Exhaust brake - How Does it Work?

Freebirdusa · 06-19-2011, 12:40 AM

How does the exhaust brake work ? Do you have a lever or switch that you operate manually when you want to activate it, or can it be switched on to work when you let off the gas pedal?

cumminsdad08 · 06-19-2011, 06:49 AM

i have driven a duramax with a factory brake, and it engaged when you got off the throtle, if the engine was over a certain speed. i personally didn't see much of an advantage with the feature on a duramax with a 6 speed standered trans. maybe someone else can chime in with that.

THedges · 06-19-2011, 07:28 AM

I love my exhaust brake! In AZ just about everywhere I tow is in the mountains. One of our favorite destinations takes us up & down a long 7% grade. When going down I tap the brake and after that the exhaust brake takes over and holds the truck & TT back. I have even had to hit the gas pedal to speed up while going down long grades. On flat terrain I can feel the E.B. kick in and help stop my rig. In the the long run I think the E.B. will add a lot of life to my brakes.

Me.Bikes.Dogs · 06-19-2011, 07:58 AM

Hi Richard,

Chevy's and Ford's don't come from the factory with exhaust braking, they use engine braking, also known as a Jake Brake.
(I stand corrected, the 2011 Chevy Silverado has an option for an exhaust brake. I'm not sure if it is switched or not)

Dodge's use Jake Brakes but they also have a switch you can flip to add exhaust braking to the mix, just like the big boys. It adds quite a bit more braking power than just engine braking.

Exhaust braking produces momentary higher cylinder pressure kind of like like having a potato in the exhaust pipe. This increase in turning crankshaft force will turn the engine into a vehicle brake.

Here is a pretty good article describing how they work and the difference.

THedges · 06-19-2011, 08:23 AM

Quote:

Originally Posted by Me.Bikes.Dogs

(I stand corrected, the 2011 Chevy Silverado has an option for an exhaust brake. I'm not sure if it is switched or not)

Yes it is switched, there is a button on the dash. Used in conjunction with the tow/haul mode on and there is a significant difference.

hankaye · 06-19-2011, 08:44 AM

Howdy All;

Just a reminder to those of you that use them alot... those little signs at the edge of towns that state NO ENGINE BRAKES or NOISE ORDINANCES ENFORCED...

Apply to pick-ups as well as Big Trucks

Some of the smaller villages love those fines (income).

hankaye

Jim W · 06-19-2011, 01:34 PM

Quote:

Originally Posted by hankaye

Howdy All;

Just a reminder to those of you that use them alot... those little signs at the edge of towns that state NO ENGINE BRAKES or NOISE ORDINANCES ENFORCED...

Apply to pick-ups as well as Big Trucks

Some of the smaller villages love those fines (income).

hankaye

Sorry Hank, this is not true for the exhaust brake on the 6.7L Cummins engine. You are encourage to use the exhaust brake all of the time. This is to keep the sliding ring in the Variable Geometry Turbo charger working correctly. The VGT sliding ring will build up with soot from the EGR system and the Turbo will have performance issues. Ask one who knows.

This is from the Cummins home page on the operation of the VGT, and I quote "The Cummins 6.7L Turbo Diesel continues to offer the most powerful integrated exhaust brake available in a heavy duty truck. Cummins best-in-class integrated exhaust brake, with a full 225 braking horsepower at the wheel, gives Ram Heavy Duty pickup customers more confidence while towing the heaviest loads down the most severe grades. Cummins proprietary sliding nozzle Variable Geometry (VG) Turbocharger is used as the integrated exhaust brake, making this unique capability standard on every Cummins 6.7L Turbo Diesel. Utilizing the VG turbocharger, the exhaust brake significantly improves control when towing heavy loads, such as pulling RV fifth wheels and horse trailers, providing added vehicle control and vehicle brake savings by using the engine for braking power. This extends the vehicle brake life, resulting in reduced total cost of ownership. "

