Sea Level vs Altitude Tuning
 

:postwhore: :cancan: In celerbration of my 200th post, I decided to start another thread:cheesy smile: :party2: :postwhore:

being that I am at 6000 ft and that there are obvious differences between Flatlander and Mountain Man tuning, I would like to get more input on this subject...

seems to play a role in Fueling and injection timing as there even separate settings for sea level and altitude in the programming... even for WOT shifting...

The Turbo in general is supposed to offset the effects of altitude found in naturally aspirated engine. So I am wondering why the altitude parameters are needed...
Oh, and at what elevation does the altitude parameter start to function? is that adjustable?????

For Jack I think the parameters would be even more significant for the Gassers being they are naturally aspirated

I can talk about what I've highlighted:

Any kind of air compressor can only boost pressure relative to the outside (ambient) pressure. At sea level, the compressor is going to push more air into the engine than it can at 6000+ feet. (Up on Pikes Peak, the effect would be even more pronounced). So, you are still getting the effect of a change in altitude even with the blower and, the fueling will have to be adjusted for it.

To give you "numbers", at 18,000 feet, (only 4,000 above Pikes Peak), you are at 1/2 standard sea level atmospheric pressure (14.7 psi), so at 18,000, the pressure is only 7.35 psi. A good turbo might give you a 40% boost, I think. At sea level, this means your intake "sees" about 20.6 psi, which really improves the engine's power. But, if you could take that turbo to 18,000 feet, the same 40% boost gives you a total of only 10.29 psi, much less than an unblown engine at sea level.

A turbo DOES allow you to run your engine at a higher altitude than an unblown one, which is why reciprocating aircraft engines might have them. But, as with all things, there is still an upper limit.

- Jack

4500 ft.

There is a "baro transfer" listing in the definitions. That would change the PCM's perception of your elevation but I am not sure how it works (as far as how to change it to correct for anything), but I know how the "map transfer" works.

Notice that the high altitude SOI is not changed for you........

Ok I found a calculator for Barometric pressure online and it says I am at 11.77psi at 6000 ft. being that most of my driving is at 5000-8000 feet how do i get the turbo to add that extra 3lbs of boost.
what sort of change should I make to these settings
low boost fuel (altitude)
Injection timing (altitude)
I would think with less air pressure the boost is going to come on later so less fuel (lower boost fuel settings) should go into the engine and go in earlier (more advanced timing) as less oxygen to support combustion

Torque Table Altitude & Torque Friction Table Altitude: do these need to be changed or are they already compensated from the factory... and what purpose do these maps serve... (i don't see how friction loss changes at altitude) same goes for the sea level map... do other parameters use the values in this map to calculate other factors like mass fuel desired etc?

There is also the Barometric Multiplier and Torque Multiplier vs Baro not sure what these do either
I already set the altitude offset for the WOT shifting higher by 200rpm as I lowered the WOT shift point anyway

Well You can't really look at boost as a percentage esp with diesels as there are quite a few diesels runing upwards of 50 PSI boost pressure :yikes2:

I don't think you're right here. Everything I've read on turbos says the good ones give a 50% boost, not 50 psi, but that since you don't get perfect efficiency out of it, you might see a 40% boost. 50 psi is about 3.4 atmospheres! That would be an enormous amount of air. You'd be burning 3.4 times the unboosted fuel volume just to maintain the correct A/F ratio!

And, there's simply no way a turbo could maintain that 50 psi boost as ambient air pressure drops. (How much boost would you get in space?) The boost value HAS to be a percentage of the ambient pressure, not a fixed pressure value.

I see I forgot to congratulate you on passing the 200 post milestone. :o I meant to, and I enjoy your thoughts.

- Jack

Jack we are talking Diesel here, NOT wimpy gassers:smiley_roll1: heck the old 5.9 cummins on my RV can hit about 28 PSI of boost.. remember Cody's post about air/fuel mixtures for diesel vs gas????

Where the heck are you getting the power to drive this blower? It's got to come from somewhere, and I doubt a turbine in the exhaust could supply it.

Is it a belt driven supercharger? And, even then, that much boost (at sea level) takes an enormous amount of power. You're talking a 340% increase!

