Part throttle boost (closed loop) tuning for FI

Discussion in 'Engine & Performance Modifications' started by Mr MoPar, Jun 7, 2009.

  1. HEMI911

    HEMI911 Platinum Supporting Member

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    Given the fact it will never be perfect, It seems like the ETC issues does not affect every one, is there any reason why some of us are having ETC issues and others are not?
     
  2. TALON

    TALON SRTV8

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    This has to be the best thread I've even read. Thanks for all the input, and knowledge.

    I've only had a Vortech V-3 blower installed for the last 3 months, and love it. I haven't had any issues to speak of other than a leaky injector, so I am a very happy camper.

    I now see the need for a EGT probe. I have everything else listed including a tuned Snow Performance Stage 3 water/meth unit. My Zeitronix unit has the ability to display the EGT function. The big question for me is, where could I mount the EGT probe on a 6.1L OEM exhaust manifold without removing it from the engine, if at all possible?

    Much Thanks in advance.

    Ken
     
  3. lafrad

    lafrad Supporting Vendor

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    The techco supercharger "draws through" the throttle body... it should be one that can be worked out without crazy amounts of trouble. there is never any boost pressure against the blade.
     
  4. Mr MoPar

    Mr MoPar New Member

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    You don't have to put it in the manifold, the cat mid pipes are easy to pull on the LX. I normally go to the drivers side, one because if there is going to be a difference in fuel it will be on that side because of the crossover line. Second, it is closest to the drivers A pillar.

    There is about 4 inches between the manifold flange and the top of the cat, put it in that section below the manifold flange above the cat, mark it before you pull the cat off so you know it will clear any obstructions in there.
     
  5. Mr MoPar

    Mr MoPar New Member

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    Thanks Mike, I figured this was what you were speaking of. These issues can be down right scary, in particular the run on. I am sure what I call touchy pedal is related as well, this is when a very light touch on the pedal causes the vehicle to suddenly take off, but that could also be connected to the acceleration circuit.

    Now, I can give you a bit of insight that may help in figuring this out. I ran a lot of ECU tunes for testing on my 300C. I saw various combination's of these issues. However, exact same vehicle, exact same system, exact same boost pressures, etc, when running the iEMS3 on an unmodified factory tune, I have never, ever had any of these issues pop up. This tells me that it must be something in the combination of tables modified for an ECU tune. The only other difference is that I am running the stock map sensor clamped. This might give a clue or shed some light on where to look. It has to be a result of something being changed or possibly something left out that may not have even been identified yet. If the vehicle does it on a modified ECU tune, and I can change it back to the iEMS3 10 minutes later and it does not have issues, then simply running the boost through the TB alone can not be the cause for it. Might be something to look into.

    Other than blow through versus draw through, I have to believe that some individuals are simply more successful balancing the changes than others. People don't tend to share their secrets when livelihood is on the line, and I can understand that.

    I really want to thank Mike for taking the time to actually explain what some of the changes in an ECU tune are for and what they can affect.
     
  6. Quick

    Quick Mgmt. - I can't help you

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    Why not? I don't think Mike is saying that it's a physical phenomenon but that it's calculations and a control problem. You're using different sensors and different calculations. Clamping the stock MAP sensor and using an addtional 2.5 bar sensor would be a major difference. You may simply be circumventing the problem.

    If you're using the ECU and manipulating a number of parameters for the desired control, it's possible it might not be a calculation problem. There is always the chance that your calculations are fine but a set of conditions you're creating is hitting a bug in the PCM programming (the executable code)? You may be outside of the envelope they tested within. Some set of conditions may be executing code paths that were never tested or you could be hitting unhandled errors. It might be something like rolling over a variable. Add too much to an n-bit variable and it either goes negative or rolls over to zero. Then things might take a bit to adjust/recover. Maybe unlikely but within the realm of possibility?
     
  7. Mr MoPar

    Mr MoPar New Member

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    No, I was not trying to imply that it is a physical problem, I have never believed that (the old boost holding the blade open). I am saying that it must be something in the modification of the data process. It could be some "bug" as you stated. The ECU program and information therein is extremely complicated, and things are being identified all the time. I am simply pointing out that it does not occur using the factory ECU program, clamping the 1 bar sensor, and providing the correct injector pulse to the injector during boost rather than trying to manipulate the ECU to calculate the correct pulse.

    I am using the factory sensors and factory programming. There are no calculations involved in trying to "calculate" a correct injector pulse length other than the factory calculations. When the vehicle is in the vacuum range, there is no difference other than the larger injectors, and as long as they are addressed, the factory calculations for pulse width are fine. When in boost, the iEMS3 provides the extended pulse width to deal with the additional fuel needs, there is no manipulation to try and make the factory ECU "calculate" what this is.

    I am working with a shop that is performing twin screw R&D work, and the ECU tunes they were provided did exhibit some of the ETC issues discussed earlier. I know they stated it was extremely touchy and wanted to take off with very little pedal input, I will have to check with them to see if they were also seeing the issue of the throttle failing to disengage after letting off the pedal. I am not so sure that it is just a blow through issue, but I will check back with them.
     
    Last edited: Jun 12, 2009
  8. TALON

    TALON SRTV8

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    Thanks Tim... Is this the section that you're talking about where I've added the AFR sensor?

    [​IMG]

    If so, it might be a little cramped in there.