Me Bikes and Dogs,
"Dodge's use Jake Brakes but they also have a switch you can flip to add exhaust braking to the mix, just like the big boys. It adds quite a bit more braking power than just engine braking. "
Sorry, this is not true either. The "Jake Brake" use air pressure to restrict the exhaust air flow thru a valve mechanism that is inserted into the exhaust system. This is what provides the compression braking.
As I stated above the VGT is a different design and uses different components to achieve the same results.
This has been extensively debated on several diesel web sites.
Jim W.

hankaye · 06-19-2011, 02:07 PM

Jim W, Howdy;

Don't want nor mean to be argumentative.... however .....

What I was attempting to say is this;

Local Municipalities (Governments), don't care a hoot about what the maker of your engine say is better for it. They (Local Governments), want it quiet.

That is why they passed noise laws.

They passed the laws because of how loud the BIG TRUCKS Engine/Jake breaks are with or without a muffler.

If Barney Phiff hears your engine brake or Jake brake he will ticket you and enjoy collecting your Vacation $'s.

That is ALL I was trying to get across.

hankaye

Freebirdusa · 06-19-2011, 04:31 PM

Thanks for the replies everyone. I drive an 18 wheeler for a living. The truck I drive has a switch to turn the jake brake off. I just wondered if the pickups were always on or could you turn them off. My tractor jake brake only comes on when you tap the brake if the switch is on. When you here these loud big trucks with straight pipes going through the gears and the jake brake activates in between gears, I assume theirs works anytime you let off of the gas pedal. Which to me would be annoying. I never use the jake brake going through cities etc. Just the interstate if even then. Mine is pretty quiet. Those trucks are noisy enough without adding straight pipes and a jake brake.
Also in the small towns with the No jake brake signs its a good idea to turn it off or Jackie Gleason might be in your rear view mirror with the blue lights on acting like you justed killed the Pope or something Lol.

cumminsdad08 · 06-19-2011, 04:58 PM

just one more reason why i am trying to stay away from the new diesel's. just had to make a perfectly already complex turbo, even more complex(LOL).
every truck that i have seen, and driven, has had a switch to engage, disengage, the braking device(which ever it may be)

Johnnyfry · 06-20-2011, 05:26 AM

I think that some explanation is in order here. A Jake brake is different from a exhaust brake in a turbo diesel. You can get a complete explanation by going to the Jacobs web site (google Jake brake) a Jake brake gets it's braking by changing the valve timing in the engine to use the engine compression as a brake and releasing the pressure at the top of the compression stroke, hence the loud noise.

An exhaust brake, on the other hand, throttles the exhaust at the output on the turbo charger by various methods and does not make any additional noise.

The reason it is needed is that diesel engines do not naturally provide any engine braking (like gas engines do) because diesel engines do not have a throttle plate on the input side.

People refer to all exhaust brakes as jake brakes, but Jake brakes are a very specific design by Jacobs engineering and are only used on large trucks, not pickups.

John

Jim W · 06-20-2011, 05:43 AM

Quote:

Originally Posted by hankaye

Jim W, Howdy;

Don't want nor mean to be argumentative.... however .....

What I was attempting to say is this;

Local Municipalities (Governments), don't care a hoot about what the maker of your engine say is better for it. They (Local Governments), want it quiet.

That is why they passed noise laws.

They passed the laws because of how loud the BIG TRUCKS Engine/Jake breaks are with or without a muffler.

If Barney Phiff hears your engine brake or Jake brake he will ticket you and enjoy collecting your Vacation $'s.

That is ALL I was trying to get across.

hankaye

Hi again,
I know what you are saying, but the new diesel engines with the exhaust brakes do sound different than the Jake brake that we are familiar with.
I live in a small town with your "Barney Phyfe" type officers. I have pulled up next to them with the brake on and nothing has ever been said. With my TBE my truck will sound like a "jet engine" with the brake on. My reply to them has been "it is the VGT and I have a clean diesel engine".
Jim W.

rturriff7 · 06-20-2011, 07:13 AM

I have a 2008 f350 Superduty. How can I tell if I have one of these brakes? Would it be obvoius?

