Engine braking now vs then.

[4x4ord]

In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph. Second gear was a run away. In 2011 I went over the same pass with the same trailer using a 2011 Powerstroke. The engine was able to hold the trailer back in 2nd gear at about 3600 rpm and 45 mph. This year with 25000 lb gcvw my 2017 Powerstroke had no trouble what so ever maintaining 55 mph in 3rd gear at 2900 rpm. It was just a matter of setting the cruise and letting the automatic exhaust brake do its thing. There are a couple tighter bends in the road that prompted me to brake slightly to drop a few mph and then press resume on the cruise. The turbo boost would rise or fall depending on how much exhaust braking was required to maintain 55 mph. I was very impressed.

[ktmrfs]

Bedlam wrote:
You lose exhaust braking when the torque convertor is no longer locked up at low speeds.

at least on my duramax I wouldn't use the word "lose", it's "reduced effectiveness". In first gear yes, torque converter isn't locked so the effect isn't as great, but it is still helping especially as the rev's increase. now once your down to 15mph or so, rpm are down, exhaust flow is down, and it isn't as effective for sure.

[Bedlam]

You lose exhaust braking when the torque convertor is no longer locked up at low speeds.

[Cummins12V98]

Mine cuts out at around 13mph. Must be the 4.10's.

[ppine]

Canada has more lenient design criteria even for their category one roads. There are some serious grades on their best highways. They can catch you off guard at first. Slow down and gear down. I remember 12% on the main highway across BC and Alberta.

[rhagfo]

I just wish exhaust brakes on new trucks worked to lower speeds. Most cut off between 10 and 20 mph, it is taking some getting use to with the new Ram to that. When I installed the PacBrake on the 2001 with manual trans it was 100% manual operation by the switch on the shiftier along switch on the accelerator pedal. Once activated it would be activated as soon as my foot was released from the accelerator and would stay activate until I flicked the shiftier switch off.

[JRscooby]

Old-Biscuit wrote:


Glad to see exhaust braking OEM ------ great tool for diesel trucks

With no add-ons there is nothing to slow the air flow thru engine. The only thing the engine does to slow the vehicle is friction in the engine. Gas engine speed/power is controlled by controlling air flow. Diesel, speed/power is controlled by controlling fuel. Gas engine, to slow, you close the throttle, stopping the air from going in. Add a exhaust brake to diesel, and you stop the air from coming out. I know a diesel with no exhaust or compression brake will not have the whoa that a gas engine half it's size would have. I would like to see a comparison for like sized gas/diesel braking power.

[4x4ord]

jbc28 wrote:

4x4ord wrote:
In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph. Second gear was a run away. In 2011 I went over the same pass with the same trailer using a 2011 Powerstroke. The engine was able to hold the trailer back in 2nd gear at about 3600 rpm and 45 mph. This year with 25000 lb gcvw my 2017 Powerstroke had no trouble what so ever maintaining 55 mph in 3rd gear at 2900 rpm. It was just a matter of setting the cruise and letting the automatic exhaust brake do its thing. There are a couple tighter bends in the road that prompted me to brake slightly to drop a few mph and then press resume on the cruise. The turbo boost would rise or fall depending on how much exhaust braking was required to maintain 55 mph. I was very impressed.

They do work well. If you were using cruise the service brakes may have been coming on too.

I noticed on the way back over the pass that the service brakes did come on a few times. When they come on the dash displays the amount of trailer braking being applied otherwise you"d be oblivious to the fact that the service brakes came on ... it is very smooth and it is possible they came on the first time over and I missed it.

