Driving with engine brake on

[select55]

Originally Posted by ernest917

Opinions: who drives with their engine brake on all the time and why???

just read your MH profile? I do not believe you even have a engine brake in your MH??
R U sure you do?

[WyoFree]

Does the Cummins 360 HP ISB have a jake break? I did a search and got all kinds of information but nothing on the Jake break?

[dan-nickie]

Originally Posted by WyoFree

Does the Cummins 360 HP ISB have a jake break? I did a search and got all kinds of information but nothing on the Jake break?

It has an exhaust brake.

[Dutch Star Don]

Everyone uses theirs differently, but here are some reasons how and why I use mine. I have a two speed engine brake and leave mine on LOW the majority of the time. I guess everyone drives differently, but the majority of my RV driving is on the freeway. When I'm on the freeway, the engine brake is on, along with the cruise control. Not all coaches will allow this, but mine does. The REASON for having it on is for emergency stopping. If something happens at freeway speeds, I don't want to worry about making emergency maneuvers and turning the engine brake on. Just the half second or more before you turn the brake on, could be the difference in stopping distance to prevent a crash.

Typically, if there is traffic, below 15 mph, engine and exhaust brakes shut off automatically and will not engage, so not an issue, leave it on.

For those with exhaust brakes, they are probably having to manipulate the braking on grades because most exhaust brakes won't hold a perfect speed, so many may be turning theirs on and off. On mine, the engine brake is tied into the cruise control. Once I start descending a grade, my engine brake turns on and off automatically. I do very little "driving" on grades as compared to when I had an exhaust brake on my previous coach.

When driving around town, the exhaust and engine brake should be turned off for two reasons. First, it can cause herky jerky braking and second, you should be using your foot brakes to keep from glazing the brakes on your coach. Many are so worried about saving the brakes, they use their exhaust or engine brakes to excess. You're not going to wear out your coach brakes.

[twinboat]

Originally Posted by WyoFree

Out of curiosity, with the jake/exhaust break on. would you stop more quickly in a "panic stop" situation?

I think if your standing on the brakes and the anti locks are kicking in, the engine brake will have no effect.

[ahicks]

Absolutely nothing to back me up (other than my butt dyno), but I think the more heavily loaded you are, the more effective the engine brake might be in a panic stop scenario.

That said, I've never heard so much as a squawk coming from any of my tires when that's happened to me. So either I haven't found it necessary to get on the brakes that hard/stop that quick, or the brakes aren't capable of locking the tires. In the case of the brakes incapable of locking the tires, I have to believe the engine brake is helping to slow the coach quicker. That's me though, all opinion.

[Big Oil Guy]

Originally Posted by Tha_Rooster -
Only when I need it, kinda hard to coast with it on.

Originally Posted by select55

exactly and having the trans downshift/upshift every time your on off the gas is very very annoying

X2...... Bottom line, use it only when you want it to help you slow down. Period! Unless you're the kind of driver that always has his foot on the accelerator or on the brake, you probably won't like it in town. Coast is my favorite gear too!

[twinboat]

Originally Posted by ahicks

Absolutely nothing to back me up (other than my butt dyno), but I think the more heavily loaded you are, the more effective the engine brake might be in a panic stop scenario.

That said, I've never heard so much as a squawk coming from any of my tires when that's happened to me. So either I haven't found it necessary to get on the brakes that hard/stop that quick, or the brakes aren't capable of locking the tires. In the case of the brakes incapable of locking the tires, I have to believe the engine brake is helping to slow the coach quicker. That's me though, all opinion.

Don't think a heavier load will affect engine brake performance but higher RPMs will.

In that panic stop, if the trans isn't downshifting rapid fire, to keep the RPMs up, your brakes are doing all of the stopping.

[ahicks]

All else being equal, the heavier the load, the more work your brakes need to get done to stop in the distance you have in front of you.

At some point, the braking capacity will be exceeded. If the brakes haven't locked up at that point, the engine brake will make a difference....

[gatorcq]

It all depends on the engine brake.
Pac Brake/Exhaust Brake Better in 4th or lower
Jake Brake works 5th or better, but works better then Exhaust brake in 6th gear.

