Community Forums

desertvince · 06-19-2015, 01:52 PM

Sounds like there are two types of exhaust brakes. What is "true" vs. "something other than true"? Thanks for the education.
With a C7 (350) on a Freightliner, what do we likely have in our MH?

Dutch Star Don · 06-19-2015, 02:23 PM

There are two types, but they're not both exhaust brakes, so there is no true vs not true exhaust brake.

An exhaust brake is a plate in the exhaust that when applied, closes off the exhaust pipe, building back pressure in a diesel engine. This, typically coupled with the transmission downshifting, gives you additional braking. Exhaust brakes GENERALLY come on smaller engines and lower level coaches in a manufacturer's lineup.

The engine brake, generally closes engine exhaust valves and creates back pressure. This type of brake is more powerful and typically has two or three speeds, giving you a choice of braking power. This is a more expensive way to add braking, consequently, it typically comes in higher priced coaches.

We had an exhaust brake in our Monaco Diplomat and it worked well about 75% of the time. On really steep grades while towing my truck, I found I had to reduce to an unsafe speed for traffic or hit my brakes several times.

On our new coach, we have the two speed engine brake. It sufficient about 95% of the time and gives me some ability to adjust my downhill speeds without going to slow for traffic.

38Chevy454 · 06-19-2015, 02:39 PM

As Don said, and quoting from another of my posts:
An exhaust brake is not the same as engine brake. Exhaust brake basically chokes down the exhaust, increasing exhaust backpressure. Whereas the engine brake bleeds off compression pressure after the work of compressing is done.

An engine brake is much stronger than exhaust brake. An engine brake has to be built into the engine design. An exhaust brake can be added later. Not all diesel engines have an engine brake, and many do not have exhaust brake either.

Typically larger diesel engines have the engine brake, smaller may have exhaust brake. Pickup diesels have a sort of modified exhaust brake, in that they use the variable vane turbo to close off exhaust to create the back pressure. A true exhaust brake is more like a butterfly in the exhaust that closes to make more restriction than the turbo vanes can.

I have no idea what if any type exhaust brake or possibly engine brake your MH has. I do not think a Cat C7 has engine brake, as it has to be built into engine design and that engine does not have it. You may have an exhaust brake though.

Bucky1320 · 06-19-2015, 02:41 PM

We have the exhaust brake in our 3126. Love it. I pull the race trailer most of the time, and with the e/b on, I hardly have to use the wheel brakes.

Stano · 06-19-2015, 03:35 PM

How does a exhaust break work anyway?

Stano

Route 66 · 06-19-2015, 03:43 PM

Jacobs Vehicle Systems | Exhaust Brakes

Compression Release Brake | Jacobs Vehicle Systems

Selah · 06-19-2015, 03:45 PM

There are two types of exhaust brakes. One is an actual butterfly valve that is in line with the exhaust pipe. The other type that is still considered an exhaust brake is the variable vane turbo charger. Both do basically the same thing, restrict the flow of exhaust.
You have now exhausted by knowledge of exhaust brakes.

Mr_D · 06-20-2015, 12:43 AM

Add this one to the types of Jake brakes:

Quote:

The ISX 650 delivers uncompromising performance for towing heavy loads and climbing steep mountain grades. Its patented Variable Geometry Turbocharger (VG Turbo) now has electric actuation for enhanced engine response at every rpm. Plus, the standard Intebrake™ system produces up to 600 braking horsepower for superior driver control on downhill slopes.

I'm not sure what the Intebrake™ is but it sure works.

38Chevy454 · 06-20-2015, 02:32 PM

Quote:

Originally Posted by Mr_D

Add this one to the types of Jake brakes:

I'm not sure what the Intebrake™ is but it sure works.

Cummins ISX has an internal engine brake, it is not an exhaust brake. The variable vane geometry turbo is for better response when you step on the throttle. The ISX engine brake is very effective, on my truck conversion MH it has 3 settings: 2, 4, or 6 cylinders to provide different levels of braking assist.

Mr_D · 07-04-2015, 11:12 PM

Quote:

Originally Posted by 38Chevy454

Cummins ISX has an internal engine brake, it is not an exhaust brake. The variable vane geometry turbo is for better response when you step on the throttle. The ISX engine brake is very effective, on my truck conversion MH it has 3 settings: 2, 4, or 6 cylinders to provide different levels of braking assist.

Yep, I know it was internal, still don't know what an Intebrake is but when that turbo spools up you do notice it even in a 50,000# MH! Getting on the freeway is no longer a hope for a BIG hole and the engine brakes is fantastic, very seldom use anything but the lowest setting of three.