You're dead right, southpaw. I know next to nothing about diesels, but the numbers you're quoting just seem way out of line.

I'm happy to have my opinion changed though. Just point me to one of these beasts that can produce those numbers and I'll crawl back under my rock. :)

- Jack

Well just look at the boost gauge in any stock or modified diesel there is a reason you can buy 60PSI boost gauges.. But we are really getting off topic and would be better in a new thread as I would really like to get some feedback on the subject of this thread:sigh:

Bill will have to answer the rest. I don't know.

Ok so I was right on the Timing, I remember reading something about someone doing dyno testing in Boulder then they went back to the flatland somewhere and said they had to retard timing 5 to 10 degrees.... that seems like a lot to me but who knows. So I want to add fuel for the low boost to try and help it spool up quicker... guess i need a different turbo :rofl: and injectors.... :D Ill wait and see what Bill has to add... Having been at Edge in Utah he must have had an opportunity to work with some high altitude tuning

Question For BILL
 

I was looking at the ALtitude and Sea level Timing maps and what I see is the pic below, My question is that the sea level tunes are all different, showing 6 different maps yet the Altitude map is the same for all six maps... Do I need to copy the Maps from the sea level over to the high altitude map for each tune or is the high altitude disabled somehow... :confused:
If so, I am open to suggestions on how to figure out by how much to change the altitude maps.... I/ or You can remove the image link if you want as its propitiatory
http://i77.photobucket.com/albums/j6...ltitudemap.png

I certainly don't think there's an issue with the graphic posted. Bill seems pretty ok with screenshots.

As far as the altitude table goes, the SOI is already higher than the sea level map in certain areas (and across the board on the stock map). I am not going to give potentially destructive advice on high-altitude SOI. Bill will probably be more helpful. I would THINK that it would be possible to "crank up the timing" on the high altitude SOI map....but I'm not going to say one way or another.

Now, Jack....

The thing we have to remember about diesel engines is that they use the control of FUEL to alter engine output. In a perfect (and naturally aspirated) world, there will always be 7.3L of air expelled per every two crankshaft revolutions. We know that's not possible due to volumetric efficiency and other factors that alter flow. That being said, there is A LOT of air being pumped through a diesel. Yes, it is possible to attain 30, 40, 70, 90, 120 PSI of boost; it's usually not really hard to do.

We need to get a little into engine mechanical design to see where this boost is coming from. First, the airflow potential comes into play. I've already discussed that. Secondly, the camshaft plays a very large role. Turbo diesel engines use a camshaft that creates very little or no valve overlap. This is very important because under high-load conditions there will be more pressure in the exhaust manifold-to-turbocharger plumbing then there is boost in the intake. If both valves were open at the same time (intake and exhaust for any given cylinder), what would happen? Passive EGR would be the result. We both know that's bad for performance. However, the downside to high drive pressure (pressure in the exhaust before it reaches the turbine housing) is that the pistons themselves are pushing against that pressure when the exhaust valves open....robbing power.

On a stock setup (99 and up 7.3L) the turbine housing (exhaust side) is very restrictive. This is GREAT for low-speed spool up. However, it begins to become a hinderance above about 2500 RPM....especially under load and ESPECIALLY with more fuel (chip, injectors, etc.). The pressures exerted on the turbine wheel are massive and the drive pressures can exceed 40 PSI on a stock (or near stock) truck. With 40 PSI driving the turbine wheel and subsequently the compressor wheel, there is a lot of "power" to drive the compressor at very high speeds.....this equals boost. Without getting into turbocharger maps and usage, it's easy to see where this boost comes from. Adding fuel at the right time or adding MORE fuel puts more heat into the drive side of the turbocharger. The more heat that is dropped across the turbine wheel (hot gasses expand as they cool) when the pressure is no longer there, the more efficient the drive to the compressor.

Now, with more correctly timed and injected fuel, the boost level will exceed 25 PSI. Using a stock turbocharger at these kind of boost levels is dangerous.....the drive pressures can skyrocket....like 60+ PSI on a stock turbocharger at boost levels around 30 PSI. Under load with a stock turbocharger, this means that there is the possibility of damage due to axial loading of the turbocharger shaft.

