Engine Braking?

We currently program exhaust braking (turbine restriction) into Duramax custom tuning as a free feature. It is transparent, requires no hardware and doubles grade braking force over what the allison alone provides. An additional 75-100HP to slow the train. It is especially appreciated by "rpm shy" customers with loads over 15K out west. The only time they hit the brakes is to force a downshift.

I can't speak for anything but GM, but I have had both gas and Diesel's and each one acted different from the other. My '98 6.5 Turbo Diesel had no engine braking what so ever. My '05 6.0 gas with the 4 speed tranny had none as well. My '07 classic Duramax had a little bit more...but the holdback of the Allison was doing most of the work. In '09 I bought another 6.0 gasser that had the GM 6 speed (non Allison) and if it was in T/H mode, a tap of the brake and it would downshift and feel like it was going to spit out a valve at 6000 rpm. My '13 Duramax has the best of both worlds. A exhaust brake and the downshifting capability of the Allison. If on cruise...it will hold that speed down hill towing or not. If not on cruise it will slow the whole package down with no service brakes if it is under about a 9% grade.
JM2C

Desert Captain wrote:
I don't tow "heavy" with the V-10 in my 2012 24' Class C but am here to tell you that V-10 is an awesome brake on the often long downhills. It is as much a function of the 5 speed Torque Shift transmission as the engine. I can cruise down a 6+% grade for ten or twelve miles and never touch the brake pedal. All that is required is to shift into the "Tow Haul" mode which locks out the 5 gear/overdrive. This holds the coach at 50-55 at around 3,000 rpm and the best part is we are not burning a drop of fuel!

If you run into more hill than that simply down shift into third (thus eliminating 4th gear), and the rpm will climb but the coach will hold at around 40 to 50 and you are again not burning any fuel. You can get much the same effect on older models (that do not have the tow haul option), by locking out overdrive. You will never harm a V-10 by inducing 3,000 to even 5,000 rpm... they are built to do that.

Don't buy into the nonsense that you have to have a diesel to get effective, efficient engine braking. I always laugh when I pass a rig who has been riding their brakes so hard that I can smell them. It's just s a shame they don't know how to drive.

:C

Desert Captain your first paragraph interest me as it alludes to basically an electronic autoshift which also has the "Tow/Haul" option
and you also belive that no deisel can outbrake you...
Sorry charlie but I have ran both gas and deisel trucks with a standard transmission and, you just need to learn how to use the Engine, Trans, and Brakes all together without frying your brakes. :B
Oh Yeah I have also ran a semi across Black Mountain with No Jake Brake just using my engine,trans, and brakes...:B

KD4UPL wrote:
You can brake with the engine on a diesel, just not nearly as well as a gas engine. That's why most diesels have exhaust brakes.

This is only true to a point! Diesels have a 17 to 1 compression, but engine speed is controlled by fuel, not available air as the air path is unrestricted.
that said if you are foot off the throttle, you are only getting enough fuel to turn the engine at about 850 rpm. The only way you see any, and I mean any engine braking from a diesel is to have it turning about 2,800 rpm with idle fuel. Some, but not as good as a gas engine.

Now put an exhaust brake on it and it is a far different story. I installed a turbo mounted Pacbrake PBXB, this has a plate with about a 3/4" to 1" hole in it, this hole is covered by another spring loaded plate. At high rpm it acts like a standard EB the pressure opens the 1" plate and it provides plenty of whoa. Then at lower rpm, the pressure can not overcome the spring pressure, and now there is a full plate closure still providing lots of whoa.

In a non panic situation I could loose the TV brakes (hydraulics) AND the trailer brakes and could bring the TV and 5er to a full stop on a flat, or even moderate down hill. The final stop would either be parking brake, or shutting off the engine.

Even on the steeps grades in the Oregon Coast range, I never need to touch my service brakes, this is with 19,000#+ GCVW.

I drive a manual, I might even pay the price of a de-tuned Cummins 6.7 just to still have a manual.

Newer diesels should have it built in. My 6.0 brakes not tooo bad in tow/haul mode. Most Ford and Chevy built in the last decade or so can have modules installed that use the variable vane turbo's to do it (Bank's spped brake comes to mind). I have heard of people wiring up the damper plate in the exhaust of the 7.3 (used to help warm up a cold engine) to use as an exhaust brake as well.

I installed a Jacobs on my 2003 Ram, and have the built in one on my 2012, and tow between 12,000 - 17,000 pounds. Personally, I would not be without one, but I live in the mountains.

I won't argue about it, but my TV is worthless down any grade with the RV hitched up without the exhaust brake on. It's a " run away " waiting to happen, or I would smoke my brakes. EB on and drop gears it holds 35 without touching the service brakes :B
Speak of smoking brakes, ah forget it IB :B

jspence1 wrote:
In the jumping off the diesel bandwagon someone mentioned the lack of the ability to brake with the engine on diesels.

1. Is this true?
2. How do you control your speed on descents without the engine slowing you?

That is why Exhaust brakes were invented. To give diesels the same type engine braking as a gas engine. However now there are other types of diesel braking. Some come with a trany brake, and others use a non exhaust engine brake.

The only time you really need a engine brake is in the mountains. Then they are priceless. If you don't have one. It would be one of the best things you could ever install on a diesel. After having driven diesels with out one. I wouldn't have a diesel unless it did have one.

I have the Ford V10 with the 4-speed transmission. On a 7% grade, downshifting to 2nd will slow me down and hold about 55 MPH, even with 15,000 pounds in tow. The vast majority of the time just turning off Overdrive is sufficient to control my speed on the freeeway. The newer transmissions with tow-haul mode will to the downshifting automatically.

I have a diesel and I'm positive I don't have an exhaust brake. Do I need to be concerned about controlling my speeds? I live in a fairly flat area but am going to be traveling through the Rockies this summer and want to be prepared. I don't want to be making my brakes glow on the way down.