[4x4ord]

FishOnOne wrote:

4x4ord wrote:
In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph. Second gear was a run away. In 2011 I went over the same pass with the same trailer using a 2011 Powerstroke. The engine was able to hold the trailer back in 2nd gear at about 3600 rpm and 45 mph. This year with 25000 lb gcvw my 2017 Powerstroke had no trouble what so ever maintaining 55 mph in 3rd gear at 2900 rpm. It was just a matter of setting the cruise and letting the automatic exhaust brake do its thing. There are a couple tighter bends in the road that prompted me to brake slightly to drop a few mph and then press resume on the cruise. The turbo boost would rise or fall depending on how much exhaust braking was required to maintain 55 mph. I was very impressed.

The 2020 Super Duty's will have even a stronger turbo so it'll be interesting to see if there's better exhaust brake performance to an already great performing exhaust break.

The larger turbo and 10 speed transmission both will contribute to even better engine braking performance. Going up the pass I was short on power. The speed limit was 100 km/hr and I was only able to do 85 km/hr on the steepest sections. 520 hp would be required to pull that pass at the speed limit.

[Bionic_Man]

Gulfcoast wrote:
Sure wish I had an exhaust brake on my Cummins 5.9, but I simply can't afford $1500 for the kit and $1000 labor. Surely there's something out there cheaper.

When I added it on my 03 I found that the local Cummins repair facility had the best price, although I don't remember what I paid. If you haven't already, it would be worth looking into.

[rhagfo]

Gulfcoast wrote:
Sure wish I had an exhaust brake on my Cummins 5.9, but I simply can't afford $1500 for the kit and $1000 labor. Surely there's something out there cheaper.

Look around, you can get the kit a bit cheaper, and $1,000 to install is a rip off.

[FishOnOne]

4x4ord wrote:
In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph. Second gear was a run away. In 2011 I went over the same pass with the same trailer using a 2011 Powerstroke. The engine was able to hold the trailer back in 2nd gear at about 3600 rpm and 45 mph. This year with 25000 lb gcvw my 2017 Powerstroke had no trouble what so ever maintaining 55 mph in 3rd gear at 2900 rpm. It was just a matter of setting the cruise and letting the automatic exhaust brake do its thing. There are a couple tighter bends in the road that prompted me to brake slightly to drop a few mph and then press resume on the cruise. The turbo boost would rise or fall depending on how much exhaust braking was required to maintain 55 mph. I was very impressed.

The 2020 Super Duty's will have even a stronger turbo so it'll be interesting to see if there's better exhaust brake performance to an already great performing exhaust break.

[ktmrfs]

Old-Biscuit wrote:
"In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph."

2003 Duramax LB7-----REV Limiter set at 3250 rpm

:H



I have a US Gear 4" exhaust brake on my 5.9L Cummins
Truck/trailer combo 22k
Exhaust brake 6% grade----55 mph
Glad to see exhaust braking OEM ------ great tool for diesel trucks

nope! duramax with grade brake or exhaust brake shuts off fuel and will rev to 5000rpm. friction increase as the cube of RPM so doesn't take much increase in rpm to increase braking.

If duramax goes above 5,000 it will shift up a gear regardless of what the gear slector is in. That's why the tach goes to 5K. And why GM eliminated the redline above 3200 because people weren't reading the diesel suppliment owners manual on how the grade brake/exhaust brake works and what rpm it can go to.

To the OP's comment. I had (son now has) an 04.5 duramax with grade brake only, and now a 15.5 with exhaust brake. While the grade brake feature provides significant retardation, it is no where near as effective as the exhaust brake.

[Chris_Bryant]

Old-Biscuit wrote:
"In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph."

2003 Duramax LB7-----REV Limiter set at 3250 rpm

The rev limiter won’t do anything for an engine braking over-rev, but if it’s limited to that 5k can’t have been good for it.

[Old-Biscuit]

"In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph."

2003 Duramax LB7-----REV Limiter set at 3250 rpm

:H



I have a US Gear 4" exhaust brake on my 5.9L Cummins
Truck/trailer combo 22k
Exhaust brake 6% grade----55 mph
Glad to see exhaust braking OEM ------ great tool for diesel trucks