More boost does not always equal more power. Once the stock compressor housing creates about 25 PSI (changes with altitude), it's not efficient anymore and it is merely adding a TON of heat to the intake charge for the intercooler to try to cool off. Airflow (and quality of air) is far more important than a higher boost level on a near stock truck. Adding a more efficient turbocharger (I'll use the Garrett GTP38R ball bearing unit as an example) will allow more air to enter and exit the engine. The added boost from the larger compressor (even though it is shrouded/ported) is largely due to the amount of air it can move from the atmosphere into the intake tract. There is less resistance to shaft rotation with the ball bearings and the exhaust housing is less restrictive. This means more (or the same) boost levels as stock, less exhaust restriction (for the pistons to push on), and cooler pre-intercooler air temps.

My fingers are tired.

http://www.youtube.com/watch?v=9ITmlyKzzg8

http://www.youtube.com/watch?v=oB4Ug...eature=related

http://www.youtube.com/watch?v=hwQBj...eature=related

My favorite...The guys who put a boost/vacuum gauge on a diesel.
http://www.youtube.com/watch?v=ffO-Hmcgw7c&NR=1

Ok I think I am gonna leave all the WHY questions to you now Cody.. then at some point I am going to put them all in one thread and get Jack to make them a sticky... Excellent explanation as usual. I give it:2thumbs:

As for my previous post, It looks like the Timing is an actual setting and not a modifier? that's why I thought it should be different for each different map... Here is the Stock sea level vs altitude map
http://i77.photobucket.com/albums/j6...tocktiming.png
The part that is Highlighted in yellow I thought was interesting.. Reason being is that we know the burn(Combustion) time is a constant at the selected altitude.. so if the engine is turning faster you should need to start the Burn earlier given the same amount of fuel. Right?
so why does the stock setting retard the timing so much in the higher RPM's in that sea level map.. also it seems like there is a mid RPM range that requires retarding the timing a bit that I am wondering the reasoning behind it (is there another modifier somewhere in the parameters that justifies the retarding of the timing that I am missing)

What do you expect from a guy driving a Dodge:smiley_roll1:
And they even know their trucks suck cuz they never refer to them as a Dodge, always as a Cummins... cuz they know the packaging it comes in is :horsepoop:

Cody, thank you. That was a very good explanation of the details of diesel turbocharging and I appreciated the videos too. I had no idea it was possible to attain that much intake manifold pressure. I also hadn't thought of the undesirable effects of compressive heating on the air charge on the intake side. It's a bit of a balancing act, isn't it?

And southpaw, I really didn't mean to sidetrack the thread with an argument over the amount of boost possible. I was really just trying to answer one of the questions you asked in your first post: "The Turbo in general is supposed to offset the effects of altitude found in naturally aspirated engine. So I am wondering why the altitude parameters are needed..." And, I'm going to stand by my original response: That 28 psi boost you have at sea level is not going to be possible with the same turbo in Colorado Springs. Since the ambient pressure there is 11.77, you're probably going to see 23.5 psi. As the ambient pressure drops, the turbocharger has less input to work with - it cannot make something out of nothing. Therefore, altitude has to be a factor in any tune for the engine, right?

Since Cody's a moderator, southpaw, he can make any thread a "sticky" - I don't have to do it! And I agree with your opinion of his answers! :thumbs up yellow:

- Jack

I also need to ask Bill if I/he can post the last paragraph of page 36 of the Minotaur manual. its one of the best explanations about the importance of Oil selection for a diesel and its many functions....

Ok, My son went down for his nap so I was able to get my test tunes loaded along with the one Cody sent me... Ill go try them out after he is awake again...
One of my test tunes is with the torque converter locking in all 4 gears.. took a quick spin around the block and seemed drivable so thats a good start ...

The problem with tuning the 7.3L is that there is no table ANYWHERE that sets start of injection. There are numerous factors that come into play and the the SOI tables are just another "modifier". Injection pressure control, engine oil temperature, boost pressure, etc. all play a part in when the PCM DECIDES to initiate SOI. It's not a simple "oh, 7 degrees BTDC is the "timing" and that's it." The PCM bases fueling rates and SOI on a large number of things.

