Using an Exhaust Brake

[cristn00]

I have an exhaust brake and was wondering if it would make sense to use it even when I am not towing. Just thinking it might save wear on the regular brakes. What are the pros and cons? Thanks

[branden.peterson]

I'm not sure of any cons, but I use mine all the time when not towing.

[Jim34RL]

On my 2008, Dodge with the 6.7L Cummins, I use my exhaust brake between 90% and 95% of the time. The only time that the exhaust brake feature is off is when I am on ice covered roads and or I forgot to turn the brake on. The engine control logic is set to default for the brake to be off on start up. You than need to manually turn the brake on sometimes it is not done until I am a couple of 100 feet or so down the road.

[DieselDrax]

Originally Posted by Jim34RL

On my 2008, Dodge with the 6.7L Cummins, I use my exhaust brake between 90% and 95% of the time. The only time that the exhaust brake feature is off is when I am on ice covered roads and or I forgot to turn the brake on. The engine control logic is set to default for the brake to be off on start up. You than need to manually turn the brake on sometimes it is not done until I am a couple of 100 feet or so down the road.

If you're handy with vehicles/electrical, there is a mod you can do that turns the EB on by default when you start the truck. PDF attached.

I did this with my 2007.5 Cummins and it worked like a charm.

[IchLiebeBier]

I use mine all the time (except when slippery conditions). My understanding is it does three main functions I care about:

1. Helps save the brake pad wear and tear
2. Helps warm the engine up more quickly
3. Helps with the regen

Just remember to turn it off when your trip is done so the EGR temp goes down more quickly.

[DieselDrax]

Originally Posted by IchLiebeBier

I use mine all the time (except when slippery conditions). My understanding is it does three main functions I care about:

1. Helps save the brake pad wear and tear
2. Helps warm the engine up more quickly
3. Helps with the regen

Just remember to turn it off when your trip is done so the EGR temp goes down more quickly.

EB has nothing to do with helping regen nor does it have anything to do with EGR temps.

[IchLiebeBier]

Originally Posted by DieselDrax

EB has nothing to do with helping regen nor does it have anything to do with EGR temps.

I'm gonna have to disagree with you on that one.

I can visibly watch the difference in EGR temps I monitor for shutdown after pushing the EB off.

The reason I say it helps for regen is because it keeps the temps up, which helps burn off the soot. That's my take on it.

[Lins]

Originally Posted by IchLiebeBier

I'm gonna have to disagree with you on that one.

I can visibly watch the difference in EGR temps I monitor for shutdown after pushing the EB off.

The reason I say it helps for regen is because it keeps the temps up, which helps burn off the soot. That's my take on it.

When mine attempts a regen at idle it kicks the exhaust brake on.

[IchLiebeBier]

does the switch light light up? just wondering how you know it does. I haven't had that happen yet.

[Lins]

Originally Posted by IchLiebeBier

does the switch light light up? just wondering how you know it does. I haven't had that happen yet.

No light I can hear it, it's obvious, just like when turning the exhaust brake on when the engine is cold (normally the exhaust brake kicks out at around 140 coolant temp at idle). In drive with foot off throttle and brake it stays on during the regen but as soon as I press either pedal it turns off. If I put it into park it goes up to 900 RPM, not the regular 1000 RPM for high idle. This is mentioned in the manual.

[DieselDrax]

Originally Posted by IchLiebeBier

I'm gonna have to disagree with you on that one.

I can visibly watch the difference in EGR temps I monitor for shutdown after pushing the EB off.

That doesn't make any sense, if the weather is warm or the engine is up to temp the EB doesn't engage at idle. Unless something changed, because my 2007.5 6.7L only engaged the EB with a cold engine at idle when enabled and when actually using the exhaust brake to slow down. EB on or off with an engine up to temp never made a difference at idle and I monitored temps with an Edge Insight CTS2.

I'm also not sure why you care about EGR temps for shutdown, pre-turbo EGT is the important temp. EGR means nothing.

The reason I say it helps for regen is because it keeps the temps up, which helps burn off the soot. That's my take on it.

This doesn't make sense, how does closing the vanes to engage the EB help keep temps up? The exhaust temps are needed to increase the DPF temp to burn soot into ash, blocking exhaust flow isn't going to help keep the DPF hot enough, let alone help the regen. This has been discussed on the Cummins Ram forums, activating the EB does nothing for regen one way or the other.

So, I guess we'll have to agree to disagree on this.

[ard58]

[QUOTE=DieselDrax;2078548]That doesn't make any sense, if the weather is warm or the engine is up to temp the EB doesn't engage at idle. Unless something changed, because my 2007.5 6.7L only engaged the EB with a cold engine at idle when enabled and when actually using the exhaust brake to slow down. EB on or off with an engine up to temp never made a difference at idle and I monitored temps with an Edge Insight CTS2.

I'm also not sure why you care about EGR temps for shutdown, pre-turbo EGT is the important temp. EGR means nothing.



