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Thread: How to tune 60lb injectors - 56k = ZZzzzzz...

  1. #1
    Advanced Tuner SJSchafer's Avatar
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    Thumbs up How to tune 60lb injectors - 56k = ZZzzzzz...

    So after 42,363,956 pms, here it is.
    First off, I need to thank everyone who helped me to learn this stuff. From Marcin Pohl to Wes Anderson and many others here and on other forums, my appreciation knows no bounds.

    ***Disclaimer - I am in no way responsible for anything that you do to your car as a direct or indirect result of anything I say or post! There is an inherent risk, any time that you make any changes to a cars computer.***

    This little how to is intended for 4cyl ecotecs with a fuel rail pressure of 58psi.

    So here we go:

    First of all, forget about all of the advertised stats for the Siemens 60lb injectors. They actually flow at somewhere around 63-65lb/hr at 43.5 psi with a factory tolerance of about 6%. It is VERY important to get your injectors flow matched and to know what the actual flow rate is. The ones I got from NewEra came with a sheet telling me the numbers, and they were flowed at 63.4lb/hr on average. I open up my "LSJ Injectors" spreadsheet. This file can be found by searching the HPT forums. I create a new worksheet and paste the numbers from the LSJ Injectors spreadsheet here. I then create a formula to divide these numbers by 1.3. It should look like this:



    Post those numbers to your IFR table:



    Now you go to your modifier table and enter 1.3 for all values.



    Now, know that there is some controversy over whether this actually works. The results have shown me and others that it does. It is not as exact as having an injector table that doesn't have to use the modifier, but it is FAR better than maxing out 2/3 of your table at 63.5. I am in the process of coming up with other ways to get around these little limit, but for now, this works.

    Okay, IFR is set. Next are the offsets. You can actually tune the offsets, but to do it correctly requires a LOT of work. You do it by tuning your MAF at the offsets that you have, then introduce a modifier. Cot is a good one. You can also try other ways, but the purpose is to get your computer to do math based on your PWs. If the changes go rich, your offsets are too high, if go lean, they are too low. Adjust the offsets, retune your MAF and do it again. An easier way is to get them from someone who actually knows them. Every injector is a tad different, but the offsets are pretty close. These are the correct offsets:




    Now is the fun part. The adder table. This is where most people completely lose it. It is simple, but incredibly hard to get perfect. The reason is because these injectors just cannot flow properly in the low pulse width areas that we need them to. A return fuel system really helps here, but that is a different how to completely.

    I start by entering .05 in the 1.000 msec cell of the adder and set the 0ms cell to somewhere above .6. Then interpolate. Set your short pulse limit to 1 and your min PW to .1:



    The short pulse limit tells your computer when to look at the adder table, so if you need to adjust the 1.125 cell a bit, change your short pulse limit to 1.125.

    Now, remember your excel spreadsheet? Add a new worksheet. Go to your adder table, highlight it and copy with labels. Paste to your new worksheet. Next, enter a formula to add the 2 together. Should look like this:



    Now, set up your AFR error histogram like this:



    This will filter out any data received when the PW is below your filter limit - in this case 1.3ms. It will only show data from 1.3ms up. Now, at this point, I recommend you set up a MAF trim histo and run in CL for a bit, to get your AFRs close. You just made some pretty drastic changes and I want your car to actually start. Once you get fairly close with the trims on, switch to open loop and tune your MAF using AFR error. You should now have a perfect MAF from 1.3 ms on up, which will include everything from the 2400 hz cell of your MAF table to RL. Now, the PW is calculated by the computer figuring out how much fuel is needed + the offset needed to deliver that amount of fuel. Because the offsets change with manvac, you will command a different PW at 2400 during accell than you will at 2400 during decel. This is going to help you. Create another histogram.:



    This will show your PWs. What I do here is, I will go through my graph and see where I am running really lean or really rich. Now in spikes, but for durations. Set the view mode to "L" for last value. As you can see from the picture above, I am really lean at .763ms. I see the lean spot on the graph, my PW histo says .763, and by following that whole "lean" spot on my graph, the PW is a steady .763. This is good info. I look at my table and see that I am at 2659hz. Well, I know that the 2400 and 2700 hz cells of my maf are tuned (above 1.3ms) so this is not a MAF error. It has to be a fueling error. I go through and make some notes at which PWs under 1.3ms gives me what errors, and make sure there are definite trends here. Forget flukes, look for consistent data. Now gather your information and go to your excel spreadsheet to see where the changes need to be made. To use the example above: I know I have a lean fueling error at .763ms. By looking at my excel spreadsheet, I see that my total at .5ms is actually .679 and my total at .625 is actually .843. Here's where it gets tough, because I need to figure out which one to change. By further studying the data, I see that everything in the low.7xxms range is lean and the low to mid .8xxx is a little rich. The lean is far more pronounced than the rich, so I bump the .5ms cell of the adder to remove the lean errors. I'll leave the rich error alone for now. You'll find that your injectors hate PWs in the low .9s. This is an example of a 60s adder table.