Here's a hint as to why the timing table has a dip in it. Compare the MFD in the "ICP desired" map. See a trend? As the ICP ramps up quickly, the SOI takes a dip. Increased injection pressure actually advances the ignition point of the fuel in the combustion chamber due to better atomization and higher fuel rate (more fuel in less time).

Higher boost pressures in the higher RPM ranges affect the ignition point as well. More boost = higher dynamic compression = earlier ignition point. So therefore, a slightly less advanced SOI.

here is a table I Just made that compares the Offset at altitude compared to sea level of the stock map as a way to look at different patterns.. I may put these values on a map just to see what it looks like in 3D
http://dygytalworld.ehost-services13...&pictureid=334

The highest advance group is at high RPM in the low to mid throttle range Based on the fact that there is a low mass fuel desired value (found in low torque demand situation).. which would most likely be found at high crusing speed... thus more advance under low load and best fuel efficency
oh the 55/2200 value is a typo, its supposed to be 9 not 90 heh

Ok, got out for a test drive this afternoon... the up down shifting issue is gone on both the tune Cody sent me and the one I made. both r are good except both and I even noticed it a bit in the 80HP tune what the the on mild acceleration the Torque Converter is a bit too firm when it locks. still tugs a bit when it locks in 3RD gear ONLY.... so need to figure out how to soften that one lockup then will be good to go.

The other tranny tune I did locking in all gears turned out to require a lot more pedal to move the vehicle than the other 2 tunes that i test ran so I think I would have to change the RPM to Mass Fuel Desired level and maybe the inferred pedal position to get it to work right... also the 1-2 and 2-3 were pretty harsh so need to soften those too... do i lengthen the lockup time or the slip time? it i want the converter to be locked as soon as it upshifts? ill try that later

I'm glad you got it figured out.

If you're still having issues with the firm TC lockup, look at the torque table in the RPM range in which it's giving you fits. I didn't mess with that map at anything above 2000 RPM if I recall...and it's pretty close to stock there along with the Lockup DC%.

Edit: I answered my own question regarding Pedal position and it didn't work just gave me DTC for low throttle position etc

You have a PM, DJ.

Ok spent some more time looking at the various Timing maps for The different tunes... The stock tim ing map seems to be a lot more complicated than the ones Bill is using in his tunes... I am guessing there was some software engineer at Ford that had nothing better to do.... My guess is they were running the engine on an Dyno and tuning the Timing and other factors to get the lowest emissions vs power output???

Anyway the one thing that stood out is that a lot of the stock timing curves seem to drop around peak torque and then rise again then taper off at high RPM after peak HP... Is there a reason for the drop around the 1600 RPM range as I am wondering if I need to preserve that in doing the altitude timing?

Also should the Advance come on later the same or earlier with the higher altitude?

Am I asking too many Questions???

Well I got a chance to play a bit an made changes to the Altitude maps for each tune's injection timing... seemed to work good so did some more tweaking with the maps and just loaded another set to run and see how they work...
the I got the Fuel Sipper Tune working real well with the modified shift points and using the stock TC lockup map etc... nice and smooth... Didn't get to agressive with the timinng for now.... Kinda want to wait on Bill's thoughts as I am sure you have done a fair amount of High Altitude tuning....
Need to test where I get excessive smoke before changing the Low boost fuel... took it down slightly on the 100hp just to see what happens

DJ,

It's great that you're getting to look at what is going on here and making changes that work for what YOU want the truck to do. That's the whole point of custom tuning.

Nobody would care about custom tuning if Ford made the trucks the way they SHOULD have been built but weren't. Although, the engineers had emissions standards they had to meet to make the ECO-NAZIS happy while making a truck that wouldn't tear itself in half in less than 36K miles.

Good job, DJ, I'm glad that you're getting closer to your goals!

Where have you ended up, DJ? Any updates on your progress? Are you happy with what you have developed on your Fuel Sipper tune?

Inquiring minds want to know. Have you figured out the dead throttle when cold yet or can I give you a hint?