This doesn't make sense, how does closing the vanes to engage the EB help keep temps up? The exhaust temps are needed to increase the DPF temp to burn soot into ash, blocking exhaust flow isn't going to help keep the DPF hot enough, let alone help the regen. This has been discussed on the Cummins Ram forums, activating the EB does nothing for regen one way or the other.

So, I guess we'll have to agree to disagree on this.

X2. Been diesel mechanic, cummins/cat, all my life, 40+ years and your correct, EB has nothing to do with regen, egr temps, or warm up. If EB activated at idle engine would most likely die.

[DieselDrax]

Originally Posted by ard58

X2. Been diesel mechanic, cummins/cat, all my life, 40+ years and your correct, EB has nothing to do with regen, egr temps, or warm up. If EB activated at idle engine would most likely die.

Well, both GM and Cummins allow the EB to partially engage at idle when cold to put a load on the engine which helps the engine warm up faster. It’s not fully engaged.

Not sure if Ford has a similar function or not but this is a well known and documented feature of the Cummins and Duramax engines.

[IchLiebeBier]

Originally Posted by ard58

X2. Been diesel mechanic, cummins/cat, all my life, 40+ years and your correct, EB has nothing to do with regen, egr temps, or warm up. If EB activated at idle engine would most likely die.

From the manual:
Operating the exhaust brake at idle will greatly improve warm up rate and will help keep the engine close to operating temperature during extended idle.

So clearly the engine won't die.


I didn't say it was designed to affect Regen or EGR temps, but how can it not? You close off the exhaust to redirect it back to the engine instead of venting out the back of the truck. Of course the EGR temps will go up. It's a closed system. And since the system heats up, wouldn't that contribute to soot burn off?

As far as EGR temps for shut down, I concur. Pre turbo is better. But if you don't have a pre turbo probe, you have to monitor something. So I monitor the one closest to the turbo. And agree or not, I can tell you, with absolute certainty, that shutting the EB off drops the EGR temp immediately.

[ard58]

Well, both GM and Cummins allow the EB to partially engage at idle when cold to put a load on the engine which helps the engine warm up faster. It’s not fully engaged.

Not sure if Ford has a similar function or not but this is a well known and documented feature of the Cummins and Duramax engines.

Point well taken. Medium duty engine operated somewhat different than heavy duty engines.

[Lins]

Attached are some pics from October when the truck wanted to do a regen at idle. It's with an older app that I don't use anymore and I couldn't get it to download values at lunch to show what commanded and actual values are at a regular idle - with or without the EB button pressed. I'll try again at some point. You can see it wants 900 rpm and shows a high value for the turbo

[DieselDrax]

Originally Posted by IchLiebeBier

I didn't say it was designed to affect Regen or EGR temps, but how can it not? You close off the exhaust to redirect it back to the engine instead of venting out the back of the truck. Of course the EGR temps will go up. It's a closed system. And since the system heats up, wouldn't that contribute to soot burn off?

The EGR valve is not always open, engaging the EB doesn't automatically increase EGR temps. If the EGR valve is closed then it's closed, no hot exhaust air is flowing through it and back into the engine regardless of EB state.

The regen has nothing to do with burning off soot in the engine. The regen is 100% for the DPF and turning soot to ash when needed due to the differential pressure sensor indicating that the DPF is blocked enough to warrant a regen. Engaging the EB would block exhaust flow through the DOC and DPF, reducing temps and hurting the ability to complete the regen.

As such, the EB would hurt, not help, the regen if it were to engage at idle on a warm engine during a regen. Since it doesn't engage under those conditions it has no impact. I can't explain why you see EGR temp differences on a warm/hot engine with the EB on vs off, doesn't make sense since the EB simply doesn't engage if the engine is up to temperature as that would just put unnecessary load on the engine and consume more fuel at idle while not actually helping anything.

As far as EGR temps for shut down, I concur. Pre turbo is better. But if you don't have a pre turbo probe, you have to monitor something. So I monitor the one closest to the turbo. And agree or not, I can tell you, with absolute certainty, that shutting the EB off drops the EGR temp immediately.

Have you turned the EB back on again and seen the temps go back up? I'd love to see a video of this phenomenon showing it goes down with the EB off and back up with the EB on. If it doesn't go back up with the EB on then how do you explain it?

[jtesta1]

When you do a couple of donuts and end up in the ditch. You may realize brakes have abs for traction control, exhaust brakes don't. They shouldn't be used when empty or on wet or icy roads.

[DieselDrax]

Originally Posted by jtesta1

When you do a couple of donuts and end up in the ditch. You may realize brakes have abs for traction control, exhaust brakes don't. They shouldn't be used when empty or on wet or icy roads.

You better let Ram/FCA know this, they say it's fine to use when empty to help maintain speed down hills and increase service brake life. I wouldn't use it when empty on icy or snowy roads, but Ram/FCA also say not to do this as well.

There's no problem using the EB when empty if the roads aren't slippery.

[cristn00]

Thanks folks, So far it looks like the consensus is use it if you have it BUT don't use it on slippery road conditions with no load.