    Ken
     
  9. Mr MoPar

    Mr MoPar New Member

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    Uh yes, and you are right it is crowded in there! You might want to move to the other side! The Autometer probes (with the yellow covering) are quite long and will more than reach from the passenger side. Make sure the probe you get is one that generally loks like an "L" where you can adjust the insertion length.

    The PLX EGT probe is very short, and will only extend 1/4" in at best, the probe should be mid stream.

    Good location for the widebands by the way.
     
  10. TALON

    TALON SRTV8

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    This is the EGT probe offered by Zeitronix, http://www.zeitronix.com/installation/EGTinstallation.htm would it be acceptable? Sorry for such a small picture.

    [​IMG]

    Ken
     
  11. Quick

    Quick Mgmt. - I can't help you

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    Since the EGT sensors extend into the pipe further than an AFR sensor are they vulnerable in the same way to being ruined by pooling condensation? That's the reason it's best to locate an AFR sensor between 9 and 3 o'clock on the pipe.

    I'm asking because there really isn't clearance on the passenger side at that location.
     
  12. Mr MoPar

    Mr MoPar New Member

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    No, the EGT probe is only about 3/16" in diameter, and it consist of a type K thermocouple that is inside a sealed stainless steel probe. A bung is installed in the pipe, normally the hole drilled is tapped for 1/8" NPT thread to allow the bung to screw in, and the probe slips into the bung and has a swage seal and nut that is tightened. It can be mounted in any orientation. In his picture, it could be fitted right between his two O2 probes.
     
  13. Mr MoPar

    Mr MoPar New Member

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    I do not particulary like that style of probe, it is shallow, the exhaust gas is hotter mid stream than along the pipe wall.

    This is a type K thermocouple, I can tell from the connector and that they use yellow on the sheath and connector, and the description on their site. They also state that the tip of the probe is designed to burn away, I have never heard of such nonsense, it is how the tip is made.

    Go look at the Autometer probe, it is a type K, the leads are plenty long, it is more compact, and has a fully sealed stainless steel probe that is not going to burn away. Zeitronix says your unit comes with the connector to plug into the Zeitronix, you would only need to put it on the autometer probe leads whcih have ring lugs attached. One is red and one is yellow, so you can't mix up which is which, red goes where marked red and yellow goes where marked yellow..
     
  14. TALON

    TALON SRTV8

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    Thanks again Tim for all your help. I'll have my new Auto Meter EGT probe # 5249 on Monday.

    Ken
     
  15. monty1269

    monty1269 LXF junkie....

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    :popcorn:
     
  16. LegMaker

    LegMaker LMI - LegMakerIntakes

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    so no need for removing the cat/mid pipe to weld in the bung for the egt??? wow, i could pull this off in my garage then!!! hell, i managed to drill and tap my oil pan for my blower line, i think i could pull this off!! lol
     
  17. Mr MoPar

    Mr MoPar New Member

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    You have to pull it off to be able to drill the hole and tap it, it is small enough to fit in between the ones you have, but you still have to install the bung.
     
  18. Quick

    Quick Mgmt. - I can't help you

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    Don't do it... unless you have some really fancy drilling equipment. I think if you get a few chunks or metal filings blown into the cats you may ruin them? (oh wait, do you still have cats?)
     
  19. TALON

    TALON SRTV8

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    Thanks Tim for all your input & knowledge. Today I was able to install the Auto Meter EGT probe, and connections to my display. I've also ordered a " Audio Visual Warning and Trigger Box alarm" to help keep me informed.

    [​IMG]

    [​IMG]

    [​IMG]

    Thanks again,

    Ken
     
  20. Mr MoPar

    Mr MoPar New Member

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    Very good, nice looking install. When you have it up and running, I would be very interested in some data. I am sure others would as well. I know on the 5.7 with MDS, I would see the hottest temps when cruising around 78 mph and MDS was engaged. I would assume that something similar would apply on the 6.1 Hemi (even without MDS). You will be looking for the hottest temps in a cruise situation (without boost), where the ECU is at maximum advance timing.

    This would give you a baseline to judge the temp gain when under boost. Both my 300C and my new Jeep both would see temps somewhere between 1150 and 1200 degrees. On my 300C under full boost, I would see about a 100 degree gain, around 1250. On the Jeep, it runs about 50 degrees hotter, 1200 in cruise, and 1300 under 6.5 psi boost. This was using water/meth spray on both.

    Once you find your baseline, see how hot the temps go under full boost where you have max fuel and timing retard from your tune, then if you care to check, see what your temps are under part throttle boost. If temps are rising, I would back out as soon as they hit the max temp you saw under a wide open throttle run. If you want to post up your WOT temps first, we can see where they are at and go from there before part throttle.

    Post them up and we will see where you are at.

    Since things seemed to have tapered off on this thread, I am writing up a summary of the key points to add in a follow up post. Keep the questions coming if you have any, and I want to thank those who have participated, it has been a great civil discussion on an important topic. It is nice to be able to conduct such a discussion without all the egos and drama I see on a lot of such topics.

    If anyone has another FI topic or specific area they want to discuss, let me know and I will start up another thread. If there is anything I can do to assist anyone with FI, let me know. Does not matter what brand or what tuning it is, I am very impartial when it comes to such discussions, and I have no problem with an open discussion.