**hankpage** · 06-20-2011, 09:18 AM

FYI .... cruise control or increasing rpm a little will also considerably add engine breaking affect on a diesel. Setting the cruise at the top of a long grade will help but kick off if you need to hit the brake ... I find it easier to use the accelerator to to maintain rpm and engine hold back. Granted it is not as effective as an exhaust brake but helps if you do not have one. It works on older Dodges without having to change valve springs. I used this method on my '94 Ram and my '04.5.

wozzukes · 06-20-2011, 12:44 PM

We have a 2011 Silverado Duramax with the exhaust brake. According to my husband this is the greatest feature of the truck. I don't know much about it or how it works, but I do know that there is a button for it under the radio to turn it on. When it is on, all he has to do is tap the brake when going down a hill and you will hear the engine downshift to slow us down. He hardly has to touch the brakes at all when going down hills, as the exhaust brake is enough to hold us back.

There is really no extra noise when the exhaust brake is on. Aside from hearing the shifting in the engine you really don't know that it's on aside for being much more in control on the descents and not having to push the hell out of your brake pedal.

As a side note, the 2011 duramax is SUPER quiet for a diesel. When DH said he wanted a diesel I told him he was crazy. I didn't want to ride in a truck that loud and smelly and reminded me of a school bus. I was really taken back when we test drove one and I found that it was no louder, if not quieter, than our gas half ton. The 2011's now have a DEF (sorry, couldn't tell you what it sounds for but some kind of fluid!) tank which helps to burn off the exhaust (or at least that's my understanding) and there is ZERO diesel smell. I lost my whole argument and he got his diesel

THedges · 06-20-2011, 05:02 PM

@ wozzukes: I love my 2011 Duramax! It is by far the best truck I have ever owned. When you are due to add DEF check out a NAPA, it's only $4 a gallon.

wozzukes · 06-20-2011, 05:37 PM

I think he has already stocked up on some DEF in preparation for the first fill that he got at NAPA. It will be a while before we get there though since it really only gets driven when we are towing, so it only has about 2,000 miles on it so far! That truck sure is his baby though and he can't say enough good things about it - and it better be for what we paid for it! It gets a bath after every trip or rainfall, which gives me lots of ammo to make fun of him with!

He really wrestled with whether or not going diesel was worth the increase in cost. I told him the decision was his since he's the one that does the driving and he's the one that does all the maintenance on the vehicles. He decided to go for it, as he didn't want to regret it later and he is so glad he did. Now that we've been towing with it he can't imagine towing with anything less, and I think the exhaust brake as a lot to do with that!

Seagull · 06-24-2011, 09:54 AM

I have just joined the Forum. I don't type or spell very well, be patient.
I have a 5er pulled by a 2007 Dodge 3500. I have installed a Banks exhaust brake. The additional noise is so little, no one would know the brake is active. I just returned from Eastern Tenn. and used the brake continully. As long as the RPM is over 1200 the break stays engaged and will help to maintain speed. The Banks has a switch to make the brake active.

Johnnyfry · 06-24-2011, 10:53 AM

Although I don't qualify as an official welcomer ( is that a word), welcome to the group AND to the unofficial Ram 3500 subgroup as well.

I have been wanting an exhaust brake for my 2006 3500 Cummins and am always looking for input.

John

kenn209 · 06-24-2011, 11:38 AM

Me too! Among a list of other things! I'm leaning towards the PacBrake. I like the air compressor, tank and the extra stuff that comes with it. I did a test drive of a 2007 3500 SLT dually the other day, Had the 6.7 in it. Nice ride, got to play with the exhaust brake. They didn't want to give me hardly anything on a trade.... Oh well will keep this one.

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