Exhaust Brake

B585Ford

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With a lot of help from Dzchey21, Tadd, and Haller, I was able to make a program that uses the VGT as an exhaust brake. It definitely does help slow the truck down and IMO it sounds good, but it's not too aggressive. It doesn't slow you down as much as some other trucks I have rode in, but IMO, it is better than nothing. Right now, I haven't figured out a way to make it engage at only one power level, but I am still working on it. Right now, it engages every time you completely let off the gas.

I will try to get screen shots and videos, but for anyone looking to try it right now, all you need to do is go to all of the "Desired Exhaust Backpressure" tables (there are 12 of them) and change all of the numbers on the X-axis on the "0" Torque line to "50". You can raise that number so it works harder, but that number does what I want it to do. It will depend on your RPMs/speed, how steep the hill is, etc. but unloaded I usually only see in the mid-30s for EBPs. I did try only adjusting one table, "Desired Exhaust Backpressure Hot Engine 1", but it never did kick in with only table modified.

I drive a stick so I can't help anyone on deciding how to lock the TC/Transmission tuning.
 

B585Ford

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I have found the exhaust brake works when the engine is above 150 degrees ECT by just modifying ONLY the first two "Desired Back Pressure" tables (Table 1 and 2). I haven't found a way to make it engage on only one power setting yet. If you the exhaust brake to be on at any engine temp, modify all 12 "Desired Exhaust Back Pressure" tables. If you want to use it only when the engine is warm, just modify the first two "Exhaust Backpressure Hot Engine 1" and "Exhaust Backpressure Hot Engine 2".

Here is a screen shot of two of the tables.


View attachment MCCExBrake.pdf
 

Dzchey21

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You can tell it's working because the boost is also up to about 5 psi even coasting. Which also helps stopping power because your forcing air in the cylinder to compress further.

Nice work
 

WoodBoy

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Have you tried it with a load? Im just curious to why the big name tuners aren't including this with the tow/haul button or tow tune?
 

UpstateDieselGuy

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It looks like you are definitely on the right path. My question is this, on the 6.0's and 6.4's you can press the Tow/Haul Button which uses the VGT to slow exhaust as well as alter the shifting schedule. I would love to look into a manual and see how the button interacts with the PCM. It has to either apply or remove power to cause the alteration. Imagine being able to do the same with your tuning at the flip of a switch.

Chris
 

B585Ford

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Have you tried it with a load? Im just curious to why the big name tuners aren't including this with the tow/haul button or tow tune?

No, not yet. I don't do much towing in the winter. I was going to wait on this but I might have to move about 26k (dozer and trailer) if the regular truck isn't fixed. There's a real nasty hill so I figured I needed all the help I could get.
 

B585Ford

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It looks like you are definitely on the right path. My question is this, on the 6.0's and 6.4's you can press the Tow/Haul Button which uses the VGT to slow exhaust as well as alter the shifting schedule. I would love to look into a manual and see how the button interacts with the PCM. It has to either apply or remove power to cause the alteration. Imagine being able to do the same with your tuning at the flip of a switch.

Chris

We are just scratching the surface on MCC, but looking at the tables, my guest at this time is no. Unless there is another way to make the exhaust brake work or unless "Hot Engine 1", Hot Engine 2", etc. is actually linked with the Tow/Haul switch, there doesn't appear to be a way to do this. Keep in mind, my statements are definitely not FACT, just my best estimate at this time based on very limited experience. Since I don't have an auto, I can't test those theories. I am hoping someone with an auto makes one so we can compare notes.
 

B585Ford

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Here's a little update on which tables work and which don't so hopefully it will help to figure out what Hot Engine 1, 2, etc. are referring to:

Changing all "Desired Exhaust Back Pressure" tables - the exhaust brake is always on
Changing Table 1 called "Desired Exhaust Back Pressure Hot Engine 1" - exhaust brake never worked
Changing Table 1 and 2 "Desired Exhaust Back Pressure Hot Engine 1" and "Desired Exhaust Back Pressure Hot Engine 2" - exhaust brake worked all the time on all power levels once the engine reached about 150 degrees or hotter
Changing Table 1 and 3 "Desired Exhaust Back Pressure Hot Engine 1" and "Desired Exhaust Back Pressure Hot Engine 3" -exhaust brake never worked

So far, I can't find a way to activate on only power setting.
 

Fordguy100

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How does it activate? Or is the BP always around 50 when driving and you only notice the "exhaust braking" when you let off the throttle?

If you can find a way to allow it to open up when driving, and close the VGT down when on the brake, you got yourself a winner. Otherwise with high BP your going to hurt fuel economy.

I heard the 6.0 has a few tunes that does this, I would love to get one.
 

B585Ford

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How does it activate? Or is the BP always around 50 when driving and you only notice the "exhaust braking" when you let off the throttle?

