Engine Braking?

[jspence1]

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?

[Devocamper]

I added The Banks Speed brake to my 07 Chevy D/A. Works well combined with the factory grade braking T/H. Was not too hard to install all plug and play and works well with the load of the trailer on the truck, a little too harsh without a load but it can be adjusted. If you use cruise control and the speed brake you almost don’t need your feet.

[tim_and_amy]

I'm not sure who you are talking to. My 04 and 05 ford 6.0L have engine braking if you are in Tow/Haul Mode.
You just tap the brake and it downshifts. My cousins have 04 Ram 2500's and his doesn't do that in T/H mode. He was complaining about burning up brakes towing his fiver. I never have issues down hilling it in the rocky mountains. But all newer trucks do have engine breaking on diesel pickups. If you are referring to pre 2004, then it is manufacture specific.
Down the road from work we have a steep hill and I kick my truck into tow haul mode every day to go down that hill. An F350 will scream down that hill if you are not in TH or on the brakes.

[wilber1]

jspence1 wrote:
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.

You always need to be concerned about controlling speed in the mountains. What you are towing? I towed a 10k 5th wheel with a 2001 Dodge CTD auto for 10 years in the mountains with no exhaust brake. Never felt I needed one but you have to drive accordingly. Slow down, gear down and don't ride the brakes. Make firm applications then give them some cooling time.

Love the EB on my present truck though. Makes a big difference on dry roads but could get you in trouble if it is slippery.

[NC_Hauler]

Before I owned a diesel with an exhaust brake I owned several D/A's and the grade braking worked pretty good, (in T/H)....on some of the steeper grades I'd run, I'd have to use my brakes and/or use the trailer brakes manually to slow down...now the GM/Chevy D/A also has an EB.

When I purchased my first Dodge it had an EB, it was awesome when in T/H, never had an issue....the 13' in my sig. has improved from the 2010, Towing my 5er in T/H mode with EB on first stage (most aggressive), I've gotten to where when I go down a steep mountain and put the truck in cruise control,at say, 50-55 mph and the truck will maintain that speed....couple examples, I26 DOWN Saluda Grade in NC, I64 going DOWN from Beckly to Sandstone Falls WV, (7% grade), and I26 coming out of NC into TN. I do not have to give throttle and do not have to brake ...its awesome:).

I've went down I26 from NC into TN with EB and T/H on sig. truck towing sig 5er loaded to 16,000#, and not in cruise contol, just taking my foot off of the throttle., truck will almost bring me to a stop....I feel a whole lot more secure now than I did before...

If one has EB and T/H on a diesel which the Big 3 does, I don't see a problem when towing with all those "tools" ON......really not an issue any more with the newer diesels, and Ive had gassers towing 5er's (last being an 8.1, D/A's , and now diesel with two stage EB, TH and it works great):)

One thing different about the Ram, even if NOT in T/H, the EB still works and can be rather agressive....

[aclay]

Halmfamily wrote:
My GMC 3500 has the Duramax/Allison combination. We keep the truck in tow/haul mode whenever towing. On downhill grades the transmission locks the torque converter and then downshifts to maintain speed. I just tap the brake as needed and the will downshift to maintain speed. I believe the turbo also acts as an exhaust brake while in tow haul, someone correct me if I'm wrong. I can keep speed on long grades without having to worry, have actually had excelerate at times to maintain speed.

I have a 2012 Chevy Duramax/Allison and keep in tow/haul mode too. The compression brake only works when you have the transmission in tow/haul mode. On my truck, it's a button below the radio that turns it on/off. I use it when going down steep grades as it works with the transmission to maintain speed. It is an engineering marvel in my mind, it works just like a cruise control. It's very steady and I love that feature. I don't leave it engaged all the time, only when going down a steep and/or long grade.

[Desert_Captain]

Led 67 wrote:

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

Huh? Where did I ever say "no diesel can out brake me"? If you actually read my post yours makes no sense at all. :h I don't need to learn how as I am doing it right and will never fry my brakes thanks to the proper use of the engine and transmission. While manual transmissions are getting to be fairly rare one can certainly mimic the Torque Shift with the proper gear selection and the judicious use of the clutch. I think some folks are just intimidated when rpm climb and they miss out on the available performance both going up and down serious grades.

The V-10 is arguably the most popular engine out there when it comes to gas motorhomes as it works very well in that application. What I alluded to were the many folks that simply do not know how to correctly use the V-10/trans combo as it was intended. Many is the time I have passed such a rig at the side of the road needlessly reeking of overheated brakes. A simple read of the owners manual would solve most of their problems.

:C

[dbbls]

I towed for years with a Ford V-10, I now tow with a diesel with an exhaust brake. The new diesel exhaust brake is much, much better than the V-10. Salt River canyon on highway 60 in Arizona is several miles of 6 to 7 percent down grade, then the reverse going back up. I have traveled this many time with the V-10, then with the new 6.7 Power stroke. I can drive this touching the brakes only three time on the decent keeping my speed under 35 with the Power stroke. I used the brakes many more times with the V-10.

[ib516]

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?

1. Yes
2. Foot brake, or, on newer models (RAM/Cummins since 2007) have a built in exhaust brake. The competition followed suit a couple years later.

Towing with a diesel not equipped with an exhaust brake isn't that bad, but with a big load on a steep downhill, you have to be pretty hard on the brakes to keep speed in check. Ask me how I know 🙂

The reason for this is because diesels do not (well until recently) have a "throttle plate" that limits the amount of air that the engine is able to take in. They add or subtract power by adding or subtracting fuel, and don't have to run at 14.7:1 air:fuel like gasoline engines do. Some of the newest crop of diesels DO have athrottle plate,but to my understanding, it is to limit the incoming air when they are doing a regen on the DPF, not for regular engine power levels like a gas engine.

[Me_Again]

rhagfo wrote:
Diesels have a 17 to 1 compression, but engine speed is controlled by fuel, not available air as the air path is unrestricted.

Compression ratio is not in play for compression braking, as the force to compress the cylinder is mostly returned on the down stroke. Chris

[Me_Again]

jspence1 wrote:
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.

Someone else with a 2001 Powerstroke should be able to answer your question. Chris

[killerbee]

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.

[mguay]

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

[Led_67]

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

[rhagfo]

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.