    You may find you are having some issues with the lower MAF cells. One thing that I have found that helps is to zero out the cells from 4200 on up, or 5400 on up, just to see what the lower cells look like. MAF is a 3rd order polynomial, so it should be smooth. If your MAF is all full of peaks and valleys, you're doing something wrong.



    Oh, and once you are done looking at your lower MAF cells, don't forget to put it back to normal. I left half of it zeroed once and my car didn't like it much.

    Edit: Okay, here is the file with the fuel tables, MAF and VE. Your results may vary.

    Sticky worthy??
    Last edited by SJSchafer; 05-11-2008 at 11:36 AM.
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  2. #2
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    excellent write up....I'm sure it'll help a lot of us out

  3. #3
    Advanced Tuner dont_blink's Avatar
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    those tables also must account for chages in pressure, the rail isn't always at 58psi due to voltage changes and injector needs and such.
    Last edited by dont_blink; 05-10-2008 at 07:51 PM.
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  4. #4
    Advanced Tuner SJSchafer's Avatar
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    Quote Originally Posted by dont_blink
    those offset tables aren't the ones I have in my LSJ. VAC goes from -120 to 80 and MAP goes from 20 to 200. those tables also must account for chages in pressure, the rail isn't always at 58psi due to voltage changes and injector needs and such.
    Are you looking at the right picture? lol

    Also, voltage has dick to do with rail pressure. Dead head systems do have creap, but there is no accounting for that.
    Last edited by SJSchafer; 05-11-2008 at 12:03 PM.
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  5. #5
    Advanced Tuner dont_blink's Avatar
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    Right, but if your rail pressure changes...your injector flow also changes. You made a bold statement saying something about "our" 58psi rail pressure. I'll be honest my car idles at about 64 and makes it's way down to about 56-57 by 7000rpm. Just trying to help you out man.
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  6. #6
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    Quote Originally Posted by dont_blink
    Right, but if your rail pressure changes...your injector flow also changes. You made a bold statement saying something about "our" 58psi rail pressure. I'll be honest my car idles at about 64 and makes it's way down to about 56-57 by 7000rpm. Just trying to help you out man.
    Honestly, I am not sure where you are going with this, other than you seem to have some idea how to correct for this? I mean, if you can reliably map this, with impecable consistancy, under all stages of VAC (or do it in MAP and convert is) then you can redesign the tables on pressure differential, and be much more precise with your tune. It is easy enough to do, IF you can get consistant data and your fuel system does the same thing every single time, which I doubt. My car ran 58 psi from decel to WOT, unless it started creaping during log idle or something. Every LSJ I have tuned has also done the same. I appreciate your input, however. This is more designed to get answers out to all the people that PM me regularly asking for my input on these injectors.
    Last edited by SJSchafer; 05-10-2008 at 08:37 PM.
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  7. #7
    Advanced Tuner dont_blink's Avatar
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    I have an 04 Redline. What are you using to log your rail pressure? I am using an Autometer sending unit hooked directly into my Pro interface with a VR. I have set up an algorithm to log rail pressure based on voltage and kpa. Makes the injectors easier to scale properly at certain kPa, not that you NEED to do this, I am just a nitpicker. On the contrary, every LSJ I have tuned fluctuates in pressure between idle and higher loads. It's the laws of physics lol. As the voltage to the pump begins to drop as it heats up and attempts to push more fuel, it can only hold a certain pressure for so long. It's not a 300lph pump or anything you know.

    Also, if you're going to use those offsets, why not put it in a table that we all can share :-)
    Last edited by dont_blink; 05-10-2008 at 08:44 PM.
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    Quote Originally Posted by dont_blink
    I have an 04 Redline. What are you using to log your rail pressure? I am using an Autometer sending unit hooked directly into my Pro interface. On the contrary, every LSJ I have tuned fluctuates in pressure between idle and higher loads. It's the laws of physics lol. As the voltage to the pump begins to drop as it heats up and attempts to push more fuel, it can only hold a certain pressure for so long. It's not a 300lph pump or anything you know.

    Also, if you're going to use those offsets, why not put it in a table that we all can share :-)
    I use an analog gauge routed to where I can see it. I get the physics part. We do have a regulator though that is designed to keep our pressure at 58psi, and I know from experience that while momentary fluctuations do occur(as they will with any dead head system),they are by no means predictable, nor large.

    As far as posting my tune... Let me put it this way. All the numbers should be legible. These numbers took me hundreds of hours and more than a few dollars to get. I also spend a lot of time helping people to better themselves as tuners. If I am willing to go through all of this (and taking the time to write this up) you can take a few minutes to write down the numbers.

