Need some guidance 06 5.9 cummins auto. stock

So I am new to hp tuners and diesel tuning all together. I just don't know where to start. I have read though a lot of these forums just to get a feel with what needs to be done.

What i have been doing to far is smoothing out the desired fuel pressure map and also main injection pulsewidth map. I have also smoothed the pedal map steady state just a little bit. But I don't know where to go next.

I looked at the timing calculator spread sheet but the desired timing final does not look right. All of then numbers are positive. When I look at my main soi timing map the numbers are way different.

What am I doing wrong and what else should I be making changes on?

Don?t smooth your pulsewidth table at all! This will just throw things way out of whack. Don?t rely on a timing calculator to ?make things right? either.

Go back to a pure stock tune. Data log the piss out of it to see where your truck runs and what?s going on through the data logs. Pick a region to start with like cruise speed at 50mph, look at your data logs to see where everything is running in the tables at that speed, then one change at a time just do something like reduce rail pressure 5mPa, data log, see how it feels, and see what the data log shows you with that change.

Don?t just blindly start smoothing every single table and throwing numbers into a timing calculator with no idea what anything is or how things work! One change at a time, test, review, repeat.

What am I really looking for on the data log? Like what conditions should I be seeing for the power side vs the eco side of things?

Look at rpm, fuel quantities, rail pressure, duration, air flow, timing, throttle position, boost pressure, ambient pressure, to name a few, compare what you see in a data log to the tables in the tune file to see what the data logs are telling you for what spots you are running in in those tables to learn how they are all connected and interact with each other. This is where learning needs to begin.

So i cant make since of the timing map. I keep reading about where everyone is putting their timing but i don't know if i am looking at the wrong map or if the stock timing is just that low on a stock engine. what does the negative numbers mean? Is that atdc or before btdc?

I wouldn?t worry about where other put their timing. 0 degrees is top dead center, anything positive is before top dead center and anything negative is after top dead center.

ok so I get your concept of wanting me to see what parameters are moving around as I am driving. But I can look at this all day long and still not know what I should be looking for if I can not compare to what everyone else is doing? I am a gas engine tuner and I know what all of those specs should look like once it is all said and done but on a diesel I have not idea what thing are supposed to be. Do you have anything that I could reference on what a nice clean data log should look like?

There's a bunch of tunes posted to this forum, dig around a bit. Download a couple tunes for reference and compare them to yours. ATDC timing is very beneficial in some circumstances, such as spool up and transient load conditions going from light to full load. Even if you download a tune for say an 03 or something, the timing tables and concepts will be very similar and will show you what you should be looking for.

HP Academy has a couple ?diesel courses? worth checking out for beginners to get the most basic of basics of fundamentals and understanding of a diesel engine. They don?t go very deep at all into diesel engine tuning, hardly even scratches the surface of it but they cover the most basic of basic fundamentals of it to get people towards the right direction and I would recommend them to someone starting out in diesel tuning.

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Originally Posted by darens

ok so I get your concept of wanting me to see what parameters are moving around as I am driving. But I can look at this all day long and still not know what I should be looking for if I can not compare to what everyone else is doing? I am a gas engine tuner and I know what all of those specs should look like once it is all said and done but on a diesel I have not idea what thing are supposed to be. Do you have anything that I could reference on what a nice clean data log should look like?

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A diesel is no different than a gas in how nice and smooth timing ramp in and out should be, no peaks and valleys under consistent load. Diesel timing does ramp in a little quicker per equivalent rpm compared to gas but you're still chasing MBT. Do not fall for the timing calc trap, no timing calculator knows your exact injector delays, current cylinder temp, or boost pressure so it will not know when and where your max cylinder pressure is occurring or where to place that pressure for that matter. Remember you only spray enough fuel to produce the power you're wanting to produce, and there is no such thing as too lean, you'll just have a lack of power or stall the engine. Watch boost pressure vs exhaust pressure as a ratio to make it easier, and keep exhaust BP as low as you can while still achieving your desired boost. As for WOT keep it under 2:1 exhaust BP to boost. Finally just Relax some, it's honestly hard to mess up a diesel unless you do some really advanced timing in higher load areas.

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Originally Posted by Jim P

HP Academy has a couple ?diesel courses? worth checking out for beginners to get the most basic of basics of fundamentals and understanding of a diesel engine. They don?t go very deep at all into diesel engine tuning, hardly even scratches the surface of it but they cover the most basic of basic fundamentals of it to get people towards the right direction and I would recommend them to someone starting out in diesel tuning.

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It's funny you say that because i thought the same exact thing about that course. It'd just get to the point of actually teaching something good and then move to the next topic instead of going into detail as i feel they should have. It has to be somewhat frustrating for those needing/wanting to learn a little bit more. But i take it for what it is, a course to teach the basics to people who don't have much experience. Andre, the original HPA guy did a good video on VNT/VGT turbos and showing how to setup and tune boost control using the Motec.

Yea, like I said, barely even scratch the surface with diesel tuning but they bring forward some important stuff and give enough to begin the understandings of a diesel engine. It?s really just help get those with zero knowledge somewhat familiar with some basic concepts and understanding. From there a person needs to learn how the ecm operates and how they tables relate, this comes from data logging and testing. I haven?t watched the VGT/VNT turbo setup video, I imagine how cummins controls the VGT turbo is quite different from how the motech does. Definitely not the same as GM if you watch HPA second diesel course when Nick touches a tiny bit on the turbo.