:giggle:

I just PM'ed Corey and she is gonna bug Bill to give us his input here... I did take a trip to Denver on Sunday with the Fuel Sipper tune and it was good.. gassed up at 18.1MPG. The throttle is more responsive now in that tune.. as for the Dead Throttle I didn't find the fix though I believe there is a setting for min trans temp or oil temp before the throttle will respond??? I tried increasing the Throttle pedal travel by grinding off the metal stops on the pedal and it just gave me errors over 90% or under 10% then the engine did not want to respond to the throttle so welded the metal back on and reset it to stock and its fine.... not sure why it only has a range of 10 to 86%. Again I think there is a setting to trigger high and low throttle position... not sure if it would make a difference if floored showed 98% instead of 86% though??/

DJ,

In order to not give away Bill's tuning expertise and secrets, I have "trimmed the fat" on this screenshot. This is the program in question vs. stock. Can you decipher WHY there is a dead pedal while the engine is cold all else being the same? The answer lies in these two maps.

Keep in mind that 40 degrees "C" is equal to about 100 degrees "F" and 100 degrees is a very cold engine and the actual additional pulse width above stock does not start to get multiplied until the engine temperature is above 22 degrees C (72 F). I don't know what the weather is like there but I haven't started the engine yet with the ambient temperature above 55 degrees and it takes a good while for the oil temperature (what the fueling is based on) to get to temperature.

Oh and as far as your data goes with APP percentage....what does the VOLTAGE say? The highest readable voltage that the PCM can compare to ground is about 4.75-4.8 volts. The software you are using may base 100% on a full 5 volts which is giving you the problem you are seeing.

Here is the attachment screenshot.

scratch this response I missed your comment on the previous page.... Ill read it then get back to ya

its easier to see once i put it in the graph format. That sure is weird at 22C. Like I said before, it must be that way due to some boneheaded emissions testing. Bet it would not be as obvious if I was running 5w40 synthetic, which i will be switching too next oil change. so if i raised that to the 3C level or so the dead throttle should go away?

another question, if i change the negative multiplier in the Adder to Pulsewidth Multiplier would that increase the boost levels? I guess it would be more accurate to call it a subtractor to Pulsewidth Multiplier

The thing I was trying to get at is that there is no pulse width multiplication above the stock values until the EOT is above 22 degrees C. Factor in that the low boost fueling is WAY LESS than stock at less than about 5 PSI and you have an absolute turd until there is some boost or until there is some engine temperature. You know that the accelerator pedal is even really "doggy" in stock when cold....well, it's even worse with this program due to the low boost fueling that has been taken away. If the numbers were to represent a percentage, there would be points of 10% less fuel in the Fuel Sipper program for any given boost/RPM combination.

You can put zeros or positive numbers in the "adder" map. It's not going to hurt anything. The PCM will not pull fuel under high boost.

I knew I read it somewhere, It was in the infamous 80E thread at PSN posted by Swamps.

"Firehunter: higher altitude = less dense air, which in turn means lower cylinder pressures and temperatures during the compression stroke, delaying the start of ignition. Advancing the injection timing under these conditions allows the start of ignition to begin at a more "optimal" point in terms of crank-angle than if the timing was left at a more retarded setting.

About 4 years ago Tadd (now Elite Diesel) and I got together at his old shop in Alamosa, CO (7500' Elev.) for a week of cylinder pressure testing and tuning on his dyno. We provided the truck with a fully built engine and everything on it and he provided the tuning, pressure transducer and scope. When I returned to Nashville (500' Elev.) I found that I had to pull 5-10* of timing out of the timing table we developed.

Aggie: Exactly--the injection delay table allows the start of injection, but even more so the start of ignition, to occur at the desired point in the engine cycle regardless of temperature or ICP pressure.
The pressure exerted on the injector intensifier piston is a function of the ICP pressure minus the pressure drop through the poppet valve. Higher viscocity oil resists flow, giving a greater pressure drop, so you end up with less pressure on the piston."

I dont think I added more than 4 degrees anywhere on the high altitude timing over what Bill had as sea level.. but I did change the high altitude maps to match his sea level maps then tweak from there... I want to wait and see what Bill's comments are on the the topic before getting to carried away. On a side note, I noticed when I tried doing a straight copy and paste I got similar aberrations to the map images on that thread that Bill posted... and the anomaly was on the copy map not the map I pasted too... Interesting, no? Then it would give an program error and shut down some of the time.