    And if you are going to doubt my numbers, you should have ones that you feel are better anyway.
    http://www.hptuners.com/forum/showth...=14101&page=13
    Last edited by SJSchafer; 05-10-2008 at 08:49 PM.
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  9. #9
    Advanced Tuner dont_blink's Avatar
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    I don't want your tune lol. Wat about the MAP table offsets?
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    Advanced Tuner SJSchafer's Avatar
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    Quote Originally Posted by dont_blink
    I don't want your tune lol. Wat about the MAP table offsets?


    Here's another story. I have since converted my fuel system to return style with a regulator that referrences manvac. I measure the psi at the regulator and at the rail. I will tell you that if I turn the car off and let it heak soak, the regulator will read 33psi at idle and the rail will read 29. I also know that if I drive around a bit and park the car with it idling, The 2 gauges will both read 33 psi. There is no constants and everything has a way of doing weird stuff when working with internal combustion engines. Some things can be tuned for and some things cannot, but one thing stands for certain - whenever you try to discover an unknown, you first start with knowns. That is what I am doing here. Giving known numbers and ways collect other knowns from them. I wrote this how to to answer scores of emails and PMs that I get on 2 different sites regarding these injectors, so that I may refer people to them to help them to understand how they work. If you were trying to post here to let me know that I forgot to mention something, or that you feel that something I did was wrong and want to correct it, so that I don't steer people the wrong way, that is one thing. I get the feeling that your reason for posting is to bust my balls and try to get people to think you know more about fueling than I do. I have news for you. You don't. And I don't honestly see how you are contributing to purpose of this thread.
    Last edited by SJSchafer; 05-10-2008 at 09:16 PM.
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  11. #11
    Advanced Tuner dont_blink's Avatar
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    Where were these numbers derived from?
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    I'm not trying to bust your balls lol. All I was doing was throwing in something you forgot. Those running the stock returnless system need to keep an eye on rail pressure. A 64lb injector at 64psi and a 64lb injector at 56psi are two different injectors. Ya know?
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  13. #13
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    Quote Originally Posted by dont_blink
    Where were these numbers derived from?
    A custom built and calibrated flow bench, that measures IFRs and offsets (among other things) at a rail pressure of 58psi using gasoline (not heptane) at 120*f. The offsets were derived by flowing them at pressure differentials that are the equivalent of the differentials cause by a consistent 58psi to the rail and changing vacuum. They were tested under all these conditions from (iirc) 9 volts to 16 volts in .5v increments. Those were used as the base and I calculated the numbers below 9 volts and above 16 volts by extrapolating on the trends. Where that method is not, by any means, the most exact way to get the upper and lower numbers, you've got other problems if you are operating in those areas anyway.

    Quote Originally Posted by dont_blink
    I'm not trying to bust your balls lol. All I was doing was throwing in something you forgot. Those running the stock returnless system need to keep an eye on rail pressure. A 64lb injector at 64psi and a 64lb injector at 56psi are two different injectors. Ya know?
    Okay, I get that. Do you know how many people who don't even know what their injectors are flowed at? If someone is actually logging their rail pressure to account for a pressure differential changing due to fluctuating conditions and wants to tune for that, they don't need this how to.
    Last edited by SJSchafer; 05-11-2008 at 12:02 PM.
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    I had a few requests, so I posted the file to the first post. This is the fueling and air tables only that are tweaked. The offsets are pretty much dead on for the Siemens 60# injectors. Although the IFR, adders,MAF and VE are optimized for my car, your injectors and car will be different, so tune accordingly.
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    Advanced Tuner dont_blink's Avatar
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    Boy it would be nice to have these numbers in a downloadable table format. I just typed the first 15 lines and I am ready to shoot myself. I think the community as a whole would love you even MORE :-)
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  16. #16
    Advanced Tuner SJSchafer's Avatar
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    Quote Originally Posted by dont_blink
    Boy it would be nice to have these numbers in a downloadable table format. I just typed the first 15 lines and I am ready to shoot myself. I think the community as a whole would love you even MORE :-)
    Read up ^^. I just posted the tune. Open as a compare file and copy/paste away...
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  17. #17
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    All I have to say is WOW! Thanks for breaking down little kid style for us beginers. Keep up the good work
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  18. #18
    Advanced Tuner dont_blink's Avatar
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    Quote Originally Posted by SJSchafer
    Read up ^^. I just posted the tune. Open as a compare file and copy/paste away...
    You got a paypal addy? If these work out the way they should, I am more than willing to donate for your efforts.
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  19. #19
    Advanced Tuner SJSchafer's Avatar
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    Quote Originally Posted by tucknuts
    All I have to say is WOW! Thanks for breaking down little kid style for us beginers. Keep up the good work
    You are welcome. Have fun!

    Quote Originally Posted by dont_blink
    You got a paypal addy? If these work out the way they should, I am more than willing to donate for your efforts.
    Thanks man. You have PM.
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  20. #20
    why not just set the short pulse limit to like .25? whats the point in putting it at 1 then doing all this other stuff