed to acomplish the same thing as his BrakeSwitch device.

BTW i used Homer's "BrakeSwitch device" from 2002 until 2011.... when Caterpillar re-programed the "Exhaust Brake Mode in the Cruise Control Perimeters" of my ECU from "manual" to "coast".

Mel
'96 Safari, 3126 Cat MD3060 Allison...(and a PacBrake)