If you can find a way to allow it to open up when driving, and close the VGT down when on the brake, you got yourself a winner. Otherwise with high BP your going to hurt. fuel economy.

I heard the 6.0 has a few tunes that does this, I would love to get one.

It activates everytime you let your foot completely off the throttle. EBP is 3 to 4 PSI when you are in nuetral or idling. EBP is the same as it was before doing the exhaust brake when you were giving it the gas. To build EBP, your engine has to be spinning....in general, the higher your RPMs, the higher the EBP which gives you more braking. When I am at 1400 RPM or lower, I cant build much EBP. For my setup with a stick, I like to have active all the time but I can control my gearing which is a big advantage. For autos, if you didn't want it active at lower RPMs, you could adjust it to activate at any RPM. If anyone is interested in that send me a PM and let me know what RPM you want it to kick in and I will send you a screen shot of what to do.
 
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B585Ford

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How does it activate? Or is the BP always around 50 when driving and you only notice the "exhaust braking" when you let off the throttle?

If you can find a way to allow it to open up when driving, and close the VGT down when on the brake, you got yourself a winner. Otherwise with high BP your going to hurt fuel economy.

I heard the 6.0 has a few tunes that does this, I would love to get one.

I usually run version. 42 but I made this program based off of version. 40 on accident. My lie-o-meter actually says I am getting a few tenths better gas mileage with the exhaust brake. I haven't done any calcs but based on the mileage I am seeing per tank, I cant appreciate any loss....if there is loss, it has to be minimal.
I don't know you could make one that only activates when you press the brake. Go back and watch the vid of the MM, it is blurry but you should be able to that the 3rd number down is EBP so you can get a better idea of what to expect.
 

powerstroked08

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I was apparently doing some of the same things as you were b585:)! I guess i need to check on here more often. Anyhow i have my back pressure set to 55 at around 3000 and then stepped it down to 50 at around 2000 and then to 40 at 1500. Then i have to bp "normal" for all rpms below 1500. It seems to work well for my truck since i cruse through my towns usually at 1300-1500 rpms and id rather not have the truck trying to slow down every time i want to leave off the throttle to coast. Once i figure out how to post a screenshot i will post it.
 

Dzchey21

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I was apparently doing some of the same things as you were b585:)! I guess i need to check on here more often. Anyhow i have my back pressure set to 55 at around 3000 and then stepped it down to 50 at around 2000 and then to 40 at 1500. Then i have to bp "normal" for all rpms below 1500. It seems to work well for my truck since i cruse through my towns usually at 1300-1500 rpms and id rather not have the truck trying to slow down every time i want to leave off the throttle to coast. Once i figure out how to post a screenshot i will post it.

That's a good idea
 

B585Ford

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I was apparently doing some of the same things as you were b585:)! I guess i need to check on here more often. Anyhow i have my back pressure set to 55 at around 3000 and then stepped it down to 50 at around 2000 and then to 40 at 1500. Then i have to bp "normal" for all rpms below 1500. It seems to work well for my truck since i cruse through my towns usually at 1300-1500 rpms and id rather not have the truck trying to slow down every time i want to leave off the throttle to coast. Once i figure out how to post a screenshot i will post it.

Yeah, like I said my earlier post, I am guessin the guys with auto would not want it to kick in until the TC is locked?

I have made a program like you did with different EBPs at different RPMs, but on the country roads, I do like it on all the time. I would definitely not have it on all the time if I plan to do some Interstate driving.

Hey, I think I figured out a way to make it brake more without raising the max EBPs too. I got home late tonight so I only got to test it on 1 hill, but it seemed to work better by altering the Vane tables....I could get more EBP at lower RPMs.

If you get a chance, send me some numbers as to what EBPs you see at a certain RPM. For example, tonight in 2nd gear at 2000 RPMs I got my EBPs to the high 30s. I am curious since we run different turbos, different up pipes, etc. as to what influence they have. Until I played with Vane tables, most times I couldn't get my EBPs anywhere near the 50 EBP that was desired. So far, it seems like I get the highest EBPs when letting off in OD going about 100 MPH. That is the only time I got my EBP to 50.
 

drunk on diesel

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do you have your vane control maximum cranked up in those ranges?

Also, I've seen some tunes with people setting vane control at 0 and 100. I don't know if the 6.4 is the same way, but back when I had a 6.0 style VNT turbo on my Dodge, Fleece recommended using 2-3 as "0" and 95-97 as "100" so as not to peg out the solenoid. Don't know if this holds true for the 6.4's VNT controller
 

drunk on diesel

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I tried this today. Don't really care for it just driving around, but may mess with the concept some more this summer in Colorado
 

Dzchey21

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I know we are missing some tables for the brake pressure to activate a more aggressive downshift schedule. I sure wish we could use that to help with exhaust braking
 

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