OH, I didn't compare that file you posted the image from to the stock map so I need to take a look when I get a chance.. Also got my Bluetooth keypad today so that will make working with the 3D maps nicer..

'Zactly! Especially the part about ICP vs. SOI. Most people don't catch that relationship and then wonder why their engines suddenly become air-cooled.

Okay... time to wear my fingers out.

The first thing you may notice is that the SOI table (fn1200) is curved while the altitude table (fn1201) is (more or less) linear. This is because fn1201 is an altitude adder to the base SOI. The amount added is not constant, but instead is a percentage value based on altitude. To be honest, I don't have a definite explanation on how the percentage is calculated in relation to altitude which is why in most cases I leave it alone and work with fn1200 instead. I'd be inclined to think that calibrations that have had to remove timing when dropping to sea-level may have had both tables modified and the PCM could no longer compensate for the change in altitude.

The "dip" in the main SOI (fn1200) map, as Cody indicated, is because of the inherent shift in SOI due to the increase in injection pressures. It is quite complex how all the maps interrelate with each other and overlooking any one component in the process can result in catastrophic failure. This is why I try to keep changes as simple and as few as possible.

Consider this...

10 years ago the only changes we made to diesel calibrations were functions 1104 and 1204 and we made 100 HP. Many people in the tuning business complain that this is NOT the way to tune engines. Part of me agrees, and part of me disagrees. The agreement comes from the fact that there is no RPM compensation for SOI so you may end up with excessive SOI at lower RPMs in order to achieve the desired SOI at higher RPMs.

The benefits from using these tables are quite clear. Since these tables are related to EOT, you can easily control at what temperatures the modified power curve comes on and this helps prevent excessive power output when the engine is below operating temperature. Also, since the fuel table (fn1104) is curved based on ICP, you can maintain a stock profile at idle/low throttle and progressively curve the fuel delivery based on driver demand.

There is no clear cut explanation on how to properly handle tuning these processors because the dynamics of tuning these engines is a bit more complex than people realize. P-pumped engines have much fewer tuning issues because the relative pressure of the injected fuel doesn't vary nearly as much and the timing curve is constant. Of course, P-pumps are louder throughout the RPM range while HEUI engines are relative quiet in comparison.

Anyway, I hope this helps a little bit. I'll get a bit more involved in this discussion as I get caught up on orders.

Take care.

How do I view the Maps by Address such as FN1200 I tried to select all, highlighting a single map etc and cannot get the view by address or ID to not be grayed out? for your explanation to make sense I need to look at those FN's and connect the dots, so to speak.
look forward to more of your explanation when u get caught up...:smiley_roll1:

Unfortunately, Addresses and Function IDs are disabled and I don't have any control over that. At some point, I can put the Function IDs in the description/name.

which one is FN1204 the others u named in your previous reply

Also am I correct in thinking that the weird looking maps for stock are somewhat related to Ford trying to optimize for emissions reasons. most of your maps seem to be a lot smoother and more linear curves.. Which seems to make more sense to me...

FN1204 = Start of Injection Delay. The one that looks like it has a valley running through the middle of it. FN1104 is a similarly shaped fuel pulsewidth multiplier table.

As for Ford's reasoning behind the maps, I don't have a reasonable explanation. You do have to consider that their tuning equipment and software was much less advanced than what we have today. When you consider where we are at with tuning nowadays compared to 6 years ago when 7.3L production was halted, the jumpiness of the mapping makes a little more sense, or is at least excusable due to limited development tools. Also, I'm not sure if they were doing steady-state tuning, loaded tuning, or what, but I'm fairly sure that they would plot along certain points in the maps and the fill in the blanks. That's my guess anyway...

Yay! My Mother-in-Law is here so I got to work on the truck today. Got all the O-rings and seals on the oil cooler replaced plus oil change and cooling system flush done...
Now back on topic, I have reread the posts in this thread a few times and it actually starting to make sense:skeptic: Think I am gonna make a flowchart of how the various parameters interact with each other... Will post it once its done...

to do a decel tune, which parameter(s) get the EBPV to close for engine braking? I have the torque converter lockup points done..