Exhaust Brake can be set for Latch or Unlatch mode. Makes for easier driving.
Jake Brake CANNOT be in latch of Unlatch mode to my knowledge.

Call your respected engine MFG and Talk to them.

[select55]

Originally Posted by gatorcq

It all depends on the engine brake.
Pac Brake/Exhaust Brake Better in 4th or lower
Jake Brake works 5th or better, but works better then Exhaust brake in 6th gear.

Exhaust Brake can be set for Latch or Unlatch mode. Makes for easier driving.
Jake Brake CANNOT be in latch of Unlatch mode to my knowledge.

Call your respected engine MFG and Talk to them.

not sure what your getting at? A engine brake is a engine brake and exhaust brake is a exhaust brake ;; both designed to assist the air brakes for slowing and stopping but entirely different in design and nature

[twinboat]

Originally Posted by gatorcq

It all depends on the engine brake.
Pac Brake/Exhaust Brake Better in 4th or lower
Jake Brake works 5th or better, but works better then Exhaust brake in 6th gear.

Exhaust Brake can be set for Latch or Unlatch mode. Makes for easier driving.
Jake Brake CANNOT be in latch of Unlatch mode to my knowledge.

Call your respected engine MFG and Talk to them.

This is from the Jake engine brake operaton manual.

The lower the gear and higher the RPM the better it works.

[theroc]

Originally Posted by WyoFree

Does the Cummins 360 HP ISB have a jake break? I did a search and got all kinds of information but nothing on the Jake break?

Wyofree, I agree with dan-nickie. I'm pretty sure that the vast majority, if not all, of the Cummins ISBs used in motorhomes will come with an exhaust brake or what Cummins calls a "Cummins E Brake." It was developed in a joint venture between Cummins and Jacobs Vehicle Systems.

The reason you may be getting confused or think you're getting conflicting information is that Jacobs also makes an exhaust brake in addition to their engine compression brake (referred to as a Jake Brake ...or true Jake Brake). Therefore, many who have an exhaust brake may mistakenly think they have a true "Jake Brake" because they misinterpreted the fact that they have a Jacobs Exhaust Brake and believe it's a true "Jake Brake because they noticed the "Jacobs" description.

Jacobs Exhaust Brake for Cummins Medium Duty Engines

Optional ISB Engine Brake

Somebody can correct me as I'm just guessing on this but most Cummins engines come with a standard exhaust brake (Cummins E Brake). A compression brake (or Jake) is an option on the ISB, ISC, ISL, and, I believe standard on the ISX.

Like I say, I believe that most motorhome manufacturers that order their chassis with an ISB will not pay the extra for the Jake Brake option so just about all the motorhomes with an ISB will have a factory exhaust brake ...again, those more in the know please feel free to correct me.

[Steve Ownby]

Originally Posted by theroc

Wyofree, I agree with dan-nickie. I'm pretty sure that the vast majority, if not all, of the Cummins ISBs used in motorhomes will come with an exhaust brake or what Cummins calls a "Cummins E Brake." It was developed in a joint venture between Cummins and Jacobs Vehicle Systems.

The reason you may be getting confused or think you're getting conflicting information is that Jacobs also makes an exhaust brake in addition to their engine compression brake (referred to as a Jake Brake ...or true Jake Brake). Therefore, many who have an exhaust brake may mistakenly think they have a true "Jake Brake" because they misinterpreted the fact that they have a Jacobs Exhaust Brake and believe it's a true "Jake Brake because they noticed the "Jacobs" description.

Jacobs Exhaust Brake for Cummins Medium Duty Engines

Optional ISB Engine Brake

Somebody can correct me as I'm just guessing on this but most Cummins engines come with a standard exhaust brake (Cummins E Brake). A compression brake (or Jake) is an option on the ISB, ISC, ISL, and, I believe standard on the ISX.

Like I say, I believe that most motorhome manufacturers that order their chassis with an ISB will not pay the extra for the Jake Brake option so just about all the motorhomes with an ISB will have a factory exhaust brake ...again, those more in the know please feel free to correct me.

In the motorhome market, I don't believe you will find a compression brake (aka true Jake) in an ISB or ISC. The ISL is available both ways depending on the year of production. An ISX will always have a compression brake.