Jake brake on or off driving on flats or small hills?

[holstein13]

One of the debates we had this week was whether you should drive with your Jake Brakes on or off while on flat land or small hills. Everyone agreed that you should use them in the mountains or steep grades.

But what about hills and flats? The tire and brake instructor said we should not use them because the brakes need a workout to prevent glazing and if you always use the Jake Brakes, you won't automatically adjust your slack adjusters.

The engine guy said that the latest evidence from Cummins suggested that the Jake Brakes helped keep the turbo chargers clean. He recommended leaving it on.

Do any of you have an opinion?

[wolfe10]

CA Traveler wrote:
Brett,

Isn't the variable vane turbo just a better exhaust brake? ie Same basic principle to restrict the exhaust.

YES.

[CA_Traveler]

Brett,

Isn't the variable vane turbo just a better exhaust brake? ie Same basic principle to restrict the exhaust, just accomplished differently.

[CA_Traveler]

old guy wrote:
if you are on the flat and you come to a town and you have your jake brake on you might get a ticket. many town frown on jake brakes being used in their city limits.

You're referring to unmuffled jake brakes which just doesn't apply to most RVs.

[wolfe10]

hershey,

Not sure I understand the term "grade brake" either in connection with a diesel.

Here are the "normal choices":

Exhaust brake
Engine compression brake (aka Jake brake)
Transmission retarder (buses and Foretravel)
And, on some newer diesels variable vane turbo

[hershey]

mowermech wrote:
"Most motorhomes..."??
I have owned three Class As and a Class C.
One of my sons had a Class C.
None had any kind of "grade retard" or retarder.
Cut......

Sorry, I stand corrected, I meant to say most Diesel MH's. Again, sorry to get your dander up.

[hershey]

.

[pulsar]

holstein13 wrote:

pulsar wrote:

holstein13 wrote:

pulsar wrote:
On our previous coach, the computer was reprogrammed so that the exhaust brake came on only if one touched the brake pedal (and the switch was on). The exhaust brake was released when the accelerator was pressed.

Our current coach is programmed in the usual fashion, but I'll have it reprogrammed next week.

Tom, this sounds like a brilliant solution. Who, exactly, would reprogram this? Also, can I get them to boost my HP to 700 while they've got the computer running and hooked up? 😉

Freightliner reprogrammed the previous coach and will do the new one next week.

They charged too much, $60 for about 5 minutes work - most of which was waiting for their laptop to boot.

Tom

$60 would be worth it to me. Can I assume this was/is a Spartan engine?

No, both are Cummins engines on Freighliner chassis. The previous coach was a 2008 Winnebago journey; the current coach is an Itasca Meridian.

The $60 is worth it to me, also. I'm having the new coach reprogrammed. I imagine the fee is even higher now. The previous coach was reprogrammed several years ago.

Tom

[holstein13]

hershey wrote:

old guy wrote:
if you are on the flat and you come to a town and you have your jake brake on you might get a ticket. many town frown on jake brakes being used in their city limits.

Most MH's have whats called a grade retard. A different animal than the Jake Brake. A grad retard doesn't make the nasty sound of a Jake brake.

I think you may be referring to the Tow / Haul switch on F-53 Chassis. Those gear down the transmissions on descents and spin the engine faster with no fuel to slow the vehicle. It's a very good system and helps a lot but it's not the optimal solution on heavy diesel motorhomes.

[mowermech]

"Most motorhomes..."??
I have owned three Class As and a Class C.
One of my sons had a Class C.
None had any kind of "grade retard" or retarder.
In some municipalities an UN-MUFFLED compression brake might get the driver a ticket. A MUFFLED compression brake usually will not.
An exhaust brake makes very little noise. I have never heard of anybody getting a ticket for using one.
Not all compression brakes are Jake Brakes, but ALL braking systems made by Jacobs are Jake Brakes according to the Jacobs website.

[hershey]

old guy wrote:
if you are on the flat and you come to a town and you have your jake brake on you might get a ticket. many town frown on jake brakes being used in their city limits.

Most MH's have whats called a grade retard. A different animal than the Jake Brake. A grad retard doesn't make the nasty sound of a Jake brake.

[Bill_Satellite]

I always leave the Jake on (mine has hi/lo and I am always on hi). I also always use by cruise control to keep the coach running steady. When the coach is on cruise the Jack does not operate which allows be to coast down hills unless I start to gain too much speed. Touching the brakes will disconnect the cruise and engage the Jake. I never have to think about what to do with the Jake as the Jake will always be doing what it was intended to do. I would hate to have to suddenly brake and not have the advantage created by the Jake because I didn't have time to turn it on.

[holstein13]

Executive wrote:
Holstein, you're from FLORIDA! Our freeway overpasses are HIGHER than your highest "mountain/hill".....:B

That said, like Ivylog, many, not all, Monaco products have a foot switch for the engine/exhaust brake. I think they are a big plus. I have a two stage engine brake with the foot pedal. On small hills and flats, I usually leave the switch on LOW which activates only three cylinders and on bigger hills/mountains, I switch over to the HIGH witch activates all six...YMMV...Dennis

True, but I haven't seen Florida in a long time. That's the great thing about full-timing. I really like the idea of a foot switch. That makes a lot of sense. Exactly where it should be.

I've got a three stage Jake brake, 2, 4, and 6 cylinder. The 4 cylinder will slow you down on even the steepest grades. I can never effectively use the 6 cylinder position because it has too much force.

[Executive45]

Holstein, you're from FLORIDA! Our freeway overpasses are HIGHER than your highest "mountain/hill".....:B

That said, like Ivylog, many, not all, Monaco products have a foot switch for the engine/exhaust brake. I think they are a big plus. I have a two stage engine brake with the foot pedal. On small hills and flats, I usually leave the switch on LOW which activates only three cylinders and on bigger hills/mountains, I switch over to the HIGH witch activates all six...YMMV...Dennis

[RCtime]

Sprink-Fitter wrote:

wolfe10 wrote:
Leaving on either an exhaust or engine compression brake 100% of the time is a good way to not use my favorite gear-- COASTING.

Particularly in rolling hills, it is much better for MPG to coast down the hill and gain a little speed to attach the next upgrade than to use your brakes going down and then have to go to WOT going up.

Stop and go traffic or technical driving brings on different priorities.

Are you really that cheap that you would actually coast downhill to save gas ?

not cheap at all, just totally practical. On some downhills, coasting is the best gear. Using the jake or compression brake in these scenarios just increases your workload as a driver.
Personally, I just use my brake when needed on downhills when The coach wants to accelerate to above normal or comfortable speeds.

[lfeather]

I leave my Jake Brake on 95% of the time. Only once and a while, I'll turn it off when I want to freely coast down a hill.

Larry