Ok so I have been reading through all of your information and others. Like on a gas engine your set your fuel pressures first. Then you you set a safe ignition timing to start dialing in your injector pulse width and then your start putting more timing in watching your egts to where you are wanting them. Is this not what you would do on a diesel? This is what I was starting to do from the beginning but I was told not to?

What you stated you were doing was smoothing out your pulsewidth table(not recommended on stock injectors, wouldn?t even recommend on 200hp injectors, this table defines your actual injector flow characteristics) and you were using a timing calculator spreadsheet and smooth out other tables.

On the 5.9L I set fuel pressure in the cruise region between 12.5kpsi and 14.5kpsi, where?s the cruise region for you? Who knows till you datalog and figure it out where in the tables you are running.

Timing isn?t quite the same in a diesel compared to a gas engine. Diesel relies on heat and you got a vast multitude of variables that affect in-cylinder heat and where in a cycle auto-ignition of the fuel will occur, thus affecting power, fuel economy and emissions.

Boost goes up, less timing needed as boost creates more heat, fuel pressure goes up, less timing is needed as the pulsewidth needed is less given same fuel quantity with higher pressure. The goal to get the most energy out of the fuel injected is for the middle of the combustion event, not injector open time, but combustion event to be a few degrees after top dead center. That?s from when pilot fuel begins igniting to the end of the late combustion phase, the middle of that a few degrees after top dead center. Break out the thermodynamics books to calculate that out.

There are so many ways to reach an end goal. It?s best to begin with a basic understanding of the Diesel engine, learn how your ecm operates and how the tables interact with each other and what they do, make one change at a time and see what it does, how it feels, do you like the result from the change? Or do you hate the result from the change? Change 20 things at once and hate it, which change is causing you to hate it? Who knows. Go with the changes that give the result of what feels good to you. This is what pretty much everyone else does.

So I do know how a diesel works. I know about enough about thermodynamics to know you will never know how to set a fixed timing that will work for everyone. Its all based off fuel pressure and pulse width and spray pattern of your injectors and temperature. I know adding boost to any engine increase combustion temp. On a diesel higher combustion temp means faster the fuel will ignite so you would decrease timing. Its fine if you all don't want to give up your secrets on tuning I get that. But if someone calls me on an generic sbc running on the street I can tell them a good place to start on fuel pressure, timing, injector pw to get them started. I understand that diesels are different but I still think there is good starting points out there. Like when you said 12.5kpsi and 14.5kpsi in the cruising region. That is experience with the 5.9 that I am looking for. Some that has a go to when they start setting up one of these

Where I set fuel pressure at Cruise on a 5.9 is my preference. It may not be others preference. It?s up to you to determine what you want and what you like is the point. There is more than one way to skin a cat. And I?m not trying to be a dick about it but when someone has no idea what a positive or negative timing number is, it raises flags... thus brings about the preach of learn first.

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Originally Posted by darens

So I do know how a diesel works. I know about enough about thermodynamics to know you will never know how to set a fixed timing that will work for everyone. Its all based off fuel pressure and pulse width and spray pattern of your injectors and temperature. I know adding boost to any engine increase combustion temp. On a diesel higher combustion temp means faster the fuel will ignite so you would decrease timing. Its fine if you all don't want to give up your secrets on tuning I get that. But if someone calls me on an generic sbc running on the street I can tell them a good place to start on fuel pressure, timing, injector pw to get them started. I understand that diesels are different but I still think there is good starting points out there. Like when you said 12.5kpsi and 14.5kpsi in the cruising region. That is experience with the 5.9 that I am looking for. Some that has a go to when they start setting up one of these

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I think you're over thinking this which is why i said relax and enjoy this process, Diesels are so much about how you personally want it to drive, yes there are averages of what has and will work, they are all over this forum. But if you want something to stand by for every 1000us of injector open time you should be close to 10* to achieve MBT. But as it's been stated well by Jim P and Dom_c13b, negative timing can do great things for spool time which goes against what i just said. If that spool region over lays your cruise region you'll get worse mileage. But the turbo response is there, do you see where we are going? We are saying There is no "perfect tune" for a diesel like a gas engine, it's all on how you like your truck to drive. The reason this is true is because we are using all that heat to drive the piston with positive timing, we have a set amount of heat to release so releasing it sooner leaves little heat left over for the turbo's turbine to use. We could add more fuel with more timing to keep the turbo lit and make more power but that negatively effects mileage.

One thing I will say to keep things within a safe limit in the upper end when dealing with pulsewidth and timing, a safe maximum timing is 1*BTDC for every 100us of injector open time. This has been stated throughout the forum in a different format, a clean safe max effort tune for a stock truck is 3200us pulsewidth and 32*BTDC. Yes you can push timing up more and stay with limits but better know what you are doing and use a dyno to play it safe to not exceed limits.

So what is better then. Less fuel pressure with longer pw and more timing or higher fuel pressure with shorter pw and less timing? I would think more fuel pressure would be better for atomization but why dont you just ramp up the rail pressure a lot faster then what some of these tunes are showing. Is it hard on the pumps and injectors?

Completely depends on what you are looking to do. More pressure doesn?t always mean better.

Attachment 98327

Is there a way you could look at this log so far. Its kind of a long log but this is what I have. I am just wondering if I am going the right way and making sure it is still safe. I hope this upload works ok